HUMAN_JJ RESOURCES_NN2 AND_CC SYSTEM_NN1 DESIGN_NN1 Concepts_NN2 The_AT human_JJ contribution_NN1 The_AT human_JJ role_NN1 as_II a_AT1 system_NN1 controller_NN1 The_AT business_NN1 of_IO designing_VVG machines_NN2 ,_, processes_NN2 and_CC systems_NN2 can_VM be_VBI pursued_VVN more_RGR or_CC less_RGR independently_RR of_IO the_AT properties_NN2 of_IO people_NN ._. 
Nevertheless_RR people_NN are_VBR always_RR involved_VVN ,_, the_AT designer_NN1 himself_PPX1 is_VBZ a_AT1 human_JJ being_NN1 and_CC his_APPGE product_NN1 will_VM shape_VVI the_AT behaviour_NN1 of_IO many_DA2 workers_NN2 and_CC other_JJ users_NN2 ._. 
More_RGR fundamentally_RR ,_, the_AT design_NN1 activity_NN1 will_VM be_VBI meaningless_JJ unless_CS it_PPH1 is_VBZ directed_VVN towards_II serving_VVG some_DD human_JJ need_NN1 ._. 
In_II31 spite_II32 of_II33 all_DB this_DD1 ,_, the_AT design_NN1 process_NN1 itself_PPX1 is_VBZ often_RR thought_VVN about_II and_CC executed_VVN without_IW any_DD formal_JJ considerations_NN2 about_II people_NN ._. 
Inevitably_RR the_AT engineer_NN1 ,_, architect_NN1 or_CC other_JJ designer_NN1 devotes_VVZ most_DAT of_IO his_APPGE attention_NN1 and_CC expertise_NN1 to_II devising_VVG mechanisms_NN2 ,_, buildings_NN2 and_RR31 so_RR32 on_RR33 which_DDQ support_VV0 some_DD human_JJ activity_NN1 more_RGR effectively_RR than_CSN those_DD2 currently_RR available_JJ ._. 
The_AT new_JJ machine_NN1 or_CC system_NN1 must_VM not_XX be_VBI very_RG different_JJ from_II the_AT old_JJ one_PN1 for_IF a_AT1 variety_NN1 of_IO reasons_NN2 ._. 
The_AT old_JJ one_PN1 did_VDD its_APPGE job_NN1 ,_, not_XX perfectly_RR but_CCB well_RR enough_RR to_TO justify_VVI its_APPGE existence_NN1 ._. 
The_AT new_JJ one_PN1 is_VBZ usually_RR designed_VVN on_II the_AT basis_NN1 of_IO copying_VVG the_AT old_JJ one_PN1 but_CCB removing_VVG as_RG many_DA2 as_CSA possible_JJ of_IO the_AT faults_NN2 ._. 
There_EX are_VBR other_JJ reasons_NN2 such_II21 as_II22 commonality_NN1 of_IO components_NN2 and_CC ,_, of_RR21 course_RR22 ,_, shortage_NN1 of_IO imagination_NN1 which_DDQ lead_VV0 to_II most_DAT design_NN1 and_CC development_NN1 being_VBG a_AT1 progressive_JJ iterative_JJ process_NN1 ._. 
This_DD1 happens_VVZ to_TO suit_VVI the_AT human_JJ operators_NN2 because_CS most_DAT of_IO their_APPGE skills_NN2 will_VM transfer_VVI along_II the_AT line_NN1 of_IO development_NN1 of_IO the_AT machines_NN2 and_CC systems_NN2 ._. 
From_II the_AT engineering_NN1 point_NN1 of_IO view_NN1 the_AT hardware_NN1 technology_NN1 is_VBZ central_JJ and_CC the_AT operators_NN2 tag_VV0 along_RP supporting_VVG the_AT activity_NN1 of_IO machines_NN2 which_DDQ are_VBR basically_RR doing_VDG the_AT work_NN1 ._. 
In_II nineteenth_MD century_NNT1 transport_NN1 for_REX21 example_REX22 ,_, the_AT coach_NN1 and_CC horses_NN2 was_VBDZ not_XX a_AT1 serious_JJ competitor_NN1 for_IF the_AT steam-engined_JJ train_NN1 ,_, nor_CC was_VBDZ the_AT man_NN1 with_IW a_AT1 spade_NN1 as_RG productive_JJ as_CSA the_AT operator_NN1 with_IW a_AT1 steam_NN1 shovel_NN1 ._. 
This_DD1 was_VBDZ the_AT earliest_JJT technology_NN1 in_II which_DDQ power_NN1 was_VBDZ derived_VVN from_II sources_NN2 other_II21 than_II22 animal_NN1 muscles_NN2 and_CC the_AT output_NN1 was_VBDZ so_RG obviously_RR superior_JJ that_CST men_NN2 did_VDD not_XX mind_VVI putting_VVG up_RP with_IW the_AT inconvenience_NN1 of_IO machines_NN2 which_DDQ were_VBDR uncomfortable_JJ or_CC awkward_JJ to_TO use_VVI ._. 
They_PPHS2 even_RR took_VVD pride_NN1 in_II developing_VVG new_JJ skills_NN2 which_DDQ enabled_VVD them_PPHO2 to_TO use_VVI difficult_JJ machines_NN2 which_DDQ inexperienced_JJ people_NN could_VM not_XX use_VVI ._. 
This_DD1 attitude_NN1 was_VBDZ reinforced_VVN by_II the_AT second_MD wave_NN1 of_IO technology_NN1 which_DDQ provided_VVD instrumentation_NN1 ,_, ways_NN2 of_IO sensing_NN1 and_CC recording_VVG data_NN which_DDQ gave_VVD more_RGR accurate_JJ and_CC reliable_JJ data_NN than_CSN that_DD1 which_DDQ can_VM be_VBI detected_VVN directly_RR by_II the_AT human_JJ senses_NN2 ._. 
At_II this_DD1 stage_NN1 the_AT typical_JJ machine_NN1 operator_NN1 manipulated_VVD machine_NN1 controls_VVZ on_II the_AT basis_NN1 of_IO data_NN presented_VVN on_II instruments_NN2 ._. 
The_AT machine_NN1 controls_NN2 caused_VVD power_NN1 to_TO be_VBI applied_VVN and_CC consequences_NN2 to_TO occur_VVI which_DDQ resulted_VVD in_II changed_JJ readings_NN2 on_II the_AT instruments_NN2 ._. 
The_AT man_NN1 was_VBDZ in_II the_AT control_NN1 loop_NN1 (_( Hick_NP1 and_CC Bates_NP1 ,_, 1950_MC )_) ._. 
More_RGR recently_RR ,_, in_II the_AT third_MD wave_NN1 of_IO technology_NN1 the_AT man_NN1 has_VHZ been_VBN removed_VVN from_II the_AT responsibility_NN1 for_IF continuous_JJ control_NN1 (_( this_DD1 is_VBZ best_RRT done_VDN by_II computers_NN2 working_VVG to_II a_AT1 moderately_RR flexible_JJ range_NN1 of_IO programs_NN2 )_) but_CCB he_PPHS1 remains_VVZ as_II the_AT monitor_NN1 of_IO the_AT system_NN1 performance_NN1 and_CC a_AT1 selector_NN1 of_IO the_AT appropriate_JJ program_NN1 determined_VVN by_II the_AT changing_JJ short-term_JJ objectives_NN2 ._. 
He_PPHS1 may_VM keep_VVI the_AT responsibility_NN1 for_IF setting-up_NN1 and_CC shutting-down_NN1 the_AT system_NN1 or_CC this_DD1 also_RR may_VM be_VBI partially_RR delegated_VVN to_II computers_NN2 ._. 
This_DD1 is_VBZ the_AT '_GE Supervisory_JJ Control_NN1 '_GE role_NN1 (_( Sheridan_NP1 and_CC Johannsen_NP1 ,_, 1976_MC )_) ._. 
Information_NN1 flow_NN1 in_II these_DD2 three_MC phases_NN2 of_IO development_NN1 of_IO system_NN1 control_NN1 is_VBZ shown_VVN in_II fig._NN1 1.1_MC Supervisory_JJ control_NN1 is_VBZ by_RR31 no_RR32 means_RR33 universal_JJ ,_, in_II fact_NN1 it_PPH1 remains_VVZ restricted_VVN to_II high_JJ technology_NN1 systems_NN2 such_II21 as_II22 aircraft_NN ,_, computer_NN1 controlled_VVD machine_NN1 tools_NN2 ,_, chemical_JJ plants_NN2 and_CC power_NN1 stations_NN2 ._. 
(_( Edwards_NP1 and_CC Lees_NP2 ,_, 1974_MC )_) ._. 
There_EX are_VBR still_RR many_DA2 systems_NN2 where_RRQ the_AT man_NN1 is_VBZ in_II the_AT control_NN1 loop_NN1 ,_, for_REX21 example_REX22 in_II vehicle_NN1 driving_VVG and_CC in_II most_DAT manufacturing_NN1 production_NN1 processes_NN2 ._. 
There_EX are_VBR many_DA2 tasks_NN2 where_RRQ the_AT operator_NN1 is_VBZ assisted_VVN only_RR by_II hand-tools_NN2 and_CC simple_JJ powered_JJ machines_NN2 ,_, for_REX21 example_REX22 in_II craft-work_NN1 and_CC surgery_NN1 ._. 
There_EX are_VBR also_RR plenty_PN of_IO tasks_NN2 ,_, although_CS these_DD2 are_VBR now_RT perhaps_RR more_RGR common_JJ in_II leisure_NN1 than_CSN in_II paid_JJ work_NN1 ,_, where_CS the_AT man_NN1 supplies_VVZ the_AT muscle_NN1 power_NN1 ,_, for_REX21 example_REX22 the_AT manual_JJ labourer_NN1 and_CC the_AT active_JJ sportsman_NN1 ._. 
In_RR21 general_RR22 ,_, the_AT working_JJ man_NN1 may_VM function_VVI at_II any_DD level_NN1 from_II the_AT senior_JJ partner_NN1 in_II high_JJ technology_NN1 operations_NN2 to_II the_AT provider_NN1 of_IO muscle_NN1 power_NN1 in_II physically_RR demanding_VVG jobs_NN2 ._. 
In_II all_DB cases_NN2 the_AT ergonomic_JJ requirement_NN1 is_VBZ that_CST the_AT task_NN1 as_CSA designed_VVN should_VM make_VVI use_NN1 of_IO his_APPGE abilities_NN2 and_CC be_VBI adaptive_JJ to_II his_APPGE limitations_NN2 ._. 
The_AT human_JJ contribution_NN1 in_II high_JJ technology_NN1 systems_NN2 All_DB working_VVG systems_NN2 ,_, including_II those_DD2 incorporating_VVG advanced_JJ technology_NN1 of_IO processes_NN2 and_CC process_VV0 control_NN1 ,_, depend_VV0 on_II skilled_JJ operators_NN2 ._. 
There_EX are_VBR social_JJ ,_, economic_JJ and_CC technical_JJ reasons_NN2 for_IF this_DD1 ._. 
Socially_RR the_AT public_NN1 will_VM not_XX easily_RR accept_VVI automatic_JJ systems_NN2 ._. 
When_CS seeking_VVG reassurance_NN1 that_CST a_AT1 system_NN1 is_VBZ safe_JJ they_PPHS2 study_VV0 the_AT people_NN who_PNQS are_VBR responsible_JJ for_IF it_PPH1 ._. 
They_PPHS2 have_VH0 no_AT means_NN of_IO assessing_VVG the_AT reliability_NN1 of_IO automatic_JJ control_NN1 systems_NN2 but_CCB they_PPHS2 can_VM make_VVI some_DD assessment_NN1 of_IO a_AT1 skilled_JJ individual_NN1 and_CC without_IW knowing_VVG very_RG much_DA1 about_II his_APPGE working_JJ procedures_NN2 they_PPHS2 will_VM trust_VVI his_APPGE actions_NN2 if_CS he_PPHS1 seems_VVZ calm_NN1 ,_, competent_JJ and_CC mature_VV0 ._. 
The_AT most_RGT direct_JJ example_NN1 is_VBZ the_AT nervous_JJ airline_NN1 passenger_NN1 who_PNQS is_VBZ comforted_VVN by_II the_AT belief_NN1 that_CST the_AT middle-aged_JJ pilot_NN1 he_PPHS1 saw_VVD sitting_VVG on_II the_AT flight_NN1 deck_NN1 is_VBZ flying_VVG the_AT aeroplane_NN1 ._. 
Less_RGR directly_RR but_CCB equally_RR importantly_RR ,_, people_NN living_VVG in_II the_AT vicinity_NN1 of_IO a_AT1 large_JJ plant_NN1 would_VM not_XX take_VVI kindly_RR to_II the_AT idea_NN1 that_CST it_PPH1 was_VBDZ not_XX under_II the_AT control_NN1 of_IO human_JJ beings_NN2 who_PNQS are_VBR on_II the_AT spot_NN1 and_CC are_VBR assumed_VVN to_TO know_VVI exactly_RR what_DDQ is_VBZ happening._NNU p_ZZ1 3:DIAGRAM/FIGURE_VV0 Economically_RR it_PPH1 remains_VVZ true_JJ that_CST it_PPH1 is_VBZ inordinately_RR expensive_JJ to_TO construct_VVI a_AT1 system_NN1 which_DDQ must_VM continue_VVI to_TO be_VBI reliable_JJ without_IW direct_JJ human_JJ intervention_NN1 ,_, for_REX21 example_REX22 under_II the_AT sea_NN1 or_CC in_II space_NN1 ._. 
Equally_RR it_PPH1 is_VBZ expensive_JJ to_TO ensure_VVI that_DD1 equipment_NN1 will_VM continue_VVI to_TO function_VVI under_II rough_JJ handling_NN1 conditions_NN2 ,_, for_REX21 example_REX22 the_AT necessary_JJ '_GE ruggedising_NN1 '_GE of_IO military_JJ equipment_NN1 ._. 
A_AT1 system_NN1 can_VM be_VBI designed_VVN much_RR more_RGR economically_RR if_CS it_PPH1 can_VM be_VBI assumed_VVN that_CST skilled_JJ personnel_NN2 are_VBR available_JJ to_TO control_VVI and_CC take_VVI care_NN1 of_IO it_PPH1 ._. 
Technically_RR the_AT state_NN1 of_IO the_AT art_NN1 seems_VVZ to_TO be_VBI that_CST systems_NN2 are_VBR most_RGT efficient_JJ ,_, reliable_JJ and_CC safe_JJ when_CS control_NN1 is_VBZ largely_RR automatic_JJ but_CCB the_AT human_JJ operator_NN1 remains_VVZ in_II a_AT1 monitoring_NN1 and_CC supervisory_JJ role_NN1 ._. 
That_REX21 is_REX22 ,_, continuous_JJ dynamic_JJ dealing_NN1 with_IW minor_JJ perturbations_NN2 is_VBZ automatic_JJ and_CC so_RG also_RR is_VBZ the_AT application_NN1 of_IO basic_JJ rules_NN2 about_II safety_NN1 ;_; for_REX21 example_REX22 ,_, the_AT system_NN1 or_CC some_DD part_NN1 of_IO it_PPH1 might_VM be_VBI programmed_VVN to_TO go_VVI through_II a_AT1 step-change_JJ function_NN1 such_II21 as_II22 a_AT1 shut-down_NN1 if_CS certain_JJ parameters_NN2 exceed_VV0 prescribed_JJ limits_NN2 ._. 
The_AT role_NN1 of_IO the_AT human_JJ operator_NN1 in_II these_DD2 circumstances_NN2 is_VBZ largely_RR specified_VVN by_II operating_NN1 instructions_NN2 which_DDQ are_VBR mandatory_JJ ._. 
Given_VVN this_DD1 and_CC this_DD1 he_PPHS1 must_VM do_VDI that_DD1 ._. 
Characteristically_RR his_APPGE intervention_NN1 in_II this_DD1 way_NN1 is_VBZ a_AT1 response_NN1 to_II some_DD other_JJ human_JJ requirement_NN1 ;_; for_REX21 example_REX22 ,_, a_AT1 maintenance_NN1 man_NN1 may_VM wish_VVI to_TO have_VHI a_AT1 particular_JJ sub-system_NN1 shut_VVD down_RP for_IF his_APPGE attention_NN1 or_CC a_AT1 user_NN1 of_IO the_AT system_NN1 product_NN1 may_VM wish_VVI to_TO receive_VVI a_AT1 different_JJ input_NN1 to_TO meet_VVI his_APPGE purposes_NN2 ._. 
Many_DA2 of_IO these_DD2 interactions_NN2 could_VM be_VBI made_VVN automatic_JJ were_VBDR it_PPH1 not_XX for_IF the_AT basic_JJ need_NN1 for_IF a_AT1 human_JJ presence_NN1 for_IF the_AT social/_JJ economic_JJ reasons_NN2 mentioned_VVN above_RL and_CC because_CS the_AT human_JJ operator_NN1 has_VHZ to_TO act_VVI as_II the_AT ultimate_JJ back-stop_NN1 when_RRQ things_NN2 go_VV0 badly_RR wrong_JJ ._. 
Things_NN2 go_VV0 badly_RR wrong_JJ when_CS there_EX has_VHZ been_VBN some_DD extreme_JJ untoward_JJ event_NN1 such_II21 as_II22 a_AT1 fire_NN1 ,_, an_AT1 earthquake_NN1 or_CC a_AT1 bomb_NN1 ,_, alternatively_RR an_AT1 unanticipated_JJ combination_NN1 of_IO faults_NN2 may_VM occur_VVI within_II the_AT plant_NN1 itself_PPX1 ._. 
In_II either_DD1 case_NN1 the_AT human_JJ intervention_NN1 must_VM be_VBI a_AT1 very_RG high_JJ level_JJ one_PN1 based_VVN on_II complex_JJ diagnosis_NN1 and_CC innovative_JJ design-type_NN1 thinking_VVG about_II how_RRQ best_RRT to_TO cope_VVI so_BCL21 as_BCL22 to_TO avoid_VVI a_AT1 catastrophe_NN1 ._. 
A_AT1 catastrophe_NN1 can_VM happen_VVI when_RRQ the_AT system_NN1 energy_NN1 is_VBZ no_RR21 longer_RR22 channelled_VVN as_CSA intended_VVN by_II the_AT designers_NN2 or_CC because_CS there_EX is_VBZ a_AT1 release_NN1 of_IO toxic_JJ substances_NN2 or_CC both_DB2 ._. 
The_AT demands_NN2 on_II the_AT operator_NN1 stem_NN1 from_II two_MC kinds_NN2 of_IO task_NN1 which_DDQ are_VBR not_XX compatible_JJ because_CS they_PPHS2 require_VV0 very_RG different_JJ levels_NN2 of_IO skill_NN1 ._. 
On_II the_AT one_MC1 hand_NN1 he_PPHS1 must_VM cope_VVI with_IW routines_NN2 where_RRQ the_AT demand_NN1 is_VBZ for_IF precise_JJ obedience_NN1 to_II established_JJ instructions_NN2 and_CC on_II the_AT other_JJ hand_NN1 he_PPHS1 might_VM suddenly_RR be_VBI faced_VVN with_IW a_AT1 need_NN1 to_TO respond_VVI in_II a_AT1 creative_JJ manner_NN1 totally_RR outside_II any_DD instructions_NN2 ._. 
Superficially_RR the_AT solution_NN1 would_VM seem_VVI to_TO be_VBI to_TO have_VHI two_MC kinds_NN2 of_IO operators_NN2 ,_, those_DD2 who_PNQS carry_VV0 out_RP the_AT routines_NN2 and_CC others_NN2 who_PNQS are_VBR on_II call_NN1 should_VM unforeseen_JJ emergencies_NN2 arise_VV0 ._. 
There_EX are_VBR two_MC snags_NN2 about_II this_DD1 approach_NN1 ._. 
Firstly_RR there_EX may_VM not_XX be_VBI time_NNT1 or_CC it_PPH1 may_VM not_XX be_VBI physically_RR possible_JJ to_TO suddenly_RR introduce_VVI a_AT1 high_JJ level_JJ operator_NN1 ,_, for_REX21 example_REX22 we_PPIS2 can_VM not_XX put_VVI a_AT1 different_JJ pilot_NN1 on_II the_AT flight_NN1 deck_NN1 when_CS an_AT1 aircraft_NN gets_VVZ into_II trouble_NN1 ._. 
Secondly_RR ,_, the_AT high_JJ level_JJ operator_NN1 will_VM not_XX maintain_VVI his_APPGE skill_NN1 and_CC familiarity_NN1 with_IW the_AT system_NN1 unless_CS he_PPHS1 operates_VVZ regularly_RR within_II it_PPH1 ._. 
His_APPGE ability_NN1 to_TO intervene_VVI effectively_RR must_VM be_VBI a_AT1 function_NN1 of_IO his_58 '_GE hands_NN2 on_II '_GE experience_NN1 supported_VVD of_RR21 course_RR22 by_II his_APPGE conceptual_JJ knowledge_NN1 of_IO how_RRQ the_AT system_NN1 functions_NN2 ._. 
This_DD1 last_MD proposition_NN1 is_VBZ based_VVN on_II experience_NN1 of_IO systems_NN2 where_RRQ the_AT intervention_NN1 requires_VVZ complex_JJ manipulative_JJ activity_NN1 ,_, for_REX21 example_REX22 a_AT1 surgeon_NN1 dealing_VVG with_IW an_AT1 emergency_NN1 during_II an_AT1 operation_NN1 or_CC an_AT1 aircraft_NN pilot_NN1 taking_VVG over_RP manually_RR ._. 
It_PPH1 is_VBZ not_XX so_RG obviously_RR true_JJ where_CS the_AT intervention_NN1 takes_VVZ the_AT form_NN1 essentially_RR of_IO a_AT1 decision_NN1 to_TO initiate_VVI a_AT1 single_JJ direct_JJ action_NN1 such_II21 as_II22 closing_VVG a_AT1 particular_JJ valve_NN1 or_CC starting_VVG up_RP a_AT1 stand-by_JJ pump_NN1 ._. 
In_II these_DD2 circumstances_NN2 it_PPH1 is_VBZ not_XX clear_JJ whether_CSW31 or_CSW32 not_CSW33 the_AT effectiveness_NN1 of_IO the_AT intervention_NN1 is_VBZ quite_RG so_RG dependent_JJ on_II operating_VVG experience_NN1 ._. 
Taking_VVG for_REX21 example_REX22 the_AT nuclear_JJ power_NN1 plant_NN1 control_NN1 room_NN1 ,_, the_AT question_NN1 is_VBZ whether_CSW the_AT desk_NN1 operators_NN2 should_VM be_VBI expected_VVN to_TO cope_VVI with_IW all_DB emergencies_NN2 which_DDQ appear_VV0 within_II the_AT total_JJ information_NN1 presentation_NN1 or_CC whether_CSW ,_, for_IF complex_JJ and_CC dangerous_JJ situations_NN2 ,_, a_AT1 more_RGR senior_JJ person_NN1 such_II21 as_II22 the_AT shift-charge_JJ engineer_NN1 should_VM be_VBI called_VVN upon_II to_TO make_VVI the_AT decisions_NN2 ._. 
This_DD1 policy_NN1 issue_NN1 must_VM be_VBI cleared_VVN before_II the_AT basic_JJ personnel_NN2 decisions_NN2 about_II selection_NN1 and_CC training_NN1 of_IO staff_NN at_II the_AT various_JJ levels_NN2 can_VM be_VBI made_VVN and_CC before_CS the_AT information_NN1 presentations_NN2 can_VM be_VBI designed_VVN ._. 
The_AT human_JJ contribution_NN1 in_II low_JJ technology_NN1 systems_NN2 The_AT extreme_JJ case_NN1 of_IO man_NN1 as_II a_AT1 source_NN1 of_IO muscle_NN1 power_NN1 is_VBZ dealt_VVN with_IW in_II the_AT previous_JJ book_NN1 in_II this_DD1 series_NN The_AT Body_NN1 at_II Work_NN1 ._. 
Such_DA working_JJ situations_NN2 are_VBR now_RT relatively_RR rare_JJ in_II developed_JJ countries_NN2 and_CC the_AT man_NN1 is_VBZ more_RGR usually_RR employed_VVN in_II tasks_NN2 where_CS there_EX is_VBZ a_AT1 considerable_JJ control_NN1 element_NN1 requiring_VVG extensive_JJ information_NN1 processing_NN1 ._. 
Such_DA tasks_NN2 range_VV0 from_II the_AT use_NN1 of_IO simple_JJ hand_NN1 tools_NN2 to_II tracking_NN1 using_VVG complex_JJ powered_JJ machinery_NN1 ._. 
Human_JJ beings_NN2 are_VBR needed_VVN for_IF those_DD2 tasks_NN2 for_IF a_AT1 variety_NN1 of_IO reasons_NN2 from_II their_APPGE highly_RR dexterous_JJ manipulative_JJ potential_NN1 through_RP to_II their_APPGE ability_NN1 to_TO accept_VVI informal_JJ instructions_NN2 ._. 
These_DD2 reasons_NN2 are_VBR given_VVN in_II detail_NN1 in_II the_AT discussion_NN1 of_IO man-machine_JJ function_NN1 allocation_NN1 (_( p._NNU 35_MC )_) ._. 
The_AT demands_NN2 on_II the_AT human_JJ operator_NN1 are_VBR difficult_JJ to_TO quantify_VVI or_CC even_RR to_TO describe_VVI because_CS the_AT process_NN1 is_VBZ essentially_RR an_AT1 interactive_JJ one_PN1 ._. 
The_AT skilled_JJ operator_NN1 is_VBZ working_VVG in_II harmony_NN1 with_IW his_APPGE tools_NN2 and_CC machines_NN2 ._. 
The_AT concept_NN1 of_IO '_GE demand_NN1 '_GE is_VBZ often_RR not_XX appropriate_JJ because_CS it_PPH1 implies_VVZ confrontation_NN1 ,_, the_AT process_NN1 is_VBZ more_RGR aptly_RR considered_VVN as_CSA one_MC1 of_IO cooperation_NN1 and_CC persuasion_NN1 ._. 
The_AT human_JJ operator_NN1 is_VBZ pursuing_VVG an_AT1 objective_NN1 ,_, usually_RR to_TO make_VVI something_PN1 or_CC to_TO go_VVI somewhere_RL ,_, and_CC he_PPHS1 achieves_VVZ this_DD1 with_IW the_AT assistance_NN1 of_IO the_AT hardware_NN1 at_II his_APPGE disposal_NN1 ._. 
This_DD1 hardware_NN1 ,_, if_CS it_PPH1 is_VBZ well-designed_JJ ,_, aids_VVZ him_PPHO1 in_II his_APPGE progress_NN1 toward_II his_APPGE objective_NN1 ._. 
There_EX may_VM be_VBI demands_NN2 in_II the_AT sense_NN1 that_CST there_EX are_VBR always_RR obstacles_NN2 to_TO be_VBI overcome_VVN but_CCB these_DD2 stem_VV0 from_II the_AT nature_NN1 and_CC the_AT variability_NN1 of_IO the_AT situation_NN1 he_PPHS1 is_VBZ in_RP ;_; that_REX21 is_REX22 ,_, the_AT materials_NN2 he_PPHS1 has_VHZ to_TO deal_VVI with_IW or_CC the_AT environment_NN1 he_PPHS1 has_VHZ to_TO move_VVI through_RP ._. 
The_AT skilled_JJ operator_NN1 will_VM aim_VVI for_IF efficient_JJ performance_NN1 ._. 
Efficiency_NN1 incorporates_VVZ not_XX only_JJ quantity_NN1 and_CC quality_NN1 of_IO achievement_NN1 but_CCB also_RR preservation_NN1 of_IO his_APPGE own_DA safety_NN1 and_CC health_NN1 and_CC that_DD1 of_IO others_NN2 who_PNQS might_VM be_VBI involved_VVN as_CSA working_VVG partners_NN2 ,_, passengers_NN2 or_CC the_AT general_JJ public_NN1 in_II the_AT neighbourhood_NN1 ._. 
Of_RR21 course_RR22 ,_, if_CS his_APPGE tasks_NN2 are_VBR badly_RR designed_VVN they_PPHS2 may_VM well_RR make_VVI unnecessary_JJ demands_NN2 ._. 
These_DD2 begin_VV0 with_IW bodily_JJ aspects_NN2 of_IO the_AT operating_NN1 posture_NN1 required_VVN and_CC the_AT forces_NN2 which_DDQ must_VM be_VBI exerted_VVN to_TO operate_VVI controls._NNU for_IF a_AT1 work-space_NN1 which_DDQ is_VBZ used_VVN full-time_RR very_RG slight_JJ departures_NN2 from_II the_AT optimum_JJ may_VM lead_VVI to_II problems_NN2 in_II the_AT long_JJ term_NN1 ,_, for_REX21 example_REX22 in_II strained_JJ ligaments_NN2 ,_, tendons_NN2 and_CC muscles_NN2 ._. 
Posture_NN1 is_VBZ constrained_VVN not_XX only_RR by_II the_AT physical_JJ dimensions_NN2 of_IO the_AT work-space_NN1 but_CCB also_RR by_II the_AT need_NN1 to_TO be_VBI in_II a_AT1 position_NN1 to_TO see_VVI certain_JJ events_NN2 and_CC to_TO feel_VVI others_NN2 through_II control_NN1 operations_NN2 or_CC machine_NN1 movement_NN1 ._. 
Other_JJ demands_NN2 will_VM arise_VVI if_CSW the_AT information_NN1 presented_VVN is_VBZ inadequate_JJ in_II content_NN1 ,_, e.g._REX poor_JJ lighting_NN1 may_VM make_VVI it_PPH1 difficult_JJ to_TO detect_VVI some_DD relevant_JJ cues_NN2 ,_, or_CC in_II structure_NN1 ,_, e.g._REX because_II21 of_II22 poor_JJ coding_NN1 and_CC presentation_NN1 of_IO information_NN1 on_II dials_NN2 ,_, charts_NN2 or_CC screens_NN2 ._. 
Correspondingly_RR there_EX may_VM be_VBI output_VVN demands_NN2 created_VVN by_II control_NN1 operations_NN2 which_DDQ result_VV0 in_II things_NN2 happening_VVG too_RG quickly_RR or_CC unexpectedly_RR ._. 
The_AT level_NN1 of_IO demand_NN1 is_VBZ to_TO do_VDI not_XX only_RR with_IW the_AT tasks_NN2 as_CSA they_PPHS2 are_VBR done_VDN but_CCB also_RR with_IW the_AT duration_NN1 for_IF which_DDQ they_PPHS2 must_VM continue_VVI to_TO be_VBI done_VDN ._. 
This_DD1 applies_VVZ particularly_RR to_II routines_NN2 and_CC repetitive_JJ work_NN1 where_CS the_AT main_JJ operator_NN1 limitation_NN1 is_VBZ not_XX capacity_NN1 or_CC skill_NN1 but_CCB stamina_NN1 ._. 
In_II principle_NN1 ,_, repetitive_JJ work_NN1 is_VBZ best_RRT left_VVN to_II automatic_JJ machines_NN2 but_CCB the_AT flexibility_NN1 of_IO human_JJ performance_NN1 is_VBZ often_RR needed_VVN because_CS slight_JJ changes_NN2 are_VBR required_VVN either_RR to_TO modify_VVI the_AT product_NN1 or_CC to_TO cope_VVI with_IW different_JJ materials_NN2 ._. 
Batch_NN1 production_NN1 work_NN1 is_VBZ often_RR of_IO this_DD1 kind_NN1 and_CC in_RR21 general_RR22 it_PPH1 is_VBZ by_RR31 no_RR32 means_RR33 as_CSA unchanging_JJ or_CC boring_JJ as_CSA it_PPH1 might_VM appear_VVI to_II the_AT casual_JJ visitor_NN1 to_II the_AT factory_NN1 ._. 
In_II all_DB the_AT clothing_NN1 trades_NN2 for_REX21 example_REX22 there_EX are_VBR continuous_JJ changes_NN2 in_II sizes_NN2 ,_, materials_NN2 ,_, colours_NN2 ,_, styles_NN2 and_RR31 so_RR32 on_RR33 which_DDQ provide_VV0 the_AT appropriate_JJ variety_NN1 for_IF the_AT customers_NN2 and_CC incidentally_RR for_IF the_AT producer_NN1 ._. 
Work_VV0 design_NN1 must_VM take_VVI account_NN1 of_IO the_AT needs_NN2 of_IO the_AT consumer_NN1 as_II31 well_II32 as_II33 those_DD2 of_IO the_AT worker_NN1 ._. 
Ergonomics_NN1 and_CC other_JJ aspects_NN2 of_IO technology_NN1 The_AT technical_JJ specialist_NN1 who_PNQS represents_VVZ the_AT people_NN point_NN1 of_IO view_NN1 implicit_JJ in_II the_AT approach_NN1 just_RR described_VVN is_VBZ the_AT ergonomist_NN1 ._. 
In_II the_AT previous_JJ book_NN1 in_II this_DD1 series_NN the_AT relationship_NN1 of_IO ergonomics_NN1 to_II other_JJ aspects_NN2 or_CC kinds_NN2 of_IO technology_NN1 was_VBDZ discussed_VVN in_II detail_NN1 ._. 
The_AT unique_JJ feature_NN1 of_IO ergonomics_NN1 is_VBZ its_APPGE emphasis_NN1 on_II the_AT characteristics_NN2 of_IO human_JJ operators_NN2 and_CC their_APPGE relevance_NN1 to_II the_AT design_NN1 of_IO work_NN1 ._. 
The_AT role_NN1 of_IO the_AT ergonomist_NN1 is_VBZ essentially_RR an_AT1 advisory_JJ one_PN1 ._. 
In_II the_AT case_NN1 of_IO high_JJ technology_NN1 design_NN1 he_PPHS1 must_VM provide_VVI a_AT1 service_NN1 for_IF the_AT engineers_NN2 and_CC scientists_NN2 who_PNQS carry_VV0 the_AT technical_JJ design_NN1 responsibility_NN1 ._. 
This_DD1 service_NN1 may_VM simply_RR be_VBI as_II a_AT1 source_NN1 of_IO information_NN1 or_CC the_AT ergonomist_NN1 can_VM have_VHI more_DAR power_NN1 in_CS21 that_CS22 the_AT design_NN1 decisions_NN2 involving_VVG people_NN have_VH0 to_TO be_VBI approved_VVN by_II him_PPHO1 ._. 
This_DD1 is_VBZ usually_RR restricted_VVN to_II obvious_JJ cases_NN2 of_IO man-machine_JJ interaction_NN1 such_II21 as_II22 the_AT design_NN1 of_IO displays_NN2 ,_, controls_NN2 and_CC work-spaces_NN2 ._. 
In_II the_AT case_NN1 of_IO low_JJ technology_NN1 design_NN1 again_RT he_PPHS1 has_VHZ an_AT1 advisory_JJ role_NN1 but_CCB with_IW a_AT1 general_JJ emphasis_NN1 on_II awareness_NN1 of_IO the_AT kinds_NN2 and_CC ranges_NN2 of_IO people_NN who_PNQS are_VBR being_VBG catered_VVN for._NNU for_IF systems_NN2 which_DDQ are_VBR already_RR operating_VVG the_AT ergonomist_NN1 is_VBZ likely_JJ to_TO cooperate_VVI with_IW occupational_JJ health_NN1 and_CC safety_NN1 specialists_NN2 and_CC to_TO play_VVI a_AT1 part_NN1 in_II the_AT consideration_NN1 of_IO accidents_NN2 and_CC occupational_JJ diseases_NN2 which_DDQ might_VM arise_VVI from_II unnecessarily_RR stressful_JJ work_NN1 situations_NN2 (_( p._NNU 294_MC )_) ._. 
It_PPH1 will_VM be_VBI appreciated_VVN that_CST for_IF most_DAT kinds_NN2 of_IO work_NN1 and_CC most_RGT working_JJ organisations_NN2 it_PPH1 is_VBZ not_XX feasible_JJ to_TO employ_VVI specialist_NN1 ergonomists_NN2 ._. 
In_II such_DA cases_NN2 those_DD2 who_PNQS have_VH0 responsibilities_NN2 for_IF work_NN1 design_NN1 need_NN1 to_TO have_VHI some_DD awareness_NN1 of_IO the_AT principles_NN2 of_IO ergonomics_NN1 ._. 
The_AT philosophy_NN1 of_IO work_NN1 Ergonomics_NN1 is_VBZ sometimes_RT confused_VVN by_II questions_NN2 such_II21 as_II22 ,_, who_PNQS is_VBZ the_AT ergonomist_NN1 servicing_VVG the_AT employer_NN1 or_CC the_AT worker_NN1 ?_? or_CC ,_, to_II whom_PNQO is_VBZ he_PPHS1 ultimately_RR responsible_JJ the_AT state_NN1 ,_, the_AT employer_NN1 ,_, the_AT producer_NN1 or_CC the_AT consumer_NN1 ?_? fortunately_RR it_PPH1 is_VBZ possible_JJ to_TO dispose_VVI of_IO these_DD2 issues_NN2 without_IW taking_VVG up_RP any_DD particular_JJ political_JJ position_NN1 ._. 
Ergonomics_NN1 seems_VVZ to_TO flourish_VVI equally_RR well_RR in_II capitalist_NN1 and_CC socialist/communist_JJ systems_NN2 ,_, ergonomics_NN1 activity_NN1 can_VM be_VBI sponsored_VVN with_IW equal_JJ validity_NN1 by_II employers_NN2 organisations_NN2 and_CC by_II workers_NN2 organisations_NN2 ._. 
This_DD1 is_VBZ because_CS ,_, as_CSA already_RR mentioned_VVN ,_, ergonomics_NN1 is_VBZ about_II efficient_JJ use_NN1 of_IO people_NN ._. 
There_EX can_VM be_VBI no_AT good_JJ reason_NN1 to_TO object_VVI to_II this_DD1 when_CS it_PPH1 is_VBZ recognised_VVN that_DD1 efficiency_NN1 incorporates_VVZ personal_JJ factors_NN2 such_II21 as_II22 safety_NN1 ,_, health_NN1 and_CC quality_NN1 of_IO working_NN1 life_NN1 as_II31 well_II32 as_II33 system_NN1 factors_NN2 such_II21 as_II22 productivity_NN1 and_CC quality_NN1 of_IO work_NN1 ._. 
There_EX is_VBZ rarely_RR any_DD conflict_NN1 in_II that_DD1 good_JJ ergonomics_NN1 is_VBZ in_II31 line_II32 with_II33 the_AT objectives_NN2 of_IO the_AT worker_NN1 ,_, the_AT employer_NN1 and_CC the_AT consumer_NN1 or_CC customer_NN1 ._. 
There_EX are_VBR sometimes_RT larger_JJR issues_NN2 of_IO whether_CSW what_DDQ the_AT system_NN1 does_VDZ is_VBZ acceptable_JJ or_CC not_XX ,_, for_REX21 example_REX22 in_II weapon_NN1 systems_NN2 ,_, and_CC the_AT ergonomist_NN1 as_II a_AT1 citizen_NN1 will_VM have_VHI his_APPGE own_DA opinion_NN1 on_II these_DD2 matters_NN2 but_CCB the_AT ergonomist_NN1 as_II an_AT1 ergonomist_NN1 is_VBZ confined_VVN to_II questions_NN2 of_IO efficiency_NN1 ._. 
There_EX is_VBZ an_AT1 underlying_JJ necessary_JJ ethic_NN1 which_DDQ is_VBZ best_RRT summarised_VVN as_II the_AT social_JJ contract_NN1 ._. 
An_AT1 individual_NN1 is_VBZ a_AT1 member_NN1 of_IO a_AT1 community_NN1 from_II which_DDQ he_PPHS1 obtains_VVZ considerable_JJ benefits_NN2 ,_, in_II return_NN1 he_PPHS1 develops_VVZ special_JJ skills_NN2 which_DDQ he_PPHS1 applies_VVZ for_IF the_AT benefit_NN1 of_IO the_AT community_NN1 ._. 
The_AT application_NN1 of_IO special_JJ skills_NN2 in_II this_DD1 way_NN1 is_VBZ called_VVN work_NN1 ._. 
The_AT ergonomist_NN1 has_VHZ to_TO believe_VVI that_DD1 work_NN1 is_VBZ a_AT1 good_JJ thing_NN1 and_CC that_DD1 to_TO conduct_VVI it_PPH1 efficiently_RR is_VBZ always_RR better_RRR than_CSN to_TO conduct_VVI it_PPH1 inefficiently_RR ._. 
The_AT design_NN1 of_IO systems_NN2 ._. 
The_AT system_NN1 concept_NN1 A_ZZ1 system_NN1 is_VBZ a_AT1 set_NN1 of_IO interacting_JJ parts_NN2 which_DDQ has_VHZ meaning_NN1 as_II a_AT1 whole_NN1 because_CS it_PPH1 is_VBZ possible_JJ to_TO define_VVI a_AT1 purpose_NN1 a_AT1 reason_NN1 why_RRQ the_AT parts_NN2 are_VBR seen_VVN to_TO be_VBI related_VVN to_II the_AT whole_NN1 and_CC a_AT1 justification_NN1 for_IF the_AT concept_NN1 of_IO the_AT whole_NN1 (_( Singleton_NP1 ,_, 1974_MC )_) ._. 
Thus_RR ,_, systems_NN2 theory_NN1 is_VBZ essentially_RR teleological_JJ explanations_NN2 are_VBR in_II31 terms_II32 of_II33 consequences_NN2 rather_II21 than_II22 causes_NN2 ._. 
The_AT parts_NN2 may_VM themselves_PPX2 be_VBI complex_JJ and_CC may_VM be_VBI conceived_VVN as_CSA having_VHG their_APPGE own_DA subsidiary_JJ purposes_NN2 in_II confluence_NN1 with_IW the_AT system_NN1 purpose_NN1 ,_, these_DD2 are_VBR sub-systems_NN2 ._. 
The_AT system_NN1 in_II turn_NN1 is_VBZ part_NN1 of_IO a_AT1 larger_JJR complex_NN1 the_AT parent_NN1 system_NN1 ._. 
Thus_RR ,_, systems_NN2 are_VBR hierarchical_JJ and_CC at_II each_DD1 level_NN1 the_AT unit_NN1 is_VBZ considered_VVN as_II a_AT1 functional_JJ rather_II21 than_II22 a_AT1 physical_JJ entity_NN1 ._. 
The_AT systems_NN2 approach_NN1 is_VBZ often_RR a_AT1 convenient_JJ way_NN1 of_IO looking_VVG at_II human_JJ behaviour_NN1 either_RR internally_RR this_DD1 is_VBZ man_NN1 as_II a_AT1 set_NN1 of_IO sub-systems_NN2 or_CC in_II31 terms_II32 of_II33 the_AT man_NN1 interacting_VVG with_IW mechanisms_NN2 man-machine_JJ systems_NN2 ,_, or_CC man_NN1 interacting_VVG with_IW organisations_NN2 socio-technical_JJ systems_NN2 ._. 
The_AT enormous_JJ flexibility_NN1 of_IO the_AT systems_NN2 approach_NN1 has_VHZ its_APPGE penalties_NN2 in_II potential_JJ confusion_NN1 due_II21 to_II22 the_AT highly_RR variable_JJ relationship_NN1 between_II functional_JJ and_CC physical_JJ entities_NN2 ._. 
Sometimes_RT this_DD1 relationship_NN1 is_VBZ fairly_RR close_JJ ;_; for_REX21 example_REX22 ,_, in_II the_AT nervous_JJ system_NN1 ,_, the_AT endocrine_JJ system_NN1 ,_, the_AT digestive_JJ system_NN1 and_RR31 so_RR32 on_RR33 ,_, and_CC sometimes_RT it_PPH1 remains_VVZ almost_RR entirely_RR unknown_JJ ,_, for_REX21 example_REX22 ,_, the_AT perceptual_JJ system_NN1 and_CC the_AT decision-making_JJ system_NN1 ._. 
These_DD2 last_MD two_MC are_VBR obviously_RR each_DD1 related_VVD to_II the_AT nervous_JJ system_NN1 and_CC to_II the_AT brain_NN1 but_CCB not_XX necessarily_RR to_II a_AT1 particular_JJ part_NN1 of_IO the_AT brain_NN1 and_CC taken_VVN together_RL they_PPHS2 overlap_VV0 in_II such_DA obscure_JJ ways_NN2 that_CST they_PPHS2 are_VBR best_RRT regarded_VVN as_II sub-systems_NN2 in_II different_JJ domains_NN2 ,_, one_PN1 can_VM talk_VVI in_II31 terms_II32 of_II33 one_MC1 or_CC the_AT other_JJ but_CCB not_XX both_RR simultaneously_RR ._. 
Systems_NN2 theory_NN1 is_VBZ a_AT1 useful_JJ way_NN1 of_IO identifying_VVG complex_JJ entities_NN2 ,_, particularly_RR those_DD2 which_DDQ have_VH0 a_AT1 functional_JJ unity_NN1 and_CC of_IO talking_VVG about_II relationships_NN2 but_CCB it_PPH1 remains_VVZ at_II some_DD level_NN1 of_IO abstraction_NN1 from_II reality._NNU for_REX21 example_REX22 ,_, to_TO solve_VVI any_DD design_NN1 problem_NN1 there_EX has_VHZ at_II some_DD stage_NN1 to_TO be_VBI a_AT1 switch_NN1 from_II systems_NN2 thinking_VVG to_II thinking_VVG in_II31 terms_II32 of_II33 physical_JJ entities_NN2 because_CS these_DD2 are_VBR the_AT things_NN2 that_CST can_VM be_VBI created_VVN ,_, precisely_RR located_VVN and_CC manipulated_VVN in_II the_AT real_JJ world_NN1 ._. 
Nevertheless_RR ,_, there_EX are_VBR enormous_JJ dividends_NN2 in_II being_VBG able_JK to_TO discuss_VVI functions_NN2 independently_RR of_IO physical_JJ mechanisms_NN2 and_CC to_TO explain_VVI relationships_NN2 without_IW being_VBG restricted_VVN to_II established_JJ and_CC readily_RR observable_JJ physical_JJ connections_NN2 or_CC separations_NN2 ._. 
For_REX21 example_REX22 ,_, thinking_NN1 of_IO a_AT1 power_NN1 station_NN1 as_II a_AT1 way_NN1 of_IO translating_VVG energy_NN1 from_II fuel_NN1 into_II electric_JJ power_NN1 enables_VVZ the_AT designer_NN1 to_TO consider_VVI various_JJ options_NN2 ._. 
Should_VM the_AT fuel_NN1 be_VBI of_IO a_AT1 fossil_NN1 type_NN1 such_II21 as_II22 coal_NN1 or_CC oil_NN1 or_CC should_VM it_PPH1 be_VBI the_AT radioactive_JJ elements_NN2 in_II a_AT1 nuclear_JJ reaction_NN1 ?_? 
When_CS the_AT heat_NN1 has_VHZ appeared_VVN how_RRQ best_VV0 should_VM it_PPH1 be_VBI taken_VVN away_RL by_II pressurised_JJ water_NN1 ,_, by_II steam_NN1 ,_, by_II liquid_JJ sodium_NN1 or_CC by_II carbon_NN1 dioxide_NN1 ?_? 
This_DD1 heat_NN1 has_VHZ to_TO be_VBI turned_VVN into_II mechanical_JJ energy_NN1 ,_, currently_RR always_RR by_II a_AT1 steam_NN1 turbine_NN1 and_CC the_AT mechanical_JJ energy_NN1 in_II a_AT1 rotating_JJ shaft_NN1 is_VBZ then_RT translated_VVN by_II a_AT1 generator_NN1 into_II electricity_NN1 ._. 
The_AT losses_NN2 in_II this_DD1 transfer_NN1 of_IO energy_NN1 from_II one_MC1 form_NN1 to_II another_DD1 can_VM be_VBI calculated_VVN and_CC the_AT flow_NN1 through_II the_AT various_JJ sub-systems_NN2 can_VM be_VBI traced_VVN ._. 
The_AT initial_JJ consideration_NN1 of_IO the_AT power_NN1 station_NN1 as_II an_AT1 energy_NN1 processing_NN1 system_NN1 aids_NN2 design_VV0 discussions_NN2 about_II the_AT relative_JJ advantages_NN2 and_CC limitations_NN2 of_IO various_JJ mechanisms_NN2 and_CC their_APPGE performance_NN1 in_II practice_NN1 ._. 
As_II the_AT system_NN1 operates_VVZ it_PPH1 has_VHZ to_TO be_VBI controlled_VVN ._. 
The_AT control_NN1 of_IO the_AT flow_NN1 of_IO energy_NN1 is_VBZ partly_RR through_II automatic_JJ servomechanisms_NN2 and_CC partly_RR through_II human_JJ operations_NN2 ._. 
The_AT design_NN1 problem_NN1 of_IO which_DDQ does_VDZ what_DDQ is_VBZ also_RR best_RRT thought_VVN about_II initially_RR in_II system_NN1 terms_NN2 ._. 
Distinct_JJ from_II the_AT flow_NN1 of_IO energy_NN1 the_AT designer_NN1 is_VBZ ,_, at_II this_DD1 stage_NN1 ,_, thinking_VVG about_II the_AT flow_NN1 of_IO information_NN1 ._. 
Energy_NN1 and_CC information_NN1 are_VBR processed_VVN by_II systems_NN2 and_CC sub-systems_NN2 ._. 
In_II these_DD2 terms_NN2 ,_, the_AT human_JJ operator_NN1 is_VBZ a_AT1 particular_JJ sub-system_NN1 ._. 
Mechanical_JJ devices_NN2 and_CC human_JJ operators_NN2 are_VBR not_XX comparable_JJ physically_RR beyond_II the_AT mundane_JJ level_NN1 of_IO size_NN1 but_CCB they_PPHS2 are_VBR comparable_JJ as_CSA different_JJ sub-systems_NN2 whose_DDQGE performance_NN1 can_VM be_VBI described_VVN and_CC assessed_VVN in_II31 terms_II32 of_II33 the_AT common_JJ metrics_NN1 of_IO energy_NN1 and_CC information_NN1 ._. 
Hence_RR the_AT importance_NN1 of_IO systems_NN2 concepts_NN2 to_II ergonomics_NN1 ._. 
If_CS the_AT human_JJ operator_NN1 is_VBZ to_TO control_VVI functions_NN2 within_II other_JJ sub-systems_NN2 he_PPHS1 must_VM receive_VVI information_NN1 about_II the_AT system_NN1 state_NN1 through_II a_AT1 man-machine_JJ interface_NN1 ._. 
This_DD1 interface_NN1 takes_VVZ its_APPGE physical_JJ form_NN1 in_II the_AT control_NN1 room_NN1 ._. 
The_AT control_NN1 room_NN1 is_VBZ part_NN1 of_IO the_AT communications_NN2 channel_VV0 between_II the_AT human_JJ operators_NN2 and_CC the_AT mechanisms_NN2 and_CC its_APPGE design_NN1 ,_, as_CSA a_AT1 man-machine_JJ interface_NN1 ,_, is_VBZ one_MC1 of_IO the_AT key_JJ ergonomics_NN1 problems_NN2 in_II power_NN1 stations_NN2 ._. 
Office_NN1 organisations_NN2 also_RR can_VM be_VBI considered_VVN as_CSA systems_NN2 ._. 
There_EX will_VM be_VBI certain_JJ physical_JJ mechanisms_NN2 such_II21 as_II22 telephones_NN2 ,_, typewriters_NN2 and_CC computers_NN2 but_CCB the_AT flow_NN1 of_IO energy_NN1 is_VBZ trivial_JJ and_CC the_AT interest_NN1 centres_NN2 entirely_RR on_II the_AT flow_NN1 of_IO information_NN1 ._. 
Consider_VV0 ,_, for_REX21 example_REX22 ,_, a_AT1 travel_NN1 office_NN1 ._. 
There_EX is_VBZ a_AT1 vast_JJ amount_NN1 of_IO information_NN1 available_JJ either_RR in_II printed_JJ form_NN1 or_CC through_II computer_NN1 networks_NN2 ._. 
The_AT objectives_NN2 are_VBR to_TO help_VVI members_NN2 of_IO the_AT public_JJ to_TO find_VVI their_APPGE way_NN1 through_II this_DD1 information_NN1 store_NN1 and_CC to_TO transmit_VVI their_APPGE orders_NN2 for_IF particular_JJ journeys_NN2 or_CC holidays_NN2 to_II the_AT providers_NN2 of_IO those_DD2 services_NN2 ._. 
The_AT manager_NN1 or_CC designer_NN1 of_IO the_AT office_NN1 has_VHZ to_TO consider_VVI the_AT various_JJ sub-systems_NN2 he_PPHS1 requires_VVZ ;_; one_PN1 for_IF dealing_VVG with_IW enquiries_NN2 ,_, one_PN1 for_IF handling_VVG money_NN1 ,_, one_PN1 for_IF receiving_VVG new_JJ information_NN1 ,_, one_PN1 for_IF confirming_VVG orders_NN2 and_RR31 so_RR32 on_RR33 ._. 
The_AT interface_NN1 between_II the_AT public_NN1 and_CC the_AT information_NN1 store_NN1 is_VBZ a_AT1 counter_NN1 manned_VVN by_II people_NN ._. 
The_AT counter_NN1 assistants_NN2 are_VBR parts_NN2 of_IO the_AT interface_NN1 ._. 
Information_NN1 is_VBZ exchanged_VVN verbally_RR and_CC through_II written_JJ documentation_NN1 ._. 
In_II this_DD1 kind_NN1 of_IO office_NN1 the_AT variety_NN1 of_IO requests_NN2 for_IF service_NN1 is_VBZ probably_RR such_CS21 that_CS22 it_PPH1 would_VM be_VBI necessary_JJ to_TO provide_VVI a_AT1 set_NN1 of_IO categories_NN2 of_IO the_AT main_JJ kinds_NN2 of_IO activities_NN2 or_CC functions_NN2 ._. 
It_PPH1 would_VM then_RT be_VBI possible_JJ to_TO devise_VVI the_AT appropriate_JJ system_NN1 for_IF presenting_VVG the_AT required_JJ information_NN1 ._. 
It_PPH1 is_VBZ a_AT1 very_RG different_JJ situation_NN1 from_II a_AT1 power_NN1 station_NN1 control_NN1 room_NN1 but_CCB nevertheless_RR the_AT same_DA principles_NN2 of_IO starting_VVG by_II the_AT analysis_NN1 of_IO the_AT required_JJ information_NN1 apply_VV0 ._. 
The_AT power_NN1 station_NN1 ,_, the_AT travel_NN1 office_NN1 and_CC all_DB other_JJ man-made_JJ systems_NN2 have_VH0 in_RR21 common_RR22 the_AT employment_NN1 of_IO people_NN so_CS21 that_CS22 sub-systems_NN2 are_VBR required_VVN which_DDQ are_VBR associated_VVN with_IW personnel_NN2 functions_NN2 ._. 
It_PPH1 is_VBZ necessary_JJ to_TO attract_VVI and_CC select_JJ staff_NN ,_, to_TO train_VVI them_PPHO2 ,_, to_TO provide_VVI them_PPHO2 with_IW various_JJ services_NN2 and_CC with_IW potentiality_NN1 for_IF advancement_NN1 as_CSA their_APPGE skills_NN2 increase_VV0 with_IW experience_NN1 ._. 
The_AT design_NN1 of_IO tasks_NN2 is_VBZ the_AT common_JJ ground_NN1 between_II personnel_NN2 activities_NN2 such_II21 as_II22 training_NN1 and_CC engineering_NN1 activities_NN2 such_II21 as_II22 workplace_NN1 design_NN1 ._. 
Consideration_NN1 of_IO people_NN in_II system_NN1 terms_NN2 provides_VVZ the_AT possibility_NN1 of_IO generalisations_NN2 which_DDQ apply_VV0 across_II great_JJ varieties_NN2 of_IO physical_JJ and_CC intellectual_JJ activities_NN2 ._. 
The_AT resulting_JJ knowledge_NN1 is_VBZ the_AT content_NN1 of_IO ergonomics_NN1 ._. 
Fig._NN1 1.2_MC shows_VVZ the_AT outline_NN1 of_IO the_AT systems_NN2 design_VV0 process_NN1 in_II a_AT1 way_NN1 which_DDQ emphasises_VVZ the_AT parallel_JJ roles_NN2 of_IO the_AT engineer_NN1 and_CC the_AT ergonomist_NN1 concerned_JJ respectively_RR with_IW the_AT design_NN1 of_IO the_AT hardware_NN1 and_CC the_AT personnel_NN2 sub-systems_NN2 and_CC their_APPGE common_JJ design_NN1 problems_NN2 of_IO allocation_NN1 of_IO function_NN1 and_CC interface_VV0 design_NN1 ._. 
The_AT design_NN1 of_IO high_JJ technology_NN1 systems_NN2 The_AT insertion_NN1 of_IO an_AT1 adequate_JJ Human_JJ factors_NN2 approach_VV0 into_II a_AT1 comprehensive_JJ design_NN1 process_NN1 is_VBZ not_XX easy_JJ ,_, partly_RR for_IF the_AT reason_NN1 mentioned_VVD already_RR that_CST it_PPH1 has_VHZ not_XX habitually_RR been_VBN regarded_VVN as_CSA necessary_JJ and_CC partly_RR because_CS it_PPH1 cuts_VVZ across_II all_DB other_JJ decision-making_NN1 ._. 
The_AT Human_JJ Factors_NN2 specialist_NN1 can_VM rightly_RR be_VBI accused_VVN of_IO wanting_VVG to_TO have_VHI a_AT1 finger_NN1 in_II every_AT1 pie_NN1 because_CS ,_, as_CSA he_PPHS1 sees_VVZ it_PPH1 ,_, behavioural_JJ considerations_NN2 do_VD0 affect_VVI every_AT1 design_NN1 decision_NN1 ._. 
If_CS ergonomics_NN1 was_VBDZ confined_VVN to_II ,_, say_VV0 ,_, the_AT determination_NN1 of_IO the_AT physical_JJ dimensions_NN2 of_IO the_AT work-space_NN1 then_RT it_PPH1 would_VM be_VBI more_RGR readily_RR accepted_VVN by_II traditional_JJ designers_NN2 ,_, but_CCB the_AT broad_JJ claim_NN1 that_CST ergonomics_NN1 has_VHZ a_AT1 contribution_NN1 to_TO make_VVI to_II every_AT1 design_NN1 and_CC operational_JJ aspect_NN1 which_DDQ involves_VVZ the_AT behaviour_NN1 of_IO people_NN is_VBZ a_AT1 proposition_NN1 which_DDQ it_PPH1 is_VBZ much_RR more_RGR difficult_JJ for_IF an_AT1 engineer_NN1 or_CC other_JJ designer_NN1 to_TO digest_VVI (_( fig._NN1 1.3_MC )_) ._. 
The_AT questions_NN2 begin_VV0 with_IW the_AT formulation_NN1 of_IO the_AT design_NN1 objectives_NN2 ._. 
What_DDQ are_VBR the_AT human_JJ requirements_NN2 which_DDQ the_AT new_JJ product_NN1 or_CC process_NN1 is_VBZ intended_VVN to_TO meet_VVI and_CC how_RGQ far_RR are_VBR they_PPHS2 not_XX met_VVN by_II those_DD2 already_RR available_JJ ?_? 
This_DD1 would_VM normally_RR be_VBI regarded_VVN as_II a_AT1 matter_NN1 for_IF economists_NN2 and_CC market-research_JJ specialists_NN2 but_CCB behind_II the_AT formidable_JJ array_NN1 of_IO evidence_NN1 which_DDQ they_PPHS2 will_VM generate_VVI are_VBR more_RGR fundamental_JJ questions_NN2 of_IO consumer_NN1 preference_NN1 ,_, customer_NN1 requirements_NN2 and_RR31 so_RR32 on_RR33 which_DDQ are_VBR matters_NN2 of_IO human_JJ needs_NN2 and_CC prejudices_NN2 ._. 
Competent_JJ market_NN1 research_NN1 should_VM cover_VVI these_DD2 aspects_NN2 but_CCB the_AT ergonomist_NN1 can_VM remind_VVI the_AT policy-makers_NN2 that_CST such_DA evidence_NN1 is_VBZ needed_VVN and_CC that_CST it_PPH1 should_VM be_VBI acquired_VVN by_II studies_NN2 of_IO people_NN which_DDQ are_VBR properly_RR conducted_VVN ._. 
If_CS the_AT evidence_NN1 is_VBZ favourable_JJ then_RT the_AT next_MD step_NN1 will_VM be_VBI to_TO set_VVI up_RP a_AT1 design_NN1 team_NN1 containing_VVG members_NN2 covering_VVG the_AT relevant_JJ range_NN1 of_IO expertise_NN1 ._. 
How_RGQ much_DA1 design_NN1 effort_NN1 is_VBZ needed_VVN in_II the_AT different_JJ areas_NN2 will_VM not_XX be_VBI clear_JJ at_II this_DD1 stage_NN1 but_CCB unless_CS the_AT system_NN1 is_VBZ very_RG simple_JJ there_EX are_VBR bound_VVNK to_TO be_VBI problems_NN2 of_IO overlap_NN1 and_CC of_IO how_RGQ far_RR to_TO arrange_VVI sub-teams_NN2 by_II discipline_NN1 ,_, by_II function_NN1 or_CC by_II problem_NN1 (_( Singleton_NP1 ,_, 1987_MC )_) ._. 
The_AT usual_JJ compromise_NN1 is_VBZ that_CST there_EX should_VM be_VBI problemorientated_JJ sub-teams_NN2 but_CCB with_IW additional_JJ support_NN1 available_JJ from_II disciplineorientated_JJ specialists_NN2 ._. 
If_CS these_DD2 latter_DA are_VBR part_NN1 of_IO the_AT design_NN1 team_NN1 then_RT already_RR we_PPIS2 have_VH0 a_AT1 matrix_NN1 organisation_NN1 but_CCB they_PPHS2 may_VM well_RR be_VBI provided_VVN on_II a_AT1 service_NN1 basis_NN1 from_II some_DD other_JJ part_NN1 of_IO the_AT parent_NN1 organisation_NN1 ._. 
Difficulties_NN2 will_VM emerge_VVI later_RRR unless_CS considerable_JJ thought_NN1 is_VBZ given_VVN at_II this_DD1 stage_NN1 to_II the_AT appropriate_JJ range_NN1 of_IO skills_NN2 required_VVN and_CC the_AT consequent_JJ problems_NN2 of_IO interdisciplinary_JJ communication_NN1 ._. 
The_AT art_NN1 of_IO good_JJ sub-system_NN1 design_NN1 is_VBZ to_TO identify_VVI problem_NN1 areas_NN2 where_RRQ work_NN1 can_VM proceed_VVI relatively_RR independently_RR of_IO other_JJ areas_NN2 so_CS21 that_CS22 the_AT need_NN1 for_IF intercommunication_NN1 is_VBZ minimised_VVN ._. 
There_EX will_VM always_RR be_VBI the_AT need_NN1 for_IF some_DD intercommunication_NN1 and_CC the_AT appropriate_JJ interfaces_NN2 should_VM be_VBI provided_VVN ._. 
Nevertheless_RR ,_, if_CS committees_NN2 ,_, working_VVG parties_NN2 and_CC task_NN1 forces_NN2 begin_VV0 to_TO proliferate_VVI within_II the_AT design_NN1 team_NN1 ,_, this_DD1 is_VBZ a_AT1 sure_JJ indication_NN1 that_CST the_AT basic_JJ allocation_NN1 into_II sub-systems_NN2 was_VBDZ not_XX optimal_JJ ._. 
Communication_NN1 should_VM be_VBI mainly_RR through_II the_AT central_JJ command_NN1 and_CC control_NN1 centre_NN1 which_DDQ may_VM be_VBI no_AT larger_JJR than_CSN the_AT project_NN1 leader_NN1 and_CC his_APPGE small_JJ personal_JJ staff_NN as_CSA may_VM be_VBI a_AT1 group_NN1 of_IO heads_NN2 of_IO sub-systems_NN2 or_CC both_DB2 ._. 
These_DD2 issues_NN2 are_VBR discussed_VVN from_II another_DD1 viewpoint_NN1 in_II Chapter_NN1 3_MC (_( p._NNU 140_MC )_) ._. 
The_AT analysis_NN1 of_IO required_JJ skills_NN2 ought_VMK in_II principle_NN1 to_TO have_VHI an_AT1 ergonomics_NN1 input_NN1 but_CCB in_II practice_NN1 it_PPH1 is_VBZ usually_RR done_VDN on_II the_AT basis_NN1 of_IO experience_NN1 of_IO similar_JJ system_NN1 designs_NN2 in_II the_AT past_NN1 ._. 
There_EX can_VM be_VBI a_AT1 useful_JJ discussion_NN1 between_II the_AT project_NN1 leader_NN1 and_CC an_AT1 ergonomist_NN1 where_CS the_AT former_DA is_VBZ invited_VVN to_TO clarify_VVI how_RRQ he_PPHS1 sees_VVZ these_DD2 intercommunication_NN1 problems_NN2 being_VBG dealt_VVN with_IW including_VVG such_DA criteria_NN2 as_CSA what_DDQ is_VBZ reported_VVN to_II him_PPHO1 ,_, what_DDQ to_II the_AT meeting_NN1 of_IO sub-heads_NN2 and_CC what_DDQ occurs_VVZ directly_RR between_II sub-teams_NN2 ._. 
Organisational_JJ rules_NN2 of_IO this_DD1 kind_NN1 can_VM be_VBI very_RG helpful_JJ in_II steering_VVG between_II the_AT excessive_JJ information_NN1 flow_NN1 ,_, e.g._REX memoranda_NN2 copied_VVN to_II many_DA2 people_NN ,_, and_CC excessive_JJ unilateralism_NN1 ,_, e.g._REX refusing_VVG further_JJR discussion_NN1 after_II the_AT issue_NN1 of_IO formal_JJ documents_NN2 ._. 
Having_VHG allocated_VVN the_AT human_NN1 and_CC other_JJ resources_NN2 needed_VVN for_IF the_AT overall_JJ design_NN1 task_NN1 it_PPH1 is_VBZ then_RT appropriate_VV0 to_TO develop_VVI a_AT1 more_RGR detailed_JJ model_NN1 of_IO the_AT system_NN1 functions_NN2 in_II31 terms_II32 of_II33 materials_NN2 ,_, energy_NN1 and_CC information_NN1 flow_NN1 ._. 
Most_DAT designers_NN2 have_VH0 an_AT1 intuitive_JJ but_CCB unformalised_JJ picture_NN1 in_II these_DD2 terms_NN2 but_CCB it_PPH1 is_VBZ of_IO great_JJ utility_NN1 to_TO produce_VVI these_DD2 pictures_NN2 in_II flow_NN1 diagram_NN1 form_NN1 so_CS21 that_CS22 any_DD differences_NN2 of_IO view_NN1 are_VBR revealed_VVN and_CC can_VM be_VBI reconciled_VVN by_II discussions_NN2 during_II the_AT process_NN1 of_IO agreeing_VVG the_AT diagrams_NN2 ._. 
When_CS there_EX are_VBR a_AT1 number_NN1 of_IO individuals_NN2 or_CC groups_NN2 from_II different_JJ disciplines_NN2 and_CC pursuing_VVG different_JJ objectives_NN2 within_II some_DD overall_JJ specification_NN1 it_PPH1 is_VBZ obviously_RR crucial_JJ that_CST all_DB their_APPGE activities_NN2 should_VM be_VBI in_II31 line_II32 with_II33 the_AT common_JJ goal_NN1 ._. 
To_II this_DD1 end_NN1 ,_, it_PPH1 is_VBZ necessary_JJ that_CST there_EX should_VM be_VBI intercommunication_NN1 not_XX only_RR about_II particular_JJ design_NN1 decisions_NN2 but_CCB also_RR about_II underlying_JJ philosophies_NN2 so_CS21 that_CS22 the_AT ultimate_JJ system_NN1 is_VBZ conceptually_RR as_CSA well_JJ as_CSA operationally_RR coherent_JJ ._. 
Sometimes_RT this_DD1 is_VBZ achieved_VVN by_II a_AT1 dominant_JJ project_NN1 leader_NN1 who_PNQS imposes_VVZ his_APPGE own_DA philosophy_NN1 and_CC then_RT makes_VVZ many_DA2 of_IO the_AT decisions_NN2 leaving_VVG only_RR detailing_VVG for_IF team_NN1 members_NN2 ._. 
In_II recent_JJ times_NNT2 it_PPH1 is_VBZ more_RGR usual_JJ to_TO have_VHI some_DD element_NN1 of_IO discussion_NN1 ,_, partly_RR because_II21 of_II22 the_AT increasingly_RR democratic_JJ style_NN1 of_IO organisations_NN2 and_CC partly_RR because_CS the_AT variety_NN1 of_IO relevant_JJ technology_NN1 requires_VVZ a_AT1 correspondingly_RR wide_JJ range_NN1 of_IO expertise_NN1 ._. 
In_II any_DD case_NN1 there_EX is_VBZ a_AT1 need_NN1 for_IF widespread_JJ intercommunication_NN1 which_DDQ may_VM be_VBI mainly_RR informal_JJ but_CCB requires_VVZ some_DD formality_NN1 to_TO ensure_VVI that_CST clashes_NN2 of_IO attitude_NN1 do_VD0 not_XX delay_VVI or_CC distort_VVI decisions_NN2 and_CC to_TO make_VVI sure_JJ also_RR that_CST finalised_VVD decisions_NN2 are_VBR unambiguously_RR recorded_VVN ._. 
If_CS this_DD1 intercommunication_NN1 is_VBZ not_XX properly_RR arranged_VVN there_RL will_VM be_VBI the_AT familiar_JJ symptoms_NN2 of_IO frustrating_JJ reiteration_NN1 ,_, decisions_NN2 being_VBG misunderstood_VVN or_CC being_VBG constantly_RR revised_VVN ,_, political_JJ manoeuvring_NN1 and_CC even_RR concealment_NN1 of_IO progress_NN1 within_II one_MC1 or_CC more_DAR of_IO the_AT teams_NN2 ._. 
As_II the_AT overall_JJ design_NN1 progresses_VVZ the_AT information_NN1 storage_NN1 system_NN1 becomes_VVZ increasingly_RR important_JJ ._. 
If_CS insufficient_JJ attention_NN1 has_VHZ been_VBN devoted_VVN to_II the_AT design_NN1 of_IO this_DD1 and_CC also_RR the_AT related_JJ access_NN1 procedures_NN2 the_AT symptoms_NN2 are_VBR a_AT1 plethora_NN1 of_IO documentation_NN1 which_DDQ no_AT individual_NN1 entirely_RR understands_VVZ ,_, the_AT temptation_NN1 to_TO do_VDI it_PPH1 again_RT rather_CS21 than_CS22 waste_VVI time_NNT1 finding_VVG out_RP how_RRQ something_PN1 has_VHZ already_RR been_VBN done_VDN and_CC too_RG much_DA1 reliance_NN1 on_II the_AT human_JJ memory_NN1 ._. 
The_AT behavioural_JJ symptoms_NN2 of_IO inadequate_JJ organisation_NN1 of_IO design_NN1 teams_NN2 are_VBR summarised_VVN in_II Table_NN1 1.1_MC ._. 
As_II the_AT system_NN1 is_VBZ made_VVN more_RGR definitive_JJ by_II the_AT selection_NN1 of_IO particular_JJ physical_JJ mechanisms_NN2 there_EX should_VM be_VBI parallel_JJ activity_NN1 in_II the_AT consideration_NN1 of_IO how_RRQ these_DD2 things_NN2 are_VBR to_TO be_VBI used_VVN and_CC maintained_VVN by_II the_AT human_JJ operator_NN1 ._. 
Note_VV0 that_CST the_AT philosophy_NN1 here_RL is_VBZ that_CST all_DB the_AT hardware_NN1 is_VBZ ultimately_RR an_AT1 extension_NN1 of_IO and_CC a_AT1 support_NN1 for_IF human_JJ functions_NN2 ._. 
This_DD1 is_VBZ the_AT concept_NN1 of_IO all_DB systems_NN2 as_CSA human_JJ beings_NN2 with_IW various_JJ kinds_NN2 of_IO engineering_NN1 aids_NN2 (_( Singleton_NP1 ,_, 1967a_FO )_) ._. 
functions_NN2 are_VBR delegated_VVN from_II the_AT human_JJ operator_NN1 rather_II21 than_II22 allocated_JJ to_II him_PPHO1 ._. 
This_DD1 extreme_JJ ergonomics_NN1 stance_NN1 serves_VVZ as_II an_AT1 antidote_NN1 to_II the_AT equally_RR extreme_JJ engineering_NN1 approach_NN1 in_II which_DDQ systems_NN2 are_VBR regarded_VVN basically_RR as_II hardware_NN1 which_DDQ for_IF reasons_NN2 of_IO economic_JJ or_CC technological_JJ limitations_NN2 have_VH0 to_TO depend_VVI occasionally_RR on_II some_DD human_JJ performance_NN1 ._. 
Even_CS21 if_CS22 there_EX is_VBZ no_AT dependence_NN1 on_II human_JJ performance_NN1 in_II the_AT on-line_JJ operational_JJ mode_NN1 it_PPH1 is_VBZ bound_VVNK to_TO exist_VVI in_II the_AT maintenance_NN1 mode_NN1 ._. 
In_II either_DD1 case_NN1 ,_, there_EX will_VM eventually_RR be_VBI a_AT1 need_NN1 for_IF the_AT consideration_NN1 of_IO the_AT kinds_NN2 of_IO human_JJ operators_NN2 required_VVN and_CC how_RRQ they_PPHS2 are_VBR to_TO be_VBI selected_VVN and_CC trained_VVN ._. 
Traditionally_RR these_DD2 personnel_NN2 functions_NN2 were_VBDR regarded_VVN as_II quite_RG separate_JJ from_II design_NN1 functions_NN2 and_CC indeed_RR they_PPHS2 were_VBDR often_RR left_VVN until_CS the_AT hardware_NN1 design_NN1 and_CC commissioning_NN1 was_VBDZ virtually_RR complete_JJ ._. 
The_AT essence_NN1 of_IO the_AT systems_NN2 approach_NN1 is_VBZ that_CST personnel_NN2 decisions_NN2 should_VM proceed_VVI in_II parallel_NN1 with_IW engineering_NN1 decisions_NN2 ,_, partly_RR to_TO economise_VVI on_II development_NN1 time_NNT1 and_CC partly_RR to_TO provide_VVI scope_NN1 for_IF trade-offs_NN2 ._. 
One_MC1 factor_NN1 which_DDQ has_VHZ given_VVN renewed_JJ emphasis_NN1 to_II this_DD1 need_NN1 for_IF cooperation_NN1 is_VBZ the_AT increased_JJ use_NN1 of_IO simulation_NN1 (_( p._NNU 128_MC )_) ._. 
Simulators_NN2 were_VBDR originally_RR considered_VVN to_TO be_VBI training_VVG devices_NN2 but_CCB their_APPGE use_NN1 is_VBZ now_RT extending_VVG into_II other_JJ fields_NN2 such_II21 as_II22 personnel_NN2 assessment_NN1 and_CC as_CSA aids_NN2 to_II the_AT design_NN1 of_IO the_AT information_NN1 interfaces_NN2 ._. 
It_PPH1 used_VMK to_TO be_VBI considered_VVN that_DD1 simulator_NN1 specifications_NN2 could_VM only_RR be_VBI proposed_VVN when_CS the_AT on-line_JJ system_NN1 design_NN1 had_VHD been_VBN completed_VVN but_CCB there_EX are_VBR considerable_JJ advantages_NN2 in_II developing_VVG the_AT simulator_NN1 before_II the_AT on-line_JJ system_NN1 so_CS21 that_CS22 it_PPH1 becomes_VVZ a_AT1 dynamic_JJ mock-up_NN1 of_IO the_AT real_JJ situation_NN1 ._. 
Detailed_JJ evaluations_NN2 can_VM be_VBI carried_VVN out_RP on_II this_DD1 mock-up_NN1 before_II the_AT real_JJ system_NN1 is_VBZ constructed_VVN ._. 
All_DB systems_NN2 are_VBR constructed_VVN from_II bought-in_JJ components_NN2 which_DDQ may_VM themselves_PPX2 be_VBI complex_JJ enough_RR to_TO warrant_VVI a_AT1 human_JJ factors_NN2 evaluation._NNU for_REX21 example_REX22 ,_, a_AT1 motor/pump_NN1 system_NN1 may_VM well_RR have_VHI its_APPGE own_DA controls_NN2 ,_, there_EX will_VM be_VBI standard_JJ maintenance_NN1 procedures_NN2 and_CC there_EX will_VM be_VBI an_AT1 operation/maintenance_NN1 manual_NN1 ._. 
All_DB of_IO these_DD2 can_VM be_VBI assessed_VVN from_II the_AT point_NN1 of_IO view_NN1 of_IO clarity_NN1 of_IO presentation_NN1 and_CC ease_NN1 of_IO use_NN1 ._. 
The_AT system_NN1 being_VBG constructed_VVN will_VM require_VVI its_APPGE own_DA operating_NN1 instructions_NN2 ,_, maintenance_NN1 procedures_NN2 and_CC perhaps_RR safety_NN1 regulations_NN2 ._. 
The_AT design_NN1 and_CC preparation_NN1 of_IO this_DD1 documentation_NN1 has_VHZ a_AT1 Human_JJ factors_NN2 component_NN1 ._. 
It_PPH1 is_VBZ a_AT1 matter_NN1 of_IO storage_NN1 ,_, access_NN1 to_II and_CC presentation_NN1 of_IO information_NN1 ._. 
Even_RR at_II the_AT design_NN1 stage_NN1 it_PPH1 is_VBZ useful_JJ also_RR to_TO recognise_VVI that_CST all_DB this_DD1 material_NN1 will_VM require_VVI procedures_NN2 for_IF updating_VVG in_II41 the_II42 light_II43 of_II44 experience_NN1 Finally_RR it_PPH1 must_VM be_VBI accepted_VVN that_CST technological_JJ and_CC operational_JJ expertise_NN1 is_VBZ never_RR complete_JJ ._. 
The_AT operators_NN2 of_IO plant_NN1 are_VBR bound_VVNK to_TO discover_VVI by_II experience_NN1 aspects_NN2 of_IO the_AT design_NN1 which_DDQ could_VM be_VBI improved_VVN ._. 
There_EX should_VM be_VBI a_AT1 mechanism_NN1 for_IF feeding_VVG this_DD1 information_NN1 back_RP to_II the_AT designers_NN2 so_CS21 that_CS22 the_AT succeeding_JJ system_NN1 designs_NN2 will_VM avoid_VVI these_DD2 problems_NN2 ._. 
In_RR21 particular_RR22 ,_, human_JJ performance_NN1 within_II systems_NN2 is_VBZ impossible_JJ to_TO predict_VVI with_IW any_DD precision_NN1 and_CC details_NN2 of_IO this_DD1 performance_NN1 as_CSA it_PPH1 occurs_VVZ in_II practice_NN1 or_CC on_II simulators_NN2 is_VBZ the_AT only_JJ basis_NN1 for_IF prediction_NN1 on_II matters_NN2 such_II21 as_II22 safety_NN1 and_CC system_NN1 reliability_NN1 either_RR for_IF the_AT current_JJ system_NN1 or_CC for_IF future_JJ systems_NN2 ._. 
Potential_JJ human_JJ factors_NN2 inputs_NN2 to_II the_AT large_JJ scale_NN1 design_NN1 process_NN1 are_VBR summarised_VVN in_II fig._NN1 1.4_MC ._. 
In_II all_DB behavioural_JJ matters_NN2 and_CC indeed_RR in_II many_DA2 technical_JJ matters_NN2 also_RR it_PPH1 is_VBZ important_JJ to_TO avoid_VVI the_AT impression_NN1 that_CST when_CS operations_NN2 in_II practice_NN1 contain_VV0 undesirable_JJ features_NN2 not_XX predicted_VVN by_II designers_NN2 then_RT the_AT designers_NN2 have_VH0 made_VVN mistakes_NN2 ._. 
This_DD1 may_VM be_VBI true_JJ in_II a_AT1 formal_JJ sense_NN1 but_CCB allocation_NN1 of_IO blame_NN1 is_VBZ not_XX usually_RR a_AT1 productive_JJ exercise_NN1 particularly_RR from_II a_AT1 learning_NN1 view-point_NN1 ._. 
It_PPH1 is_VBZ valuable_JJ to_TO inculcate_VVI the_AT attitude_NN1 that_CST everyone_PN1 learns_VVZ ,_, that_REX21 is_REX22 ,_, design_NN1 and_CC operating_VVG staff_NN all_RR improve_VV0 on_II the_AT basis_NN1 of_IO experience_NN1 with_IW feed-back_NN1 ._. 
The_AT exposure_NN1 and_CC remedy_NN1 of_IO facets_NN2 of_IO systems_NN2 performance_NN1 which_DDQ are_VBR not_XX entirely_RR as_CSA predicted_VVN is_VBZ in_II everyone_PN1 's_GE interest_NN1 ._. 
One_MC1 example_NN1 of_IO this_DD1 is_VBZ matters_NN2 to_TO do_VDI with_IW safety_NN1 :_: it_PPH1 is_VBZ always_RR useful_JJ to_TO collect_VVI '_GE critical_JJ incident_NN1 '_GE data_NN as_II31 well_II32 as_II33 accident_NN1 data_NN as_CSA one_MC1 part_NN1 of_IO the_AT feed-back_NN1 about_II system_NN1 performances_NN2 ._. 
The_AT setting_NN1 up_RP of_IO routines_NN2 for_IF this_DD1 communication_NN1 is_VBZ another_DD1 aspect_NN1 of_IO ergonomics_NN1 ._. 
In_II summary_NN1 ,_, although_CS the_AT basic_JJ contribution_NN1 of_IO the_AT ergonomist_NN1 is_VBZ to_II the_AT design_NN1 of_IO information_NN1 interfaces_VVZ these_DD2 interfaces_NN2 extend_VV0 far_RR beyond_II the_AT man-machine_JJ interface_NN1 found_VVN in_II the_AT control_NN1 room_NN1 ._. 
They_PPHS2 include_VV0 the_AT documentation_NN1 of_IO the_AT design_NN1 itself_PPX1 ,_, communication_NN1 within_II the_AT design_NN1 team_NN1 ,_, between_II designers_NN2 and_CC suppliers_NN2 and_CC between_II designers_NN2 and_CC operators_NN2 (_( fig._NN1 1.5_MC )_) ._. 
The_AT operations_NN2 staff_NN include_VV0 those_DD2 who_PNQS set_VV0 it_PPH1 up_RP ,_, those_DD2 who_PNQS control_VV0 it_PPH1 during_II operations_NN2 ,_, those_DD2 who_PNQS maintain_VV0 it_PPH1 ,_, and_CC eventually_RR those_DD2 who_PNQS have_VH0 to_TO dismantle_VVI it_PPH1 ._. 
To_TO give_VVI one_MC1 example_NN1 of_IO the_AT size_NN1 of_IO the_AT documentation_NN1 problem_NN1 it_PPH1 is_VBZ not_XX unusual_JJ for_IF a_AT1 large_JJ process_NN1 plant_NN1 to_TO have_VHI two_MC or_CC three_MC hundred_NNO volumes_NN2 of_IO instructions_NN2 ._. 
These_DD2 include_VV0 the_AT operating_NN1 instructions_NN2 ,_, the_AT maintenance_NN1 instructions_NN2 ,_, the_AT suppliers_NN2 '_GE instruction_NN1 manuals_NN2 ,_, the_AT safety_NN1 regulations_NN2 and_CC instructions_NN2 for_IF particular_JJ emergencies._NNU pp_NNU2 1718:DIAGRAM/FIGURE_VV0 The_AT design_NN1 of_IO smaller_JJR systems_NN2 The_AT design_NN1 of_IO a_AT1 machine_NN1 or_CC device_NN1 which_DDQ is_VBZ assigned_VVN as_II an_AT1 aid_NN1 for_IF one_MC1 person_NN1 will_VM not_XX usually_RR encounter_VVI the_AT problems_NN2 associated_VVN with_IW elaborate_JJ design_NN1 teams_NN2 just_RR described_VVN ,_, but_CCB nevertheless_RR some_DD human_JJ factors_NN2 sensitivity_NN1 will_VM help_VVI to_TO provide_VVI a_AT1 better_JJR product_NN1 ._. 
This_DD1 can_VM be_VBI important_JJ not_XX only_RR from_II the_AT point_NN1 of_IO view_NN1 of_IO efficiency_NN1 in_II design_NN1 and_CC use_NN1 but_CCB also_RR in_II improving_VVG the_AT sales_NN appeal_VV0 ._. 
It_PPH1 is_VBZ increasingly_RR common_JJ for_IF advertisements_NN2 to_TO emphasise_VVI features_NN2 such_II21 as_II22 '_GE man-machine_JJ harmony_NN1 '_GE or_CC '_GE user_NN1 friendliness_NN1 '_GE ._. 
The_AT implication_NN1 is_VBZ that_DD1 ergonomics_NN1 has_VHZ been_VBN properly_RR applied_VVN ._. 
There_EX is_VBZ a_AT1 need_NN1 for_IF formal_JJ ergonomics_NN1 in_II any_DD design_NN1 where_CS the_AT designer_NN1 himself_PPX1 is_VBZ not_XX an_AT1 experienced_JJ user_NN1 ._. 
Some_DD hand_NN1 tools_NN2 are_VBR beautifully_RR designed_VVN to_TO match_VVI the_AT user_NN1 ,_, e.g._REX the_AT two-handed_JJ scythe_NN1 ._. 
In_II these_DD2 cases_NN2 it_PPH1 is_VBZ clear_JJ that_CST the_AT design_NN1 developed_VVN by_II constant_JJ trial_NN1 in_II practice_NN1 ._. 
There_EX are_VBR others_NN2 ,_, however_RR ,_, where_CS even_RR after_II centuries_NNT2 of_IO use_NN1 this_DD1 matching_NN1 is_VBZ not_XX obviously_RR satisfactory_JJ ,_, for_REX21 example_REX22 violin_NN1 playing_VVG would_VM seem_VVI to_TO be_VBI posturally_RR a_AT1 disaster_NN1 ,_, but_CCB there_EX may_VM be_VBI some_DD subtle_JJ aids_NN2 to_II very_RG precise_JJ control_NN1 of_IO the_AT sound_NN1 generated_VVN in_II having_VHG the_AT source_NN1 of_IO sound_NN1 very_RG close_JJ to_II the_AT ear_NN1 and_CC perhaps_RR some_DD vibration_NN1 transmission_NN1 by_II the_AT direct_JJ contact_NN1 of_IO this_DD1 instrument_NN1 and_CC the_AT jawbone_NN1 ._. 
Ergonomics_NN1 is_VBZ concerned_JJ with_IW the_AT transmission_NN1 of_IO information._NNU for_IF modest_JJ design_NN1 enterprises_NN2 information_NN1 exchange_NN1 is_VBZ needed_VVN between_II the_AT designer_NN1 and_CC the_AT potential_JJ user_NN1 ,_, between_II the_AT designer_NN1 and_CC the_AT producer_NN1 and_CC between_II the_AT designer/producer_NN1 and_CC the_AT customer/actual_FU user_NN1 (_( Fig._NN1 1.6_MC )_) ._. 
The_AT designer_NN1 needs_VVZ to_TO know_VVI about_II the_AT tasks_NN2 which_DDQ his_APPGE new_JJ device_NN1 is_VBZ intended_VVN to_TO aid_VVI and_CC also_RR about_II the_AT kind_NN1 of_IO person_NN1 who_PNQS will_VM use_VVI it_PPH1 ._. 
Clearly_RR ,_, designing_VVG for_IF fit_JJ young_JJ men_NN2 in_II the_AT armed_JJ forces_NN2 has_VHZ different_JJ constraints_NN2 from_II designing_VVG for_IF middle-aged_JJ female_JJ workers_NN2 in_II manufacturing_NN1 ._. 
Some_DD of_IO the_AT required_JJ information_NN1 may_VM be_VBI susceptible_JJ to_II precise_JJ description_NN1 in_II numerical_JJ terms_NN2 such_II21 as_II22 body_NN1 size_NN1 and_CC strength_NN1 ,_, but_CCB most_DAT of_IO it_PPH1 will_VM be_VBI of_IO the_AT '_GE awareness_NN1 '_GE kind_NN1 when_CS the_AT designer_NN1 recognises_VVZ broadly_RR that_DD1 particular_JJ kinds_NN2 of_IO people_NN have_VH0 particular_JJ advantages_NN2 and_CC limitations_NN2 ._. 
Similarly_RR the_AT range_NN1 of_IO tasks_NN2 for_IF which_DDQ the_AT device_NN1 is_VBZ required_VVN may_VM not_XX be_VBI known_VVN in_II the_AT kind_NN1 of_IO detail_NN1 which_DDQ is_VBZ available_JJ from_II comprehensive_JJ task_NN1 descriptions_NN2 but_CCB the_AT designer_NN1 will_VM consider_VVI the_AT extremes_NN2 of_IO what_DDQ it_PPH1 is_VBZ likely_JJ to_TO be_VBI used_VVN for_IF and_CC the_AT environment_NN1 in_II which_DDQ it_PPH1 will_VM be_VBI used_VVN ,_, for_REX21 example_REX22 designing_VVG a_AT1 machine-tool_NN1 for_IF use_NN1 in_II a_AT1 factory_NN1 has_VHZ different_JJ requirements_NN2 from_II designing_VVG a_AT1 powered_JJ garden_NN1 tool_NN1 where_CS the_AT user_NN1 could_VM be_VBI wearing_VVG heavy_JJ gloves_NN2 ,_, will_VM not_XX be_VBI wearing_VVG safety-boots_NN2 and_CC will_VM not_XX receive_VVI any_DD formal_JJ training_NN1 ._. 
Communication_NN1 between_II the_AT designer_NN1 and_CC the_AT producer_NN1 used_VMK to_TO be_VBI done_VDN almost_RR entirely_RR by_II traditional_JJ engineering_NN1 drawings_NN2 but_CCB there_EX is_VBZ now_RT a_AT1 tendency_NN1 to_TO use_VVI sketches_NN2 ,_, schematic_JJ drawings_NN2 ,_, photographs_NN2 and_CC models_NN2 including_II computer-based_JJ models_NN2 ,_, for_REX21 example_REX22 complicated_JJ shapes_NN2 in_II three_MC dimensions_NN2 are_VBR difficult_JJ to_TO represent_VVI as_RG rectangular_JJ projections_NN2 and_CC are_VBR not_XX easily_RR interpreted_VVN ._. 
Communication_NN1 with_IW the_AT customer/user_NN1 takes_VVZ the_AT form_NN1 of_IO operating_NN1 instructions_NN2 which_DDQ are_VBR contained_VVN in_II an_AT1 instruction_NN1 book_NN1 ._. 
The_AT design_NN1 of_IO this_DD1 book_NN1 ,_, booklet_NN1 or_CC even_RR leaflet_NN1 is_VBZ a_AT1 much_RR neglected_JJ art_NN1 and_CC is_VBZ frequently_RR very_RG badly_RR executed_VVN hence_RR the_AT common_JJ attitude_NN1 reflected_VVN in_II the_AT aphorism_NN1 '_GE when_CS all_DB else_RR fails_VVZ try_NN1 reading_VVG the_AT instructions_NN2 '_GE ._. 
The_AT most_RGT common_JJ failings_NN2 are_VBR to_TO rely_VVI too_RG much_DA1 on_II words_NN2 rather_II21 than_II22 extensively_RR labelled_VVN diagrams_NN2 ,_, to_TO use_VVI technical_JJ terms_NN2 and_CC concepts_NN2 which_DDQ the_AT user_NN1 may_VM not_XX understand_VVI ,_, to_TO focus_VVI on_II what_DDQ it_PPH1 is_VBZ at_II the_AT expense_NN1 of_IO what_DDQ it_PPH1 does_VDZ and_CC to_TO fail_VVI to_TO separate_VVI the_AT needs_NN2 of_IO the_AT operator_NN1 from_II the_AT details_NN2 which_DDQ are_VBR needed_VVN to_TO set_VVI up_RP the_AT device_NN1 ,_, to_TO locate_VVI faults_NN2 ,_, to_TO provide_VVI remedies_NN2 and_CC to_TO provide_VVI routine_NN1 maintenance_NN1 ._. 
An_AT1 extended_JJ booklet_NN1 should_VM have_VHI a_AT1 very_RG good_JJ index_NN1 or_CC other_JJ access_NN1 system_NN1 to_II the_AT information_NN1 ._. 
The_AT designer_NN1 is_VBZ not_XX the_AT person_NN1 to_TO evaluate_VVI the_AT clarity_NN1 and_CC usability_NN1 of_IO instructions_NN2 ,_, a_AT1 sample_NN1 of_IO actual_JJ users_NN2 will_VM provide_VVI a_AT1 much_RR better_JJR assessment._NNU further_JJR details_NN2 are_VBR given_VVN on_II p._NNU 76_MC ._. 
The_AT design_NN1 of_IO macro-systems_NN2 The_AT larger_JJR systems_NN2 which_DDQ make_VV0 up_RP communities_NN2 and_CC nations_NN2 are_VBR currently_RR in_II a_AT1 state_NN1 of_IO flux_NN1 because_II21 of_II22 the_AT impact_NN1 of_IO technology_NN1 ._. 
The_AT provision_NN1 of_IO such_DA a_AT1 variety_NN1 of_IO telecommunication_NN1 and_CC travel_VV0 facilities_NN2 makes_VVZ it_PPH1 impossible_JJ for_IF any_DD community_NN1 however_RGQV large_JJ or_CC small_JJ to_TO develop_VVI in_II isolation_NN1 ._. 
The_AT consequence_NN1 is_VBZ an_AT1 increasingly_RR standardised_JJ way_NN1 of_IO life_NN1 or_CC at_RR21 least_RR22 aspirations_NN2 towards_II a_AT1 particular_JJ way_NN1 of_IO life_NN1 across_II the_AT world_NN1 ._. 
The_AT differences_NN2 which_DDQ remain_VV0 are_VBR enforced_VVN mainly_RR by_II differences_NN2 in_II average_JJ income_NN1 and_CC in_II style_NN1 of_IO government_NN1 ._. 
Technology_NN1 continues_VVZ to_TO change_VVI jobs_NN2 with_IW consequent_JJ changes_NN2 in_II ways_NN2 of_IO life_NN1 and_CC it_PPH1 also_RR changes_VVZ life-expectation_NN1 which_DDQ has_VHZ profound_JJ effects_NN2 on_II all_DB communities_NN2 ._. 
However_RR ,_, just_RR as_CSA hardware_NN1 systems_NN2 are_VBR dominated_VVN by_II engineering_NN1 thinking_NN1 ,_, macro-systems_NN2 are_VBR dominated_VVN by_II economic_JJ thinking_NN1 ._. 
There_EX is_VBZ excessive_JJ reliance_NN1 on_II the_AT adaptability_NN1 of_IO people_NN who_PNQS are_VBR required_VVN to_TO adjust_VVI to_II whatever_DDQV is_VBZ dictated_VVN by_II economic_JJ and_CC technological_JJ policies_NN2 ._. 
Politicians_NN2 in_II all_DB countries_NN2 would_VM accept_VVI the_AT proposition_NN1 that_CST the_AT system_NN1 should_VM be_VBI designed_VVN to_TO serve_VVI the_AT people_NN but_CCB whatever_DDQV the_AT political_JJ philosophy_NN1 behind_II the_AT system_NN1 ,_, the_AT people_NN always_RR seem_VV0 to_TO be_VBI more_RRR its_APPGE servants_NN2 than_CSN its_APPGE masters_NN2 ._. 
Economic_JJ issues_NN2 are_VBR real_RG enough_RR and_CC it_PPH1 is_VBZ often_RR pointed_VVN out_RP that_DD1 politics_NN1 is_VBZ about_II priorities_NN2 ._. 
The_AT priorities_NN2 are_VBR assessed_VVN on_II the_AT basis_NN1 of_IO evidence_NN1 and_CC unfortunately_RR evidence_NN1 about_II people_NN is_VBZ not_XX so_RG readily_RR quantified_VVN as_CSA evidence_NN1 about_II financial_JJ and_CC physical_JJ resources_NN2 ._. 
The_AT result_NN1 is_VBZ that_CST systems_NN2 at_II every_AT1 level_NN1 from_II the_AT state_NN1 to_II the_AT small_JJ company_NN1 are_VBR evaluated_VVN and_CC policies_NN2 are_VBR developed_VVN which_DDQ are_VBR not_XX sufficiently_RR orientated_VVN to_II the_AT needs_NN2 and_CC aspirations_NN2 of_IO the_AT people_NN within_II the_AT system_NN1 ._. 
This_DD1 is_VBZ a_AT1 very_RG large_JJ issue_NN1 mostly_RR beyond_II the_AT scope_NN1 of_IO this_DD1 book_NN1 except_CS to_TO note_VVI that_DD1 ergonomics_NN1 is_VBZ an_AT1 exemplar_JJ of_IO a_AT1 style_NN1 of_IO thinking_VVG which_DDQ is_VBZ based_VVN on_II characteristics_NN2 of_IO people_NN ._. 
Ergonomics_NN1 can_VM be_VBI defined_VVN as_CSA systems_NN2 design_VV0 with_IW the_AT attributes_NN2 of_IO people_NN as_II the_AT frame_NN1 of_IO reference_NN1 ._. 
Although_CS the_AT human_JJ operator_NN1 is_VBZ for_IF many_DA2 purposes_NN2 within_II ergonomics_NN1 appropriately_RR considered_VVN as_II a_AT1 mere_JJ information_NN1 processing_NN1 device_NN1 ,_, any_DD design_NN1 issue_NN1 must_VM be_VBI considered_VVN in_II the_AT context_NN1 that_CST these_DD2 human_JJ operators_NN2 are_VBR individuals_NN2 and_CC citizens_NN2 within_II communities_NN2 ._. 
What_DDQ they_PPHS2 believe_VV0 ,_, what_DDQ they_PPHS2 want_VV0 ,_, what_DDQ they_PPHS2 like_VV0 ,_, what_DDQ they_PPHS2 dislike_VV0 and_CC whether_CSW they_PPHS2 work_VV0 efficiently_RR or_CC not_XX are_VBR determined_VVN by_II the_AT societal_JJ context_NN1 as_II31 well_II32 as_II33 by_II the_AT physical_JJ environment_NN1 ._. 
It_PPH1 is_VBZ therefore_RR appropriate_JJ to_TO bear_VVI in_II mind_NN1 the_AT position_NN1 and_CC trends_NN2 in_II human_JJ resources_NN2 in_II the_AT community_NN1 of_IO which_DDQ the_AT workers_NN2 are_VBR members_NN2 ._. 
For_IF such_DA macro-systems_NN2 ,_, the_AT principle_NN1 that_CST the_AT designer_NN1 produces_VVZ what_DDQ he_PPHS1 thinks_VVZ the_AT users_NN2 need_VV0 is_VBZ being_VBG replaced_VVN by_II the_AT principle_NN1 that_CST the_AT users_NN2 themselves_PPX2 decide_VV0 what_DDQ they_PPHS2 want_VV0 and_CC the_AT professionals_NN2 assist_VV0 them_PPHO2 in_II designing_VVG as_CSA specified_VVN by_II the_AT users_NN2 ._. 
This_DD1 approach_NN1 generates_VVZ another_DD1 duty_NN1 for_IF designers_NN2 and_CC ergonomists_NN2 ,_, to_TO present_VVI to_II the_AT users_NN2 an_AT1 array_NN1 of_IO possible_JJ options_NN2 which_DDQ will_VM aid_VVI their_APPGE discussions_NN2 and_CC choices_NN2 ._. 
Knowledge_NN1 Demographic_JJ data_NN Currently_RR there_EX are_VBR about_RG 4.5_MC billion_NNO people_NN in_II the_AT world_NN1 ,_, 1_MC1 billion_NNO in_II the_AT developed_JJ world_NN1 and_CC 3.5_MC billion_NNO in_II the_AT developing_JJ world_NN1 (_( Table_NN1 1.2_MC )_) ._. 
This_DD1 puts_VVZ a_AT1 correct_JJ perspective_NN1 on_II the_AT contents_NN2 of_IO this_DD1 book_NN1 which_DDQ are_VBR mainly_RR concerned_JJ with_IW technologically-based_JJ societies_NN2 although_CS there_EX is_VBZ a_AT1 section_NN1 in_II Chapter_NN1 3_MC on_II ergonomics_NN1 in_II developing_JJ countries_NN2 ._. 
Most_DAT of_IO the_AT evidence_NN1 and_CC experience_NN1 reported_VVD here_RL has_VHZ been_VBN derived_VVN from_II the_AT 16%_NNU of_IO the_AT world_NN1 population_NN1 living_VVG in_II Europe_NP1 and_CC North_ND1 America_NP1 ._. 
The_AT two_MC worlds_NN2 differ_VV0 markedly_RR in_II the_AT distribution_NN1 of_IO populations_NN2 ,_, developed_JJ countries_NN2 have_VH0 about_RG 65%_NNU of_IO the_AT population_NN1 in_II the_AT economically_RR active_JJ age_NN1 range_NN1 from_II 1564_MC years_NNT2 ,_, about_RG 25%_NNU under_RG 15_MC and_CC the_AT remaining_JJ 10%_NNU in_II retirement_NN1 ._. 
This_DD1 last_MD group_NN1 is_VBZ still_RR increasing_VVG quite_RG rapidly_RR ._. 
The_AT retired_JJ group_NN1 is_VBZ much_RR smaller_JJR in_II developing_JJ countries_NN2 where_CS about_RG 55%_NNU are_VBR in_II the_AT economically_RR active_JJ age_NN1 range_NN1 and_CC more_DAR than_CSN 40%_NNU are_VBR under_RG 15_MC ._. 
Life_NN1 expectation_NN1 at_II birth_NN1 is_VBZ about_RG 45_MC years_NNT2 in_II developing_JJ countries_NN2 and_CC more_DAR than_CSN 70_MC years_NNT2 in_II developed_JJ countries_NN2 ._. 
The_AT longer_JJR life_NN1 expectation_NN1 of_IO females_NN2 is_VBZ more_RGR marked_JJ in_II the_AT developed_JJ countries_NN2 (_( Table_NN1 1.3_MC )_) ._. 
The_AT age_NN1 distribution_NN1 of_IO the_AT working_JJ population_NN1 for_IF two_MC countries_NN2 ,_, one_MC1 developed_VVN and_CC one_PN1 developing_VVG ,_, which_DDQ happen_VV0 to_TO have_VHI the_AT same_DA sized_JJ labour_NN1 force_NN1 is_VBZ shown_VVN in_II fig._NN1 1.7_MC ._. 
West_NP1 Germany_NP1 has_VHZ a_AT1 greater_JJR proportion_NN1 of_IO people_NN economically_RR active_JJ but_CCB they_PPHS2 start_VV0 work_VV0 later_RRR and_CC retire_VV0 earlier_RRR than_CSN do_VD0 workers_NN2 in_II Pakistan_NP1 ._. 
There_EX are_VBR about_RG 4_MC million_NNO research_NN1 and_CC development_NN1 scientists_NN2 and_CC engineers_NN2 in_II the_AT world_NN1 ,_, 3.5_MC million_NNO in_II developed_JJ countries_NN2 and_CC 0.5_MC million_NNO in_II developing_JJ countries_NN2 ,_, almost_RR all_DB this_DD1 latter_DA 0.5_MC million_NNO are_VBR in_II Asia_NP1 ,_, the_AT numbers_NN2 in_II Latin_JJ America_NP1 and_CC Africa_NP1 are_VBR very_RG small_JJ (_( UNESCO_NP1 statistical_JJ year_NNT1 book_NN1 )_) ._. 
The_AT differences_NN2 in_II various_JJ amenities_NN2 are_VBR shown_VVN in_II Table_NN1 1.4_MC ._. 
The_AT energy_NN1 consumption_NN1 is_VBZ about_RG 100_MC units_NN2 (_( kg_NNU of_IO coal_NN1 equivalent_NN1 per_II person_NN1 )_) in_II a_AT1 developing_JJ country_NN1 and_CC about_RG 10000_MC units_NN2 in_II Europe_NP1 and_CC the_AT U.S.A._NP1 This_DD1 is_VBZ affected_VVN by_II the_AT fact_NN1 that_CST developing_JJ countries_NN2 mostly_RR have_VH0 tropical_JJ or_CC subtropical_JJ climates_NN2 while_CS developed_JJ countries_NN2 are_VBR in_II the_AT temperate_JJ zone_NN1 ,_, but_CCB there_EX is_VBZ a_AT1 similar_JJ difference_NN1 of_IO about_RG 100_MC :_: 1_MC1 in_II income_NN1 per_II head_NN1 between_II the_AT rich_JJ countries_NN2 and_CC the_AT poor_JJ countries_NN2 (_( The_AT Economist_NN1 the_AT world_NN1 in_II figures_NN2 )_) ._. 
Within_II any_DD country_NN1 the_AT Human_JJ Resource_NN1 situation_NN1 can_VM be_VBI approached_VVN by_II this_DD1 basic_JJ division_NN1 into_II the_AT '_GE economically_RR active_JJ '_GE and_CC others_NN2 who_PNQS ,_, for_IF one_MC1 reason_NN1 or_CC another_DD1 ,_, are_VBR supported_VVN by_II the_AT workers_NN2 ._. 
Those_DD2 supported_VVN include_VV0 young_JJ children_NN2 ,_, students_NN2 ,_, retired_JJ persons_NN2 ,_, seriously_RR disabled_JJ persons_NN2 ,_, people_NN living_VVG on_II independent_JJ means_NN and_CC ,_, somewhat_RR unfairly_RR ,_, women_NN2 doing_VDG domestic_JJ work_NN1 ._. 
The_AT numbers_NN2 and_CC proportions_NN2 of_IO those_DD2 economically_RR active_JJ in_II a_AT1 sample_NN1 of_IO developed_JJ countries_NN2 are_VBR shown_VVN in_II Table_NN1 1.5_MC ._. 
It_PPH1 will_VM be_VBI seen_VVN that_CST in_II each_DD1 country_NN1 this_DD1 economically_RR active_JJ group_NN1 is_VBZ about_RG half_DB the_AT total_JJ population._NNU for_IF males_NN2 the_AT proportion_NN1 is_VBZ usually_RR about_RG 55%_NNU and_CC for_IF females_NN2 about_RG 45%_NNU ._. 
A_AT1 very_RG large_JJ economy_NN1 such_II21 as_II22 the_AT U.S.A._NP1 has_VHZ more_DAR than_CSN 100_MC million_NNO workers_NN2 ,_, the_AT large_JJ European_JJ countries_NN2 have_VH0 about_RG 25_MC million_NNO workers_NN2 ._. 
Japan_NP1 is_VBZ about_RG half-way_RR between_RL with_IW about_RG 60_MC million_NNO workers_NN2 ._. 
The_AT smaller_JJR European_JJ countries_NN2 have_VH0 less_DAR than_CSN 5_MC million_NNO workers_NN2 ._. 
Workers_NN2 in_II this_DD1 sense_NN1 are_VBR a_AT1 country_NN1 's_GE Human_JJ Resource_NN1 which_DDQ is_VBZ deployed_VVN for_IF the_AT benefit_NN1 of_IO the_AT community_NN1 generally_RR ._. 
The_AT primary_JJ need_NN1 of_IO any_DD person_NN1 or_CC population_NN1 is_VBZ water_NN1 and_CC food_NN1 and_CC in_II primitive_JJ societies_NN2 the_AT supply_NN1 of_IO these_DD2 commodities_NN2 will_VM absorb_VVI the_AT effort_NN1 of_IO almost_RR all_DB the_AT workforce_NN1 ._. 
As_CSA food_NN1 supplies_NN2 improve_VV0 it_PPH1 is_VBZ possible_JJ to_TO move_VVI some_DD of_IO the_AT Human_JJ Resource_NN1 into_II construction_NN1 and_CC manufacturing_NN1 ._. 
In_II the_AT U.K._NP1 the_AT concentration_NN1 on_II manufacturing_NN1 in_II the_AT nineteenth_MD century_NNT1 was_VBDZ balanced_VVN by_II the_AT importing_NN1 of_IO food_NN1 ._. 
France_NP1 ,_, by_II contrast_NN1 ,_, had_VHD a_AT1 smaller_JJR manufacturing_NN1 base_NN1 but_CCB remained_VVD self-sufficient_JJ in_II food_NN1 so_CS21 that_CS22 the_AT dramatic_JJ fall_NN1 of_IO proportion_NN1 of_IO workers_NN2 in_II primary_JJ industries_NN2 did_VDD not_XX occur_VVI until_CS after_II World_NN1 War_NN1 II_MC (_( fig._NN1 1.8_MC )_) ._. 
In_II the_AT U.S.A._NP1 even_RR at_II the_AT time_NNT1 of_IO President_NNB Lincoln_NP1 about_RG 1860_MC there_EX was_VBDZ serious_JJ debate_NN1 as_II21 to_II22 whether_CSW the_AT economy_NN1 should_VM remain_VVI agricultural_JJ or_CC whether_CSW there_EX should_VM be_VBI a_AT1 positive_JJ attempt_NN1 to_TO develop_VVI manufacturing_NN1 ._. 
In_II India_NP1 the_AT total_JJ population_NN1 is_VBZ currently_RR about_RG 665_MC million_NNO of_IO which_DDQ 244_MC million_NNO (_( 37%_NNU )_) are_VBR economically_RR active._NNU 153_MC million_NNO are_VBR engaged_VVN in_II agriculture_NN1 and_CC fishing_NN1 ,_, that_DD1 is_VBZ 63%_NNU of_IO the_AT working_JJ population_NN1 (_( I.L.O._NP1 data_NN )_) ._. 
In_II the_AT U.K._NP1 less_DAR than_CSN 3%_NNU of_IO the_AT working_JJ population_NN1 are_VBR now_RT employed_VVN in_II agriculture_NN1 ,_, in_II most_DAT advanced_JJ countries_NN2 this_DD1 figure_NN1 is_VBZ now_RT well_JJ below_RG 10%_NNU ,_, as_CSA illustrated_VVN in_II fig._NN1 1.9_MC ._. 
This_DD1 also_RR shows_VVZ that_CST the_AT predominant_JJ way_NN1 of_IO earning_VVG a_AT1 living_NN1 in_II a_AT1 developed_JJ country_NN1 now_RT is_VBZ in_II the_AT service_NN1 industries._NNU fig._NN1 1._MC 10_MC shows_VVZ the_AT current_JJ distribution_NN1 of_IO U.K._NP1 Human_JJ Resources_NN2 ._. 
The_AT former_DA basic_JJ industries_NN2 mining_VVG ,_, agriculture_NN1 ,_, construction_NN1 and_CC manufacturing_NN1 now_RT employ_VV0 about_RG a_AT1 third_MD of_IO the_AT total_JJ workforce_NN1 ._. 
In_II manufacturing_NN1 between_II 1980_MC and_CC 1985_MC output_NN1 measured_VVN per_II person-hour_NNT1 or_CC per_II person_NN1 employed_VVD increased_VVN by_RP about_II 25%_NNU but_CCB the_AT total_JJ output_NN1 remained_VVD roughly_RR constant_JJ ,_, that_DD1 is_VBZ the_AT manufacturing_NN1 labour_NN1 force_NN1 is_VBZ still_RR falling_VVG rapidly_RR (_( Economic_JJ Trends_NN2 1985_MC )_) ._. 
Some_DD consequences_NN2 of_IO these_DD2 trends_NN2 are_VBR discussed_VVN in_II more_DAR detail_NN1 in_II Singleton_NP1 and_CC Crawley_NP1 (_( 1980_MC )_) ._. 
p_ZZ1 24:DIAGRAM/FIGURE_VV0 p_ZZ1 26:DIAGRAM/FIGURE_VV0 From_II the_AT end_NN1 of_IO World_NN1 War_NN1 II_MC to_II the_AT early_JJ 1970s_MC2 there_EX was_VBDZ virtually_RR full_JJ employment_NN1 in_II developed_JJ countries_NN2 ,_, but_CCB in_II the_AT last_MD ten_MC years_NNT2 the_AT position_NN1 has_VHZ changed_VVN considerably_RR as_CSA shown_VVN in_II fig._NN1 1.11_MC ._. 
Apart_II21 from_II22 Ireland_NP1 it_PPH1 would_VM seem_VVI that_CST the_AT smaller_JJR European_JJ countries_NN2 have_VH0 contained_VVN the_AT situation_NN1 better_RRR than_CSN have_VH0 the_AT larger_JJR ones_NN2 ,_, but_CCB this_DD1 is_VBZ an_AT1 artefact_NN1 since_CS other_JJ small_JJ countries_NN2 such_II21 as_II22 Belgium_NP1 ,_, Netherlands_NP1 and_CC Denmark_NP1 follow_VV0 the_AT same_DA trend_NN1 as_CSA the_AT larger_JJR countries_NN2 ._. 
It_PPH1 should_VM be_VBI noted_VVN that_CST the_AT trend_NN1 of_IO an_AT1 increase_NN1 in_II unemployment_NN1 from_II about_RG 5%_NNU to_II about_RG 10%_NNU over_II ten_MC years_NNT2 is_VBZ sufficiently_RR general_JJ to_TO indicate_VVI that_CST it_PPH1 is_VBZ not_XX a_AT1 function_NN1 of_IO the_AT style_NN1 of_IO government_NN1 ._. 
These_DD2 data_NN for_IF countries_NN2 do_VD0 not_XX reveal_VVI considerable_JJ underlying_JJ differences_NN2 within_II countries_NN2 ._. 
In_II England_NP1 for_REX21 example_REX22 ,_, unemployment_NN1 in_II the_AT North_ND1 is_VBZ twice_RR that_CST in_II the_AT South-East_ND1 ,_, and_CC in_II most_DAT European_JJ countries_NN2 there_EX are_VBR lesser_JJ employment_NN1 opportunities_NN2 in_II rural_JJ areas_NN2 as_II31 opposed_II32 to_II33 urban_JJ areas_NN2 resulting_VVG in_II depopulation_NN1 of_IO the_AT countryside_NN1 and_CC an_AT1 increase_NN1 in_II the_AT size_NN1 of_IO cities_NN2 ._. 
This_DD1 trend_NN1 is_VBZ even_RR more_RRR marked_VVN in_II developing_JJ countries_NN2 ._. 
Human_JJ resource_NN1 utilisation_NN1 This_DD1 brief_JJ excursion_NN1 into_II the_AT complex_JJ field_NN1 of_IO labour_NN1 statistics_NN is_VBZ intended_VVN to_TO illustrate_VVI the_AT following_JJ points_NN2 which_DDQ are_VBR relevant_JJ to_II the_AT theory_NN1 and_CC practice_NN1 of_IO ergonomics._NNU 1_MC1 ._. 
Since_CS the_AT beginnings_NN2 of_IO technology_NN1 ,_, now_RT about_RG 200_MC years_NNT2 ago_RA in_II the_AT case_NN1 of_IO the_AT U.K._NP1 ,_, the_AT labour_NN1 market_NN1 has_VHZ been_VBN in_II a_AT1 continuous_JJ state_NN1 of_IO flux._NNU 2_MC ._. 
The_AT overall_JJ shift_NN1 has_VHZ not_XX been_VBN so_RG much_DA1 from_II agriculture_NN1 to_II manufacturing_NN1 but_CCB rather_RG a_AT1 steady_JJ rise_NN1 in_II the_AT service_NN1 industries_NN2 ,_, and_CC a_AT1 fall_NN1 in_II primary_JJ industries._NNU 3_MC ._. 
The_AT manufacturing_NN1 labour_NN1 force_NN1 in_II developed_JJ countries_NN2 is_VBZ now_RT in_II accelerating_JJ decline_NN1 as_CSA productivity_NN1 and_CC the_AT investment_NN1 per_II worker_NN1 increases_NN2 ,_, this_DD1 is_VBZ resulting_VVG in_II a_AT1 further_JJR increase_NN1 in_II service_NN1 industries_NN2 and_CC an_AT1 increase_NN1 in_II unemployment._NNU 4_MC ._. 
There_EX are_VBR considerable_JJ differences_NN2 between_II the_AT problems_NN2 of_IO so-called_JJ developed_JJ and_CC developing_JJ countries_NN2 ._. 
This_DD1 dichotomy_NN1 is_VBZ useful_JJ but_CCB is_VBZ an_AT1 oversimplification_NN1 ;_; degree_NN1 of_IO development_NN1 as_CSA measured_VVN for_REX21 example_REX22 by_II income_NN1 per_II head_NN1 or_CC technology_NN1 utilisation_NN1 is_VBZ best_RRT described_VVN by_II a_AT1 continuous_JJ scale_NN1 ._. 
A_AT1 particular_JJ country_NN1 is_VBZ at_II one_MC1 point_NN1 on_II that_DD1 scale_NN1 at_II one_MC1 time_NNT1 by_II one_MC1 measure._NNU 5_MC ._. 
Accelerating_JJ technological_JJ development_NN1 has_VHZ pushed_VVN the_AT government_NN1 of_IO every_AT1 country_NN1 off-balance_JJ in_II the_AT past_JJ decade_NNT1 ._. 
This_DD1 is_VBZ illustrated_VVN in_II developed_JJ countries_NN2 by_II the_AT increase_NN1 in_II unemployment_NN1 which_DDQ is_VBZ fundamentally_RR a_AT1 failure_NN1 to_TO properly_RR utilise_VVI the_AT total_JJ Human_JJ Resource_NN1 ._. 
In_II developing_JJ countries_NN2 there_EX are_VBR many_DA2 contrasts_NN2 in_II that_DD1 high_JJ technology_NN1 (_( airlines_NN2 ,_, nuclear_JJ power_NN1 ,_, information_NN1 systems_NN2 ;_; etc._RA )_) exists_VVZ in_II small_JJ pockets_NN2 alongside_II the_AT still_JJ unresolved_JJ traditional_JJ problems_NN2 of_IO inadequate_JJ nutrition_NN1 and_CC health._NNU 6_MC ._. 
Ergonomics_NN1 also_RR is_VBZ pushed_VVN off-balance_JJ because_CS the_AT variety_NN1 of_IO human_JJ work_NN1 increases_VVZ in_II parallel_NN1 with_IW technology_NN1 ._. 
The_AT traditional_JJ problems_NN2 of_IO heat_NN1 stress_NN1 and_CC physical_JJ work-load_NN1 remain_VV0 ,_, particularly_RR in_II the_AT developing_JJ countries_NN2 ,_, while_CS new_JJ problems_NN2 appear_VV0 as_RG more_RGR complex_JJ systems_NN2 are_VBR designed_VVN requiring_VVG new_JJ operator_NN1 roles_NN2 and_CC more_RGR serious_JJ consequences_NN2 of_IO inadequate_JJ performance._NNU 7_MC ._. 
Nevertheless_RR technology_NN1 now_RT provides_VVZ the_AT possibility_NN1 of_IO allocating_VVG high_JJ energy_NN1 and_CC repetitive_JJ work_NN1 to_II machines_NN2 so_CS21 that_CS22 the_AT typical_JJ man_NN1 at_II work_NN1 is_VBZ in_II a_AT1 supervising_NN1 rather_II21 than_II22 an_AT1 operating_NN1 mode._NNU 8_MC ._. 
When_RRQ machines_NN2 provide_VV0 the_AT energy_NN1 and_CC set_VV0 the_AT pace_NN1 the_AT objective_NN1 of_IO the_AT operator_NN1 (_( and_CC consequently_RR of_IO ergonomics_NN1 )_) shifts_VVZ from_II rates_NN2 and_CC amounts_VVZ to_II quality_NN1 ,_, reliability_NN1 and_CC safety._NNU 9_MC ._. 
The_AT general_JJ concept_NN1 of_IO work_NN1 is_VBZ also_RR shifting_VVG from_II man-machine_JJ interaction_NN1 to_II man-man_JJ interaction_NN1 with_IW machines_NN2 as_CSA aids._NNU 10_MC ._. 
Many_DA2 of_IO the_AT policy_NN1 issues_NN2 are_VBR mistakenly_RR addressed_VVN in_II that_DD1 there_EX is_VBZ too_RG much_DA1 emphasis_NN1 on_II finding_VVG uses_NN2 for_IF what_DDQ technology_NN1 can_VM provide_VVI rather_II21 than_II22 driving_JJ technology_NN1 by_II the_AT needs_NN2 of_IO people_NN ._. 
The_AT behavioural_JJ specialists_NN2 are_VBR responsible_JJ for_IF providing_VVG data_NN and_CC attitudes_NN2 for_IF the_AT policy-makers_NN2 which_DDQ should_VM redress_VVI the_AT balance._NNU 11_MC ._. 
The_AT economic_JJ concept_NN1 of_IO work_NN1 is_VBZ too_RG narrow_JJ for_IF ergonomics_NN1 ._. 
There_EX are_VBR many_DA2 ergonomics_NN1 problems_NN2 in_II the_AT non-economically_RR active_JJ half_NN1 of_IO the_AT population_NN1 ._. 
If_CS ergonomics_NN1 is_VBZ regarded_VVN as_II the_AT science_NN1 of_IO work_NN1 then_RT work_VV0 must_VM be_VBI defined_VVN as_CSA purposeful_JJ activity_NN1 rather_II21 than_II22 merely_RR as_CSA activity_NN1 for_IF economic_JJ gain._NNU 12_MC ._. 
This_DD1 brief_JJ statistical_JJ survey_NN1 reveals_VVZ the_AT scale_NN1 and_CC diversity_NN1 of_IO problems_NN2 associated_VVN with_IW the_AT mind_NN1 at_II work_NN1 ._. 
This_DD1 is_VBZ daunting_JJ but_CCB it_PPH1 is_VBZ also_RR challenging_JJ and_CC stimulating_JJ ._. 
Principles_NN2 ,_, methods_NN2 and_CC procedures_NN2 Education_NN1 ,_, work_NN1 and_CC leisure_NN1 Virtually_RR all_DB human_JJ societies_NN2 have_VH0 developed_VVN the_AT principle_NN1 that_CST the_AT pattern_NN1 of_IO personal_JJ activity_NN1 should_VM change_VVI with_IW age_NN1 ._. 
In_II the_AT early_JJ years_NNT2 there_EX is_VBZ extensive_JJ leisure_NN1 devoted_VVD to_TO play_VVI in_II which_DDQ the_AT basic_JJ manipulative_JJ and_CC social_JJ skills_NN2 are_VBR developed_VVN ._. 
There_EX is_VBZ also_RR more_RGR formalised_JJ learning_NN1 through_II an_AT1 educational_JJ system_NN1 which_DDQ concentrates_VVZ mainly_RR on_II information_NN1 processing_NN1 :_: reading_NN1 ,_, writing_VVG and_CC arithmetic_NN1 and_CC more_RGR elaborate_JJ symbolic_JJ and_CC organisational_JJ skills_NN2 ._. 
When_CS the_AT individual_NN1 has_VHZ matured_VVN he_PPHS1 usually_RR accepts_VVZ responsibilities_NN2 for_IF child-rearing_NN1 and_CC for_IF work_NN1 ._. 
In_II his_APPGE declining_JJ years_NNT2 the_AT proportion_NN1 of_IO leisure_NN1 increases_VVZ again_RT ,_, sometimes_RT suddenly_RR when_CS he_PPHS1 '_" retires_58 '_GE but_CCB preferably_RR gradually_RR as_CSA his_APPGE energies_NN2 diminish_VV0 ._. 
Thus_RR we_PPIS2 can_VM normally_RR expect_VVI a_AT1 mature_JJ mind_NN1 in_II a_AT1 person_NN1 at_II work_NN1 and_CC although_CS developmental_JJ processes_NN2 of_IO growth_NN1 and_CC senescence_NN1 are_VBR of_IO some_DD interest_NN1 ,_, studies_NN2 of_IO the_AT person_NN1 working_VVG usually_RR assume_VV0 that_CST we_PPIS2 are_VBR dealing_VVG with_IW a_AT1 mind_NN1 which_DDQ is_VBZ equipped_VVN with_IW the_AT basic_JJ skills_NN2 derived_VVN from_II play_NN1 and_CC education_NN1 but_CCB one_PN1 which_DDQ has_VHZ not_XX been_VBN subject_II21 to_II22 any_DD serious_JJ diminution_NN1 of_IO capacity_NN1 ._. 
This_DD1 is_VBZ not_XX to_TO suggest_VVI that_CST the_AT age_NN1 variable_NN1 can_VM be_VBI ignored_VVN ._. 
It_PPH1 is_VBZ accepted_VVN that_CST ageing_JJ is_VBZ a_AT1 continuous_JJ process_NN1 from_II birth_NN1 to_II death_NN1 and_CC there_EX are_VBR considerable_JJ differences_NN2 between_II the_AT average_JJ worker_NN1 in_II the_AT 2545_MC age_NN1 group_NN1 and_CC the_AT apparent_JJ equivalent_NN1 in_II the_AT 4665_MC age_NN1 group_NN1 ._. 
The_AT age_NN1 distribution_NN1 of_IO a_AT1 particular_JJ workforce_NN1 can_VM materially_RR affect_VVI the_AT problems_NN2 of_IO work_NN1 design_NN1 and_CC training_NN1 ._. 
Correspondingly_RR it_PPH1 must_VM be_VBI recognised_VVN that_CST an_AT1 individual_NN1 has_VHZ entered_VVN work_NN1 with_IW a_AT1 particular_JJ educational_JJ standard_NN1 ._. 
During_II his_APPGE working_JJ years_NNT2 he_PPHS1 has_VHZ considerable_JJ leisure_NN1 which_DDQ is_VBZ bound_VVNK to_TO have_VHI some_DD interactions_NN2 with_IW work._NNU for_IF approximate_JJ computational_JJ purposes_NN2 it_PPH1 is_VBZ normally_RR assumed_VVN in_II the_AT western_JJ world_NN1 that_CST a_AT1 full_JJ working_JJ year_NNT1 is_VBZ no_AT more_DAR than_CSN 200_MC man-days_NNT2 ._. 
The_AT remaining_JJ 165_MC days_NNT2 disappear_VV0 in_II week-ends_NNT2 ,_, holidays_NN2 and_CC absence_NN1 for_IF training_NN1 ,_, sickness_NN1 and_RR31 so_RR32 on_RR33 ._. 
There_EX is_VBZ also_RR a_AT1 widespread_JJ convention_NN1 that_CST the_AT working_JJ day_NNT1 should_VM be_VBI 78_MC hours_NNT2 ,_, that_DD1 is_VBZ about_RG a_AT1 third_MD of_IO the_AT total_JJ day_NNT1 ._. 
Thus_RR the_AT full-time_JJ worker_NN1 is_VBZ in_II fact_NN1 working_VVG for_IF less_DAR than_CSN 200%_NNU of_IO the_AT total_JJ time_NNT1 ._. 
The_AT distinction_NN1 between_II work_NN1 and_CC leisure_NN1 and_CC between_II work_NN1 and_CC education_NN1 is_VBZ an_AT1 arbitrary_JJ one_PN1 from_II the_AT point_NN1 of_IO view_NN1 of_IO stress_NN1 on_II the_AT person._NNU for_REX21 example_REX22 ,_, many_DA2 city_NN1 office_NN1 workers_NN2 regard_VV0 the_AT main_JJ stress_NN1 of_IO the_AT day_NNT1 as_II the_AT difficulties_NN2 in_II getting_VVG from_II home_NN1 to_II work_NN1 and_CC back_RP again_RT with_IW work_NN1 as_II a_AT1 relatively_RR relaxed_JJ period_NN1 between_II ._. 
Even_RR more_RGR strikingly_RR ,_, some_DD working_JJ mothers_NN2 regard_VV0 a_AT1 period_NN1 at_II work_NN1 ,_, particularly_RR if_CS it_PPH1 is_VBZ part-time_JJ ,_, as_CSA a_AT1 welcome_JJ respite_NN1 from_II the_AT great_JJ variety_NN1 of_IO stresses_NN2 arising_VVG in_II looking_VVG after_II a_AT1 home_NN1 and_CC children_NN2 ._. 
Some_DD of_IO the_AT most_RGT exacting_JJ university_NN1 degrees_NN2 ,_, such_II21 as_II22 those_DD2 in_II the_AT biological_JJ and_CC physical_JJ sciences_NN2 demand_VV0 a_AT1 level_NN1 of_IO work_NN1 load_NN1 from_II the_AT conscientious_JJ student_NN1 which_DDQ is_VBZ greater_JJR than_CSN that_DD1 expected_VVD in_II most_DAT occupations_NN2 ._. 
One_PN1 would_VM expect_VVI self-selected_JJ leisure_NN1 activities_NN2 to_TO be_VBI different_JJ from_II and_CC complementary_JJ to_II those_DD2 at_II work._NNU for_REX21 example_REX22 ,_, the_AT manual_JJ labourer_NN1 is_VBZ unlikely_JJ to_TO take_VVI up_RP an_AT1 energetic_JJ hobby_NN1 such_II21 as_II22 cycling_NN1 and_CC he_PPHS1 is_VBZ likely_JJ to_TO spend_VVI his_APPGE holidays_NN2 relaxing_VVG at_II the_AT seaside_NN1 rather_II21 than_II22 walking_VVG in_II the_AT mountains_NN2 ._. 
The_AT young_JJ office_NN1 worker_NN1 in_II a_AT1 safe_JJ sedentary_JJ job_NN1 may_VM well_RR take_VVI up_RP rock-climbing_VVG as_II a_AT1 dangerous_JJ ,_, physically_RR exacting_JJ antidote_NN1 for_IF the_AT dull_JJ occupational_JJ part_NN1 of_IO his_APPGE life_NN1 ._. 
Although_CS it_PPH1 would_VM be_VBI convenient_JJ scientifically_RR and_CC sometimes_RT personally_RR to_TO regard_VVI work_NN1 as_II a_AT1 separable_JJ part_NN1 of_IO a_AT1 human_JJ life_NN1 this_DD1 separation_NN1 is_VBZ never_RR entirely_RR valid_JJ and_CC can_VM be_VBI misleading_JJ ._. 
The_AT mind_NN1 at_II work_NN1 is_VBZ part_NN1 of_IO the_AT person_NN1 at_II work_NN1 and_CC that_DD1 same_DA person_NN1 has_VHZ many_DA2 other_JJ activities_NN2 in_II the_AT past_NN1 and_CC the_AT future_NN1 and_CC in_II parallel_NN1 which_DDQ have_VH0 their_APPGE interactions_NN2 with_IW the_AT work_NN1 ._. 
In_II system_NN1 jargon_NN1 ,_, the_AT working_JJ world_NN1 is_VBZ one_MC1 sub-system_NN1 within_II a_AT1 complete_JJ set_NN1 of_IO sub-systems_NN2 which_DDQ make_VV0 up_RP the_AT total_JJ environment_NN1 or_CC life_NN1 space_NN1 of_IO the_AT individual_NN1 ._. 
To_TO study_VVI one_MC1 sub-system_NN1 in_II detail_NN1 without_IW regard_NN1 to_II interactions_NN2 with_IW the_AT others_NN2 is_VBZ usually_RR inadequate_JJ ,_, but_CCB on_II the_AT other_JJ hand_NN1 ,_, to_TO try_VVI to_TO examine_VVI simultaneously_RR the_AT whole_JJ complex_NN1 of_IO sub-systems_NN2 is_VBZ to_TO invite_VVI disorientation_NN1 ._. 
The_AT remedy_NN1 is_VBZ a_AT1 compromise_NN1 in_II which_DDQ activity_NN1 in_II one_MC1 sub-system_NN1 such_II21 as_II22 that_DD1 which_DDQ incorporates_VVZ work_NN1 is_VBZ studied_VVN but_CCB in_II the_AT context_NN1 of_IO sensitivity_NN1 to_II external_JJ influences_NN2 ._. 
Systems_NN2 theory_NN1 can_VM be_VBI applied_VVN in_II many_DA2 ways_NN2 to_II behaviour_NN1 at_II work_NN1 ._. 
The_AT two_MC main_JJ theories_NN2 emphasise_VV0 respectively_RR interactions_NN2 with_IW other_JJ people_NN ;_; sociotechnical_JJ systems_NN2 and_CC interactions_NN2 with_IW machines_NN2 ;_; man-machine_JJ systems_NN2 ._. 
Socio-technical_JJ systems_NN2 In_II the_AT period_NN1 of_IO technological_JJ innovation_NN1 following_VVG the_AT second_MD world_NN1 war_NN1 a_AT1 group_NN1 of_IO human_JJ relations_NN2 specialists_NN2 ,_, working_VVG from_II the_AT Tavistock_NP1 Institute_NN1 in_II London_NP1 ,_, noted_VVD that_CST the_AT social_JJ behaviour_NN1 of_IO workers_NN2 and_CC their_APPGE organisational_JJ structure_NN1 in_II groups_NN2 and_CC teams_NN2 was_VBDZ influenced_VVN by_II the_AT technical_JJ systems_NN2 associated_VVN with_IW that_DD1 work_NN1 ._. 
The_AT first_MD studies_NN2 were_VBDR in_II coal_NN1 mines_NN2 where_CS there_EX were_VBDR different_JJ degrees_NN2 of_IO mechanisation_NN1 associated_VVN with_IW the_AT same_DA type_NN1 of_IO working_JJ group_NN1 and_CC it_PPH1 was_VBDZ also_RR possible_JJ to_TO distinguish_VVI different_JJ social_JJ organisations_NN2 working_VVG in_II similar_JJ technical_JJ environments_NN2 (_( Trist_NN1 and_CC Murray_NP1 ,_, 1948_MC )_) ._. 
Some_DD groups_NN2 were_VBDR organised_VVN so_CS21 that_CS22 each_DD1 worker_NN1 carried_VVD out_RP an_AT1 independent_JJ part-task_NN1 with_IW little_DA1 reference_NN1 to_II the_AT total_JJ task_NN1 ,_, whereas_CS in_II other_JJ cases_NN2 each_DD1 worker_NN1 had_VHD a_AT1 commitment_NN1 to_II the_AT total_JJ task_NN1 and_CC carried_VVD out_RP various_JJ sub-tasks_NN2 in_II this_DD1 context_NN1 ._. 
This_DD1 latter_DA ,_, labelled_VVN a_AT1 '_GE composite_NN1 '_GE group_NN1 as_CSA distinct_JJ from_II a_AT1 conventional_JJ group_NN1 ,_, had_VHD greater_JJR productive_JJ achievement_NN1 and_CC lower_JJR absenteeism_NN1 ._. 
More_RGR generally_RR ,_, the_AT effectiveness_NN1 of_IO the_AT production_NN1 system_NN1 depends_VVZ on_II the_AT way_NN1 the_AT social_JJ system_NN1 is_VBZ adjusted_VVN to_II the_AT technical_JJ requirements_NN2 (_( Emery_NN1 and_CC Trist_NN1 ,_, 1960_MC )_) ._. 
Technological_JJ decisions_NN2 necessarily_RR dominate_VV0 the_AT design_NN1 of_IO the_AT system_NN1 in_II the_AT sense_NN1 of_IO how_RRQ the_AT collective_JJ task_NN1 of_IO transforming_VVG inputs_NN2 into_II outputs_NN2 is_VBZ achieved_VVN ._. 
Nevertheless_RR ,_, the_AT social_JJ system_NN1 which_DDQ integrates_VVZ the_AT activities_NN2 of_IO the_AT workers_NN2 and_CC provides_VVZ the_AT flexibility_NN1 for_IF relating_VVG separate_JJ tasks_NN2 to_II the_AT needs_NN2 of_IO the_AT production_NN1 system_NN1 as_II a_AT1 whole_NN1 must_VM be_VBI considered_VVN ._. 
Hence_RR the_AT concept_NN1 of_IO the_AT socio-technical_JJ system_NN1 where_CS technical_JJ and_CC social_JJ requirements_NN2 are_VBR harmonised_VVN into_II one_MC1 effective_JJ organisation_NN1 ._. 
The_AT organisation_NN1 ,_, like_II a_AT1 living_JJ organism_NN1 ,_, maintains_VVZ a_AT1 dynamic_JJ equilibrium_NN1 with_IW the_AT environment_NN1 ._. 
Thus_RR it_PPH1 is_VBZ an_AT1 open_JJ system_NN1 rather_II21 than_II22 a_AT1 closed_JJ one_PN1 and_CC its_APPGE behaviour_NN1 can_VM not_XX be_VBI understood_VVN by_II simply_RR looking_VVG at_II the_AT relationship_NN1 between_II inputs_NN2 and_CC outputs_NN2 ._. 
The_AT adaptability_NN1 of_IO the_AT enterprise_NN1 may_VM lie_VVI in_II providing_VVG appropriate_JJ outputs_NN2 to_TO match_VVI the_AT changes_NN2 of_IO the_AT market_NN1 from_II relatively_RR stable_JJ physical_JJ inputs_NN2 or_CC may_VM lie_VVI in_II providing_VVG a_AT1 fixed_JJ output_NN1 with_IW changing_JJ sources_NN2 of_IO inputs_NN2 ._. 
In_II either_DD1 case_NN1 there_EX is_VBZ no_AT fixed_JJ relationship_NN1 between_II physical_JJ inputs_NN2 and_CC outputs_NN2 ,_, the_AT system_NN1 responds_VVZ to_II the_AT environment_NN1 ._. 
It_PPH1 follows_VVZ that_CST one_MC1 of_IO the_AT main_JJ tasks_NN2 of_IO management_NN1 is_VBZ to_TO control_VVI the_AT interaction_NN1 with_IW the_AT environment_NN1 ._. 
The_AT implication_NN1 also_RR is_VBZ that_CST ,_, if_CS management_NN1 has_VHZ got_VVN the_AT technology_NN1 right_NN1 within_II the_AT system_NN1 design_NN1 ,_, it_PPH1 should_VM then_RT attend_VVI to_II the_AT environment_NN1 and_CC should_VM allow_VVI ,_, within_II the_AT internal_JJ activities_NN2 ,_, scope_NN1 for_IF self-organising_JJ into_II autonomous_JJ groups_NN2 ._. 
If_CS ,_, on_II the_AT contrary_NN1 ,_, there_EX is_VBZ a_AT1 rigid_JJ internal_JJ separation_NN1 between_II the_AT roles_NN2 of_IO setting_VVG standards_NN2 and_CC meeting_VVG standards_NN2 then_RT conflict_NN1 has_VHZ been_VBN built_VVN into_II the_AT system_NN1 (_( Klein_NP1 ,_, 1979_MC )_) ._. 
This_DD1 approach_NN1 can_VM legitimately_RR be_VBI regarded_VVN as_II the_AT parent_NN1 of_IO organisation_NN1 theory_NN1 (_( p._NNU 143_MC )_) ,_, and_CC of_IO the_AT '_GE quality_NN1 of_IO working_NN1 life_NN1 '_GE (_( QWOL_NP1 )_) ,_, sometimes_RT also_RR called_VVN the_AT '_GE job_NN1 design_NN1 '_GE movement_NN1 (_( Davis_NP1 and_CC Cherns_VVZ 1975_MC ,_, Davis_NP1 and_CC Taylor_NP1 1972_MC )_) ._. 
It_PPH1 provides_VVZ considerable_JJ insight_NN1 into_II the_AT eventual_JJ difficulties_NN2 of_IO the_AT early_JJ twentieth_MD century_NNT1 mass_JJ production_NN1 methods_NN2 as_CSA exemplified_VVN by_II the_AT moving_JJ belt_NN1 type_NN1 assembly_NN1 line_NN1 ._. 
On_II the_AT other_JJ hand_NN1 it_PPH1 does_VDZ not_XX provide_VVI remedies_NN2 for_IF production_NN1 problems_NN2 which_DDQ can_VM be_VBI applied_VVN as_CSA standard_JJ recipes_NN2 or_CC procedures_NN2 ._. 
Again_RT ,_, because_II21 of_II22 the_AT elusive_JJ if_CS all-pervading_JJ nature_NN1 of_IO the_AT theme_NN1 ,_, it_PPH1 is_VBZ difficult_JJ to_TO formalise_VVI into_II legislation_NN1 on_II humanising_VVG work_NN1 as_CSA several_DA2 European_JJ countries_NN2 have_VH0 discovered_VVN by_II experience_NN1 ._. 
It_PPH1 has_VHZ emerged_VVN in_II many_DA2 countries_NN2 that_CST ,_, as_CSA the_AT standard_NN1 of_IO living_JJ rises_NN2 ,_, it_PPH1 is_VBZ more_RGR and_CC more_RGR difficult_JJ to_TO run_VVI an_AT1 autocratic_JJ production_NN1 system_NN1 using_VVG the_AT indigenous_JJ labour_NN1 force_NN1 ._. 
The_AT first_MD management_NN1 remedy_NN1 is_VBZ to_TO import_VVI a_AT1 more_RGR docile_JJ labour_NN1 force_NN1 from_II another_DD1 country_NN1 or_CC from_II a_AT1 less_RGR developed_JJ part_NN1 of_IO the_AT same_DA country_NN1 ._. 
This_DD1 is_VBZ only_RR a_AT1 temporary_JJ solution_NN1 and_CC there_EX have_VH0 been_VBN many_DA2 attempts_NN2 to_TO organise_VVI more_RGR humane_JJ working_JJ systems_NN2 ._. 
The_AT danger_NN1 here_RL is_VBZ that_CST ,_, although_CS things_NN2 may_VM be_VBI pleasant_JJ for_IF the_AT workers_NN2 ,_, the_AT incentive_NN1 to_TO work_VVI very_RG hard_RR is_VBZ not_XX so_RG direct_JJ and_CC it_PPH1 may_VM not_XX be_VBI possible_JJ to_TO maintain_VVI a_AT1 competitive_JJ position_NN1 in_II31 comparison_II32 with_II33 the_AT same_DA industry_NN1 in_II a_AT1 developing_JJ country_NN1 ._. 
Hence_RR a_AT1 further_JJR development_NN1 of_IO research_NN1 on_II work_NN1 motivation_NN1 (_( p._NNU 144_MC )_) ._. 
Taking_VVG a_AT1 more_RGR global_JJ view_NN1 ,_, one_MC1 opinion_NN1 is_VBZ that_CST the_AT manufacturing_NN1 industries_NN2 should_VM indeed_RR move_VVI to_II developing_JJ countries_NN2 whilst_CS the_AT advanced_JJ industries_NN2 orientate_VV0 their_APPGE labour_NN1 forces_NN2 toward_II information_NN1 and_CC other_JJ service_NN1 industries_NN2 ._. 
There_EX is_VBZ a_AT1 trend_NN1 in_II this_DD1 direction_NN1 (_( Singleton_NP1 and_CC Crawley_NP1 ,_, 1980_MC )_) ,_, but_CCB ,_, of_RR21 course_RR22 ,_, it_PPH1 is_VBZ not_XX the_AT complete_JJ answer_NN1 ._. 
There_EX are_VBR other_JJ complications_NN2 ._. 
Robots_NN2 ,_, for_REX21 example_REX22 ,_, are_VBR best_RRT suited_VVN for_IF the_AT highly_RR repetitive_JJ manufacturing_NN1 tasks_NN2 which_DDQ are_VBR the_AT ones_NN2 least_RRT suited_VVN to_II human_JJ efforts_NN2 so_CS21 that_CS22 robotisation_NN1 can_VM cure_VVI some_DD of_IO the_AT ills_NN2 of_IO mass_JJ production_NN1 ._. 
Looking_VVG at_II the_AT environment_NN1 ,_, as_CSA market_NN1 demands_NN2 become_VV0 more_RGR sophisticated_JJ so_CS there_EX is_VBZ a_AT1 need_NN1 for_IF operator_NN1 flexibility_NN1 in_II production_NN1 system_NN1 outputs_NN2 ,_, which_DDQ has_VHZ its_APPGE counterpart_NN1 in_II greater_JJR variety_NN1 of_IO work_NN1 within_II the_AT production_NN1 system_NN1 (_( Lupton_NP1 and_CC Tanner_NP1 ,_, 1980_MC )_) ._. 
Socio-technical_JJ system_NN1 theory_NN1 has_VHZ been_VBN highly_RR fruitful_JJ in_II generating_VVG other_JJ academic_JJ lines_NN2 of_IO development_NN1 :_: organisation_NN1 theory_NN1 ,_, quality_NN1 of_IO working_NN1 life_NN1 concepts_NN2 and_CC work_VV0 motivation_NN1 ,_, in_II stimulating_JJ many_DA2 innovations_NN2 in_II production_NN1 organisation_NN1 and_CC in_II provoking_VVG governments_NN2 to_TO consider_VVI legislation_NN1 in_II matters_NN2 such_II21 as_II22 humanisation_NN1 of_IO work_NN1 (_( Germany_NP1 )_) and_CC co-determination_NN1 at_II work_NN1 (_( Sweden_NP1 )_) ._. 
Paradoxically_RR it_PPH1 has_VHZ not_XX developed_VVN a_AT1 formalised_JJ set_NN1 of_IO principles_NN2 or_CC immutable_JJ knowledge_NN1 which_DDQ could_VM ,_, for_REX21 example_REX22 ,_, be_VBI structured_VVN into_II an_AT1 academic_JJ text-book_NN1 about_II socio-technical_JJ systems_NN2 ._. 
The_AT problem_NN1 seems_VVZ to_TO be_VBI that_CST it_PPH1 is_VBZ fundamentally_RR about_II attitudes_NN2 to_TO work_VVI and_CC such_DA attitudes_NN2 are_VBR subject_II21 to_II22 an_AT1 inextricable_JJ and_CC non-monotonic_JJ range_NN1 of_IO influences_NN2 not_XX only_RR from_II work_NN1 itself_PPX1 ,_, with_IW all_DB the_AT pressures_NN2 of_IO technological_JJ change_NN1 ,_, but_CCB also_RR from_II prevailing_JJ economic_JJ ,_, social_JJ and_CC cultural_JJ changes_NN2 in_II the_AT community_NN1 generally_RR ._. 
Man-machine_JJ systems_NN2 Work_VV0 is_VBZ very_RG rarely_RR performed_VVN by_II a_AT1 man_NN1 without_IW the_AT aid_NN1 of_IO some_DD machinery_NN1 and_CC correspondingly_RR machines_NN2 rarely_RR function_VV0 for_IF very_RG long_RR without_IW human_JJ intervention_NN1 ._. 
Man_NN1 and_CC machine_NN1 can_VM be_VBI regarded_VVN as_II sub-systems_NN2 each_DD1 making_VVG a_AT1 distinctive_JJ contribution_NN1 towards_II the_AT achievement_NN1 of_IO the_AT purposes_NN2 of_IO the_AT working_JJ system_NN1 ._. 
The_AT system_NN1 itself_PPX1 can_VM be_VBI described_VVN as_II a_AT1 set_NN1 of_IO functions_NN2 necessary_JJ for_IF the_AT overall_JJ purpose_NN1 ._. 
The_AT emphasis_NN1 on_II defining_VVG the_AT system_NN1 in_II31 terms_II32 of_II33 its_APPGE purposes_NN2 or_CC objectives_NN2 and_CC analysing_VVG it_PPH1 in_II31 terms_II32 of_II33 its_APPGE functions_NN2 are_VBR the_AT characteristics_NN2 of_IO the_AT systems_NN2 approach_NN1 ._. 
It_PPH1 follows_VVZ that_CST at_II some_DD stage_NN1 in_II the_AT design_NN1 process_VV0 it_PPH1 should_VM be_VBI useful_JJ to_TO consider_VVI how_RRQ the_AT various_JJ functions_NN2 are_VBR most_RGT effectively_RR allocated_VVN to_II man_NN1 or_CC to_TO machine_VVI ._. 
Fig._NN1 1.2_MC shows_VVZ the_AT essentials_NN2 of_IO the_AT system_NN1 design_NN1 process_NN1 but_CCB since_CS feed-back_NN1 paths_NN2 are_VBR omitted_VVN this_DD1 figure_NN1 does_VDZ not_XX indicate_VVI either_RR the_AT repetition_NN1 and_CC iteration_NN1 which_DDQ goes_VVZ on_RP in_II operational_JJ design_NN1 or_CC the_AT different_JJ possible_JJ priorities_NN2 and_CC variability_NN1 in_II the_AT order_NN1 of_IO decision-making_NN1 ._. 
The_AT engineering_NN1 emphasis_NN1 will_VM be_VBI on_II the_AT search_NN1 for_IF mechanisms_NN2 which_DDQ can_VM most_RGT effectively_RR perform_VVI the_AT required_JJ functions_NN2 with_IW the_AT human_JJ operator_NN1 in_II a_AT1 support_NN1 role_NN1 undertaking_NN1 functions_NN2 which_DDQ are_VBR not_XX readily_RR mechanised_JJ ._. 
The_AT ergonomics_NN1 emphasis_NN1 will_VM be_VBI on_II the_AT human_JJ operator_NN1 as_II the_AT navigator_NN1 moving_VVG towards_II the_AT system_NN1 objectives_NN2 supported_VVN by_II various_JJ mechanisms_NN2 ._. 
One_MC1 neutral_JJ viewpoint_NN1 is_VBZ to_TO consider_VVI formally_RR the_AT relative_JJ advantages_NN2 and_CC limitations_NN2 of_IO men_NN2 and_CC machines_NN2 ._. 
These_DD2 can_VM be_VBI listed_VVN (_( Table_NN1 1.6_MC )_) on_II what_DDQ is_VBZ called_VVN a_AT1 '_GE Fitts_NP1 List_NN1 '_GE after_II Paul_NP1 Fitts_NP1 who_PNQS originally_RR proposed_VVN this_DD1 approach_NN1 (_( Fitts_NP1 ,_, 1951_MC )_) ._. 
At_II the_AT time_NNT1 it_PPH1 was_VBDZ hoped_VVN that_CST eventually_RR it_PPH1 would_VM be_VBI possible_JJ to_TO refine_VVI the_AT quantitative_JJ distinctions_NN2 between_II the_AT performance_NN1 of_IO men_NN2 and_CC machines_NN2 so_CS21 that_CS22 allocation_NN1 of_IO function_NN1 decisions_NN2 would_VM be_VBI unambiguous_JJ (_( Wuffeck_NP1 and_CC Zeitlin_NP1 ,_, 1962_MC )_) ,_, but_CCB this_DD1 has_VHZ not_XX happened_VVN ._. 
The_AT reason_NN1 seems_VVZ to_TO be_VBI that_CST men_NN2 and_CC machines_NN2 are_VBR fundamentally_RR complementary_JJ rather_II21 than_II22 comparable_JJ ,_, this_DD1 point_NN1 was_VBDZ originally_RR made_VVN by_II Jordan_NP1 (_( 1963_MC )_) ._. 
If_CS a_AT1 required_JJ function_NN1 can_VM be_VBI specified_VVN precisely_RR then_RT a_AT1 mechanism_NN1 can_VM be_VBI designed_VVN to_TO perform_VVI it_PPH1 ._. 
The_AT reasons_NN2 for_IF incorporating_VVG men_NN2 in_II systems_NN2 are_VBR to_TO do_VDI with_IW properties_NN2 such_II21 as_II22 flexibility_NN1 and_CC adaptability_NN1 which_DDQ by_II their_APPGE nature_NN1 are_VBR not_XX specifiable_JJ in_II numerical_JJ terms_NN2 ._. 
Incidentally_RR this_DD1 clarifies_VVZ why_RRQ the_AT man-machine_JJ system_NN1 is_VBZ such_DA a_AT1 potent_JJ combination_NN1 ._. 
Each_DD1 provides_VVZ attributes_NN2 which_DDQ are_VBR not_XX easily_RR available_JJ from_II the_AT other_JJ ._. 
A_AT1 man_NN1 without_IW the_AT support_NN1 of_IO machinery_NN1 is_VBZ physically_RR weak_JJ and_CC informationally_RR slow_JJ ._. 
A_AT1 machine_NN1 without_IW human_JJ guidance_NN1 is_VBZ inflexible_JJ and_CC highly_RR limited_VVN in_II recognition_NN1 and_CC learning_VVG facilities_NN2 ._. 
Nevertheless_RR it_PPH1 is_VBZ not_XX common_JJ practice_NN1 to_TO consider_VVI the_AT man-machine_JJ allocation_NN1 of_IO function_NN1 as_II an_AT1 isolated_JJ design_NN1 decision_NN1 ._. 
More_RGR usually_RR the_AT allocation_NN1 emerges_VVZ from_II a_AT1 pattern_NN1 of_IO related_JJ decisions_NN2 including_II what_DDQ can_VM be_VBI reliably_RR and_CC economically_RR achieved_VVN by_II hardware_NN1 and_CC software_NN1 ,_, what_DDQ the_AT allocated_JJ tasks_NN2 look_VV0 like_II as_RG integrated_JJ jobs_NN2 for_IF the_AT human_JJ operators_NN2 ,_, the_AT skills_NN2 and_CC traditions_NN2 of_IO the_AT available_JJ work-force_NN1 ,_, the_AT importance_NN1 of_IO safety_NN1 and_CC reliability_NN1 and_RR31 so_RR32 on_RR33 (_( Table_NN1 1.7_MC )_) ._. 
As_CSA potential_JJ functional_JJ weaknesses_NN2 emerge_VV0 during_II the_AT design_NN1 appraisal_NN1 further_RRR consideration_NN1 is_VBZ given_VVN to_II what_DDQ functions_NN2 might_VM be_VBI allocated_VVN to_II the_AT man_NN1 or_CC machine_VV0 to_TO provide_VVI greater_JJR mutual_JJ support_NN1 ._. 
The_AT result_NN1 of_IO selective_JJ competent_JJ design_NN1 along_II these_DD2 lines_NN2 should_VM be_VBI a_AT1 system_NN1 with_IW optimal_JJ man-machine_JJ allocation_NN1 given_VVN the_AT technological_JJ state_NN1 of_IO the_AT art_NN1 and_CC a_AT1 comprehensive_JJ sensitivity_NN1 to_II the_AT feasibility_NN1 of_IO the_AT human_JJ tasks_NN2 ._. 
A_AT1 detailed_JJ discussion_NN1 of_IO the_AT historical_JJ development_NN1 of_IO the_AT allocation_NN1 of_IO function_NN1 concept_NN1 is_VBZ given_VVN in_II Singleton_NP1 (_( 1974_MC )_) ._. 
This_DD1 approach_NN1 contravenes_VVZ currently_RR fashionable_JJ Human_JJ Factors_NN2 methodology_NN1 that_CST there_EX should_VM be_VBI a_AT1 formal_JJ attempt_NN1 to_TO carry_VVI out_RP man-machine_JJ allocation_NN1 ._. 
Operational_JJ experience_NN1 of_IO real_JJ systems_NN2 design_NN1 reinforces_VVZ doubts_NN2 about_II the_AT allocation_NN1 of_IO function_NN1 concept_NN1 as_II a_AT1 basis_NN1 for_IF a_AT1 unitary_JJ systematic_JJ procedure_NN1 ._. 
The_AT paradigm_NN1 illustrated_VVN in_II fig._NN1 1.12_MC has_VHZ the_AT virtue_NN1 of_IO simplicity_NN1 ._. 
Like_II many_DA2 block_NN1 diagrams_NN2 this_DD1 conceals_VVZ the_AT practical_JJ problems._NNU from_II such_DA a_AT1 simple_JJ diagram_NN1 it_PPH1 is_VBZ easy_JJ to_TO assume_VVI that_CST all_DB the_AT thinking_NN1 is_VBZ done_VDN in_II31 terms_II32 of_II33 functions_NN2 ._. 
This_DD1 can_VM not_XX be_VBI sustained_VVN because_CS the_AT only_JJ way_NN1 to_TO validate_VVI task_NN1 analysis_NN1 is_VBZ to_TO switch_VVI from_II functional_JJ concepts_NN2 to_II behavioural_JJ concepts_NN2 and_CC the_AT only_JJ way_NN1 to_TO validate_VVI hardware_NN1 concepts_NN2 is_VBZ to_TO switch_VVI to_II thinking_VVG in_II31 terms_II32 of_II33 specific_JJ mechanisms_NN2 ._. 
Thus_RR ,_, allocation_NN1 of_IO function_NN1 requires_VVZ a_AT1 continuous_JJ juggling_NN1 of_IO functional_JJ ,_, mechanistic_JJ and_CC behavioural_JJ approaches_NN2 ._. 
In_II31 addition_II32 to_II33 the_AT separate_JJ criteria_NN2 related_VVN to_II men_NN2 and_CC mechanisms_NN2 there_EX are_VBR others_NN2 to_TO do_VDI with_IW information_NN1 acquisition_NN1 ,_, storage_NN1 and_CC presentation_NN1 focussing_VVG on_II the_AT interface_NN1 design_NN1 which_DDQ has_VHZ its_APPGE own_DA design_NN1 criteria_NN2 ._. 
Note_VV0 that_CST a_AT1 real_JJ problem_NN1 usually_RR involves_VVZ men_NN2 rather_II21 than_II22 one_MC1 man_NN1 and_CC thus_RR there_EX are_VBR extensive_JJ man-man_JJ communication_NN1 issues_NN2 where_RRQ few_DA2 of_IO the_AT functions_NN2 could_VM conceivably_RR be_VBI allocated_VVN to_II non-human_JJ mechanisms_NN2 ._. 
In_II a_AT1 military_JJ command_NN1 and_CC control_NN1 situation_NN1 these_DD2 will_VM typically_RR be_VBI sub-system_NN1 operators_NN2 ,_, supervisors_NN2 and_CC customers_NN2 using_VVG the_AT output_NN1 (_( p._NNU 243_MC )_) ._. 
Even_CS21 when_CS22 design_NN1 attention_NN1 can_VM be_VBI focussed_VVN on_II the_AT interaction_NN1 within_II a_AT1 single_JJ man-machine_JJ sub-system_NN1 it_PPH1 emerges_VVZ that_CST the_AT man_NN1 may_VM have_VHI very_RG different_JJ roles_NN2 in_II setting-up_NN1 ,_, operation_NN1 and_CC maintenance_NN1 of_IO his_APPGE particular_JJ machine_NN1 and_CC each_DD1 role_NN1 may_VM require_VVI separate_JJ man-machine_JJ allocation_NN1 considerations_NN2 ._. 
A_AT1 designer_NN1 is_VBZ often_RR restricted_VVN by_II various_JJ mandatory_JJ requirements_NN2 based_VVN for_REX21 example_REX22 on_II imagined_JJ safeguards_NN2 against_II accidents_NN2 ._. 
There_EX are_VBR also_RR unspecifiable_JJ but_CCB none_RR31 the_RR32 less_RR33 potent_JJ political_JJ restrictions_NN2 ,_, some_DD from_II within_II the_AT organisation_NN1 ,_, some_DD from_II outside_RL it_PPH1 ._. 
For_REX21 example_REX22 the_AT use_NN1 of_IO nuclear_JJ power_NN1 in_II either_RR the_AT military_JJ or_CC the_AT civil_JJ sense_NN1 is_VBZ regarded_VVN as_II qualitatively_RR different_JJ from_II non-nuclear_JJ power_NN1 in_II its_APPGE safety_NN1 ,_, control_NN1 and_CC management_NN1 requirements_NN2 ._. 
Design_NN1 is_VBZ never_RR an_AT1 isolated_JJ logical_JJ process_NN1 ._. 
There_EX is_VBZ a_AT1 legacy_NN1 of_IO experience_NN1 from_II earlier_JJR designs_NN2 which_DDQ inevitably_RR guide_VV0 and_CC inhibit_VV0 a_AT1 new_JJ design_NN1 ._. 
The_AT shifts_NN2 of_IO allocation_NN1 of_IO function_NN1 from_II this_DD1 point_NN1 of_IO view_NN1 are_VBR illustrated_VVN in_II Fig._NN1 1.13_MC ._. 
Swain_NP1 and_CC Wohl_NP1 (_( 1961_MC )_) argue_VV0 that_CST the_AT man-machine_JJ concept_NN1 is_VBZ oversimplified_VVN ,_, it_PPH1 should_VM be_VBI man-machine_JJ procedures_NN2 allocation_NN1 and_CC also_RR that_DD1 prime_JJ equipment_NN1 should_VM be_VBI separated_VVN from_II check-out_NN1 equipment_NN1 (_( Fig._NN1 1._MC 14_MC )_) In_II equipment_NN1 involving_VVG advanced_JJ technology_NN1 the_AT allocation_NN1 of_IO the_AT control_NN1 function_NN1 is_VBZ between_II the_AT on-line_JJ operator_NN1 and_CC the_AT designer_NN1 ._. 
The_AT latter_DA builds_VVZ decisions_NN2 into_II the_AT hardware_NN1 and_CC software_NN1 based_VVN on_II his_APPGE knowledge_NN1 of_IO the_AT limitations_NN2 of_IO the_AT mechanisms_NN2 ._. 
High_JJ technology_NN1 can_VM also_RR be_VBI used_VVN to_TO provide_VVI the_AT operator_NN1 with_IW flexibility_NN1 in_II the_AT allocation_NN1 of_IO functions_NN2 ,_, he_PPHS1 can_VM make_VVI his_APPGE own_DA decision_NN1 about_II when_RRQ to_TO control_VVI manually_RR and_CC when_RRQ to_TO leave_VVI it_PPH1 to_II the_AT mechanisms_NN2 ._. 
This_DD1 is_VBZ called_VVN supervisory_JJ control_NN1 (_( Fig._NN1 1._MC 15_MC )_) pp_NNU2 3839_MC :_: FIGURE/DIAGRAM_NN1 It_PPH1 emerges_VVZ from_II the_AT above_JJ discussion_NN1 that_CST man-machine_JJ allocation_NN1 of_IO function_NN1 is_VBZ at_RR21 best_RR22 an_AT1 oversimplification_NN1 and_CC it_PPH1 may_VM lead_VVI to_II the_AT neglect_NN1 of_IO some_DD key_JJ features_NN2 of_IO human_JJ performance_NN1 ._. 
Only_RR the_AT human_JJ operator_NN1 can_VM cope_VVI with_IW the_AT concept_NN1 of_IO purposes_NN2 and_CC goals_NN2 and_CC more_RGR particularly_RR with_IW their_APPGE modification_NN1 in_II41 the_II42 light_II43 of_II44 changing_JJ circumstances_NN2 ._. 
Knowledge_NN1 of_IO circumstances_NN2 is_VBZ communicated_VVN partly_RR by_II information_NN1 exchange_NN1 across_II man-machine_JJ interfaces_NN2 but_CCB also_RR by_II verbal_JJ exchanges_NN2 between_II people_NN ._. 
These_DD2 verbal_JJ exchanges_NN2 can_VM be_VBI factual_JJ but_CCB can_VM also_RR be_VBI diffuse_JJ in_II the_AT sharing_NN1 of_IO attitudes_NN2 ,_, beliefs_NN2 ,_, urgencies_NN2 ,_, doubts_NN2 and_RR31 so_RR32 on_RR33 ._. 
These_DD2 features_NN2 are_VBR just_RR as_RG important_JJ to_II efficient_JJ performance_NN1 as_CSA are_VBR data_NN about_II plant_NN1 functions_NN2 but_CCB they_PPHS2 can_VM not_XX be_VBI incorporated_VVN in_II a_AT1 man-machine_JJ allocation_NN1 process_NN1 ._. 
Implicit_JJ in_II the_AT attempt_NN1 to_TO complete_VVI a_AT1 systematic_JJ man-machine_JJ function_NN1 allocation_NN1 is_VBZ the_AT principle_NN1 that_CST some_DD trade-off_NN1 is_VBZ possible_JJ ._. 
More_DAR attention_NN1 to_II the_AT hardware_NN1 and_CC information_NN1 presentation_NN1 will_VM yield_VVI improved_JJ operator_NN1 support_NN1 whereas_CS more_DAR attention_NN1 to_II operator_NN1 training_NN1 will_VM minimise_VVI the_AT difficulties_NN2 of_IO interpreting_VVG information_NN1 presentations_NN2 and_CC thereby_RR making_VVG full_JJ use_NN1 of_IO machines_NN2 (_( Singleton_NP1 ,_, 1967b_FO )_) ._. 
These_DD2 alternative_JJ procedures_NN2 are_VBR summarised_VVN by_II the_AT expressions_NN2 '_GE fitting_VVG the_AT man_NN1 to_II the_AT job_NN1 '_GE or_CC '_GE fitting_VVG the_AT job_NN1 to_II the_AT man_NN1 '_GE ._. 
The_AT systems_NN2 approach_NN1 indicates_VVZ that_CST the_AT two_MC should_VM be_VBI balanced_VVN on_II technical_JJ ,_, economic_JJ and_CC behavioural_JJ criteria_NN2 (_( Table_NN1 1.8_MC ._. )_) ._. 
To_TO proceed_VVI systematically_RR ,_, both_DB2 require_VV0 that_CST there_EX should_VM be_VBI the_AT greatest_JJT possible_JJ understanding_NN1 of_IO what_DDQ the_AT man_NN1 is_VBZ required_VVN to_TO do_VDI ._. 
The_AT design_NN1 of_IO the_AT man-machine_JJ interface_NN1 must_VM develop_VVI from_II an_AT1 understanding_NN1 of_IO how_RRQ the_AT man_NN1 is_VBZ expected_VVN to_TO interact_VVI with_IW the_AT machine_NN1 and_CC correspondingly_RR the_AT design_NN1 of_IO selection_NN1 ,_, allocation_NN1 and_CC training_NN1 schemes_NN2 depends_VVZ on_II knowing_VVG what_DDQ is_VBZ required_VVN of_IO the_AT operator_NN1 ._. 
The_AT study_NN1 of_IO demands_NN2 on_II the_AT operator_NN1 requires_VVZ task_NN1 analysis_NN1 ._. 
In_II this_DD1 context_NN1 the_AT term_NN1 '_GE machine_NN1 '_GE is_VBZ used_VVN as_CSA shorthand_NN1 for_IF the_AT total_JJ hardware_NN1 and_CC software_NN1 system_NN1 or_CC ,_, in_II other_JJ terminology_NN1 ,_, the_AT plant_NN1 ._. 
For_IF information_NN1 systems_NN2 the_AT allocation_NN1 of_IO function_NN1 and_CC interface_VV0 design_NN1 issues_NN2 merge_VV0 into_II the_AT procedure_NN1 for_IF considering_VVG the_AT required_JJ points_NN2 of_IO human_JJ intervention_NN1 in_II the_AT total_JJ information_NN1 network_NN1 ._. 
From_II this_DD1 point_NN1 of_IO view_NN1 the_AT allocation_NN1 of_IO function_NN1 and_CC interface_VV0 design_NN1 are_VBR one_MC1 core_NN1 design_NN1 activity_NN1 based_VVN on_II the_AT man-machine_JJ concept_NN1 ._. 
Task_NN1 analysis_NN1 Terminology_NN1 In_II the_AT context_NN1 of_IO systems_NN2 design_VV0 ,_, task_NN1 analysis_NN1 has_VHZ become_VVN the_AT generic_JJ term_NN1 applicable_JJ to_II the_AT field_NN1 study_NN1 of_IO human_JJ performance_NN1 ._. 
This_DD1 is_VBZ somewhat_RR confusing_JJ because_CS the_AT centre_NN1 of_IO interest_NN1 may_VM be_VBI jobs_NN2 or_CC skills_NN2 rather_II21 than_II22 tasks_NN2 ,_, and_CC strictly_RR the_AT procedure_NN1 is_VBZ often_RR more_RGR accurately_RR described_VVN as_II one_MC1 of_IO synthesis_NN1 rather_II21 than_II22 analysis_NN1 ._. 
For_REX21 example_REX22 ,_, a_AT1 designer_NN1 may_VM build_VVI up_RP a_AT1 sequence_NN1 of_IO actions_NN2 which_DDQ an_AT1 operator_NN1 must_VM follow_VVI in_BCL21 order_BCL22 to_TO cause_VVI his_APPGE product_NN1 to_TO function_VVI properly_RR he_PPHS1 has_VHZ synthesised_VVN the_AT task_NN1 from_II a_AT1 knowledge_NN1 of_IO how_RRQ the_AT machine_NN1 or_CC other_JJ product_NN1 was_VBDZ designed_VVN to_TO function_VVI ._. 
Nevertheless_RR ,_, such_DA activity_NN1 comes_VVZ under_II the_AT heading_NN1 of_IO task_NN1 analysis_NN1 (_( Fig._NN1 1.16_MC )_) ._. 
Tasks_NN2 represent_VV0 the_AT human_JJ contribution_NN1 to_II system_NN1 performance_NN1 but_II21 for_II22 purposes_NN2 of_IO personnel_NN2 selection_NN1 ,_, training_NN1 and_CC allocation_NN1 ,_, it_PPH1 is_VBZ necessary_JJ for_IF tasks_NN2 to_TO be_VBI separated_VVN or_CC combined_VVN into_II jobs_NN2 ._. 
For_IF systems_NN2 which_DDQ have_VH0 evolved_VVN on_II the_AT basis_NN1 of_IO operational_JJ experience_NN1 rather_II21 than_II22 those_DD2 which_DDQ have_VH0 been_VBN created_VVN by_II a_AT1 formal_JJ design_NN1 process_NN1 ,_, job_NN1 analysis_NN1 rather_II21 than_II22 task_NN1 analysis_NN1 may_VM be_VBI the_AT starting_NN1 point_NN1 of_IO human_JJ factors_NN2 studies_NN2 ._. 
The_AT ergonomist_NN1 will_VM begin_VVI his_APPGE investigation_NN1 by_II the_AT consideration_NN1 of_IO what_DDQ the_AT personnel_NN2 actually_RR do_VD0 in_II their_APPGE jobs_NN2 which_DDQ have_VH0 emerged_VVN and_CC been_VBN refined_VVN by_II practice_NN1 and_CC personal_JJ preference_NN1 rather_CS21 than_CS22 design_VVI ._. 
A_AT1 task_NN1 is_VBZ usually_RR considered_VVN to_TO be_VBI an_AT1 integrated_JJ sub-activity_NN1 with_IW a_AT1 particular_JJ purpose_NN1 as_CSA distinct_JJ from_II a_AT1 job_NN1 which_DDQ is_VBZ a_AT1 particular_JJ kind_NN1 of_IO work_NN1 carried_VVN out_RP by_II an_AT1 individual_NN1 in_II a_AT1 system_NN1 context_NN1 ._. 
Jobs_NN2 are_VBR collections_NN2 of_IO tasks_NN2 or_CC parts_NN2 of_IO tasks_NN2 ._. 
Occupation_NN1 is_VBZ the_AT wider_JJR term_NN1 which_DDQ covers_VVZ a_AT1 range_NN1 of_IO jobs_NN2 and_CC the_AT career_NN1 of_IO an_AT1 individual_NN1 in_II a_AT1 community_NN1 context_NN1 ._. 
For_REX21 example_REX22 ,_, management_NN1 is_VBZ an_AT1 occupation_NN1 ,_, a_AT1 production_NN1 manager_NN1 is_VBZ a_AT1 job_NN1 ,_, and_CC work_VV0 scheduling_NN1 is_VBZ a_AT1 task_NN1 ._. 
These_DD2 distinctions_NN2 are_VBR demonstrated_VVN in_II Fig._NN1 1._MC 17_MC ._. 
Another_DD1 source_NN1 of_IO ambiguity_NN1 is_VBZ that_DD1 task_NN1 analysis_NN1 is_VBZ often_RR used_VVN as_II a_AT1 generic_JJ term_NN1 covering_VVG any_DD study_NN1 and_CC description_NN1 relating_VVG to_II people_NN at_II work_NN1 ._. 
Sometimes_RT this_DD1 is_VBZ no_AT more_DAR than_CSN a_AT1 description_NN1 of_IO what_DDQ has_VHZ to_TO be_VBI done_VDN but_CCB sometimes_RT it_PPH1 incorporates_VVZ how_RRQ the_AT operator_NN1 does_VDZ it_PPH1 or_CC should_VM do_VDI it_PPH1 ._. 
Strictly_RR ,_, this_DD1 latter_DA should_VM be_VBI called_VVN a_AT1 skill_NN1 description_NN1 rather_II21 than_II22 a_AT1 task_NN1 description_NN1 ._. 
In_II principle_NN1 a_AT1 task_NN1 description_NN1 is_VBZ not_XX necessarily_RR an_AT1 activity_NN1 of_IO a_AT1 person_NN1 ,_, the_AT task_NN1 might_VM possibly_RR be_VBI completed_VVN automatically_RR ._. 
There_EX is_VBZ no_AT such_DA ambiguity_NN1 about_II a_AT1 skills_NN2 analysis_NN1 which_DDQ is_VBZ always_RR person-orientated_JJ and_CC not_XX just_RR system-orientated_JJ ._. 
This_DD1 confusion_NN1 of_IO terms_NN2 obscures_VVZ even_RR further_RRR the_AT difficult_JJ technical_JJ problems_NN2 of_IO moving_VVG from_II a_AT1 task_NN1 description_NN1 to_II a_AT1 skill_NN1 description_NN1 ._. 
The_AT task_NN1 description_NN1 should_VM emerge_VVI logically_RR from_II the_AT system_NN1 design_NN1 and_CC more_RGR particularly_RR from_II the_AT allocation_NN1 of_IO functions_NN2 ._. 
There_EX is_VBZ no_AT such_DA deductive_JJ way_NN1 of_IO getting_VVG at_II the_AT skill_NN1 description_NN1 ._. 
This_DD1 can_VM only_RR be_VBI done_VDN by_II studying_VVG operators_NN2 ._. 
There_EX are_VBR two_MC problems_NN2 in_II analysing_VVG tasks_NN2 :_: one_PN1 is_VBZ to_TO acquire_VVI the_AT evidence_NN1 on_II which_DDQ to_TO base_VVI the_AT task_NN1 description_NN1 ,_, the_AT other_NN1 is_VBZ to_TO record_VVI what_DDQ has_VHZ been_VBN found_VVN out_RP in_II a_AT1 way_NN1 such_CS21 that_CS22 other_JJ people_NN ,_, notably_RR the_AT interface_NN1 designers_NN2 and_CC the_AT personnel_NN2 specialists_NN2 ,_, can_VM use_VVI it_PPH1 effectively_RR to_TO assist_VVI in_II their_APPGE work_NN1 ._. 
It_PPH1 aids_VVZ clarity_NN1 to_TO reserve_VVI the_AT term_NN1 analysis_NN1 to_TO mean_VVI the_AT acquisition_NN1 of_IO evidence_NN1 and_CC description_NN1 to_TO mean_VVI the_AT presentation_NN1 of_IO the_AT evidence_NN1 ._. 
The_AT test_NN1 of_IO a_AT1 task_NN1 description_NN1 is_VBZ :_: does_VDZ it_PPH1 indicate_VVI a_AT1 necessary_JJ function_NN1 within_II the_AT system_NN1 performance_NN1 ?_? 
The_AT test_NN1 of_IO a_AT1 skill_NN1 description_NN1 is_VBZ :_: does_VDZ it_PPH1 indicate_VVI how_RRQ an_AT1 individual_NN1 goes_VVZ about_II a_AT1 task_NN1 ,_, does_VDZ it_PPH1 allow_VVI for_IF individual_JJ differences_NN2 such_II21 as_II22 those_DD2 between_II a_AT1 highly_RR skilled_JJ operator_NN1 and_CC a_AT1 mediocre_JJ one_PN1 ?_? 
For_IF routine_NN1 lowlevel_NN1 tasks_NN2 there_EX may_VM be_VBI no_AT great_JJ distinction_NN1 between_II a_AT1 task_NN1 description_NN1 and_CC skill_NN1 description_NN1 but_II21 for_II22 high-level_JJ tasks_NN2 there_EX will_VM be_VBI a_AT1 considerable_JJ difference_NN1 ._. 
Skills_NN2 analysis_NN1 is_VBZ an_AT1 attempt_NN1 to_TO get_VVI at_II what_DDQ is_VBZ going_VVG on_RP in_II the_AT operator_NN1 's_GE mind_NN1 ._. 
For_IF a_AT1 repetitive_JJ task_NN1 there_EX may_VM be_VBI comparatively_RR little_RR going_VVG on_RP in_II the_AT mind_NN1 which_DDQ emerges_VVZ at_II the_AT level_NN1 of_IO consciousness_NN1 ._. 
For_REX21 example_REX22 ,_, the_AT assembly_NN1 of_IO a_AT1 set_NN1 of_IO components_NN2 will_VM be_VBI carried_VVN out_RP by_II an_AT1 experienced_JJ operator_NN1 without_IW thinking_VVG about_II it_PPH1 ._. 
He_PPHS1 may_VM be_VBI surprised_JJ when_CS the_AT analyst_NN1 reveals_VVZ the_AT complexities_NN2 of_IO his_APPGE hand_NN1 movements_NN2 and_CC finger_NN1 manipulations_NN2 ._. 
The_AT only_JJ way_NN1 he_PPHS1 can_VM recall_VVI what_DDQ he_PPHS1 does_VDZ is_VBZ by_II doing_VDG it_PPH1 ,_, literally_RR '_GE going_VVG through_II the_AT motions_NN2 '_GE ._. 
On_II the_AT other_JJ hand_NN1 ,_, for_IF a_AT1 task_NN1 such_II21 as_II22 fault_NN1 diagnosis_NN1 he_PPHS1 will_VM be_VBI thinking_VVG about_II it_PPH1 in_II various_JJ structured_JJ ways_NN2 which_DDQ he_PPHS1 can_VM reveal_VVI by_II talking_VVG about_II it_PPH1 and_CC exploring_VVG verbally_RR why_RRQ he_PPHS1 looks_VVZ at_II particular_JJ indications_NN2 or_CC takes_VVZ particular_JJ actions_NN2 ._. 
Human_JJ tasks_NN2 and_CC the_AT purposes_NN2 of_IO task_NN1 analysis_NN1 are_VBR too_RG varied_JJ for_IF there_RL to_TO be_VBI one_MC1 standard_JJ procedure_NN1 for_IF either_RR analysis_NN1 or_CC description_NN1 ._. 
Analysing_VVG a_AT1 task_NN1 where_CS the_AT main_JJ requirement_NN1 is_VBZ speed_NN1 of_IO response_NN1 is_VBZ different_JJ from_II analysing_VVG a_AT1 task_NN1 in_II which_DDQ problem_NN1 solving_NN1 is_VBZ required_VVN ._. 
A_AT1 task_NN1 analysis_NN1 in_II the_AT context_NN1 of_IO '_GE fitting_VVG the_AT man_NN1 to_II the_AT job_NN1 '_GE can_VM be_VBI very_RG different_JJ from_II one_PN1 designed_VVN to_TO assist_VVI in_II '_GE fitting_VVG the_AT job_NN1 to_II the_AT man_NN1 '_GE ._. 
As_CSA mentioned_VVN above_RL the_AT two_MC extremes_NN2 of_IO human_JJ tasks_NN2 are_VBR the_AT procedure_NN1 and_CC the_AT diagnosis_NN1 ._. 
Procedural_JJ task_NN1 analysis_NN1 is_VBZ usually_RR initiated_VVN on_II the_AT basis_NN1 of_IO technology_NN1 and_CC logic_NN1 by_II the_AT designer_NN1 ._. 
A_AT1 task_NN1 has_VHZ been_VBN allocated_VVN to_II the_AT human_JJ operator_NN1 and_CC what_DDQ he_PPHS1 must_VM do_VDI is_VBZ a_AT1 function_NN1 of_IO the_AT needs_NN2 of_IO the_AT hardware_NN1 ._. 
Such_DA tasks_NN2 may_VM be_VBI in_II operation_NN1 or_CC maintenance_NN1 ._. 
In_II either_DD1 case_NN1 the_AT designer_NN1 writes_VVZ down_RP the_AT sequence_NN1 of_IO actions_NN2 which_DDQ must_VM be_VBI taken_VVN coupled_VVN with_IW informational_JJ indications_NN2 of_IO what_DDQ should_VM be_VBI happening_VVG ._. 
For_REX21 example_REX22 ,_, in_II starting_VVG up_RP a_AT1 machine_NN1 or_CC system_NN1 (_( Table_NN1 1.9_MC )_) ._. 
Effectively_RR the_AT operating_NN1 instructions_NN2 are_VBR the_AT task_NN1 description_NN1 ._. 
It_PPH1 is_VBZ ,_, of_RR21 course_RR22 ,_, desirable_JJ to_TO check_VVI that_CST nothing_PN1 has_VHZ been_VBN forgotten_VVN and_CC to_II this_DD1 end_NN1 it_PPH1 is_VBZ usual_JJ to_TO ask_VVI an_AT1 operator_NN1 to_TO go_VVI through_II the_AT designed_JJ procedure_NN1 while_CS observing_VVG what_DDQ he_PPHS1 does_VDZ and_CC also_RR observing_VVG that_CST the_AT system_NN1 performs_VVZ as_CSA expected_VVN ._. 
This_DD1 may_VM be_VBI done_VDN on_II the_AT machine_NN1 if_CS it_PPH1 is_VBZ available_JJ ,_, or_CC on_II a_AT1 simulator_NN1 or_CC on_II some_DD kind_NN1 of_IO mock-up_NN1 of_IO what_DDQ the_AT system_NN1 will_VM be_VBI like_II ._. 
This_DD1 is_VBZ known_VVN as_II the_AT talk_NN1 through_II or_CC walk_VV0 through_II method_NN1 of_IO task_NN1 analysis_NN1 ._. 
The_AT difference_NN1 is_VBZ only_RR in_II the_AT kind_NN1 of_IO task_NN1 and_CC size_NN1 of_IO hardware_NN1 ._. 
For_REX21 example_REX22 ,_, in_II the_AT case_NN1 of_IO starting_VVG up_RP a_AT1 machine_NN1 at_II a_AT1 control_NN1 panel_NN1 the_AT operator_NN1 will_VM be_VBI given_VVN the_AT instructions_NN2 and_CC asked_VVN to_TO provide_VVI a_AT1 verbal_JJ commentary_NN1 as_CSA he_PPHS1 actuates_VVZ the_AT various_JJ controls_NN2 and_CC checks_VVZ the_AT various_JJ indications_NN2 ,_, this_DD1 is_VBZ a_AT1 '_GE talk_NN1 through_II '_GE ._. 
On_II the_AT other_JJ hand_NN1 ,_, a_AT1 maintenance_NN1 check_NN1 of_IO a_AT1 series_NN of_IO related_JJ machines_NN2 may_VM involve_VVI moving_VVG to_RL31 and_RL32 fro_RL33 between_II them_PPHO2 while_CS activating_VVG this_DD1 and_CC that_DD1 ,_, this_DD1 is_VBZ a_AT1 '_GE walk_NN1 through_II '_GE ._. 
The_AT operating_NN1 instructions/task_FU description_NN1 can_VM be_VBI modified_VVN if_CS the_AT analysis_NN1 reveals_VVZ any_DD problems_NN2 from_II the_AT operator_NN1 's_GE point_NN1 of_IO view_NN1 ;_; anything_PN1 which_DDQ the_AT designer_NN1 may_VM have_VHI omitted_VVN or_CC any_DD difficulties_NN2 the_AT operator_NN1 has_VHZ in_II moving_VVG around_RP ,_, manipulating_VVG controls_NN2 or_CC checking_VVG information_NN1 presentations_NN2 ._. 
Ultimately_RR ,_, the_AT machine_NN1 layout_NN1 or_CC interface_VV0 design_NN1 may_VM be_VBI modified_VVN to_TO make_VVI the_AT operating_NN1 instructions_NN2 easier_RRR to_TO follow_VVI ._. 
For_IF complex_JJ processes_NN2 the_AT procedures_NN2 can_VM include_VVI stages_NN2 of_IO diagnosis_NN1 (_( see_VV0 below_RL )_) because_CS the_AT operator_NN1 has_VHZ to_TO monitor_VVI and_CC interpret_VVI what_DDQ is_VBZ happening_VVG in_II the_AT plant_NN1 ._. 
In_RR21 particular_RR22 he_PPHS1 is_VBZ aware_JJ of_IO various_JJ conditional_JJ constraints_NN2 which_DDQ form_VV0 a_AT1 multidimensional_JJ envelope_NN1 ,_, and_CC whatever_DDQV happens_VVZ he_PPHS1 must_VM keep_VVI the_AT plant_NN1 state_NN1 within_II this_DD1 envelope_NN1 ._. 
Thus_RR he_PPHS1 must_VM have_VHI extensive_JJ knowledge_NN1 of_IO the_AT parameters_NN2 and_CC their_APPGE relationship_NN1 ,_, e.g._REX pressure/temperature_NN1 curves_NN2 ,_, together_RL with_IW the_AT safety_NN1 limits_NN2 of_IO each_DD1 parameter_NN1 ._. 
Sometimes_RT the_AT safety_NN1 limits_NN2 are_VBR fixed_VVN ,_, sometimes_RT they_PPHS2 are_VBR conditional_JJ on_II the_AT state_NN1 of_IO other_JJ variables_NN2 or_CC plant_NN1 ,_, sometimes_RT they_PPHS2 are_VBR merely_RR probabilistic_JJ ._. 
This_DD1 is_VBZ an_AT1 extremely_RR difficult_JJ task_NN1 ,_, and_CC the_AT operator_NN1 requires_VVZ various_JJ aids_NN2 such_II21 as_II22 alarm_NN1 systems_NN2 and_CC automatic_JJ cutout_NN1 devices_NN2 which_DDQ are_VBR also_RR effectively_RR monitoring_VVG the_AT parameters_NN2 approaching_VVG limits_NN2 (_( see_VV0 alarm_NN1 systems_NN2 p._NN1 225_MC )_) ._. 
Diagnostic_JJ task_NN1 analysis_NN1 is_VBZ even_RR more_RGR complex_JJ and_CC may_VM indeed_RR be_VBI virtually_RR impossible_JJ to_TO complete_VVI ._. 
It_PPH1 depends_VVZ on_II the_AT complexity_NN1 of_IO the_AT task_NN1 faced_VVN by_II the_AT operator_NN1 ._. 
The_AT range_NN1 of_IO diagnostic_JJ task_NN1 difficulties_NN2 for_IF a_AT1 control_NN1 centre_NN1 is_VBZ shown_VVN in_II Table_NN1 1.10_MC ._. 
The_AT operator_NN1 is_VBZ assumed_VVN to_TO be_VBI reacting_VVG to_II a_AT1 situation_NN1 in_II a_AT1 control_NN1 room_NN1 ,_, containing_VVG a_AT1 great_JJ variety_NN1 of_IO dials_NN2 ,_, charts_NN2 ,_, and_CC computer_NN1 driven_JJ displays_NN2 together_RL with_IW the_AT controls_NN2 needed_VVN to_TO take_VVI action_NN1 in_II any_DD part_NN1 of_IO the_AT system_NN1 ._. 
The_AT simplest_JJT thing_NN1 that_CST can_VM go_VVI wrong_RR is_VBZ the_AT failure_NN1 of_IO one_MC1 mechanism_NN1 such_II21 as_II22 a_AT1 pump_NN1 ,_, valve_NN1 or_CC thermostat_NN1 ._. 
This_DD1 will_VM be_VBI indicated_VVN in_II the_AT control_NN1 room_NN1 by_II changes_NN2 in_II pressures_NN2 and_CC temperatures_NN2 which_DDQ the_AT skilled_JJ operator_NN1 will_VM trace_VVI readily_RR to_II the_AT particular_JJ failure_NN1 ._. 
Usually_RR there_EX will_VM be_VBI some_DD redundancy_NN1 in_II the_AT system_NN1 so_CS21 that_CS22 other_JJ mechanisms_NN2 can_VM take_VVI over_RP ._. 
If_CS the_AT hiatus_NN1 is_VBZ serious_JJ he_PPHS1 may_VM have_VHI to_TO shut_VVI down_RP all_DB or_CC part_NN1 of_IO the_AT system_NN1 or_CC it_PPH1 may_VM trip_NN1 automatically_RR and_CC the_AT operator_NN1 's_GE task_NN1 is_VBZ to_TO observe/control_VVI the_AT shut-down_NN1 to_II a_AT1 quiescent_JJ state_NN1 ._. 
The_AT worst_JJT possible_JJ condition_NN1 that_CST can_VM be_VBI envisaged_VVN is_VBZ one_PN1 in_II which_DDQ there_EX is_VBZ an_AT1 expert_NN1 in_II the_AT plant_NN1 aiming_VVG to_TO do_VDI the_AT maximum_JJ possible_JJ damage_NN1 and_CC aware_JJ of_IO the_AT indications_NN2 of_IO his_APPGE actions_NN2 which_DDQ are_VBR transmitted_VVN to_II the_AT operator_NN1 this_DD1 is_VBZ not_XX quite_RG science-fiction_JJ ,_, it_PPH1 could_VM happen_VVI as_II a_AT1 form_NN1 of_IO sabotage_NN1 ,_, ._. 
A_AT1 much_RR less_RGR demanding_JJ condition_NN1 is_VBZ one_PN1 in_II which_DDQ the_AT saboteur_NN1 is_VBZ attempting_VVG to_TO damage_VVI a_AT1 plant_NN1 about_II which_DDQ he_PPHS1 has_VHZ little_RR or_CC no_AT technical_JJ knowledge_NN1 ._. 
However_RR ,_, the_AT difficult_JJ condition_NN1 which_DDQ requires_VVZ the_AT most_DAT consideration_NN1 because_CS it_PPH1 is_VBZ not_XX that_DD1 unlikely_JJ is_VBZ one_PN1 in_II which_DDQ the_AT operator_NN1 is_VBZ faced_VVN with_IW a_AT1 situation_NN1 where_RRQ various_JJ things_NN2 have_VH0 gone_VVN wrong_RR naturally_RR or_CC by_II inadvertent_JJ human_JJ interference_NN1 in_II the_AT plant_NN1 or_CC instrumentation_NN1 ._. 
His_APPGE diagnostic_JJ task_NN1 is_VBZ somehow_RR to_TO differentiate_VVI between_II the_AT information_NN1 he_PPHS1 is_VBZ receiving_VVG which_DDQ is_VBZ false_JJ and_CC that_DD1 which_DDQ is_VBZ valid_JJ and_CC follow_VV0 this_DD1 by_II the_AT selection_NN1 of_IO a_AT1 remedial_JJ strategy_NN1 ._. 
There_EX are_VBR further_JJR complications_NN2 in_II that_DD1 ,_, because_II21 of_II22 the_AT plant_NN1 failures_NN2 ,_, not_XX all_DB the_AT standard_JJ range_NN1 of_IO remedial_JJ actions_NN2 will_VM be_VBI available_JJ ._. 
Some_DD automatic_JJ reactions_NN2 may_VM be_VBI taking_VVG place_NN1 which_DDQ might_VM help_VVI or_CC hinder_VVI ,_, and_CC he_PPHS1 must_VM also_RR stay_VVI within_II the_AT mandatory_JJ operating_NN1 instructions_NN2 ._. 
Unfortunately_RR ,_, because_CS such_DA situations_NN2 are_VBR created_VVN by_II combinations_NN2 of_IO events_NN2 the_AT number_NN1 of_IO possibilities_NN2 is_VBZ very_RG large_JJ and_CC it_PPH1 would_VM be_VBI prohibitively_RR tedious_JJ to_TO enumerate_VVI all_DB of_IO them_PPHO2 ._. 
A_AT1 complete_JJ task_NN1 description_NN1 is_VBZ impossible_JJ and_CC the_AT appropriate_JJ preparation_NN1 for_IF the_AT operator_NN1 is_VBZ not_XX in_II direct_JJ training_NN1 but_CCB rather_RR in_II education/understanding_NN1 of_IO the_AT system_NN1 and_CC the_AT way_NN1 it_PPH1 operates_VVZ ._. 
He_PPHS1 must_VM attempt_VVI his_APPGE diagnosis_NN1 by_II returning_VVG to_II the_AT relevant_JJ scientific_JJ and_CC technological_JJ principles_NN2 ._. 
How_RRQ he_PPHS1 does_VDZ this_DD1 in_II general_JJ terms_NN2 is_VBZ illustrated_VVN in_II Fig._NN1 1._MC 18_MC ._. 
The_AT task_NN1 analysis_NN1 will_VM take_VVI the_AT form_NN1 of_IO a_AT1 consideration_NN1 of_IO the_AT most_RGT likely_JJ or_CC most_RGT dangerous_JJ failure_NN1 and_CC combinations_NN2 of_IO failures_NN2 and_CC the_AT ways_NN2 in_II which_DDQ these_DD2 will_VM appear_VVI as_CSA indications_NN2 in_II the_AT control_NN1 room_NN1 ._. 
This_DD1 should_VM occur_VVI not_XX only_RR at_II the_AT design_NN1 stage_NN1 but_CCB also_RR as_CSA experience_NN1 develops_VVZ in_II operating_VVG the_AT plant_NN1 and_CC data_NN on_II actual_JJ failures_NN2 and_CC failure_NN1 rates_NN2 become_VV0 available_JJ ._. 
Such_DA task_NN1 analysis_NN1 can_VM only_RR be_VBI carried_VVN out_RP to_II some_DD cost-effective_JJ limit_NN1 beyond_II which_DDQ the_AT skilled_JJ operator_NN1 must_VM be_VBI trusted_VVN to_TO get_VVI things_NN2 right_RR by_II applying_VVG his_APPGE broad_JJ expertise_NN1 ._. 
This_DD1 is_VBZ not_XX as_RG much_DA1 of_IO a_AT1 gamble_NN1 as_CSA it_PPH1 may_VM appear_VVI at_II first_MD sight_NN1 ,_, there_EX are_VBR general_JJ principles_NN2 of_IO how_RRQ to_TO cope_VVI with_IW the_AT system_NN1 ,_, some_DD of_IO which_DDQ can_VM be_VBI built_VVN into_II automatic_JJ safeguards_NN2 and_CC some_DD of_IO which_DDQ can_VM be_VBI conveyed_VVN to_II the_AT operator_NN1 as_CSA knowledge_NN1 and_CC instructions_NN2 ._. 
In_II serious_JJ cases_NN2 the_AT aim_NN1 is_VBZ to_TO shut_VVI down_RP the_AT system_NN1 safely_RR ._. 
In_II less_RGR serious_JJ cases_NN2 the_AT operator_NN1 may_VM for_IF a_AT1 while_NNT1 maintain_VV0 certain_JJ parameters_NN2 at_II appropriate_JJ levels_NN2 without_IW diverting_VVG his_APPGE attention_NN1 to_II detailed_JJ diagnosis_NN1 ,_, this_DD1 is_VBZ called_VVN function_NN1 control_NN1 ._. 
In_II dealing_VVG with_IW lower_JJR technology_NN1 or_CC less_RGR formal_JJ system_NN1 design_NN1 ,_, there_EX is_VBZ a_AT1 range_NN1 of_IO relatively_RR standard_JJ ways_NN2 of_IO finding_VVG out_RP about_II operator_NN1 performance_NN1 by_II studying_VVG it_PPH1 directly_RR ._. 
Task_NN1 analysis_NN1 ,_, in_II31 common_II32 with_II33 every_AT1 other_JJ perceptual_JJ process_NN1 ,_, is_VBZ a_AT1 matter_NN1 of_IO setting_VVG up_RP mechanisms_NN2 for_IF categorisation_NN1 and_CC filtering_NN1 ._. 
The_AT analyst_NN1 is_VBZ faced_VVN with_IW an_AT1 activity_NN1 which_DDQ is_VBZ continuous_JJ ,_, homogeneous_JJ and_CC full_JJ of_IO detail_NN1 ,_, some_DD of_IO which_DDQ is_VBZ significant_JJ and_CC relevant_JJ and_CC some_DD of_IO which_DDQ is_VBZ of_IO no_AT consequence_NN1 ._. 
For_REX21 example_REX22 ,_, the_AT worker_NN1 may_VM pause_VVI at_II one_MC1 point_NN1 and_CC scratch_VVI his_APPGE nose_NN1 ,_, this_DD1 may_VM indicate_VVI that_CST a_AT1 critical_JJ decision_NN1 is_VBZ being_VBG made_VVN or_CC it_PPH1 may_VM indicate_VVI simply_RR that_CST his_APPGE nose_NN1 was_VBDZ itching_VVG ._. 
The_AT art_NN1 of_IO task_NN1 analysis_NN1 always_RR is_VBZ to_TO select_VVI what_DDQ does_VDZ matter_VVI ,_, reject_VV0 what_DDQ does_VDZ not_XX matter_VVI and_CC separate_VVI into_II categories_NN2 or_CC stages_VVZ something_PN1 which_DDQ seems_VVZ at_II first_MD sight_NN1 to_TO have_VHI no_AT internal_JJ boundaries_NN2 ._. 
As_CSA already_RR mentioned_VVN what_DDQ is_VBZ significant_JJ for_IF a_AT1 task_NN1 description_NN1 leading_VVG to_II an_AT1 interface_NN1 design_NN1 may_VM be_VBI different_JJ from_II what_DDQ is_VBZ significant_JJ for_IF personnel_NN2 allocation_NN1 and_CC training_NN1 but_CCB the_AT available_JJ procedures_NN2 are_VBR the_AT same_DA ._. 
The_AT acquisition_NN1 of_IO evidence_NN1 and_CC the_AT presentation_NN1 of_IO evidence_NN1 are_VBR linked_VVN ,_, of_RR21 course_RR22 ,_, in_CS21 that_CS22 it_PPH1 may_VM be_VBI necessary_JJ to_TO decide_VVI what_DDQ should_VM be_VBI presented_VVN before_CS it_PPH1 is_VBZ acquired_VVN although_CS more_RGR usually_RR it_PPH1 is_VBZ a_AT1 matter_NN1 of_IO presenting_VVG what_DDQ can_VM be_VBI acquired_VVN ._. 
The_AT range_NN1 of_IO human_JJ tasks_NN2 has_VHZ already_RR been_VBN indicated_VVN by_II the_AT description_NN1 of_IO the_AT extremes_NN2 of_IO procedural_JJ and_CC diagnostic_JJ task_NN1 analysis_NN1 ._. 
The_AT simplest_JJT kind_NN1 of_IO human_JJ task_NN1 ,_, and_CC the_AT most_RGT straightforward_JJ to_TO observe_VVI and_CC analyse_VVI ,_, is_VBZ that_DD1 in_II which_DDQ the_AT operator_NN1 goes_VVZ through_II a_AT1 standard_JJ sequence_NN1 of_IO actions_NN2 ._. 
These_DD2 are_VBR still_RR common_JJ in_II industrial_JJ assembly_NN1 and_CC inspection_NN1 tasks_NN2 ._. 
The_AT most_RGT complex_JJ and_CC most_RGT difficult_JJ to_TO analyse_VVI are_VBR tasks_NN2 requiring_VVG original_JJ thinking_NN1 often_RR with_IW many_DA2 apparently_RR random_JJ alternations_NN2 between_II deduction_NN1 and_CC induction_NN1 ,_, this_DD1 occurs_VVZ in_II fault_NN1 diagnosis_NN1 tasks_NN2 ._. 
There_EX are_VBR at_RR21 least_RR22 two_MC dimensions_NN2 of_IO complexity_NN1 :_: the_AT kind_NN1 of_IO task_NN1 and_CC whether_CSW the_AT analysis_NN1 focuses_VVZ on_II material_NN1 ,_, information_NN1 or_CC people_NN ._. 
These_DD2 are_VBR illustrated_VVN in_II Table_NN1 1._MC 11_MC ._. 
Each_DD1 cell_NN1 in_II this_DD1 table_NN1 represents_VVZ an_AT1 enormous_JJ variety_NN1 of_IO human_JJ work_NN1 but_CCB this_DD1 is_VBZ hardly_RR surprising_JJ since_CS the_AT total_NN1 of_IO eighteen_MC cells_NN2 covers_VVZ all_DB human_JJ work_NN1 ._. 
There_EX is_VBZ a_AT1 variety_NN1 of_IO task_NN1 analysis_NN1 methods_NN2 available_JJ and_CC the_AT selection_NN1 of_IO an_AT1 appropriate_JJ set_NN1 varies_VVZ with_IW the_AT kind_NN1 of_IO work_NN1 (_( as_CSA represented_VVN by_II these_DD2 cells_NN2 )_) and_CC also_RR with_IW the_AT purposes_NN2 of_IO the_AT analysis_NN1 ._. 
Table_NN1 1.12_MC gives_VVZ examples_NN2 of_IO kinds_NN2 of_IO task_NN1 and_CC the_AT probably_RR appropriate_JJ method_NN1 of_IO task_NN1 analysis_NN1 for_IF each_DD1 cell_NN1 in_II Table_NN1 1.11_MC ._. 
It_PPH1 should_VM be_VBI emphasised_VVN that_CST this_DD1 is_VBZ only_RR a_AT1 tentative_JJ illustration_NN1 ._. 
The_AT method_NN1 used_VVN for_IF a_AT1 particular_JJ analysis_NN1 depends_VVZ on_II a_AT1 great_JJ variety_NN1 of_IO factors_NN2 including_II the_AT analyst_NN1 's_GE expertise_NN1 ,_, the_AT time_NNT1 available_JJ ,_, the_AT situations_NN2 accessible_JJ for_IF study_NN1 ,_, the_AT related_JJ information_NN1 already_RR available_JJ ,_, the_AT purpose_NN1 of_IO the_AT analysis_NN1 and_RR31 so_RR32 on_RR33 ._. 
Task_NN1 analysis_NN1 by_II observation_NN1 Process_NN1 charts_NN2 ._. 
Accurate_JJ observation_NN1 of_IO what_DDQ a_AT1 person_NN1 is_VBZ doing_VDG is_VBZ not_XX easy_JJ ._. 
The_AT observer_NN1 needs_VVZ some_DD discipline_NN1 which_DDQ ensures_VVZ that_CST he_PPHS1 really_RR does_VDZ focus_VVI on_II the_AT detail_NN1 and_CC separates_VVZ the_AT action_NN1 into_II a_AT1 coherent_JJ sequence_NN1 ._. 
The_AT required_JJ discipline_NN1 is_VBZ provided_VVN by_II the_AT attempt_NN1 to_TO complete_VVI a_AT1 chart_NN1 such_II21 as_II22 a_AT1 flow_NN1 process_NN1 chart_NN1 using_VVG the_AT A.S.M.E._NP1 symbols_NN2 ._. 
These_DD2 were_VBDR originally_RR standardised_VVN by_II the_AT American_JJ Society_NN1 of_IO Mechanical_JJ Engineers_NN2 ._. 
The_AT symbols_NN2 and_CC an_AT1 illustration_NN1 of_IO a_AT1 flow_NN1 process_NN1 chart_NN1 are_VBR shown_VVN in_II Fig._NN1 1.19_MC ._. 
It_PPH1 is_VBZ assumed_VVN that_CST whatever_DDQV an_AT1 operator_NN1 is_VBZ doing_VDG can_VM be_VBI classified_VVN into_II one_MC1 of_IO five_MC categories_NN2 :_: operation_NN1 ,_, inspection_NN1 ,_, transport_NN1 ,_, delay_NN1 and_CC storage_NN1 ._. 
Delay_NN1 occurs_VVZ when_RRQ the_AT operator_NN1 is_VBZ doing_VDG nothing_PN1 usually_RR waiting_VVG for_IF a_AT1 machine_NN1 to_TO complete_VVI a_AT1 subtask_NN1 it_PPH1 differs_VVZ from_II storage_NN1 where_CS there_EX has_VHZ been_VBN a_AT1 particular_JJ decision_NN1 to_TO put_VVI something_PN1 aside_RL ._. 
For_REX21 example_REX22 ,_, storage_NN1 for_IF a_AT1 hand_NN1 implies_VVZ some_DD static_JJ work_NN1 the_AT operator_NN1 is_VBZ holding_VVG something_PN1 or_CC exerting_VVG a_AT1 force_NN1 of_IO some_DD kind_NN1 although_CS there_EX is_VBZ no_AT resulting_JJ movement_NN1 ._. 
Process_VV0 charts_NN2 may_VM concentrate_VVI on_II material_NN1 ,_, operator_NN1 actions_NN2 or_CC the_AT events_NN2 in_II the_AT process_NN1 ._. 
These_DD2 are_VBR known_VVN respectively_RR as_CSA material-type_JJ ,_, man-type_JJ or_CC process-type_JJ charts_NN2 ._. 
More_DAR details_NN2 of_IO these_DD2 charts_NN2 and_CC how_RRQ to_TO complete_VVI them_PPHO2 are_VBR given_VVN in_II ILO_NP1 (_( 1979_MC )_) ._. 
The_AT same_DA symbols_NN2 are_VBR used_VVN for_IF a_AT1 two-handed_JJ process_NN1 chart_NN1 in_II which_DDQ a_AT1 detailed_JJ description_NN1 of_IO what_DDQ each_DD1 hand_NN1 is_VBZ doing_VDG separately_RR is_VBZ provided_VVN (_( Fig._NN1 1.20_MC )_) ._. 
The_AT meaning_NN1 of_IO the_AT symbols_NN2 changes_VVZ somewhat_RR because_CS the_AT separation_NN1 of_IO events_NN2 is_VBZ much_RR more_RGR detailed_JJ ._. 
The_AT same_DA symbols_NN2 can_VM also_RR be_VBI made_VVN to_TO follow_VVI the_AT concurrent_JJ behaviour_NN1 of_IO members_NN2 of_IO a_AT1 team_NN1 (_( Chapanis_NP1 ,_, 1959_MC )_) ._. 
p_ZZ1 52:DIAGRAM/FIGURE_VV0 Note_VV0 that_CST ,_, apart_II21 from_II22 the_AT inspection_NN1 category_NN1 ,_, the_AT emphasis_NN1 is_VBZ entirely_RR on_II what_DDQ the_AT operator_NN1 does_VDZ ._. 
Little_DA1 attention_NN1 is_VBZ paid_VVN to_II the_AT input_NN1 side_NN1 as_CSA distinct_JJ from_II the_AT output_NN1 side_NN1 ,_, the_AT sensory_JJ information_NN1 and_CC feed-back_NN1 which_DDQ the_AT operator_NN1 is_VBZ using_VVG to_TO control_VVI what_DDQ he_PPHS1 is_VBZ doing_VDG is_VBZ neglected_VVN ._. 
This_DD1 is_VBZ appropriate_JJ enough_RR for_IF highly_RR repetitive_JJ routine_NN1 tasks_NN2 because_CS ,_, as_CSA mentioned_VVN earlier_RRR ,_, the_AT operator_NN1 is_VBZ probably_RR proceeding_VVG with_IW little_DA1 conscious_JJ attention_NN1 and_CC the_AT limitation_NN1 on_II performance_NN1 is_VBZ in_II the_AT speed_NN1 of_IO the_AT action_NN1 rather_II21 than_II22 in_II the_AT informational_JJ control_NN1 ._. 
To_TO broaden_VVI the_AT emphasis_NN1 on_II a_AT1 two-handed_JJ process_NN1 chart_NN1 it_PPH1 is_VBZ possible_JJ to_TO add_VVI another_DD1 column_NN1 labelled_JJ '_GE attention_NN1 '_GE or_CC '_GE sensory_JJ activity_NN1 '_GE and_CC to_TO try_VVI to_TO describe_VVI human_JJ activity_NN1 in_II these_DD2 areas_NN2 at_II particular_JJ points_NN2 in_II the_AT sequence_NN1 ._. 
This_DD1 goes_VVZ beyond_II direct_JJ observations_NN2 and_CC requires_VVZ some_DD inference_NN1 or_CC speculation_NN1 on_II41 the_II42 part_II43 of_II44 the_AT observer._NNU pp_NNU2 5354:DIAGRAM/FIGURE_VV0 Finer_JJR analysis_NN1 of_IO hand_NN1 movements_NN2 is_VBZ possible_JJ using_VVG classifications_NN2 such_II21 as_II22 Therbligs_NP1 (_( Shaw_NP1 ,_, 1952_MC )_) ,_, or_CC Methods-Time-Measurement_NN2 symbols_NN2 (_( Maynard_NP1 et_RA21 al._RA22 ,_, 1956_MC )_) ._. 
Analysis_NN1 at_II this_DD1 level_NN1 of_IO detail_NN1 is_VBZ not_XX usually_RR attempted_VVN by_II direct_JJ observation_NN1 but_CCB rather_RR by_II film_NN1 or_CC video_NN1 analysis_NN1 ._. 
Sequence_NN1 charts_NN2 ._. 
These_DD2 are_VBR similar_JJ to_TO flow_VVI process_NN1 charts_NN2 except_CS21 that_CS22 no_AT standard_JJ symbols_NN2 are_VBR used_VVN ,_, the_AT chart_NN1 is_VBZ simply_RR a_AT1 list_NN1 of_IO the_AT actions_NN2 the_AT operator_NN1 takes_VVZ but_CCB there_EX may_VM well_RR be_VBI additional_JJ columns_NN2 referring_VVG to_II the_AT events_NN2 which_DDQ occur_VV0 and_CC the_AT consequent_JJ information_NN1 which_DDQ appears_VVZ ._. 
A_AT1 sequence_NN1 chart_NN1 is_VBZ more_RGR appropriate_JJ for_IF a_AT1 routine_NN1 interaction_NN1 with_IW a_AT1 machine_NN1 rather_II21 than_II22 a_AT1 physical_JJ manipulation_NN1 of_IO objects_NN2 ._. 
An_AT1 example_NN1 is_VBZ given_VVN in_II Table_NN1 1._MC 1_MC1 3_MC ._. 
Sequence_NN1 charts_NN2 are_VBR particularly_RR useful_JJ for_IF the_AT study_NN1 and_CC description_NN1 of_IO starting_VVG up_RP and_CC shutting_VVG down_RP procedures_NN2 ._. 
They_PPHS2 form_VV0 the_AT basis_NN1 for_IF procedural_JJ training_NN1 ._. 
Link_VV0 design_NN1 charts_NN2 ._. 
This_DD1 is_VBZ a_AT1 detailed_JJ sequence_NN1 chart_NN1 orientated_VVN more_RRR towards_II operator_NN1 choice_NN1 of_IO actions_NN2 and_CC correspondingly_RR relevant_JJ to_II the_AT study_NN1 of_IO interface_NN1 design_NN1 rather_II21 than_II22 training_NN1 (_( Singleton_NP1 ,_, 1964_MC )_) ._. 
It_PPH1 is_VBZ assumed_VVN that_CST for_IF every_AT1 action_NN1 the_AT operator_NN1 has_VHZ a_AT1 purpose_NN1 ,_, the_AT choice_NN1 of_IO the_AT particular_JJ action_NN1 at_II the_AT particular_JJ time_NNT1 or_CC point_NN1 in_II the_AT sequence_NN1 is_VBZ triggered_VVN by_II some_DD other_JJ event_NN1 ,_, usually_RR the_AT successful_JJ completion_NN1 of_IO an_AT1 action_NN1 is_VBZ indicated_VVN by_II a_AT1 particular_JJ information_NN1 presentation_NN1 which_DDQ also_RR is_VBZ noted_VVN on_II the_AT chart_NN1 ._. 
The_AT chart_NN1 is_VBZ particularly_RR useful_JJ for_IF detecting_VVG when_RRQ information_NN1 about_II action_NN1 completion_NN1 is_VBZ not_XX available_JJ and_CC when_CS an_AT1 action_NN1 is_VBZ required_VVN which_DDQ is_VBZ not_XX triggered_VVN by_II information_NN1 from_II the_AT situation_NN1 ._. 
That_REX21 is_REX22 ,_, the_AT operator_NN1 has_VHZ to_TO depend_VVI on_II his_APPGE memory_NN1 (_( which_DDQ is_VBZ unreliable_JJ )_) ._. 
An_AT1 example_NN1 is_VBZ given_VVN in_II Table_NN1 1._MC 14_MC ._. 
Flow_NN1 charts_NN2 ._. 
These_DD2 are_VBR more_RGR graphical_JJ presentations_NN2 as_CSA distinct_JJ from_II verbal_JJ listings_NN2 ._. 
They_PPHS2 are_VBR used_VVN to_TO indicate_VVI the_AT spatial_JJ location_NN1 and_CC separation_NN1 of_IO events_NN2 which_DDQ are_VBR integral_JJ parts_NN2 of_IO the_AT same_DA process_NN1 ._. 
An_AT1 illustration_NN1 of_IO a_AT1 flow_NN1 chart_NN1 is_VBZ given_VVN in_II Fig._NN1 1.21_MC ._. 
It_PPH1 is_VBZ possible_JJ to_TO obtain_VVI a_AT1 kind_NN1 of_IO flow_NN1 chart_NN1 automatically_RR as_RR31 it_RR32 were_RR33 by_II using_VVG successive_JJ photographs_NN2 of_IO operator_NN1 positions_NN2 on_II the_AT same_DA photographic_JJ plate_NN1 ._. 
More_RGR usually_RR ,_, this_DD1 is_VBZ done_VDN by_II attaching_VVG lights_NN2 to_II the_AT wrists_NN2 or_CC to_II other_JJ parts_NN2 of_IO the_AT body_NN1 ,_, if_CS the_AT light_NN1 is_VBZ flashing_VVG at_II a_AT1 known_JJ frequency_NN1 the_AT relative_JJ time_NNT1 of_IO particular_JJ positions_NN2 as_II31 well_II32 as_II33 the_AT sequence_NN1 can_VM be_VBI measured_VVN ._. 
This_DD1 is_VBZ called_VVN a_AT1 chronocyclograph_NN1 ._. 
Flow_NN1 charts_NN2 are_VBR a_AT1 useful_JJ record_NN1 of_IO a_AT1 process_NN1 but_CCB are_VBR not_XX particularly_RR suited_VVN as_II a_AT1 basis_NN1 for_IF analysis_NN1 which_DDQ might_VM lead_VVI to_II improved_JJ job_NN1 design_NN1 or_CC training_NN1 ._. 
On_II the_AT other_JJ hand_NN1 ,_, they_PPHS2 can_VM clearly_RR indicate_VVI differences_NN2 in_II ways_NN2 of_IO doing_VDG something_PN1 ._. 
Block_NN1 diagrams_NN2 ._. 
These_DD2 are_VBR particularly_RR useful_JJ to_TO describe_VVI situations_NN2 where_RRQ events_NN2 occur_VV0 in_II parallel_NN1 or_CC in_II patterns_NN2 rather_II21 than_II22 in_II a_AT1 single_JJ series_NN ._. 
The_AT block_NN1 diagram_NN1 is_VBZ highly_RR versatile_JJ as_II a_AT1 spatial_JJ representation_NN1 of_IO any_DD process_NN1 at_II any_DD level_NN1 ,_, that_DD1 is_VBZ the_AT same_DA process_NN1 can_VM be_VBI represented_VVN by_II one_MC1 block_NN1 or_CC by_II very_RG many_DA2 blocks_NN2 which_DDQ provide_VV0 more_DAR detail_NN1 ._. 
The_AT art_NN1 of_IO useful_JJ block_NN1 diagram_NN1 production_NN1 is_VBZ to_TO select_VVI the_AT appropriate_JJ level_NN1 of_IO detail_NN1 ._. 
Most_DAT people_NN find_VV0 such_DA diagrams_NN2 much_RR easier_JJR to_TO understand_VVI than_CSN paragraphs_NN2 of_IO explanatory_JJ prose_NN1 but_CCB the_AT flexibility_NN1 itself_PPX1 can_VM lead_VVI to_II the_AT difficulties_NN2 illustrated_VVN in_II Fig._NN1 1.22._MC p_ZZ1 5758:DIAGRAM/FIGURE_VV0 It_PPH1 is_VBZ important_JJ that_CST blocks_NN2 are_VBR at_II about_II the_AT same_DA level_NN1 of_IO complexity_NN1 within_II one_MC1 diagram_NN1 ._. 
Blocks_NN2 may_VM represent_VVI physical_JJ entities_NN2 ,_, topics_NN2 ,_, concepts_NN2 ,_, decisions_NN2 ,_, actions_NN2 or_CC processes_NN2 ._. 
If_CS these_DD2 are_VBR mixed_VVN in_II the_AT same_DA diagram_NN1 the_AT distinctions_NN2 between_II categories_NN2 should_VM be_VBI indicated_VVN by_II using_VVG differently_RR shaped_JJ blocks_NN2 ._. 
Many_DA2 of_IO the_AT figures_NN2 in_II this_DD1 chapter_NN1 illustrate_VV0 this_DD1 convention_NN1 ._. 
Homogeneity_NN1 is_VBZ also_RR desirable_JJ in_II the_AT meaning_NN1 of_IO lines_NN2 and_CC arrows_NN2 ._. 
A_AT1 line_NN1 may_VM indicate_VVI a_AT1 causal_JJ link_NN1 but_CCB simple_JJ cause-effect_JJ relationships_NN2 are_VBR destroyed_VVN if_CS there_EX are_VBR feed-back_NN1 lines_NN2 ._. 
Usually_RR the_AT line_NN1 represents_VVZ the_AT flow_NN1 of_IO something_PN1 but_CCB that_DD1 something_PN1 might_VM be_VBI material_NN1 ,_, energy_NN1 ,_, information_NN1 or_CC time_NNT1 but_CCB again_RT these_DD2 should_VM not_XX be_VBI mixed_VVN on_II the_AT same_DA diagram_NN1 unless_CS differently_RR coded_JJ lines_NN2 are_VBR used_VVN ._. 
It_PPH1 is_VBZ usually_RR possible_JJ to_TO invert_VVI a_AT1 diagram_NN1 so_RR that_CST blocks_NN2 and_CC lines_NN2 are_VBR interchanged_VVN ._. 
One_MC1 of_IO the_AT more_RGR subtle_JJ failures_NN2 is_VBZ to_TO confuse_VVI a_AT1 block_NN1 diagram_NN1 with_IW its_APPGE inverse_NN1 ._. 
An_AT1 inverted_JJ block_NN1 diagram_NN1 can_VM be_VBI a_AT1 path-node_JJ diagram_NN1 ._. 
The_AT advantage_NN1 of_IO these_DD2 is_VBZ that_CST the_AT length_NN1 of_IO the_AT path_NN1 can_VM be_VBI used_VVN to_TO indicate_VVI time_NNT1 taken_VVN ._. 
This_DD1 is_VBZ the_AT basis_NN1 of_IO '_GE critical-path_JJ analysis_NN1 '_GE where_CS such_DA a_AT1 network_NN1 can_VM be_VBI analysed_VVN ._. 
The_AT shortest_JJT path_NN1 through_II a_AT1 network_NN1 is_VBZ the_AT minimum_JJ time_NNT1 in_II which_DDQ the_AT whole_JJ process_NN1 represented_VVN could_VM be_VBI completed_VVN ._. 
The_AT longest_JJT sequence_NN1 of_IO required_JJ activities_NN2 is_VBZ the_AT time_NNT1 it_PPH1 will_VM take_VVI if_CSW no_AT adjustments_NN2 are_VBR made_VVN ._. 
An_AT1 optimum_JJ path_NN1 can_VM be_VBI selected_VVN and_CC other_JJ activities_NN2 adjusted_VVN to_II phase_NN1 in_RP with_IW those_DD2 on_II this_58 '_GE critical_JJ path_NN1 '_GE ._. 
There_EX are_VBR formal_JJ techniques_NN2 of_IO network_NN1 analysis_NN1 which_DDQ occasionally_RR prove_VV0 useful_JJ ;_; for_REX21 example_REX22 ,_, in_II identifying_VVG equivalent_JJ diagrams_NN2 or_CC ways_NN2 of_IO simplifying_JJ diagrams_NN2 (_( Battersby_NP1 ,_, 1970_MC )_) ._. 
Algorithm_NN1 charts_NN2 ._. 
These_DD2 are_VBR a_AT1 particular_JJ form_NN1 of_IO block_NN1 diagram_NN1 where_CS the_AT emphasis_NN1 is_VBZ on_II binary_JJ choices_NN2 ._. 
Again_RT there_EX can_VM be_VBI concentration_NN1 on_II events_NN2 or_CC on_II operator_NN1 decisions_NN2 ._. 
In_II the_AT latter_DA case_NN1 these_DD2 are_VBR usually_RR an_AT1 oversimplification_NN1 because_CS there_EX is_VBZ an_AT1 underlying_JJ assumption_NN1 that_CST decisions_NN2 are_VBR being_VBG made_VVN in_II a_AT1 simple_JJ logical_JJ sequence_NN1 ._. 
In_II practice_NN1 ,_, the_AT operator_NN1 jumps_VVZ forwards_RL and_CC backwards_RL within_II the_AT pattern_NN1 indicated_VVN on_II the_AT chart_NN1 rechecking_VVG some_DD decisions_NN2 and_CC anticipating_VVG others_NN2 ._. 
Nevertheless_RR ,_, by_II relating_VVG required_JJ information_NN1 to_II decision_NN1 points_VVZ any_DD lack_NN1 of_IO information_NN1 can_VM be_VBI revealed_VVN ._. 
It_PPH1 invariably_RR turns_VVZ out_RP that_CST an_AT1 operator_NN1 makes_VVZ a_AT1 series_NN of_IO decisions_NN2 partly_RR on_II the_AT basis_NN1 of_IO what_DDQ is_VBZ currently_RR displayed_VVN (_( on-line_JJ information_NN1 )_) and_CC partly_RR on_II the_AT basis_NN1 of_IO other_JJ material_NN1 obtained_VVN from_II his_APPGE knowledge_NN1 of_IO the_AT system_NN1 performance_NN1 ,_, his_APPGE briefing_NN1 and_CC his_APPGE operating_NN1 instructions_NN2 (_( off-line_JJ information_NN1 )_) ._. 
Adequate_JJ on-line_JJ and_CC off-line_JJ information_NN1 is_VBZ essential_JJ for_IF apposite_JJ decision-making_NN1 ._. 
Fig._NN1 1.23_MC shows_VVZ such_DA a_AT1 chart._NNU p_ZZ1 60:DIAGRAM/FIGURE_VV0 F.A.S._NP1 T._NP1 diagram_NN1 ._. 
Function_NN1 Analysis_NN1 System_NN1 Technique_NN1 was_VBDZ developed_VVN by_II Bytheway_NP1 (_( 1977_MC )_) within_II value_NN1 engineering_NN1 ._. 
It_PPH1 imposes_VVZ useful_JJ discipline_NN1 on_II the_AT production_NN1 of_IO a_AT1 functional_JJ diagram_NN1 in_II two_MC ways_NN2 ._. 
Within_II each_DD1 block_NN1 the_AT function_NN1 should_VM be_VBI described_VVN by_II a_AT1 verb_NN1 and_CC a_AT1 noun_NN1 ._. 
The_AT functions_NN2 are_VBR arranged_VVN in_II a_AT1 sequence_NN1 such_CS21 that_CS22 an_AT1 arrow_NN1 to_II the_AT right_NN1 on_II any_DD line_NN1 indicates_VVZ HOW_RRQ ?_? and_CC an_AT1 arrow_NN1 to_II the_AT left_NN1 indicates_VVZ WHY_RRQ ?_? 
If_CS these_DD2 criteria_NN2 can_VM not_XX be_VBI met_VVN then_RT either_RR the_AT functions_NN2 are_VBR in_II the_AT wrong_JJ order_NN1 or_CC some_DD are_VBR missing_VVG ._. 
The_AT diagram_NN1 should_VM be_VBI produced_VVN by_II writing_VVG each_DD1 function_NN1 on_II a_AT1 card_NN1 ,_, the_AT cards_NN2 are_VBR then_RT arranged_VVN to_TO meet_VVI the_AT criteria_NN2 ._. 
Unfortunately_RR the_AT resulting_JJ diagram_NN1 is_VBZ not_XX so_RG easy_JJ to_TO interpret_VVI as_CSA are_VBR some_DD of_IO the_AT other_JJ forms_NN2 of_IO chart_NN1 ._. 
In_RR21 particular_RR22 there_EX is_VBZ no_AT obvious_JJ starting_NN1 or_CC ending_VVG point_NN1 and_CC the_AT lines_NN2 do_VD0 not_XX indicate_VVI a_AT1 sequence_NN1 ._. 
Fig._NN1 1.24_MC shows_VVZ an_AT1 example_NN1 ._. 
General_JJ functional_JJ diagrams_NN2 ._. 
As_II a_AT1 Task_NN1 Description_NN1 ,_, a_AT1 block_NN1 diagram_NN1 is_VBZ intended_VVN to_TO illustrate_VVI the_AT dynamic_JJ behaviour_NN1 of_IO the_AT system_NN1 with_IW emphasis_NN1 on_II human_JJ interactions_NN2 within_II the_AT system_NN1 ._. 
For_IF some_DD purposes_NN2 it_PPH1 is_VBZ appropriate_JJ to_TO use_VVI blocks_NN2 and_CC lines_NN2 to_TO indicate_VVI the_AT flow_NN1 of_IO energy_NN1 or_CC material_NN1 and_CC to_TO indicate_VVI all_DB the_AT ways_NN2 in_II which_DDQ the_AT human_JJ operator_NN1 can_VM affect_VVI this_DD1 flow_NN1 ._. 
This_DD1 is_VBZ not_XX a_AT1 performance_NN1 diagram_NN1 but_CCB a_AT1 potential_JJ performance_NN1 diagram_NN1 (_( Fig._NN1 1.25_MC )_) ._. 
For_IF other_JJ purposes_NN2 it_PPH1 is_VBZ appropriate_JJ to_TO concentrate_VVI on_II a_AT1 specific_JJ sequential_JJ task_NN1 and_CC illustrate_VV0 the_AT order_NN1 of_IO events_NN2 involving_VVG human_JJ actions_NN2 (_( e.g._REX Figs._NN2 1._MC 19_MC and_CC 1.20_MC )_) ._. 
If_CS a_AT1 particular_JJ dimension_NN1 (_( usually_RR left_VVN to_II right_NN1 or_CC up_II21 to_II22 down_NN1 )_) indicates_VVZ a_AT1 time_NNT1 scale_NN1 as_II31 well_II32 as_II33 sequence_NN1 this_DD1 is_VBZ called_VVN a_AT1 time-line_JJ diagram_NN1 ._. 
The_AT blocks_NN2 may_VM even_RR be_VBI omitted_VVN to_TO further_RRR emphasise_VVI the_AT relative_JJ timing_NN1 of_IO events_NN2 ._. 
(_( Fig._NN1 1.26_MC )_) ._. 
Alternatively_RR if_CS the_AT process_NN1 is_VBZ highly_RR complex_JJ the_AT emphasis_NN1 may_VM be_VBI on_II the_AT pattern_NN1 of_IO events_NN2 as_CSA indicated_VVN by_II a_AT1 network_NN1 of_IO blocks_NN2 with_IW a_AT1 specialist_NN1 symbol_NN1 indicating_VVG the_AT many_DA2 points_NN2 within_II the_AT system_NN1 for_IF which_DDQ information_NN1 for_IF the_AT operator_NN1 might_VM appear_VVI and_CC another_DD1 symbol_NN1 for_IF points_NN2 where_RRQ he_PPHS1 can_VM interfere_VVI in_II the_AT system_NN1 dynamics_NN (_( Fig._NN1 1.27_MC )_) ._. 
Task_NN1 analysis_NN1 by_II discussion_NN1 Observation_NN1 of_IO operator_NN1 performance_NN1 within_II many_DA2 high_JJ technology_NN1 systems_NN2 reveals_VVZ nothing_PN1 more_DAR than_CSN a_AT1 person_NN1 sitting_VVG at_II a_AT1 desk_NN1 scanning_VVG various_JJ kinds_NN2 of_IO displays_NN2 at_II intervals_NN2 and_CC just_RR occasionally_RR picking_VVG up_RP a_AT1 telephone_NN1 ,_, making_VVG a_AT1 note_NN1 in_II a_AT1 log-book_NN1 or_CC manipulating_VVG a_AT1 control_NN1 ._. 
In_II such_DA situations_NN2 ,_, the_AT task_NN1 analysis_NN1 requires_VVZ extensive_JJ discussion_NN1 rather_II21 than_II22 observation_NN1 ._. 
Such_DA discussions_NN2 will_VM centre_NN1 on_II the_AT operators_NN2 themselves_PPX2 but_CCB may_VM also_RR involve_VVI others_NN2 such_II21 as_II22 the_AT management_NN1 ,_, the_AT training_NN1 officers_NN2 ,_, the_AT safety_NN1 specialists_NN2 and_CC the_AT system_NN1 designers_NN2 ._. 
There_EX will_VM often_RR be_VBI complications_NN2 in_CS21 that_CS22 there_EX can_VM be_VBI two_MC or_CC more_DAR operators_NN2 working_VVG simultaneously_RR with_IW overlapping_JJ tasks_NN2 ._. 
The_AT supervisor_NN1 may_VM also_RR monitor_VVI the_AT same_DA information_NN1 or_CC may_VM have_VHI his_APPGE own_DA separate_JJ displays_NN2 or_CC both_DB2 ._. 
In_II such_DA a_AT1 team_NN1 operation_NN1 there_EX will_VM normally_RR be_VBI a_AT1 clear_JJ standard_JJ mandatory_JJ difference_NN1 of_IO responsibility_NN1 but_CCB in_II practice_NN1 what_DDQ they_PPHS2 actually_RR do_VD0 can_VM overlap_VVI and_CC overlap_VVI differently_RR for_IF different_JJ teams_NN2 ._. 
Inevitably_RR ,_, discussion_NN1 with_IW different_JJ individuals_NN2 about_II a_AT1 particular_JJ task_NN1 will_VM yield_VVI very_RG different_JJ versions_NN2 of_IO what_DDQ is_VBZ being_VBG done_VDN or_CC should_VM be_VBI done_VDN ._. 
If_CS there_EX is_VBZ a_AT1 written_JJ version_NN1 of_IO what_DDQ ought_VMK to_TO be_VBI being_VBG done_VDN this_DD1 is_VBZ a_AT1 useful_JJ basic_JJ document_NN1 ._. 
However_RRQV the_AT supervisor_NN1 will_VM point_VVI out_RP that_CST things_NN2 have_VH0 changed_VVN since_CS that_DD1 was_VBDZ produced_VVN and_CC he_PPHS1 will_VM have_VHI his_APPGE own_DA view_NN1 of_IO the_AT essentials_NN2 of_IO the_AT task_NN1 ._. 
The_AT operators_NN2 themselves_PPX2 will_VM again_RT have_VHI a_AT1 different_JJ version_NN1 ._. 
The_AT differences_NN2 will_VM be_VBI mainly_RR in_II emphasis_NN1 on_II what_DDQ is_VBZ important_JJ central_JJ activity_NN1 and_CC what_DDQ is_VBZ peripheral_JJ ._. 
Even_RR between_II operators_NN2 carrying_VVG out_RP what_DDQ is_VBZ ostensibly_RR the_AT same_DA task_NN1 there_EX will_VM be_VBI discrepancies_NN2 ,_, particularly_RR if_CS the_AT discussion_NN1 extends_VVZ from_II what_DDQ is_VBZ required_VVN to_II the_AT way_NN1 these_DD2 requirements_NN2 are_VBR met_VVN ._. 
Similarly_RR the_AT specialists_NN2 ,_, the_AT training_NN1 officers_NN2 ,_, task_NN1 designers_NN2 and_CC safety_NN1 officers_NN2 will_VM have_VHI their_APPGE own_DA version_NN1 structured_VVN in_II31 terms_II32 of_II33 the_AT particular_JJ difficulties_NN2 they_PPHS2 have_VH0 had_VHN in_II their_APPGE specific_JJ contributions_NN2 to_II the_AT task_NN1 performance_NN1 ._. 
Finally_RR ,_, task_NN1 descriptions_NN2 differ_VV0 with_IW the_AT personal_JJ biases_NN2 of_IO analysts_NN2 and_CC the_AT reasons_NN2 why_RRQ they_PPHS2 are_VBR conducting_VVG the_AT analysis_NN1 ._. 
However_RR ,_, in_II31 spite_II32 of_II33 all_DB these_DD2 sources_NN2 of_IO ambiguity_NN1 the_AT comprehensive_JJ task_NN1 description_NN1 is_VBZ the_AT essential_JJ starting_NN1 point_NN1 for_IF most_DAT human_JJ factors_NN2 work_VV0 ._. 
An_AT1 approach_NN1 structured_VVN by_II a_AT1 particular_JJ procedure_NN1 is_VBZ of_IO considerable_JJ assistance_NN1 in_II reducing_VVG ambiguity_NN1 and_CC ensuring_VVG that_CST the_AT result_NN1 is_VBZ comprehensive_JJ ._. 
The_AT approach_NN1 might_VM consist_VVI of_IO any_DD one_MC1 or_CC any_DD combination_NN1 of_IO the_AT following_JJ techniques_NN2 ._. 
Responsibility_NN1 charts_NN2 ._. 
A_AT1 useful_JJ starting_NN1 point_NN1 for_IF the_AT study_NN1 of_IO any_DD system_NN1 is_VBZ a_AT1 responsibility_NN1 chart_NN1 ._. 
This_DD1 can_VM indicate_VVI not_XX only_RR the_AT hierarchy_NN1 but_CCB also_RR the_AT different_JJ levels_NN2 of_IO modelling_VVG the_AT system_NN1 ._. 
Normally_RR ,_, the_AT operators_NN2 closest_RRT to_II the_AT plant_NN1 will_VM have_VHI the_AT most_RGT detailed_JJ information_NN1 and_CC this_DD1 gets_VVZ condensed_JJ or_CC reduced_VVD as_CSA one_PN1 moves_VVZ up_RP the_AT hierarchy_NN1 ._. 
For_REX21 example_REX22 in_II a_AT1 power_NN1 station_NN1 the_AT desk_NN1 operator_NN1 will_VM monitor_VVI the_AT detail_NN1 of_IO the_AT plant_NN1 performance_NN1 ,_, the_AT supervisor_NN1 will_VM have_VHI more_DAR summarised_JJ information_NN1 and_CC greater_JJR contact_NN1 with_IW the_AT national_JJ grid_NN1 ,_, while_CS the_AT station_NN1 manager_NN1 's_GE on-line_JJ information_NN1 about_II the_AT plant_NN1 is_VBZ presented_VVN on_II one_MC1 or_CC at_II the_AT most_RGT two_MC dials_NN2 in_II his_APPGE office_NN1 which_DDQ indicate_VV0 station_NN1 output_NN1 ._. 
A_AT1 responsibility_NN1 chart_NN1 can_VM indicate_VVI not_XX only_RR decisions_NN2 and_CC duties_NN2 but_CCB also_RR the_AT information_NN1 needed_VVD to_TO discharge_VVI these_DD2 duties_NN2 (_( Table_NN1 1._MC 1_MC1 5_MC )_) ._. 
Although_CS it_PPH1 is_VBZ usual_JJ to_TO model_VVI responsibilities_NN2 in_II31 terms_II32 of_II33 a_AT1 hierarchical_JJ tree_NN1 there_EX are_VBR bound_VVNK to_TO be_VBI overlaps_NN2 between_II what_DDQ appear_VV0 to_TO be_VBI different_JJ levels_NN2 of_IO the_AT hierarchy_NN1 ._. 
These_DD2 shared_JJ or_CC duplicated_VVD responsibilities_NN2 are_VBR unavoidable_JJ and_CC often_RR in_II fact_NN1 are_VBR desirable_JJ because_CS the_AT process_NN1 is_VBZ one_MC1 of_IO mutual_JJ monitoring_NN1 which_DDQ usually_RR improves_VVZ reliability_NN1 ._. 
Occasionally_RR overlap_NN1 may_VM have_VHI the_AT opposite_JJ effect_NN1 due_II21 to_II22 the_AT '_GE falling_VVG between_II two_MC stools_NN2 '_GE phenomenon_NN1 ,_, two_MC operators_NN2 at_II the_AT same_DA level_NN1 or_CC at_II different_JJ levels_NN2 may_VM each_DD1 assume_VVI that_CST the_AT other_NN1 has_VHZ taken_VVN a_AT1 particular_JJ action_NN1 which_DDQ they_PPHS2 both_DB2 know_VV0 is_VBZ required_VVN ._. 
The_AT remedy_NN1 is_VBZ adequate_JJ information_NN1 feed-back_NN1 and_CC continuous_JJ checking_NN1 but_CCB the_AT need_NN1 for_IF this_DD1 may_VM not_XX be_VBI obvious_JJ from_II the_AT chart_NN1 because_CS the_AT areas_NN2 of_IO overlap_NN1 are_VBR difficult_JJ to_TO illustrate_VVI ._. 
It_PPH1 makes_VVZ for_IF much_RR neater_JJR charting_NN1 to_TO assume_VVI that_CST there_EX are_VBR no_AT overlaps_NN2 but_CCB this_DD1 defeats_VVZ one_MC1 of_IO the_AT main_JJ purposes_NN2 of_IO the_AT chart_NN1 ._. 
Hence_RR the_AT most_RGT comprehensive_JJ and_CC useful_JJ charts_NN2 often_RR have_VH0 many_DA2 irregular_JJ comments_NN2 ,_, asterisks_NN2 ,_, footnotes_NN2 ,_, directing_VVG arrows_NN2 and_RR31 so_RR32 on_RR33 ,_, which_DDQ at_II first_MD sight_NN1 detract_VV0 from_II the_AT clarity_NN1 of_IO the_AT presentation_NN1 ._. 
Hierarchical_JJ Analysis_NN1 ._. 
Tasks_NN2 ,_, in_II31 common_II32 with_II33 responsibilities_NN2 ,_, are_VBR susceptible_JJ to_II subdivision_NN1 at_II different_JJ levels_NN2 ._. 
A_AT1 useful_JJ way_NN1 of_IO describing_VVG a_AT1 complex_JJ task_NN1 is_VBZ to_TO separate_VVI it_PPH1 into_II sub-tasks_NN2 and_CC further_RRR separate_VV0 these_DD2 sub-tasks_NN2 into_II even_RR smaller_JJR units_NN2 ._. 
This_DD1 provides_VVZ a_AT1 very_RG clear_JJ picture_NN1 of_IO the_AT total_JJ activity_NN1 although_CS the_AT order_NN1 of_IO doing_VDG things_NN2 may_VM not_XX be_VBI obvious_JJ ._. 
Such_DA an_AT1 hierarchical_JJ table_NN1 (_( Fig._NN1 1.28_MC )_) can_VM be_VBI supplemented_VVN by_II lists_NN2 or_CC sequences_NN2 of_IO operations_NN2 which_DDQ define_VV0 a_AT1 plan_NN1 or_CC a_AT1 subroutine_NN1 within_II a_AT1 total_JJ task_NN1 ._. 
Correspondingly_RR ,_, a_AT1 tree_NN1 or_CC network_NN1 of_IO operations_NN2 can_VM define_VVI a_AT1 pattern_NN1 of_IO decision-making_NN1 ._. 
This_DD1 technique_NN1 ,_, originally_RR developed_VVN by_II Annett_NP1 et_RA21 al_RA22 (_( 1971_MC )_) ,_, has_VHZ been_VBN used_VVN extensively_RR as_II a_AT1 basis_NN1 for_IF training_NN1 and_CC retraining_VVG requirements_NN2 (_( Duncan_NP1 ,_, 1975_MC ,_, Shepherd_NP1 and_CC Duncan_NP1 ,_, 1980_MC )_) ,_, and_CC also_RR for_IF the_AT study_NN1 of_IO job_NN1 satisfaction_NN1 (_( Crawley_NP1 and_CC Spurgeon_NP1 ,_, 1979_MC )_) ._. 
For_IF a_AT1 particular_JJ system_NN1 there_EX may_VM be_VBI many_DA2 different_JJ but_CCB equally_RR valid_JJ ways_NN2 of_IO separating_JJ tasks_NN2 into_II sub-tasks_NN2 depending_II21 on_II22 the_AT relative_JJ emphasis_NN1 on_II training_NN1 ,_, interface_VV0 design_NN1 and_CC other_JJ system_NN1 design_NN1 aspects_NN2 ._. 
Sometimes_RT a_AT1 '_GE bottom-up_NN1 '_GE approach_NN1 may_VM be_VBI better_JJR than_CSN a_AT1 '_GE top-down_JJ '_GE one_MC1 ._. 
Protocol_NN1 analysis_NN1 ._. 
An_AT1 operator_NN1 carrying_VVG out_RP a_AT1 task_NN1 can_VM be_VBI asked_VVN to_TO talk_VVI about_II what_DDQ he_PPHS1 is_VBZ doing_VDG as_CSA he_PPHS1 does_VDZ it_PPH1 ._. 
Clearly_RR this_DD1 is_VBZ useful_JJ for_IF tasks_NN2 which_DDQ involve_VV0 extensive_JJ scanning_NN1 of_IO information_NN1 sources_NN2 and_CC deliberations_NN2 about_II what_DDQ action_NN1 to_TO take_VVI ._. 
The_AT visible_JJ action_NN1 may_VM apparently_RR be_VBI trivial_JJ adjusting_VVG one_MC1 or_CC two_MC of_IO very_RG many_DA2 available_JJ controls_NN2 or_CC may_VM even_RR be_VBI non-existent_JJ ._. 
This_DD1 sort_NN1 of_IO task_NN1 is_VBZ very_RG common_JJ in_II process_NN1 control_NN1 situations_NN2 where_RRQ the_AT operator_NN1 often_RR makes_VVZ a_AT1 preliminary_JJ three-way_JJ decision_NN1 corresponding_VVG to_II the_AT worldwide_JJ system_NN1 of_IO red_NN1 ,_, amber_JJ and_CC green_JJ traffic_NN1 lights_NN2 ._. 
That_REX21 is_REX22 ,_, he_PPHS1 does_VDZ nothing_PN1 ,_, he_PPHS1 does_VDZ nothing_PN1 at_II the_AT moment_NN1 but_CCB prepares_VVZ for_IF action_NN1 ,_, or_CC he_PPHS1 takes_VVZ action_NN1 ._. 
Because_CS so_RG much_DA1 of_IO the_AT activity_NN1 is_VBZ in_II searching_VVG for_IF information_NN1 and_CC processing_VVG it_PPH1 leading_VVG to_II a_AT1 decision_NN1 ,_, the_AT observed_JJ output_NN1 is_VBZ obviously_RR a_AT1 poor_JJ indicator_NN1 of_IO total_JJ activity_NN1 and_CC his_APPGE verbal_JJ commentary_NN1 is_VBZ a_AT1 much_RR better_JJR guide_NN1 to_II his_APPGE task_NN1 performance_NN1 ._. 
Such_DA a_AT1 commentary_NN1 can_VM be_VBI recorded_VVN or_CC notes_NN2 can_VM be_VBI taken_VVN directly_RR by_II the_AT analyst_NN1 ._. 
The_AT snag_NN1 about_II recording_NN1 is_VBZ that_CST an_AT1 enormous_JJ amount_NN1 of_IO material_NN1 is_VBZ produced_VVN which_DDQ is_VBZ very_RG tedious_JJ to_TO analyse_VVI ._. 
The_AT presentation_NN1 of_IO the_AT result_NN1 may_VM use_VVI any_DD of_IO the_AT charting_JJ methods_NN2 described_VVN in_II this_DD1 chapter_NN1 ,_, or_CC may_VM take_VVI the_AT form_NN1 of_IO a_AT1 descriptive_JJ narrative_NN1 ._. 
M.C.I._MC Job-process_JJ analysis_NN1 ._. 
Man-Computer_JJ Interaction_NN1 has_VHZ further_RRR complicated_VVN the_AT relationship_NN1 between_II human_JJ operators_NN2 and_CC other_JJ parts_NN2 of_IO a_AT1 system_NN1 but_CCB the_AT computer_NN1 can_VM help_VVI to_TO analyse_VVI these_DD2 interactions_NN2 ._. 
Tainsh_NP1 (_( 1985_MC )_) has_VHZ developed_VVN a_AT1 technique_NN1 in_II which_DDQ a_AT1 computer-based_JJ simulation_NN1 of_IO a_AT1 generic_JJ information_NN1 handling_NN1 task_NN1 is_VBZ used_VVN to_TO assist_VVI in_II analysing_VVG the_AT behaviour_NN1 of_IO an_AT1 operator_NN1 or_CC a_AT1 team_NN1 of_IO operators_NN2 ._. 
There_EX are_VBR two_MC V.D.U.s_NP1 ,_, one_MC1 displaying_VVG alphanumeric_JJ data_NN ,_, the_AT other_JJ graphical_JJ data_NN ._. 
A_AT1 group_NN1 of_IO operators_NN2 (_( note_VV0 ,_, these_DD2 are_VBR people_NN with_IW extensive_JJ experience_NN1 of_IO the_AT same_DA or_CC similar_JJ tasks_NN2 ,_, not_XX the_AT unskilled_JJ performer_NN1 normally_RR used_VVN in_II human_JJ performance_NN1 experiments_NN2 )_) run_VV0 through_II a_AT1 task_NN1 using_VVG this_DD1 equipment_NN1 ._. 
Their_APPGE behaviour_NN1 and_CC achievements_NN2 are_VBR observed_VVN and_CC discussed_VVN amongst_II themselves_PPX2 and_CC with_IW the_AT analyst_NN1 (_( Fig._NN1 1.29_MC )_) ._. 
p_ZZ1 6768:DIAGRAM/FIGURE_VV0 Conclusion_NN1 Task_NN1 analysis_NN1 has_VHZ not_XX and_CC can_VM not_XX be_VBI reduced_VVN to_II a_AT1 set_NN1 of_IO standardised_JJ procedures_NN2 which_DDQ the_AT aspiring_JJ analyst_NN1 could_VM acquire_VVI in_II a_AT1 formal_JJ training_NN1 course_NN1 ._. 
The_AT techniques_NN2 just_RR described_VVN are_VBR no_AT more_DAR than_CSN guidelines_NN2 in_II what_DDQ remains_VVZ the_AT creative_JJ art_NN1 of_IO studying_VVG and_CC describing_VVG what_DDQ an_AT1 experienced_JJ worker_NN1 is_VBZ doing_VDG or_CC will_VM be_VBI required_VVN to_TO do_VDI ._. 
The_AT danger_NN1 in_II being_VBG too_RG rigid_JJ is_VBZ that_DD1 justice_NN1 will_VM not_XX be_VBI done_VDN to_II the_AT flexibility_NN1 and_CC complexity_NN1 of_IO human_JJ performance_NN1 ._. 
The_AT danger_NN1 of_IO being_VBG too_RG flexible_JJ is_VBZ that_CST the_AT ergonomists_NN2 will_VM have_VHI an_AT1 inadequate_JJ basis_NN1 from_II which_DDQ to_TO design_VVI interfaces_NN2 ,_, training_NN1 courses_NN2 and_CC other_JJ operator_NN1 aids_NN2 ._. 
If_CS a_AT1 comprehensive_JJ task_NN1 description_NN1 can_VM be_VBI completed_VVN then_RT it_PPH1 is_VBZ legitimate_JJ to_TO enquire_VVI why_RRQ the_AT task_NN1 can_VM not_XX be_VBI allocated_VVN to_II a_AT1 technical_JJ device_NN1 rather_II21 than_II22 a_AT1 human_JJ being_NN1 ._. 
Yet_RR without_IW a_AT1 reasonably_RR comprehensive_JJ task_NN1 description_NN1 the_AT total_JJ system_NN1 performance_NN1 may_VM be_VBI unreliable_JJ or_CC unpredictable_JJ ._. 
There_EX is_VBZ a_AT1 necessary_JJ compromise_NN1 which_DDQ can_VM only_RR be_VBI arrived_VVN at_II in_II the_AT context_NN1 of_IO a_AT1 particular_JJ system_NN1 ._. 
As_CSA mentioned_VVN earlier_RRR there_EX are_VBR always_RR the_AT twin_NN1 problems_NN2 of_IO how_RRQ to_TO get_VVI the_AT information_NN1 and_CC how_RRQ to_TO present_VVI it_PPH1 ._. 
It_PPH1 is_VBZ sometimes_RT easier_JJR to_TO proceed_VVI on_II the_AT basis_NN1 of_IO :_: '_GE If_CS I_PPIS1 were_VBDR doing_VDG the_AT job_NN1 this_DD1 is_VBZ how_RRQ I_PPIS1 would_VM do_VDI it_PPH1 '_VBZ ,_, but_CCB this_DD1 can_VM be_VBI delusory_JJ even_RR for_IF analysts_NN2 who_PNQS have_VH0 past_JJ experience_NN1 as_CSA operators_NN2 ._. 
For_IF analysts_NN2 who_PNQS are_VBR designers_NN2 creating_VVG a_AT1 new_JJ task_NN1 there_EX may_VM be_VBI no_AT alternative_NN1 ,_, but_CCB any_DD task_NN1 description_NN1 arrived_VVN at_II by_II this_DD1 method_NN1 should_VM be_VBI checked_VVN against_II the_AT behaviour_NN1 of_IO real_JJ operators_NN2 as_CSA they_PPHS2 gain_VV0 experience_NN1 ._. 
A_AT1 particular_JJ difficulty_NN1 about_II task_NN1 synthesis_NN1 is_VBZ that_CST there_EX is_VBZ no_AT easy_JJ way_NN1 of_IO confirming_VVG completeness_NN1 ._. 
A_AT1 task_NN1 description_NN1 which_DDQ is_VBZ part_NN1 of_IO a_AT1 design_NN1 process_NN1 should_VM be_VBI fully_RR documented_VVN in_II31 terms_II32 of_II33 the_AT origins_NN2 of_IO information_NN1 ,_, the_AT assumptions_NN2 made_VVN and_CC the_AT methods_NN2 used_VVD ._. 
The_AT standard_JJ method_NN1 of_IO producing_VVG task_NN1 descriptions_NN2 is_VBZ to_TO write_VVI all_DB the_AT separate_JJ sub-tasks_NN2 at_II various_JJ levels_NN2 on_II cards_NN2 and_CC then_RT assemble_VV0 the_AT cards_NN2 in_II a_AT1 network_NN1 ._. 
There_EX is_VBZ a_AT1 temptation_NN1 to_TO make_VVI these_DD2 final_JJ diagrams_NN2 very_RG large_JJ ,_, but_CCB often_RR it_PPH1 is_VBZ more_RGR useful_JJ to_TO separate_VVI into_II small_JJ units_NN2 with_IW cross-referencing_NN1 ._. 
The_AT optimum_JJ size_NN1 seems_VVZ to_TO be_VBI A3_FO ,_, this_DD1 is_VBZ easily_RR copied_VVN and_CC circulated_VVN but_CCB is_VBZ large_JJ enough_RR to_TO contain_VVI considerable_JJ detail_NN1 ._. 
The_AT procedure_NN1 can_VM be_VBI computerised_JJ ,_, there_EX are_VBR programmes_NN2 available_JJ for_IF the_AT easy_JJ production_NN1 ,_, manipulation_NN1 and_CC storage_NN1 of_IO block_NN1 diagrams_NN2 with_IW useful_JJ cross-referencing_NN1 facilities_NN2 ._. 
There_EX is_VBZ an_AT1 inherent_JJ difficulty_NN1 in_II that_DD1 often_RR the_AT main_JJ dividend_NN1 from_II a_AT1 task_NN1 analysis_NN1 is_VBZ from_II the_AT act_NN1 of_IO obtaining_VVG it_PPH1 ._. 
Those_DD2 not_XX involved_VVN find_VV0 it_PPH1 difficult_JJ to_TO gain_VVI very_RG much_DA1 from_II a_AT1 presentation_NN1 of_IO a_AT1 task_NN1 description_NN1 ._. 
Like_II reference_NN1 books_NN2 ,_, they_PPHS2 have_VH0 to_TO be_VBI used_VVN rather_CS21 than_CS22 read_VVI ._. 
Task_NN1 analysis_NN1 can_VM be_VBI very_RG expensive_JJ in_II skilled_JJ manpower_NN1 ,_, but_CCB in_II looking_VVG at_II cost/value_NN1 it_PPH1 is_VBZ important_JJ to_TO include_VVI in_II value_NN1 the_AT increase_NN1 in_II mutual_JJ understanding_NN1 which_DDQ occurs_VVZ when_RRQ a_AT1 multi-disciplinary_JJ team_NN1 conducts_VVZ the_AT analysis_NN1 ._. 
If_CS such_DA a_AT1 team_NN1 is_VBZ used_VVN the_AT required_JJ man-hours_NNT2 can_VM be_VBI optimised_VVN by_II using_VVG the_AT Delphi_NP1 method_NN1 rather_II21 than_II22 a_AT1 long_JJ series_NN of_IO group_NN1 meetings_NN2 ._. 
Political_JJ ,_, economic_JJ and_CC social_JJ issues_NN2 which_DDQ arise_VV0 in_II conducting_VVG Task_NN1 Analyses_NN2 are_VBR discussed_VVN in_II the_AT context_NN1 of_IO Job_NN1 Analysis_NN1 (_( p._NNU 148_MC )_) ._. 
Application_NN1 Man-power_NN1 planning_VVG The_AT '_GE Human_JJ Resource_NN1 '_GE concept_NN1 of_IO man-power_NN1 as_II the_AT central_JJ profitgenerating_JJ asset_NN1 of_IO any_DD organisation_NN1 has_VHZ made_VVN some_DD progress_NN1 over_II the_AT past_JJ twenty_MC years_NNT2 ._. 
There_EX was_VBDZ particular_JJ interest_NN1 around_RG 1970_MC when_RRQ companies_NN2 were_VBDR prosperous_JJ ,_, stable_JJ and_CC innovative_JJ (_( IPM_NP1 ,_, 1972_MC ,_, Patten_NP1 ,_, 1971_MC )_) ._. 
The_AT objective_NN1 is_VBZ to_TO revise_VVI and_CC almost_RR reverse_VVI the_AT traditional_JJ accountancy_NN1 concept_NN1 of_IO man-power_NN1 as_II a_AT1 resource_NN1 consuming_VVG factor_NN1 requiring_VVG regular_JJ payments_NN2 ,_, overheads_NN2 in_II the_AT form_NN1 of_IO heated_JJ ,_, lighted_VVD ,_, equipped_VVN workspaces_NN2 and_RR31 so_RR32 on_RR33 ._. 
From_II the_AT narrow_JJ accountancy_NN1 viewpoint_NN1 ,_, people_NN are_VBR a_AT1 cost_NN1 and_CC it_PPH1 is_VBZ desirable_JJ to_TO keep_VVI this_DD1 cost_NN1 as_RG low_JJ as_CSA possible_JJ ._. 
In_II these_DD2 terms_NN2 it_PPH1 is_VBZ very_RG difficult_JJ to_TO justify_VVI ,_, for_REX21 example_REX22 ,_, sending_VVG a_AT1 member_NN1 of_IO staff_NN on_II a_AT1 training_NN1 course_NN1 ._. 
The_AT training_NN1 requires_VVZ expenditure_NN1 and_CC so_RG also_RR does_VDZ the_AT replacement_NN1 for_IF the_AT person_NN1 away_RL ._. 
Where_RRQ is_VBZ the_AT return_NN1 ?_? 
The_AT return_NN1 is_VBZ actually_RR in_II the_AT improved_JJ human_JJ resource_NN1 but_CCB this_DD1 is_VBZ not_XX readily_RR measurable_JJ in_II terms_NN2 which_DDQ accountants_NN2 use_VV0 ._. 
There_EX have_VH0 been_VBN two_MC attempts_NN2 to_TO reduce_VVI human_JJ resources_NN2 to_II this_DD1 form_NN1 of_IO measurement_NN1 (_( Giles_NP1 and_CC Robinson_NP1 ,_, 1972_MC )_) ._. 
One_MC1 is_VBZ to_TO acquire_VVI a_AT1 human_JJ asset_NN1 multiplier_NN1 for_IF each_DD1 level_NN1 of_IO staff_NN ._. 
The_AT multiplier_NN1 for_IF manual_JJ staff_NN might_VM be_VBI unity_NN1 but_CCB it_PPH1 increases_VVZ with_IW staff_NN level_JJ and_CC becomes_VVZ three_MC or_CC more_RRR for_IF management_NN1 ._. 
The_AT other_NN1 is_VBZ to_TO add_VVI together_RL all_DB the_AT personnel_NN2 costs_VVZ for_IF each_DD1 kind_NN1 of_IO worker_NN1 from_II the_AT original_JJ job_NN1 advertisement_NN1 through_RP to_II the_AT retirement_NN1 or_CC redundancy_NN1 payments_NN2 ._. 
The_AT first_MD does_VDZ attempt_VVI to_TO obtain_VVI a_AT1 value_NN1 ,_, the_AT second_MD remains_VVZ essentially_RR a_AT1 cost_NN1 and_CC not_XX a_AT1 value_NN1 ._. 
It_PPH1 would_VM be_VBI unduly_RR optimistic_JJ to_TO assume_VVI that_DD1 management_NN1 skills_NN2 have_VH0 risen_VVN to_II a_AT1 level_NN1 such_CS21 that_CS22 costs_NN2 undertaken_VVN can_VM be_VBI assumed_VVN to_TO be_VBI equivalent_JJ to_II value_NN1 ._. 
A_AT1 less_RGR direct_JJ measure_NN1 which_DDQ is_VBZ applicable_JJ only_RR to_II the_AT most_RGT senior_JJ management_NN1 is_VBZ to_TO observe_VVI the_AT fall_NN1 or_CC rise_NN1 of_IO the_AT share_NN1 price_NN1 when_CS a_AT1 particular_JJ executive_NN1 leaves_NN2 or_CC joins_VVZ a_AT1 company_NN1 ._. 
This_DD1 can_VM be_VBI very_RG high_JJ ,_, for_IF a_AT1 large_JJ company_NN1 a_AT1 change_NN1 in_II market_NN1 value_NN1 of_IO millions_NNO2 of_IO pounds_NN2 is_VBZ not_XX unusual_JJ ._. 
The_AT most_RGT serious_JJ consequence_NN1 of_IO the_AT accountancy_NN1 view_NN1 of_IO man-power_NN1 is_VBZ that_DD1 high_JJ level_JJ policy_NN1 decision-making_NN1 does_VDZ not_XX give_VVI this_DD1 factor_NN1 sufficient_JJ weight_NN1 ._. 
For_REX21 example_REX22 ,_, the_AT main_JJ board_NN1 of_IO a_AT1 company_NN1 will_VM have_VHI complete_JJ details_NN2 of_IO cost_NN1 and_CC values_NN2 of_IO physical_JJ resources_NN2 such_II21 as_II22 buildings_NN2 and_CC equipment_NN1 but_CCB relatively_RR scanty_JJ data_NN about_II the_AT man-power_NN1 which_DDQ is_VBZ their_APPGE most_RGT important_JJ asset_NN1 ._. 
Indeed_RR it_PPH1 will_VM be_VBI described_VVN almost_RR entirely_RR as_II a_AT1 liability_NN1 because_CS the_AT costs_NN2 will_VM be_VBI known_VVN ._. 
Similarly_RR ,_, broad_JJ factors_NN2 such_II21 as_II22 the_AT state_NN1 of_IO morale_NN1 will_VM again_RT only_RR be_VBI described_VVN by_II negative_JJ features_NN2 such_II21 as_II22 absenteeism_NN1 ,_, stoppages_NN2 ,_, strikes_NN2 ,_, low_JJ quality_NN1 output_NN1 and_RR31 so_RR32 on_RR33 ._. 
It_PPH1 is_VBZ obvious_JJ that_CST company_NN1 output_NN1 and_CC projects_NN2 must_VM reflect_VVI the_AT man-power_NN1 and_CC its_APPGE performance_NN1 level_NN1 ,_, but_CCB ,_, if_CS this_DD1 is_VBZ acknowledged_VVN at_RR21 all_RR22 ,_, it_PPH1 is_VBZ only_RR in_II brief_JJ verbal_JJ terms_NN2 within_RL ,_, for_REX21 example_REX22 ,_, the_AT chairman_NN1 's_GE annual_JJ report_NN1 ._. 
The_AT obsession_NN1 ,_, of_IO current_JJ management_NN1 ,_, with_IW measurement_NN1 and_CC the_AT reduction_NN1 of_IO every_AT1 variable_NN1 to_II numbers_NN2 for_IF ease_NN1 of_IO computer_NN1 manipulation_NN1 has_VHZ worsened_VVN the_AT situation_NN1 ._. 
Unfortunately_RR there_EX is_VBZ no_AT easy_JJ remedy_NN1 ._. 
Human_JJ resources_NN2 are_VBR too_RG complex_JJ a_AT1 variable_NN1 to_TO be_VBI easily_RR susceptible_JJ to_II measurement_NN1 beyond_II the_AT level_NN1 of_IO counting_VVG heads_NN2 and_CC trades_NN2 ._. 
Key_JJ variables_NN2 such_II21 as_II22 the_AT quality_NN1 of_IO staff_NN at_II any_DD level_NN1 and_CC the_AT current_JJ morale_NN1 are_VBR only_RR expressible_JJ in_RR21 general_RR22 verbal_JJ descriptive_JJ terms_NN2 ._. 
It_PPH1 is_VBZ generally_RR accepted_VVN (_( p._NNU 145_MC )_) that_DD1 '_VBZ hygiene_NN1 '_GE type_NN1 variables_NN2 such_II21 as_II22 pay_NN1 and_CC working_VVG conditions_NN2 can_VM ,_, if_CS they_PPHS2 are_VBR inappropriately_RR specified_VVN ,_, depress_VV0 morale_NN1 and_CC motivation_NN1 but_CCB they_PPHS2 will_VM not_XX in_II themselves_PPX2 result_VV0 in_II very_RG high_JJ levels_NN2 of_IO these_DD2 parameters_NN2 ._. 
Morale_NN1 and_CC motivation_NN1 are_VBR influenced_VVN more_RRR by_II conditions_NN2 of_IO work_NN1 in_II the_AT sense_NN1 of_IO work_NN1 variety_NN1 opportunities_NN2 and_CC attitudes_NN2 of_IO management_NN1 ._. 
These_DD2 factors_NN2 are_VBR worthy_JJ of_IO emphasis_NN1 because_CS in_II practice_NN1 they_PPHS2 are_VBR still_RR dealt_VVN with_IW very_RG badly_RR in_II many_DA2 organisations_NN2 and_CC yet_RR it_PPH1 takes_VVZ little_DA1 trouble_NN1 or_CC expertise_NN1 to_TO make_VVI an_AT1 enormous_JJ difference._NNU for_REX21 example_REX22 ,_, very_RG few_DA2 senior_JJ managements_NN2 take_VV0 the_AT trouble_NN1 to_TO keep_VVI workers_NN2 fully_RR informed_VVN about_II policies_NN2 and_CC likely_JJ changes_NN2 ._. 
The_AT result_NN1 is_VBZ excessive_JJ reliance_NN1 on_II rumour_NN1 and_CC continuous_JJ speculation_NN1 which_DDQ is_VBZ not_XX only_RR time-consuming_JJ but_CCB is_VBZ also_RR highly_RR deleterious_JJ in_II morale_NN1 terms_NN2 ._. 
The_AT two_MC human_JJ factors_NN2 which_DDQ can_VM be_VBI unambiguously_RR measured_VVN are_VBR age_NN1 and_CC sex_NN1 ._. 
The_AT age_NN1 distribution_NN1 of_IO a_AT1 work_NN1 force_NN1 is_VBZ always_RR an_AT1 interesting_JJ and_CC important_JJ source_NN1 of_IO information_NN1 ._. 
For_IF most_DAT purposes_NN2 a_AT1 rectangular_JJ distribution_NN1 is_VBZ the_AT most_RGT desirable_JJ because_CS it_PPH1 provides_VVZ the_AT appropriate_JJ mix_NN1 of_IO youthful_JJ enthusiasm_NN1 and_CC ageing_JJ experience_NN1 ._. 
It_PPH1 also_RR makes_VVZ for_IF regular_JJ changes_NN2 as_CSA staff_NN retire_VV0 and_CC are_VBR replaced_VVN ._. 
Many_DA2 distributions_NN2 show_VV0 a_AT1 peak_NN1 in_II a_AT1 particular_JJ age_NN1 group_NN1 mainly_RR associated_VVN with_IW taking_VVG on_RP a_AT1 large_JJ number_NN1 of_IO young_JJ people_NN when_CS the_AT organisation_NN1 was_VBDZ started_VVN or_CC reorganised_VVD ,_, this_DD1 is_VBZ not_XX desirable_JJ because_CS it_PPH1 leads_VVZ to_II excessive_JJ competition_NN1 for_IF promotion_NN1 at_II particular_JJ stages_NN2 ._. 
These_DD2 comments_NN2 are_VBR obviously_RR most_RGT relevant_JJ for_IF work_NN1 forces_NN2 where_CS there_EX is_VBZ little_DA1 tendency_NN1 to_TO move_VVI out_RP ,_, this_DD1 is_VBZ characteristic_JJ of_IO a_AT1 surprisingly_RR large_JJ number_NN1 of_IO organisations_NN2 in_II European_JJ countries_NN2 and_CC in_II Japan_NP1 but_CCB much_RR less_RGR so_RR in_II the_AT U.S.A._NP1 Stable_JJ work_NN1 forces_NN2 have_VH0 their_APPGE advantages_NN2 in_II31 terms_II32 of_II33 familiarity_NN1 with_IW the_AT enterprise_NN1 and_CC its_APPGE peculiar_JJ needs_NN2 but_CCB they_PPHS2 do_VD0 result_VVI in_II problems_NN2 if_CS the_AT market_NN1 for_IF the_AT products_NN2 is_VBZ erratic_JJ or_CC otherwise_RR unpredictable_JJ ._. 
This_DD1 is_VBZ particularly_RR so_RR in_II high_JJ technology_NN1 e.g._REX design_NN1 and_CC construction_NN1 of_IO ships_NN2 ,_, aircraft_NN ,_, power_NN1 stations_NN2 and_CC chemical_JJ plant_NN1 ,_, where_CS the_AT product_NN1 unit_NN1 is_VBZ large_JJ and_CC expensive_JJ and_CC the_AT variety_NN1 of_IO required_JJ expertise_NN1 is_VBZ extensive_JJ ._. 
Some_DD peaks_NN2 of_IO demand_NN1 can_VM be_VBI dealt_VVN with_IW by_II using_VVG consultants_NN2 ,_, but_CCB they_PPHS2 tend_VV0 to_TO be_VBI expensive_JJ and_CC do_VD0 not_XX always_RR fit_VVI well_RR with_IW ill-defined_JJ but_CCB important_JJ factors_NN2 such_II21 as_II22 the_AT favoured_JJ style_NN1 of_IO the_AT organisation_NN1 ._. 
In_II well_RR ordered_VVN systems_NN2 it_PPH1 may_VM be_VBI possible_JJ to_TO calculate_VVI the_AT length_NN1 of_IO in-house_JJ experience_NN1 required_VVN to_TO achieve_VVI the_AT required_JJ level_NN1 of_IO expertise_NN1 in_II particular_JJ topics_NN2 and_CC compare_VV0 this_DD1 with_IW the_AT lead_NN1 time_NNT1 for_IF particular_JJ product_NN1 requirements_NN2 ._. 
Given_VVN time_NNT1 available_JJ to_TO train_VVI new_JJ staff_NN it_PPH1 is_VBZ not_XX necessary_JJ to_TO keep_VVI more_DAR than_CSN a_AT1 nucleus_NN1 in_II that_DD1 particular_JJ expertise_NN1 ._. 
On_II the_AT other_JJ hand_NN1 ,_, if_CS there_EX is_VBZ usually_RR insufficient_JJ notice_NN1 of_IO need_NN1 it_PPH1 may_VM be_VBI necessary_JJ to_TO keep_VVI staff_NN who_PNQS have_VH0 periods_NN2 with_IW little_DA1 to_TO do_VDI between_II projects_NN2 ._. 
It_PPH1 is_VBZ also_RR desirable_JJ to_TO have_VHI the_AT possibility_NN1 of_IO shifting_JJ staff_NN between_II design_NN1 and_CC operational_JJ duties_NN2 ._. 
This_DD1 not_XX only_RR provides_VVZ flexibility_NN1 in_II the_AT use_NN1 of_IO man-power_NN1 ,_, it_PPH1 also_RR improves_VVZ communication_NN1 ._. 
These_DD2 real_JJ difficulties_NN2 of_IO man-power_NN1 utilisation_NN1 are_VBR such_II21 as_II22 to_TO force_VVI many_DA2 organisations_NN2 to_TO become_VVI larger_JJR and_CC larger_JJR if_CS they_PPHS2 are_VBR to_TO remain_VVI economic_JJ ._. 
Size_NN1 provides_VVZ a_AT1 cushion_NN1 to_II the_AT vicissitudes_NN2 of_IO markets_NN2 but_CCB it_PPH1 creates_VVZ other_JJ problems_NN2 ._. 
For_REX21 example_REX22 ,_, difficulties_NN2 of_IO communications_NN2 and_CC in_RR21 particular_RR22 ,_, how_RRQ to_TO inculcate_VVI the_AT feeling_NN1 within_II each_DD1 individual_NN1 that_CST he_PPHS1 and_CC his_APPGE performance_NN1 are_VBR important_JJ to_II the_AT organisation_NN1 ._. 
This_DD1 is_VBZ considered_VVN in_II more_DAR detail_NN1 in_II Chapter_NN1 3_MC ._. 
Human_JJ resources_NN2 should_VM be_VBI fundamental_JJ to_II subjects_NN2 such_II21 as_II22 ergonomics_NN1 which_DDQ are_VBR essentially_RR people-centred_JJ but_CCB the_AT concept_NN1 remains_VVZ procedurally_RR undeveloped_JJ at_II any_DD level_NN1 from_II a_AT1 continent_NN1 through_II countries_NN2 ,_, regions_NN2 and_CC companies_NN2 down_RP to_II particular_JJ working_JJ systems_NN2 ._. 
This_DD1 is_VBZ one_MC1 reason_NN1 why_RRQ policy_NN1 makers_NN2 never_RR seem_VV0 to_TO take_VVI account_NN1 fully_RR of_IO the_AT people_NN affected_VVN by_II their_APPGE decisions_NN2 ._. 
The_AT design_NN1 of_IO procedures_NN2 The_AT increased_JJ importance_NN1 of_IO standardised_JJ informational_JJ support_NN1 for_IF both_RR machines_NN2 and_CC operators_NN2 has_VHZ led_VVN to_II the_AT concept_NN1 of_IO procedures_NN2 as_II a_AT1 separate_JJ design_NN1 issue_NN1 within_II a_AT1 system_NN1 (_( Fig._NN1 1.30_MC )_) ._. 
Much_DA1 of_IO this_DD1 information_NN1 can_VM be_VBI incorporated_VVN in_II computer_NN1 programs_NN2 but_CCB there_EX is_VBZ also_RR a_AT1 need_NN1 for_IF extensive_JJ printed_JJ paper_NN1 for_IF the_AT use_NN1 of_IO the_AT operator_NN1 ._. 
This_DD1 takes_VVZ three_MC main_JJ forms_NN2 :_: checklists_NN2 ,_, routines_NN2 and_CC knowledge-texts_NN2 ._. 
The_AT terminology_NN1 in_II this_DD1 field_NN1 is_VBZ not_XX standardised_VVN ._. 
Software_NN1 might_VM be_VBI restricted_VVN ,_, as_CSA in_II this_DD1 book_NN1 ,_, to_II computer_NN1 programs_NN2 but_CCB it_PPH1 is_VBZ sometimes_RT used_VVN as_II the_AT generic_JJ term_NN1 to_TO include_VVI all_DB sources_NN2 of_IO information_NN1 ._. 
Procedures_NN2 is_VBZ sometimes_RT used_VVN for_IF what_DDQ are_VBR here_RL called_VVN routines_NN2 and_CC sometimes_RT to_TO indicate_VVI all_DB the_AT operator_NN1 's_GE information_NN1 support_NN1 except_II software_NN1 ._. 
The_AT situation_NN1 is_VBZ further_RRR confused_VVN when_CS some_DD but_CCB not_XX all_DB the_AT operator_NN1 information_NN1 support_NN1 is_VBZ itself_PPX1 computer-based_JJ ._. 
Sometimes_RT the_AT term_NN1 firm-ware_NN1 is_VBZ used_VVN ._. 
However_RRQV whatever_DDQV the_AT terminology_NN1 used_VVD there_EX is_VBZ a_AT1 requirement_NN1 for_IF design_NN1 effort_NN1 ._. 
The_AT quality_NN1 of_IO procedures_NN2 would_VM be_VBI much_RR improved_VVN if_CS designers_NN2 followed_VVD some_DD simple_JJ guide-lines_NN2 (_( Table_NN1 1.16_MC )_) ._. 
Many_DA2 documents_NN2 are_VBR written_VVN on_II the_AT implicit_JJ assumption_NN1 that_CST the_AT reader_NN1 is_VBZ much_RR like_II the_AT writer_NN1 in_II31 terms_II32 of_II33 expertise_NN1 and_CC style_NN1 of_IO thinking_NN1 ._. 
Similarly_RR it_PPH1 is_VBZ assumed_VVN that_CST the_AT conditions_NN2 under_II which_DDQ the_AT reading_NN1 will_VM take_VVI place_NN1 are_VBR the_AT same_DA as_CSA those_DD2 of_IO writing_NN1 which_DDQ are_VBR usually_RR a_AT1 clean_JJ well-lit_JJ office_NN1 ._. 
They_PPHS2 may_VM have_VHI to_TO be_VBI read_VVN in_II the_AT open_JJ air_NN1 ,_, in_II rain_NN1 and_CC darkness_NN1 or_CC within_II a_AT1 plant_NN1 under_II oily_JJ ,_, cramped_VVN ,_, poorly_RR lit_VVN conditions_NN2 ._. 
The_AT user_NN1 probably_RR has_VHZ limited_VVN expertise_NN1 and_CC he_PPHS1 may_VM be_VBI working_VVG under_II various_JJ stress_NN1 conditions_NN2 ._. 
The_AT material_NN1 on_II which_DDQ the_AT information_NN1 is_VBZ printed_VVN ,_, the_AT typeface_NN1 used_VVD ,_, the_AT sequence_NN1 ,_, the_AT structure_NN1 and_CC the_AT format_NN1 generally_RR should_VM reflect_VVI the_AT conditions_NN2 of_IO use_NN1 ,_, (_( Easterby_NP1 and_CC Zwaga_NP1 ,_, 1984_MC )_) ._. 
All_DB these_DD2 things_NN2 can_VM be_VBI achieved_VVN if_CS it_PPH1 is_VBZ acknowledged_VVN that_CST all_DB procedures_NN2 should_VM a_AT1 validated_JJ by_II users_NN2 under_II the_AT normal_JJ conditions_NN2 of_IO use_NN1 ._. 
Checklists_NN2 Checklists_NN2 are_VBR used_VVN in_II the_AT pre-start_JJ mode_NN1 ,_, for_IF routine_NN1 maintenance_NN1 and_CC for_IF fault-finding_NN1 ._. 
They_PPHS2 normally_RR take_VV0 the_AT form_NN1 of_IO a_AT1 series_NN of_IO questions_NN2 or_CC statements_NN2 which_DDQ the_AT operator_NN1 uses_VVZ to_TO guide_VVI and_CC structure_NN1 his_APPGE inspection_NN1 of_IO the_AT hardware_NN1 and_CC other_JJ system_NN1 components_NN2 ._. 
The_AT sequence_NN1 is_VBZ dictated_VVN by_II the_AT optimal_JJ order_NN1 in_II which_DDQ actions_NN2 should_VM be_VBI taken_VVN ,_, for_REX21 example_REX22 in_II starting_VVG up_RP an_AT1 aircraft_NN ._. 
There_EX are_VBR many_DA2 situations_NN2 when_RRQ the_AT order_NN1 is_VBZ of_IO no_AT great_JJ consequence_NN1 ,_, for_REX21 example_REX22 a_AT1 safety_NN1 audit_NN1 of_IO a_AT1 new_JJ machine_NN1 ,_, and_CC in_II this_DD1 latter_DA case_NN1 some_DD logical_JJ structure_NN1 is_VBZ needed_VVN ._. 
As_CSA mentioned_VVN above_RL ,_, the_AT logic_NN1 of_IO the_AT design_NN1 may_VM not_XX be_VBI the_AT optimal_JJ basis_NN1 if_CS the_AT way_NN1 the_AT operator_NN1 thinks_VVZ and_CC acts_NN2 is_VBZ different_JJ ._. 
Baker_NP1 (_( 1984_MC )_) suggests_VVZ that_CST four_MC kinds_NN2 of_IO shortcoming_NN1 emerge_VV0 when_RRQ checklists_NN2 are_VBR validated_VVN in_II the_AT real_JJ situation_NN1 ._. 
The_AT operator_NN1 may_VM deviate_VVI from_II the_AT listed_JJ procedure_NN1 because_CS it_PPH1 may_VM require_VVI excessive_JJ moving_VVG about_RP or_CC because_CS he_PPHS1 is_VBZ interrupted_VVN by_II the_AT requirements_NN2 of_IO other_JJ tasks_NN2 ._. 
Systematic_JJ use_NN1 of_IO a_AT1 checklist_NN1 often_RR reveals_VVZ faults_NN2 in_II work_NN1 design_NN1 such_II21 as_II22 inadequate_JJ access_NN1 ,_, visibility_NN1 and_CC labelling_NN1 ._. 
The_AT checklist_NN1 itself_PPX1 may_VM be_VBI inconsistent_JJ ,_, incomplete_JJ ,_, imprecise_JJ or_CC ambiguous_JJ ._. 
Finally_RR the_AT checklist_NN1 may_VM have_VHI reprographic_JJ limitations_NN2 such_II21 as_II22 inadequate_JJ vertical_JJ or_CC horizontal_JJ structure_NN1 ,_, poor_JJ typefaces_NN2 and_CC insufficient_JJ linking_NN1 of_IO requirements_NN2 ,_, descriptions_NN2 ,_, remarks_NN2 and_CC tick-off_JJ points_NN2 ._. 
The_AT International_JJ Ergonomics_NN1 Association_NN1 developed_VVD a_AT1 general_JJ ergonomics_NN1 checklist_NN1 which_DDQ is_VBZ reproduced_VVN in_II Edholm_NP1 (_( 1967_MC )_) ._. 
There_EX is_VBZ a_AT1 deceptive_JJ simplicity_NN1 about_II such_DA lists_NN2 which_DDQ requires_VVZ extensive_JJ effort_NN1 to_TO ensure_VVI a_AT1 comprehensive_JJ but_CCB coherent_JJ content_NN1 ._. 
The_AT context_NN1 is_VBZ ,_, of_RR21 course_RR22 ,_, the_AT context_NN1 of_IO ergonomics_NN1 as_CSA conceived_VVN by_II the_AT designers_NN2 of_IO the_AT list_NN1 ._. 
Routines_NN2 A_ZZ1 routine_NN1 is_VBZ the_AT most_RGT common_JJ form_NN1 of_IO instructional_JJ material_NN1 ._. 
The_AT reader_NN1 is_VBZ required_VVN to_TO follow_VVI a_AT1 series_NN of_IO steps_NN2 which_DDQ might_VM ,_, for_REX21 example_REX22 ,_, introduce_VV0 a_AT1 change_NN1 in_II the_AT performance_NN1 of_IO a_AT1 complex_JJ system_NN1 ._. 
Normally_RR routines_NN2 are_VBR single_JJ chains_NN2 of_IO instructions_NN2 although_CS it_PPH1 is_VBZ possible_JJ to_TO have_VHI some_DD conditional_JJ branching_JJ ._. 
Each_DD1 step_NN1 should_VM be_VBI simple_JJ and_CC complete_VV0 in_II itself_PPX1 preferably_RR with_IW some_DD indication_NN1 that_CST successful_JJ completion_NN1 has_VHZ been_VBN achieved_VVN ,_, for_REX21 example_REX22 the_AT appearance_NN1 or_CC the_AT change_NN1 of_IO colour_NN1 of_IO a_AT1 signal_NN1 light_NN1 ,_, or_CC the_AT noise_NN1 of_IO a_AT1 motor_NN1 starting_NN1 or_CC a_AT1 change_NN1 of_IO pressure_NN1 which_DDQ indicates_VVZ that_CST there_EX has_VHZ been_VBN a_AT1 change_NN1 in_II the_AT flow_NN1 of_IO some_DD material_NN1 ._. 
As_CSA mentioned_VVN earlier_RRR a_AT1 routine_NN1 can_VM often_RR be_VBI regarded_VVN as_II a_AT1 written_JJ task_NN1 description_NN1 ._. 
By_II definition_NN1 and_CC design_NN1 intention_NN1 routines_NN2 are_VBR inflexible_JJ ._. 
The_AT user_NN1 is_VBZ intended_VVN to_TO behave_VVI exactly_RR according_II21 to_II22 their_APPGE instruction_NN1 ._. 
No_AT great_JJ skill_NN1 or_CC intellectual_JJ effort_NN1 is_VBZ required_VVN ,_, which_DDQ is_VBZ one_MC1 way_NN1 of_IO saying_VVG that_CST the_AT human_JJ operator_NN1 is_VBZ being_VBG under-used_VVN ,_, but_CCB the_AT purpose_NN1 of_IO a_AT1 routine_NN1 is_VBZ usually_RR to_TO avoid_VVI common_JJ human_JJ error_NN1 such_II21 as_II22 omitting_VVG a_AT1 step_NN1 or_CC reversing_VVG steps_NN2 ._. 
In_RR21 general_RR22 the_AT value_NN1 of_IO formal_JJ routines_NN2 is_VBZ precisely_RR that_CST the_AT operator_NN1 ,_, left_VVN to_II himself_PPX1 ,_, will_VM not_XX normally_RR function_VVI in_II such_DA a_AT1 systematic_JJ sequential_JJ manner_NN1 ._. 
Knowledge_NN1 texts_NN2 Knowledge_NN1 is_VBZ contained_VVN in_II documents_NN2 which_DDQ may_VM vary_VVI from_II single_JJ sheet_NN1 presentations_NN2 to_II large_JJ manuals_NN2 ._. 
As_CSA instructional_JJ material_NN1 it_PPH1 is_VBZ indirect_JJ in_CS21 that_CS22 the_AT reader_NN1 is_VBZ not_XX necessarily_RR told_VVN what_DDQ to_TO do_VDI ,_, as_CSA in_II a_AT1 routine_NN1 ._. 
Rather_RR he_PPHS1 is_VBZ informed_VVN about_II the_AT situation_NN1 and_CC the_AT purpose_NN1 of_IO informing_VVG him_PPHO1 is_VBZ to_TO provide_VVI a_AT1 knowledge_NN1 base_NN1 from_II which_DDQ he_PPHS1 can_VM work_VVI out_RP his_APPGE own_DA actions_NN2 ._. 
Nevertheless_RR ,_, the_AT relevant_JJ action_NN1 remains_VVZ important_JJ and_CC the_AT knowledge_NN1 provided_VVN should_VM be_VBI carefully_RR and_CC stringently_RR selected_VVN ._. 
It_PPH1 is_VBZ too_RG easy_JJ to_TO follow_VVI the_AT academic_JJ tradition_NN1 and_CC provide_VV0 knowledge_NN1 for_IF its_APPGE own_DA sake_NN1 ._. 
The_AT '_GE need_NN1 to_TO know_VVI '_GE criterion_NN1 is_VBZ crucial_JJ because_CS unless_CS it_PPH1 is_VBZ applied_VVN ,_, the_AT operator_NN1 can_VM be_VBI overburdened_VVN with_IW unnecessary_JJ material_NN1 ._. 
Correspondingly_RR the_AT material_NN1 should_VM be_VBI structured_VVN in_II31 terms_II32 of_II33 how_RRQ it_PPH1 is_VBZ most_RGT likely_JJ to_TO be_VBI used_VVN ._. 
In_II this_DD1 context_NN1 the_AT operator_NN1 requires_VVZ a_AT1 guide_NN1 for_IF action_NN1 and_CC not_XX a_AT1 scientific_JJ text-book_NN1 ._. 
It_PPH1 is_VBZ invariably_RR better_JJR to_TO provide_VVI material_NN1 diagrammatically_RR ,_, systematically_RR or_CC at_RR21 least_RR22 in_II well-structured_JJ short_JJ paragraphs_NN2 rather_II21 than_II22 in_II flowing_JJ prose_NN1 ._. 
Consider_VV0 for_REX21 example_REX22 how_RGQ readily_RR information_NN1 about_II the_AT relative_JJ position_NN1 of_IO streets_NN2 is_VBZ available_JJ from_II a_AT1 map_NN1 of_IO a_AT1 town_NN1 centre_NN1 rather_II21 than_II22 a_AT1 verbal_JJ description_NN1 of_IO all_DB the_AT streets_NN2 ._. 
Such_DA a_AT1 map_NN1 will_VM enable_VVI the_AT reader_NN1 to_TO work_VVI out_RP for_IF himself_PPX1 how_RRQ to_TO get_VVI from_II one_MC1 location_NN1 to_II another_DD1 within_II the_AT town_NN1 ._. 
Note_VV0 the_AT enormous_JJ flexibility_NN1 compared_VVN with_IW a_AT1 routine_NN1 which_DDQ would_VM tell_VVI him_PPHO1 only_RR how_RRQ to_TO get_VVI from_II one_MC1 particular_JJ point_NN1 to_II another_DD1 ._. 
A_AT1 second_MD important_JJ difference_NN1 is_VBZ that_CST if_CS he_PPHS1 misses_VVZ his_APPGE place_NN1 in_II a_AT1 routine_NN1 he_PPHS1 will_VM be_VBI totally_RR lost_VVN ,_, whereas_CS if_CS he_PPHS1 happens_VVZ to_TO go_VVI in_II the_AT wrong_JJ direction_NN1 while_CS using_VVG a_AT1 map_NN1 he_PPHS1 is_VBZ still_RR able_JK to_TO make_VVI whatever_DDQV correction_NN1 is_VBZ necessary_JJ ._. 
However_RRQV the_AT map_NN1 does_VDZ require_VVI more_RGR intellectual_JJ effort_NN1 than_CSN does_VDZ the_AT routine_NN1 not_XX only_RR in_II making_VVG decisions_NN2 about_II how_RRQ to_TO proceed_VVI but_CCB also_RR in_II filtering_VVG out_RP the_AT required_JJ information_NN1 from_II the_AT massive_JJ irrelevance_NN1 (_( for_IF a_AT1 particular_JJ task_NN1 )_) which_DDQ is_VBZ equally_RR available_JJ ._. 
Thus_RR ,_, one_PN1 would_VM expect_VVI the_AT use_NN1 of_IO the_AT maps_NN2 to_TO be_VBI slower_JJR than_CSN the_AT use_NN1 of_IO routines_NN2 with_IW the_AT human_JJ performance_NN1 being_VBG more_RGR versatile_JJ but_CCB less_RGR predictable_JJ ._. 
With_IW two-dimensional_JJ representations_NN2 such_II21 as_II22 maps_NN2 it_PPH1 remains_VVZ important_JJ to_TO avoid_VVI too_RG much_DA1 homogeneity_NN1 and_CC provide_VVI substructure_NN1 in_II the_AT form_NN1 of_IO main_JJ roads_NN2 and_CC key_JJ buildings_NN2 or_CC other_JJ features_NN2 such_II21 as_II22 rivers_NN2 ._. 
See_VV0 ,_, for_REX21 example_REX22 ,_, Fig._NN1 5.3_MC Manuals_NN2 which_DDQ may_VM contain_VVI maps_NN2 ,_, schematic_JJ diagrams_NN2 and_CC other_JJ materials_NN2 warrant_VV0 separate_JJ consideration_NN1 ._. 
The_AT design_NN1 of_IO manuals_NN2 A_ZZ1 manual_NN1 is_VBZ usually_RR in_II the_AT form_NN1 of_IO a_AT1 book_NN1 or_CC booklet_NN1 which_DDQ is_VBZ sent_VVN with_IW the_AT hardware_NN1 from_II the_AT maker_NN1 to_II the_AT customer_NN1 ._. 
It_PPH1 is_VBZ part_NN1 of_IO the_AT communication_NN1 package_NN1 from_II the_AT designer_NN1 to_II the_AT user_NN1 ._. 
Thus_RR it_PPH1 is_VBZ a_AT1 particular_JJ form_NN1 of_IO job_NN1 aid_NN1 which_DDQ provides_VVZ the_AT operator_NN1 with_IW information_NN1 on_II a_AT1 system_NN1 and_CC its_APPGE performance_NN1 ._. 
The_AT standard_NN1 of_IO manual_JJ design_NN1 has_VHZ traditionally_RR been_VBN very_RG low_JJ for_IF several_DA2 reasons_NN2 ._. 
For_IF this_DD1 purpose_NN1 ,_, the_AT designer_NN1 is_VBZ too_RG familiar_JJ with_IW the_AT product_NN1 and_CC he_PPHS1 rarely_RR takes_VVZ the_AT trouble_NN1 to_TO find_VVI out_RP what_DDQ the_AT user_NN1 really_RR needs_VVZ to_TO know_VVI ._. 
Often_RR the_AT manual_NN1 has_VHZ to_TO be_VBI provided_VVN hurriedly_RR at_II the_AT end_NN1 of_IO a_AT1 project_NN1 when_CS the_AT budget_NN1 is_VBZ running_VVG out_RP ,_, and_CC it_PPH1 is_VBZ regarded_VVN as_II a_AT1 tiresome_JJ chore_NN1 still_RR required_VVN after_II the_AT essential_JJ design_NN1 work_NN1 has_VHZ been_VBN completed_VVN ._. 
The_AT problem_NN1 is_VBZ particularly_RR acute_JJ for_IF computers_NN2 ._. 
Manuals_NN2 for_IF cars_NN2 ,_, machine_VV0 tools_NN2 and_RR31 so_RR32 on_RR33 are_VBR poor_JJ but_CCB at_RR21 least_RR22 it_PPH1 is_VBZ possible_JJ to_TO observe_VVI the_AT mechanisms_NN2 and_CC their_APPGE functions_NN2 ._. 
Most_DAT computer_NN1 operators_NN2 do_VD0 not_XX know_VVI or_CC wish_VVI to_TO know_VVI about_II the_AT mechanisms_NN2 ,_, and_CC in_II any_DD case_NN1 these_DD2 are_VBR not_XX accessible_JJ to_II vision_NN1 and_CC manipulation_NN1 ._. 
The_AT computer_NN1 operator_NN1 is_VBZ entirely_RR dependent_JJ on_II the_AT manual_NN1 ,_, at_RR21 least_RR22 in_II the_AT early_JJ stages_NN2 of_IO gaining_VVG familiarity_NN1 with_IW the_AT system_NN1 and_CC its_APPGE functions_NN2 ._. 
He_PPHS1 is_VBZ usually_RR very_RG badly_RR served_VVN although_CS the_AT principles_NN2 of_IO manual_JJ design_NN1 are_VBR well_RR known_VVN ._. 
For_IF most_DAT systems_NN2 the_AT manual_NN1 is_VBZ best_RRT divided_VVN into_II parts_NN2 as_CSA indicated_VVN in_II Table_NN1 1.17_MC ._. 
The_AT first_MD part_NN1 should_VM be_VBI a_AT1 general_JJ introduction_NN1 which_DDQ orientates_VVZ the_AT readers_NN2 towards_II the_AT system_NN1 ,_, its_APPGE purpose_NN1 ,_, its_APPGE functional_JJ structure_NN1 and_CC mode_NN1 of_IO operation_NN1 and_CC its_APPGE performance_NN1 limits_NN2 ._. 
This_DD1 should_VM be_VBI followed_VVN by_II a_AT1 separate_JJ section_NN1 on_II how_RRQ to_TO set_VVI the_AT system_NN1 up_RP in_II the_AT first_MD place_NN1 and_CC how_RRQ to_TO check_VVI that_CST it_PPH1 is_VBZ working_VVG properly_RR ._. 
If_CS it_PPH1 is_VBZ fairly_RR small_JJ it_PPH1 may_VM be_VBI necessary_JJ to_TO describe_VVI how_RRQ to_TO unpack_VVI it_PPH1 ,_, fix_VV0 it_PPH1 into_II position_NN1 ,_, connect_VV0 it_PPH1 to_II power_NN1 supplies_NN2 and_CC start_VV0 it_PPH1 up_RP ._. 
If_CS it_PPH1 is_VBZ large_JJ ,_, the_AT emphasis_NN1 will_VM be_VBI on_II the_AT start_NN1 up_II procedure_NN1 ._. 
The_AT section_NN1 describing_VVG the_AT operation_NN1 of_IO the_AT system_NN1 should_VM cover_VVI not_XX only_RR how_RRQ the_AT system_NN1 operates_VVZ but_CCB also_RR how_RRQ the_AT user_NN1 can_VM operate_VVI it_PPH1 ._. 
Extensive_JJ use_NN1 of_IO line_NN1 drawings_NN2 ,_, schematic_JJ diagrams_NN2 ,_, algorithmic_JJ lists_NN2 is_VBZ desirable_JJ ,_, and_CC where_RRQ prose_NN1 is_VBZ used_VVN this_DD1 also_RR should_VM be_VBI structured_VVN into_II short_JJ sentences_NN2 with_IW meaningful_JJ separation_NN1 into_II paragraphs_NN2 ._. 
The_AT maintenance_NN1 section_NN1 should_VM indicate_VVI what_DDQ ,_, if_CS anything_PN1 ,_, the_AT operator_NN1 is_VBZ expected_VVN to_TO do_VDI and_CC the_AT symptoms_NN2 which_DDQ indicate_VV0 that_CST more_DAR specialist_NN1 maintenance_NN1 skills_NN2 are_VBR required_VVN ._. 
Tables_NN2 subdivided_VVN into_II Faults/Reasons/Remedies_NN2 can_VM be_VBI extremely_RR helpful_JJ ._. 
Parts_NN2 lists_VVZ including_II description_NN1 reference_NN1 numbers_NN2 and_CC sometimes_RT drawings_NN2 are_VBR necessary_JJ if_CS the_AT user_NN1 is_VBZ expected_VVN to_TO deal_VVI with_IW his_APPGE own_DA replacements_NN2 ._. 
A_AT1 standard_JJ fault_NN1 is_VBZ to_TO assume_VVI that_CST the_AT reader_NN1 is_VBZ familiar_JJ with_IW the_AT jargon_NN1 which_DDQ the_AT designer_NN1 habitually_RR uses_VVZ ._. 
A_AT1 glossary_NN1 of_IO terms_NN2 and_CC acronyms_NN2 used_VVN can_VM be_VBI very_RG helpful_JJ not_XX only_RR to_II the_AT reader_NN1 but_CCB also_RR to_II the_AT writer_NN1 who_PNQS is_VBZ forced_VVN to_TO consider_VVI carefully_RR how_RRQ he_PPHS1 is_VBZ using_VVG various_JJ technical_JJ terms_NN2 ._. 
Finally_RR ,_, all_DB manuals_NN2 should_VM end_VVI with_IW an_AT1 index_NN1 which_DDQ supplements_NN2 the_AT table_NN1 of_IO contents_NN2 at_II the_AT beginning_NN1 ._. 
SKILL_NN1 AND_CC TRAINING_NN1 Concepts_NN2 ._. 
Development_NN1 aspects_NN2 Most_DAT laboratory_NN1 and_CC field_NN1 studies_NN2 of_IO human_JJ behaviour_NN1 involve_VV0 taking_VVG a_AT1 situational_JJ snap-shot_NN1 at_II a_AT1 given_JJ time_NNT1 in_II a_AT1 given_JJ place_NN1 ._. 
It_PPH1 is_VBZ easy_JJ to_TO overlook_VVI the_AT continuously_RR changing_JJ nature_NN1 both_RR of_IO people_NN and_CC of_IO work_NN1 situations_NN2 ._. 
When_CS the_AT skilled_JJ manager_NN1 encounters_NN2 what_DDQ ,_, on_II the_AT face_NN1 of_IO it_PPH1 ,_, is_VBZ an_AT1 intolerable_JJ set_NN1 of_IO work_NN1 practices_NN2 ,_, attitudes_NN2 and_CC performance_NN1 he_PPHS1 does_VDZ not_XX necessarily_RR take_VVI drastic_JJ action_NN1 ,_, he_PPHS1 identifies_VVZ the_AT natural_JJ processes_NN2 of_IO change_NN1 and_CC accelerates_VVZ them_PPHO2 ._. 
In_II a_AT1 remarkably_RR short_JJ time_NNT1 changes_NN2 in_II procedures_NN2 ,_, products_NN2 and_CC work-load_NN1 ,_, promotions_NN2 ,_, resignations_NN2 ,_, retirements_NN2 and_RR31 so_RR32 on_RR33 can_VM transform_VVI any_DD situation_NN1 ._. 
The_AT changes_NN2 within_II an_AT1 individual_NN1 are_VBR even_RR more_RGR inexorably_RR continuous_JJ ._. 
Again_RT it_PPH1 is_VBZ easy_JJ to_TO develop_VVI the_AT illusion_NN1 that_CST a_AT1 worker_NN1 is_VBZ a_AT1 constant_JJ factor_NN1 in_II a_AT1 changing_JJ situation_NN1 particularly_RR for_IF a_AT1 person_NN1 in_II the_AT middle_JJ period_NN1 of_IO working_NN1 life_NN1 ._. 
This_DD1 was_VBDZ encouraged_VVN by_II the_AT traditional_JJ view_NN1 of_IO a_AT1 skilled_JJ man_NN1 as_CSA one_PN1 who_PNQS learned_VVD his_APPGE trade_NN1 by_II the_AT age_NN1 of_IO 21_MC and_CC thereafter_RT practised_VVD it_PPH1 for_IF more_DAR than_CSN forty_MC years_NNT2 until_CS he_PPHS1 retired_VVD at_II 65_MC ._. 
This_DD1 was_VBDZ never_RR the_AT case_NN1 and_CC in_II the_AT current_JJ working_JJ world_NN1 it_PPH1 is_VBZ even_RR less_RGR so_RR because_II21 of_II22 developing_JJ technology_NN1 which_DDQ has_VHZ its_APPGE impact_NN1 on_II almost_RR all_DB jobs_NN2 and_CC also_RR on_II the_AT social_JJ context_NN1 of_IO work_NN1 ._. 
For_REX21 example_REX22 ,_, because_II21 of_II22 employment_NN1 levels_NN2 there_EX is_VBZ currently_RR an_AT1 emphasis_NN1 on_II earlier_JJR retirement_NN1 from_II and_CC later_JJR entry_NN1 into_II the_AT working_JJ world_NN1 ._. 
These_DD2 trends_NN2 are_VBR particularly_RR marked_VVN in_II manufacturing_NN1 industry_NN1 where_CS the_AT work_NN1 force_NN1 is_VBZ falling_VVG and_CC the_AT capital_NN1 investment_NN1 per_II worker_NN1 is_VBZ rising_VVG rapidly_RR ._. 
For_IF these_DD2 reasons_NN2 industry_NN1 is_VBZ moving_VVG towards_II a_AT1 concept_NN1 of_IO the_AT ideal_JJ worker_NN1 as_II a_AT1 physically_RR fit_VV0 adaptable_JJ young_JJ person_NN1 ._. 
The_AT labour_NN1 force_NN1 is_VBZ becoming_VVG more_RRR like_II the_AT military_JJ with_IW the_AT use_NN1 of_IO a_AT1 limited_JJ age_NN1 range_NN1 and_CC the_AT screening_NN1 out_II21 of_II22 anyone_PN1 with_IW any_DD kind_NN1 of_IO disability_NN1 who_PNQS might_VM not_XX be_VBI able_JK to_TO work_VVI at_II a_AT1 pace_NN1 and_CC with_IW the_AT flexibility_NN1 and_CC precision_NN1 which_DDQ will_VM maintain_VVI the_AT return_NN1 on_II the_AT very_RG large_JJ capital_NN1 investment_NN1 ._. 
Even_RR21 so_RR22 ,_, it_PPH1 remains_VVZ true_JJ that_CST the_AT performance_NN1 of_IO the_AT individual_NN1 is_VBZ a_AT1 function_NN1 of_IO the_AT way_NN1 he_PPHS1 developed_VVD skills_NN2 in_II his_APPGE earlier_JJR more_RRR formative_JJ years_NNT2 and_CC the_AT way_NN1 in_II which_DDQ his_APPGE capacities_NN2 and_CC skills_NN2 are_VBR still_RR changing_VVG in_II the_AT work_NN1 environment_NN1 ._. 
Human_JJ development_NN1 can_VM be_VBI described_VVN in_II31 terms_II32 of_II33 three_MC attributes_NN2 :_: capacities_NN2 ,_, skills_NN2 and_CC aspirations_NN2 (_( Singleton_NP1 ,_, 198_MC 1_MC1 )_) ._. 
The_AT healthy_JJ ,_, well-adapted_JJ individual_NN1 keeps_VVZ them_PPHO2 in_II balance_NN1 in_II a_AT1 dynamic_JJ equilibrium_NN1 ._. 
His_APPGE natural_JJ endowment_NN1 consists_VVZ of_IO a_AT1 particular_JJ range_NN1 of_IO capacities_NN2 :_: physical_JJ strength_NN1 ,_, mobility_NN1 ,_, vision_NN1 ,_, hearing_VVG ,_, intellect_NN1 and_RR31 so_RR32 forth_RR33 ._. 
These_DD2 form_VV0 the_AT basis_NN1 for_IF the_AT development_NN1 of_IO a_AT1 repertoire_NN1 of_IO skills_NN2 dictated_VVD partly_RR by_II capacities_NN2 and_CC partly_RR by_II environmental_JJ circumstances_NN2 such_II21 as_II22 the_AT particular_JJ family_NN1 ,_, community_NN1 and_CC region_NN1 he_PPHS1 is_VBZ born_VVN into_II and_CC the_AT available_JJ facilities_NN2 for_IF play_NN1 ,_, education_NN1 and_CC training_NN1 ._. 
The_AT balance_NN1 and_CC integration_NN1 of_IO capacities_NN2 and_CC skills_NN2 is_VBZ achieved_VVN by_II the_AT third_MD attribute_NN1 of_IO aspirations_NN2 ._. 
These_DD2 are_VBR partly_RR determined_VVN by_II and_CC partly_RR determine_VV0 the_AT other_JJ attributes_NN2 ._. 
The_AT individual_NN1 is_VBZ in_II difficulties_NN2 if_CS his_APPGE aspirations_NN2 do_VD0 not_XX match_VVI his_APPGE capacities_NN2 and_CC skills_NN2 but_CCB most_DAT people_NN are_VBR sufficiently_RR realistic_JJ and_CC have_VH0 sufficient_JJ self-knowledge_NN1 to_TO keep_VVI these_DD2 attributes_NN2 in_II line_NN1 ._. 
The_AT most_RGT flexible_JJ attribute_NN1 is_VBZ the_AT skills_NN2 ,_, these_DD2 can_VM be_VBI developed_VVN or_CC changed_VVN in_II31 line_II32 with_II33 capacities_NN2 and_CC aspirations_NN2 ._. 
A_AT1 well-ordered_JJ civilisation_NN1 demands_VVZ standard_JJ basic_JJ skills_NN2 of_IO a_AT1 physical_JJ kind_NN1 :_: mobility_NN1 and_CC manipulation_NN1 ,_, and_CC also_RR of_IO a_AT1 mental_JJ kind_NN1 :_: reading_NN1 ,_, writing_VVG and_CC arithmetic_NN1 ._. 
On_II the_AT basis_NN1 of_IO these_DD2 standard_JJ skills_NN2 there_EX is_VBZ enormous_JJ flexibility_NN1 for_IF the_AT individual_JJ to_TO develop_VVI his_APPGE own_DA identity_NN1 and_CC to_TO express_VVI it_PPH1 through_II his_APPGE specialised_JJ skills_NN2 ._. 
As_II the_AT individual_NN1 gets_VVZ older_JJR ,_, he_PPHS1 continues_VVZ to_TO acquire_VVI new_JJ skills_NN2 for_IF two_MC reasons_NN2 ._. 
Firstly_RR ,_, the_AT passage_NN1 of_IO time_NNT1 provides_VVZ more_DAR and_CC more_DAR experience_NN1 and_CC this_DD1 is_VBZ inevitably_RR reflected_VVN in_II the_AT skill_NN1 repertoire_NN1 ._. 
Secondly_RR ,_, the_AT ageing_JJ individual_NN1 suffers_VVZ a_AT1 steady_JJ diminution_NN1 of_IO capacities_NN2 ,_, for_REX21 example_REX22 the_AT decrease_NN1 in_II adaptability_NN1 to_TO lower_VVI lighting_NN1 levels_NN2 and_CC the_AT decrease_NN1 in_II physical_JJ stamina_NN1 ._. 
Skills_NN2 develop_VV0 and_CC change_VV0 to_TO compensate_VVI partially_RR for_IF the_AT changing_JJ capacities_NN2 ._. 
It_PPH1 follows_VVZ ,_, of_RR21 course_RR22 ,_, that_DD1 decreasing_JJ capacities_NN2 as_CSA such_DA are_VBR not_XX direct_JJ predictors_NN2 of_IO decreasing_JJ performance_NN1 ._. 
This_DD1 is_VBZ true_JJ not_XX only_RR for_IF ageing_JJ but_CCB also_RR for_IF the_AT onset_NN1 of_IO disabilities_NN2 (_( see_VV0 Chapter_NN1 7_MC )_) ._. 
Human_JJ skill_NN1 Skills_NN2 are_VBR the_AT residues_NN2 of_IO learning_NN1 ._. 
To_TO describe_VVI behaviour_NN1 as_CSA skilled_JJ is_VBZ to_TO say_VVI no_AT more_DAR than_CSN that_CST it_PPH1 has_VHZ been_VBN influenced_VVN by_II training_NN1 and_CC experience_NN1 ._. 
There_EX is_VBZ often_RR an_AT1 implication_NN1 that_CST skilled_JJ means_NN highly_RR skilled_JJ although_CS this_DD1 connotation_NN1 confuses_VVZ the_AT concept_NN1 of_IO existence_NN1 and_CC level_NN1 ._. 
Unskilled_JJ is_VBZ also_RR used_VVN to_TO imply_VVI a_AT1 low_JJ level_NN1 of_IO skill_NN1 rather_II21 than_II22 its_APPGE absence_NN1 ._. 
Level_NN1 of_IO skill_NN1 is_VBZ usually_RR assessed_VVN in_II31 terms_II32 of_II33 extent_NN1 of_IO formal_JJ training_NN1 although_CS this_DD1 is_VBZ only_RR one_MC1 of_IO the_AT relevant_JJ factors_NN2 :_: others_NN2 include_VV0 length_NN1 of_IO experience_NN1 and_CC degree_NN1 of_IO integration_NN1 ._. 
Foundation_NN1 skills_NN2 are_VBR acquired_VVN in_II the_AT first_MD five_MC years_NNT2 of_IO life_NN1 ._. 
These_DD2 include_VV0 not_XX only_RR perceptual-motor_NN1 skills_NN2 but_CCB also_RR the_AT basic_JJ language_NN1 and_CC social_JJ skills_NN2 ._. 
Thereafter_RT the_AT educational_JJ system_NN1 supplements_NN2 the_AT interaction_NN1 with_IW family_NN1 and_CC friends_NN2 in_II providing_VVG facilities_NN2 and_CC exemplars_NN2 for_IF further_RRR symbolic_JJ and_CC social_JJ skill_NN1 development_NN1 ._. 
More_DAR details_NN2 of_IO all_DB these_DD2 skills_NN2 are_VBR contained_VVN in_II Table_NN1 2.1_MC ._. 
The_AT specific_JJ skills_NN2 which_DDQ a_AT1 person_NN1 acquires_VVZ whilst_CS earning_VVG a_AT1 living_NN1 are_VBR combinations_NN2 and_CC developments_NN2 of_IO the_AT standard_JJ skills_NN2 of_IO the_AT normal_JJ healthy_JJ adult_NN1 ._. 
This_DD1 is_VBZ not_XX to_TO denigrate_VVI the_AT uniqueness_NN1 and_CC quality_NN1 of_IO working_VVG skills_NN2 ._. 
They_PPHS2 are_VBR of_IO the_AT underrated_JJ because_CS the_AT universal_JJ characteristic_NN1 of_IO high_JJ skill_NN1 is_VBZ that_CST ,_, to_II an_AT1 observer_NN1 ,_, the_AT performance_NN1 does_VDZ not_XX appear_VVI to_TO be_VBI very_RG difficult_JJ ._. 
This_DD1 is_VBZ because_CS the_AT skilled_JJ individual_NN1 is_VBZ normally_RR working_VVG well_RR within_II his_APPGE capacities_NN2 ,_, he_PPHS1 does_VDZ not_XX have_VHI to_TO search_VVI desperately_RR for_IF information_NN1 because_CS he_PPHS1 knows_VVZ exactly_RR what_DDQ to_TO look_VVI for_IF ,_, his_APPGE movements_NN2 are_VBR not_XX hurried_VVN because_CS they_PPHS2 are_VBR integrated_VVN into_II smooth_JJ chains_NN2 and_CC he_PPHS1 does_VDZ not_XX react_VVI suddenly_RR because_CS he_PPHS1 anticipates_VVZ what_DDQ is_VBZ going_VVGK to_TO happen_VVI ._. 
In_RR21 general_RR22 ,_, he_PPHS1 works_VVZ on_II the_AT principle_NN1 of_IO minimal_JJ effort_NN1 to_TO achieve_VVI the_AT required_JJ objectives_NN2 in_II31 terms_II32 of_II33 both_RR speed_VV0 and_CC quality_NN1 ._. 
The_AT importance_NN1 of_IO skill_NN1 theory_NN1 is_VBZ that_CST it_PPH1 relates_VVZ human_JJ performance_NN1 to_II systems_NN2 concepts_NN2 and_CC to_II individual_JJ differences_NN2 ._. 
The_AT performer_NN1 is_VBZ pursuing_VVG an_AT1 objective_NN1 and_CC the_AT great_JJ variety_NN1 of_IO his_APPGE activity_NN1 has_VHZ meaning_NN1 in_II31 relation_II32 to_II33 his_APPGE objective_NN1 ._. 
Skill_NN1 is_VBZ a_AT1 functional_JJ concept_NN1 aimed_VVN at_II the_AT understanding_NN1 of_IO how_RRQ it_PPH1 is_VBZ done_VDN without_IW recourse_NN1 to_II the_AT detail_NN1 of_IO underlying_JJ physiological_JJ mechanisms_NN2 ._. 
Individual_JJ differences_NN2 are_VBR obviously_RR a_AT1 consequence_NN1 of_IO the_AT particular_JJ past_JJ experience_NN1 of_IO each_DD1 person_NN1 who_PNQS has_VHZ thereby_RR acquired_VVN a_AT1 unique_JJ set_NN1 of_IO skills_NN2 based_VVN on_II a_AT1 natural_JJ endowment_NN1 which_DDQ was_VBDZ also_RR unique_JJ ._. 
Skill_NN1 theory_NN1 also_RR emphasises_VVZ the_AT closely_RR integrated_JJ nature_NN1 of_IO behaviour_NN1 in_II real_JJ situations_NN2 ,_, it_PPH1 is_VBZ not_XX readily_RR susceptible_JJ to_II analysis_NN1 into_II discrete_JJ components_NN2 ._. 
The_AT internal_JJ representation_NN1 of_IO a_AT1 skill_NN1 is_VBZ called_VVN a_AT1 schema_NN1 ._. 
A_AT1 schema_NN1 is_VBZ an_AT1 internal_JJ model_NN1 which_DDQ can_VM be_VBI used_VVN to_TO relate_VVI external_JJ events_NN2 to_II a_AT1 current_JJ purpose_NN1 (_( Head_NN1 1920_MC )_) ._. 
It_PPH1 is_VBZ modified_VVN continuously_RR as_CSA external_JJ data_NN is_VBZ received_VVN and_CC transformed_VVN into_II information_NN1 ._. 
Schemata_NN2 may_VM be_VBI person_NN1 centred_VVN or_CC situation_NN1 centred_VVD ._. 
For_IF a_AT1 more_RGR extensive_JJ discussion_NN1 of_IO schemata_NN2 ,_, how_RRQ they_PPHS2 differ_VV0 and_CC how_RRQ they_PPHS2 function_VV0 ,_, see_VV0 Singleton_NP1 (_( 1981_MC )_) ._. 
Acquisition_NN1 of_IO skills_NN2 Skills_NN2 are_VBR acquired_VVN by_II a_AT1 process_NN1 of_IO trial_NN1 and_CC error_NN1 but_CCB the_AT trials_NN2 are_VBR not_XX entirely_RR random_JJ as_CSA is_VBZ assumed_VVN in_II classical_JJ trial_NN1 and_CC error_NN1 learning_NN1 (_( Thorndike_NP1 ,_, 191_MC 1_MC1 )_) ._. 
However_RR ,_, the_AT more_RGR primitive_JJ the_AT skill_NN1 the_AT more_RRR there_EX must_VM be_VBI an_AT1 element_NN1 of_IO chance_NN1 ._. 
For_REX21 example_REX22 ,_, one_MC1 of_IO the_AT skills_NN2 developed_VVN in_II the_AT first_MD few_DA2 years_NNT2 of_IO life_NN1 involves_VVZ the_AT integration_NN1 of_IO data_NN arriving_VVG through_II the_AT different_JJ sensory_JJ channels_NN2 ._. 
The_AT fact_NN1 that_CST a_AT1 visually_RR observed_VVN impact_NN1 between_II two_MC bodies_NN2 in_II the_AT physical_JJ world_NN1 is_VBZ normally_RR associated_VVN with_IW a_AT1 particular_JJ sound_NN1 has_VHZ to_TO be_VBI learned_VVN ._. 
Hence_RR the_AT importance_NN1 of_IO play_NN1 in_II hitting_VVG ,_, say_VV0 ,_, tins_NN2 with_IW spoons_NN2 the_AT visual_JJ ,_, auditory_JJ and_CC tactile_JJ impressions_NN2 are_VBR being_VBG integrated_VVN ._. 
Similarly_RR the_AT kinaesthetic_JJ sensation_NN1 of_IO a_AT1 limb_NN1 moving_NN1 has_VHZ to_TO be_VBI associated_VVN with_IW the_AT visual_JJ sensation_NN1 obtained_VVN by_II observing_VVG the_AT limb_NN1 hence_RR the_AT countless_JJ hours_NNT2 which_DDQ babies_NN2 spend_VV0 just_RR watching_VVG their_APPGE own_DA limbs_NN2 move_VV0 ._. 
This_DD1 is_VBZ how_RRQ manipulative_JJ skills_NN2 begin_VV0 ,_, but_CCB it_PPH1 will_VM be_VBI noted_VVN that_CST even_RR these_DD2 are_VBR not_XX purely_RR '_GE motor_NN1 '_GE ,_, they_PPHS2 are_VBR mainly_RR '_GE perceptual_JJ '_GE ._. 
Greater_JJR precision_NN1 is_VBZ achieved_VVN by_II more_RGR definitive_JJ selection_NN1 and_CC guidance_NN1 ._. 
Unskilled_JJ activity_NN1 is_VBZ to_TO do_VDI everything_PN1 rather_II21 than_II22 to_II do_VD0 nothing_PN1 ._. 
The_AT concept_NN1 of_IO motor_NN1 skill_NN1 is_VBZ associated_VVN ,_, with_IW the_AT development_NN1 of_IO longer_JJR and_CC more_RGR complex_JJ patterns_NN2 of_IO activity_NN1 which_DDQ can_VM be_VBI reeled_VVN off_II following_VVG a_AT1 single_JJ trigger_NN1 and_CC which_DDQ are_VBR monitored_VVN on_II the_AT basis_NN1 that_CST only_JJ feedback_NN1 which_DDQ indicates_VVZ errors_NN2 needs_VVZ attention_NN1 ._. 
Industrial_JJ training_NN1 for_IF manual_JJ operations_NN2 is_VBZ designed_VVN to_TO encourage_VVI this_DD1 kind_NN1 of_IO development_NN1 (_( Seymour_NP1 ,_, 1966_MC )_) ._. 
Perceptual_JJ skills_NN2 by_II contrast_NN1 are_VBR developments_NN2 to_TO do_VDI with_IW the_AT greater_JJR selectivity_NN1 of_IO information_NN1 needed_VVD to_TO monitor_VVI situations_NN2 and_CC guide_VVI actions_NN2 ._. 
These_DD2 begin_VV0 from_II an_AT1 appreciation_NN1 of_IO the_AT complementary_JJ nature_NN1 of_IO data_NN arriving_VVG through_II the_AT different_JJ sensory_JJ channels_NN2 and_CC expand_VV0 by_II the_AT acquisition_NN1 of_IO concepts_NN2 such_II21 as_II22 the_AT continuity_NN1 of_IO the_AT physical_JJ world_NN1 ,_, e.g._REX a_AT1 person_NN1 who_PNQS walks_VVZ behind_II a_AT1 screen_NN1 has_VHZ not_XX vanished_VVN ,_, it_PPH1 is_VBZ accepted_VVN that_CST he_PPHS1 is_VBZ still_RR there_RL even_CS21 though_CS22 temporarily_RR there_EX is_VBZ no_AT sense_NN1 data_NN to_TO confirm_VVI it_PPH1 ,_, but_CCB a_AT1 hypothesis_NN1 will_VM be_VBI generated_VVN which_DDQ supposes_VVZ that_CST ,_, if_CS he_PPHS1 walked_VVD behind_II a_AT1 screen_NN1 at_II a_AT1 constant_JJ speed_NN1 ,_, he_PPHS1 ought_VMK to_TO reappear_VVI at_II a_AT1 given_JJ time_NNT1 at_II the_AT other_JJ side_NN1 of_IO the_AT screen_NN1 ._. 
Similarly_RR it_PPH1 is_VBZ soon_RR accepted_VVN that_CST the_AT '_GE ostrich_NN1 '_GE theory_NN1 of_IO closing_VVG one_PN1 's_GE eyes_NN2 and_CC assuming_VVG that_CST thereby_RR either_RR oneself_PNX1 or_CC things_NN2 in_II the_AT environment_NN1 will_VM actually_RR disappear_VVI is_VBZ not_XX tenable_JJ ._. 
In_II this_DD1 phase_NN1 babies_NN2 and_CC young_JJ children_NN2 enjoy_VV0 '_GE peep_NN1 '_GE type_NN1 games_NN2 ._. 
There_EX is_VBZ an_AT1 important_JJ stage_NN1 at_II which_DDQ the_AT person-centred_JJ world_NN1 is_VBZ superseded_VVN or_CC rather_RR supplemented_VVN by_II the_AT world_NN1 of_IO which_DDQ the_AT person_NN1 is_VBZ one_MC1 part_NN1 ._. 
Incidentally_RR this_DD1 is_VBZ analogous_JJ to_II the_AT distinction_NN1 between_II displays_NN2 which_DDQ are_VBR '_GE inside_NN1 looking_VVG out_RP '_GE and_CC those_DD2 which_DDQ are_VBR '_GE outside_NN1 looking_VVG in_II '_GE (_( p._NNU 251_MC )_) ._. 
The_AT perceptual_JJ system_NN1 can_VM function_VVI either_DD1 way_NN1 which_DDQ is_VBZ ,_, of_RR21 course_RR22 ,_, why_RRQ each_DD1 of_IO the_AT two_MC types_NN2 of_IO display_NN1 has_VHZ its_APPGE utility_NN1 ._. 
This_DD1 development_NN1 is_VBZ one_PN1 utilising_VVG pictorial_JJ skills_NN2 as_CSA distinct_JJ from_II enactive_JJ skills_NN2 ._. 
The_AT latter_DA are_VBR based_VVN on_II the_AT body_NN1 ,_, its_APPGE extensions_NN2 and_CC images_NN2 ,_, the_AT former_DA are_VBR based_VVN on_II internal_JJ '_GE pictures_NN2 '_GE of_IO the_AT world_NN1 which_DDQ are_VBR one_MC1 kind_NN1 of_IO schema_NN1 or_CC mental_JJ model_NN1 (_( see_VV0 next_MD section_NN1 )_) ._. 
Social_JJ skills_NN2 are_VBR in_II principle_NN1 more_RGR complex_JJ than_CSN perceptual-motor_NN1 skills_NN2 because_CS the_AT latter_DA assume_VV0 (_( correctly_RR )_) a_AT1 passive_JJ world_NN1 which_DDQ will_VM react_VVI neutrally_RR ,_, according_II21 to_II22 the_AT laws_NN2 of_IO physics_NN1 ._. 
In_II31 spite_II32 of_II33 occasional_JJ feelings_NN2 to_II the_AT contrary_NN1 ,_, usually_RR described_VVN as_CSA good_JJ or_CC bad_JJ luck_NN1 ,_, the_AT physical_JJ world_NN1 is_VBZ neither_RR for_IF nor_CC against_II the_AT actions_NN2 of_IO the_AT individual_NN1 (_( except_CS in_II the_AT robotic_JJ sense_NN1 of_IO Le_NP1 Chatilier_NP1 's_GE principle_NN1 which_DDQ states_VVZ that_CST whenever_RRQV a_AT1 constraint_NN1 is_VBZ placed_VVN on_II a_AT1 system_NN1 in_II equilibrium_NN1 ,_, the_AT equilibrium_NN1 is_VBZ altered_VVN in_II such_DA a_AT1 way_NN1 as_CSA to_TO annul_VVI the_AT efforts_NN2 of_IO the_AT constraint_NN1 )_) ._. 
In_II social_JJ situations_NN2 it_PPH1 has_VHZ to_TO be_VBI recognised_VVN that_CST there_EX is_VBZ at_RR21 least_RR22 one_MC1 other_JJ sentient_NN1 being_VBG present_NN1 who_PNQS has_VHZ his_APPGE own_DA objectives_NN2 which_DDQ might_VM accord_VVI with_IW or_CC oppose_VV0 those_DD2 of_IO the_AT first_MD person_NN1 ._. 
Thus_RR ,_, social_JJ skills_NN2 involve_VV0 assessing_VVG the_AT skills_NN2 of_IO the_AT other_JJ person_NN1 ,_, a_AT1 process_NN1 known_VVN as_II mutual_JJ construing_NN1 ._. 
The_AT evidence_NN1 about_II the_AT constructs_NN2 of_IO another_DD1 person_NN1 is_VBZ indirect_JJ and_CC may_VM have_VHI been_VBN deliberately_RR obscured_VVN or_CC falsified_VVD ._. 
Nevertheless_RR ,_, it_PPH1 is_VBZ true_JJ for_IF all_DB skills_NN2 that_CST a_AT1 person_NN1 developing_VVG skills_NN2 is_VBZ indulging_VVG in_II a_AT1 process_NN1 of_IO constructing_VVG models_NN2 of_IO what_DDQ is_VBZ happening_VVG externally_RR ._. 
These_DD2 models_NN2 develop_VV0 continuously_RR while_CS attempting_VVG to_TO modify_VVI the_AT external_JJ situation_NN1 (_( physical_JJ or_CC social_JJ )_) ._. 
What_DDQ seems_VVZ to_TO happen_VVI is_VBZ that_CST an_AT1 individual_JJ ,_, given_VVN his_APPGE arrival_NN1 in_II a_AT1 situation_NN1 ,_, reviews_VVZ it_PPH1 in_II the_AT context_NN1 of_IO his_APPGE own_DA objectives_NN2 and_CC decides_VVZ that_CST if_CS he_PPHS1 takes_VVZ certain_JJ actions_NN2 ,_, the_AT situation_NN1 will_VM change_VVI in_II the_AT direction_NN1 of_IO his_APPGE objectives_NN2 ._. 
He_PPHS1 then_RT takes_VVZ the_AT action_NN1 ,_, observes_VVZ the_AT changes_NN2 and_CC compares_VVZ them_PPHO2 with_IW his_APPGE stored_JJ version_NN1 of_IO those_DD2 expected_VVN ._. 
If_CS they_PPHS2 correspond_VV0 ,_, then_RT all_DB is_VBZ well_JJ ,_, his_APPGE concept_NN1 of_IO the_AT situation_NN1 is_VBZ confirmed_VVN and_CC he_PPHS1 can_VM progress_VVI to_II the_AT next_MD step_NN1 in_II the_AT context_NN1 of_IO his_APPGE objectives_NN2 ._. 
If_CS ,_, however_RR ,_, the_AT observed_JJ changes_NN2 are_VBR not_XX what_DDQ was_VBDZ predicted_VVN ,_, then_RT he_PPHS1 has_VHZ made_VVN an_AT1 error_NN1 but_CCB he_PPHS1 has_VHZ also_RR learned_VVN because_CS he_PPHS1 must_VM now_RT modify_VVI his_APPGE view_NN1 of_IO the_AT situation_NN1 accordingly_RR ._. 
For_REX21 example_REX22 ,_, I_PPIS1 might_VM decide_VVI the_AT angle_NN1 of_IO light_NN1 on_II my_APPGE desk_NN1 is_VBZ not_XX as_CSA I_PPIS1 require_VV0 it_PPH1 on_II the_AT basis_NN1 of_IO assessing_VVG the_AT illumination_NN1 and_CC the_AT lamp_NN1 which_DDQ is_VBZ the_AT source_NN1 of_IO it_PPH1 ._. 
I_PPIS1 hypothesise_VV0 that_CST if_CS I_PPIS1 move_VV0 and_CC turn_VV0 the_AT lamp_NN1 in_II a_AT1 particular_JJ way_NN1 I_PPIS1 will_VM get_VVI the_AT result_NN1 I_PPIS1 want_VV0 ._. 
So_RR I_PPIS1 reach_VV0 out_RP ,_, move_VV0 and_CC turn_VV0 the_AT lamp_NN1 and_CC check_VV0 the_AT result_NN1 ._. 
If_CS the_AT result_NN1 is_VBZ as_CSA intended_VVN there_RL has_VHZ been_VBN no_AT learning_NN1 but_CCB equally_RR none_PN was_VBDZ needed_VVN because_CS I_PPIS1 understood_VVD the_AT situation_NN1 ,_, I_PPIS1 achieved_VVD my_APPGE objective_NN1 and_CC I_PPIS1 can_VM move_VVI on_RP to_II other_JJ problems_NN2 ._. 
In_II a_AT1 more_RGR complex_JJ case_NN1 I_PPIS1 might_VM sit_VVI in_RP on_II a_AT1 discussion_NN1 within_II a_AT1 committee_NN1 but_CCB begin_VV0 to_TO consider_VVI that_CST it_PPH1 is_VBZ not_XX moving_VVG in_II a_AT1 direction_NN1 that_CST suits_VVZ me_PPIO1 ._. 
I_PPIS1 therefore_RR form_VV0 a_AT1 hypothesis_NN1 about_II an_AT1 appropriate_JJ contribution_NN1 based_VVN on_II the_AT proposition_NN1 being_VBG considered_VVN ,_, the_AT associated_JJ facts_NN2 and_CC logic_NN1 ,_, the_AT personalities_NN2 of_IO my_APPGE fellow_JJ committee_NN1 members_NN2 and_CC my_APPGE own_DA standing_NN1 within_II the_AT committee_NN1 ._. 
I_PPIS1 then_RT state_VV0 my_APPGE proposition_NN1 and_CC observe_VV0 its_APPGE effects_NN2 ._. 
If_CS I_PPIS1 get_VV0 the_AT result_NN1 I_PPIS1 wanted_VVD there_EX is_VBZ consolidation_NN1 rather_II21 than_II22 extension_NN1 of_IO my_APPGE committee_NN1 skills_NN2 ,_, but_CCB if_CS I_PPIS1 do_VD0 not_XX get_VVI the_AT result_NN1 I_PPIS1 wanted_VVD then_RT I_PPIS1 have_VH0 learned_VVN something_PN1 and_CC I_PPIS1 form_VV0 a_AT1 new_JJ hypothesis_NN1 about_II my_APPGE next_MD interjection_NN1 strengthened_VVN by_II this_DD1 new_JJ learning_NN1 ._. 
It_PPH1 will_VM be_VBI noted_VVN that_CST errors_NN2 are_VBR the_AT basis_NN1 of_IO further_JJR skill_NN1 acquisition_NN1 ._. 
Facilitating_VVG the_AT acquisition_NN1 of_IO skill_NN1 is_VBZ a_AT1 matter_NN1 of_IO providing_VVG situations_NN2 where_RRQ the_AT skill_NN1 can_VM be_VBI practised_VVN with_IW adequate_JJ ,_, sometimes_RT enhanced_VVD ,_, feedback_NN1 so_CS21 that_CS22 there_EX can_VM be_VBI learning_VVG from_II mistakes_NN2 ._. 
The_AT necessary_JJ conditions_NN2 for_IF learning_NN1 are_VBR feedback_NN1 and_CC motivation_NN1 ,_, the_AT result_NN1 of_IO actions_NN2 must_VM matter_VVI to_II the_AT individual_NN1 ._. 
All_DB this_DD1 is_VBZ quite_RG generally_RR true_JJ ,_, it_PPH1 applies_VVZ equally_RR to_TO motor_VVI skills_NN2 ,_, perceptual_JJ skills_NN2 and_CC social_JJ skills_NN2 ._. 
Mental_JJ models_NN2 The_AT principles_NN2 of_IO perception_NN1 indicate_VV0 that_CST the_AT human_JJ operator_NN1 does_VDZ not_XX react_VVI unambiguously_RR to_II stimuli_NN2 which_DDQ arrive_VV0 via_II the_AT sensory_JJ mechanisms_NN2 (_( p._NNU 196_MC )_) ._. 
To_TO assume_VVI that_CST he_PPHS1 responds_VVZ directly_RR to_II data_NN from_II the_AT real_JJ world_NN1 is_VBZ to_TO oversimplify_VVI the_AT relationship_NN1 between_II his_APPGE inputs_NN2 and_CC outputs_NN2 ._. 
The_AT skill_NN1 model_NN1 described_VVN above_RL implies_VVZ that_CST ,_, except_CS in_II highly_RR restricted_VVN artificial_JJ situations_NN2 ,_, his_APPGE information_NN1 processing_NN1 must_VM be_VBI described_VVN in_II31 terms_II32 of_II33 patterns_NN2 of_IO stimuli_NN2 related_VVN to_II patterns_NN2 of_IO responses_NN2 ._. 
It_PPH1 is_VBZ also_RR true_JJ that_CST responses_NN2 are_VBR a_AT1 function_NN1 of_IO enormous_JJ differences_NN2 between_II and_CC within_II individuals_NN2 ._. 
To_TO encompass_VVI all_DB these_DD2 parameters_NN2 ,_, it_PPH1 is_VBZ currently_RR fashionable_JJ to_TO describe_VVI the_AT person_NN1 as_II responding_VVG in_II31 terms_II32 of_II33 his_APPGE mental_JJ model_NN1 of_IO the_AT situation_NN1 rather_II21 than_II22 to_II the_AT situation_NN1 itself_PPX1 ._. 
The_AT idea_NN1 is_VBZ that_CST any_DD person_NN1 in_II any_DD situation_NN1 builds_VVZ an_AT1 internal_JJ model_NN1 of_IO the_AT situation_NN1 which_DDQ is_VBZ being_VBG reported_VVN to_II him_PPHO1 ,_, as_RR31 it_RR32 were_RR33 ,_, by_II sensory_JJ data_NN ._. 
He_PPHS1 uses_VVZ each_DD1 perceptual_JJ datum_NN1 to_TO update_VVI his_APPGE model_NN1 of_IO the_AT situation_NN1 ._. 
The_AT model_NN1 is_VBZ his_APPGE picture_NN1 of_IO what_DDQ is_VBZ going_VVG on_RP outside_II him_PPHO1 and_CC it_PPH1 is_VBZ essentially_RR an_AT1 hypothesis_NN1 based_VVN on_II the_AT available_JJ evidence_NN1 ._. 
This_DD1 theory_NN1 explains_VVZ nicely_RR why_RRQ he_PPHS1 sometimes_RT does_VDZ not_XX react_VVI in_II tune_NN1 with_IW his_APPGE own_DA interests_NN2 ,_, that_REX21 is_REX22 ,_, he_PPHS1 gets_VVZ it_PPH1 wrong_JJ ._. 
In_II these_DD2 circumstances_NN2 he_PPHS1 is_VBZ considered_VVN to_TO have_VHI developed_VVN a_AT1 model_NN1 which_DDQ does_VDZ not_XX bridge_VVI the_AT gap_NN1 between_II reality_NN1 and_CC his_APPGE aspirations_NN2 ._. 
These_DD2 models_NN2 are_VBR most_RGT easy_JJ to_TO visualise_VVI in_II pictorial_JJ terms_NN2 the_AT human_JJ operator_NN1 has_VHZ his_APPGE internal_JJ picture_NN1 which_DDQ topographically_RR matches_VVZ the_AT real_JJ world_NN1 ._. 
Models_NN2 can_VM ,_, however_RR ,_, be_VBI simpler_JJR than_CSN these_DD2 and_CC can_VM take_VVI the_AT form_NN1 of_IO rules_NN2 or_CC they_PPHS2 can_VM be_VBI more_RGR complex_JJ in_II that_DD1 symbolism_NN1 can_VM be_VBI used_VVN ._. 
Thus_RR a_AT1 model_NN1 can_VM be_VBI entirely_RR abstract_VV0 using_VVG symbols_NN2 which_DDQ have_VH0 no_AT pictorial_JJ quality_NN1 as_CSA in_II the_AT use_NN1 of_IO language_NN1 and_CC mathematics_NN1 ._. 
Even_RR when_CS a_AT1 picture_NN1 is_VBZ used_VVN ,_, it_PPH1 is_VBZ not_XX complete_JJ ,_, it_PPH1 takes_VVZ the_AT form_NN1 of_IO an_AT1 icon_NN1 which_DDQ contains_VVZ what_DDQ the_AT perceiver_NN1 considers_VVZ matters_NN2 at_II the_AT time_NNT1 ._. 
For_REX21 example_REX22 ,_, a_AT1 person_NN1 working_VVG in_II a_AT1 room_NN1 with_IW or_CC without_IW other_JJ people_NN can_VM easily_RR develop_VVI the_AT misconception_NN1 that_CST he_PPHS1 has_VHZ a_AT1 complete_JJ picture_NN1 in_II his_APPGE mind_NN1 of_IO the_AT physical_JJ environment_NN1 ._. 
In_II fact_NN1 the_AT picture_NN1 is_VBZ complete_JJ only_RR in_II the_AT sense_NN1 that_CST it_PPH1 contains_VVZ the_AT details_NN2 which_DDQ are_VBR relevant_JJ to_II his_APPGE activity_NN1 in_II that_DD1 room_NN1 ,_, it_PPH1 certainly_RR does_VDZ not_XX contain_VVI all_DB the_AT detail_NN1 which_DDQ is_VBZ available_JJ to_II the_AT senses_NN2 ._. 
This_DD1 is_VBZ readily_RR demonstrated_VVN by_II asking_VVG him_PPHO1 to_TO close_VVI his_APPGE eyes_NN2 and_CC answer_VVI questions_NN2 such_II21 as_II22 '_GE is_VBZ there_RL a_AT1 picture_NN1 on_II the_AT wall_NN1 on_II the_AT left_JJ ?_? '_GE or_CC '_" what_DDQ colour_NN1 are_VBR the_AT eyes_NN2 of_IO the_AT person_NN1 you_PPY are_VBR talking_VVG to_II ?_? 
'_" This_DD1 is_VBZ the_AT kind_NN1 of_IO data_NN which_DDQ is_VBZ not_XX relevant_JJ to_II his_APPGE objectives_NN2 and_CC thus_RR it_PPH1 is_VBZ not_XX recorded_VVN in_II his_APPGE model_NN1 ._. 
On_II the_AT other_JJ hand_NN1 he_PPHS1 will_VM be_VBI able_JK to_TO answer_VVI questions_NN2 such_II21 as_II22 '_GE is_VBZ the_AT door_NN1 behind_II you_PPY to_II the_AT left_JJ or_CC to_II the_AT right_NN1 ?_? '_GE because_CS he_PPHS1 has_VHZ used_VVN that_DD1 door_NN1 and_CC needs_VVZ to_TO use_VVI it_PPH1 again_RT ._. 
He_PPHS1 knows_VVZ where_RRQ it_PPH1 is_VBZ even_CS21 though_CS22 he_PPHS1 can_VM not_XX currently_RR see_VVI it_PPH1 ._. 
Thus_RR the_AT visually-based_JJ mental_JJ picture_NN1 is_VBZ invariably_RR an_AT1 icon_NN1 in_II the_AT literal_JJ sense_NN1 of_IO a_AT1 '_GE symbolic_JJ representation_NN1 '_GE rather_II21 than_II22 a_AT1 complete_JJ reproduction_NN1 ._. 
At_II a_AT1 more_RGR abstract_JJ level_NN1 the_AT mathematician_NN1 or_CC scientist_NN1 will_VM perform_VVI manipulations_NN2 within_II a_AT1 set_NN1 of_IO symbols_NN2 which_DDQ follow_VV0 certain_JJ rules_NN2 but_CCB neither_RR the_AT symbols_NN2 nor_CC the_AT rules_NN2 need_VM have_VHI direct_JJ representation_NN1 in_II reality_NN1 ._. 
Indeed_RR any_DD attempt_NN1 to_TO relate_VVI them_PPHO2 prematurely_RR to_II reality_NN1 may_VM restrict_VVI the_AT development_NN1 of_IO the_AT model_NN1 ._. 
However_RR ,_, at_II some_DD stage_NN1 he_PPHS1 will_VM return_VVI to_II reality_NN1 and_CC say_VVI ,_, for_REX21 example_REX22 ,_, '_" what_DDQ this_DD1 means_VVZ in_II practice_NN1 or_CC in_II31 terms_II32 of_II33 my_APPGE next_MD experiment_NN1 ..._... 
'_GE The_AT skilled_JJ thinker_NN1 has_VHZ an_AT1 extraordinary_JJ facility_NN1 not_XX only_RR to_TO develop_VVI varieties_NN2 of_IO abstract_JJ models_NN2 but_CCB also_RR to_TO switch_VVI rapidly_RR between_II them_PPHO2 and_CC between_II them_PPHO2 and_CC reality_NN1 ._. 
The_AT switching_NN1 takes_VVZ place_NN1 up_RP and_CC down_RP a_AT1 hierarchy_NN1 of_IO abstraction_NN1 and_CC generality_NN1 ._. 
Consider_VV0 for_REX21 example_REX22 the_AT maintenance_NN1 engineer_NN1 operating_NN1 as_II a_AT1 diagnostician_NN1 ._. 
He_PPHS1 will_VM look_VVI at_II a_AT1 piece_NN1 of_IO equipment_NN1 to_TO try_VVI to_TO detect_VVI signs_NN2 which_DDQ indicate_VV0 what_DDQ is_VBZ wrong_JJ ._. 
Is_VBZ there_EX a_AT1 gap_NN1 or_CC a_AT1 hole_NN1 which_DDQ indicates_VVZ a_AT1 leak_NN1 ?_? 
Is_VBZ there_EX a_AT1 part_NN1 which_DDQ is_VBZ too_RG hot_JJ ?_? 
Most_DAT of_IO this_DD1 information_NN1 comes_VVZ not_XX so_RG much_DA1 from_II what_DDQ is_VBZ happening_VVG but_CCB from_II what_DDQ is_VBZ not_XX happening_VVG ._. 
Basically_RR the_AT thing_NN1 is_VBZ not_XX working_VVG as_CSA it_PPH1 should_VM ,_, the_AT outputs_NN2 are_VBR not_XX as_CSA they_PPHS2 should_VM be_VBI so_RR he_PPHS1 will_VM probably_RR begin_VVI by_II checking_VVG that_CST the_AT inputs_NN2 are_VBR present_JJ ,_, that_DD1 is_VBZ the_AT electric_JJ power_NN1 or_CC fuel_NN1 or_CC other_JJ materials_NN2 are_VBR available_JJ ._. 
He_PPHS1 will_VM then_RT envisage_VVI the_AT designed_JJ chain_NN1 of_IO events_NN2 between_II input_NN1 and_CC output_NN1 and_CC look_VV0 for_IF the_AT hiatus_NN1 ,_, he_PPHS1 may_VM do_VDI this_DD1 by_II rules_NN2 ,_, by_II a_AT1 pictorial_JJ model_NN1 or_CC by_II a_AT1 model_NN1 involving_VVG some_DD symbolism_NN1 such_II21 as_II22 expected_JJ voltage_NN1 levels_NN2 ._. 
He_PPHS1 will_VM shift_VVI very_RG rapidly_RR between_II different_JJ representations_NN2 of_IO the_AT equipment_NN1 ;_; the_AT thing_NN1 itself_PPX1 ,_, his_APPGE maintenance_NN1 instructions_NN2 ,_, the_AT manual_NN1 ,_, the_AT drawings_NN2 of_IO the_AT system_NN1 ,_, verbal_JJ discussion_NN1 with_IW a_AT1 colleague_NN1 ,_, his_APPGE recollection_NN1 of_IO what_DDQ has_VHZ happened_VVN to_II it_PPH1 in_II the_AT past_NN1 and_RR31 so_RR32 on_RR33 ._. 
He_PPHS1 may_VM think_VVI in_II31 terms_II32 of_II33 bits_NN2 of_IO equipment_NN1 ,_, flows_NN2 of_IO material_NN1 ,_, flows_NN2 of_IO energy_NN1 or_CC flows_NN2 of_IO information_NN1 ._. 
He_PPHS1 will_VM shift_VVI through_II levels_NN2 of_IO generality_NN1 and_CC levels_NN2 of_IO abstraction_NN1 until_CS he_PPHS1 has_VHZ formulated_VVN an_AT1 hypothesis_NN1 which_DDQ takes_VVZ the_AT form_NN1 of_IO '_GE if_CS I_PPIS1 do_VD0 this_DD1 that_CST should_VM happen_VVI '_GE ._. 
He_PPHS1 will_VM then_RT perform_VVI an_AT1 action_NN1 and_CC check_VVI its_APPGE results_NN2 ._. 
There_EX are_VBR many_DA2 interesting_JJ facets_NN2 of_IO this_DD1 complex_JJ diagnostic_JJ process_NN1 and_CC three_MC are_VBR worthy_JJ of_IO re-emphasis_NN1 :_: firstly_RR most_DAT of_IO his_APPGE information_NN1 comes_VVZ not_XX from_II positive_JJ signals_NN2 ,_, stimuli_NN2 or_CC cues_NN2 but_CCB from_II their_APPGE absence_NN1 ,_, secondly_RR he_PPHS1 is_VBZ relying_VVG on_II a_AT1 hybrid_JJ model_NN1 a_AT1 mixture_NN1 of_IO rules_NN2 ,_, mental_JJ pictures_NN2 and_CC symbolism_NN1 ,_, thirdly_RR it_PPH1 all_DB happens_VVZ without_IW very_RG much_DA1 conscious_JJ guidance_NN1 one_MC1 mental_JJ or_CC physical_JJ event_NN1 leads_VVZ to_II another_DD1 and_CC each_DD1 event_NN1 in_II the_AT chain_NN1 plays_VVZ its_APPGE part_NN1 before_II handing_VVG over_RP to_II the_AT next_MD one_PN1 ._. 
There_EX is_VBZ some_DD analogy_NN1 with_IW a_AT1 control_NN1 system_NN1 used_VVN in_II early_JJ naval_JJ warfare_NN1 ._. 
There_EX was_VBDZ not_XX one_MC1 ship_NN1 permanently_RR in_II command_NN1 ,_, the_AT particular_JJ ship_NN1 in_II most_DAT direct_JJ contact_NN1 with_IW the_AT enemy_NN1 was_VBDZ in_II command_NN1 until_CS the_AT leading_JJ position_NN1 was_VBDZ taken_VVN over_RP by_II another_DD1 ship_NN1 which_DDQ then_RT assumed_VVD command_NN1 as_II31 well_II32 as_II33 action_NN1 ._. 
The_AT working_JJ situation_NN1 is_VBZ different_JJ from_II the_AT training_NN1 school_NN1 and_CC even_RR more_RRR from_II the_AT educational_JJ system_NN1 ._. 
However_RRQV it_PPH1 does_VDZ seem_VVI that_DD1 mental_JJ models_NN2 can_VM be_VBI developed_VVN in_II the_AT abstract_JJ without_IW the_AT need_NN1 to_II resort_NN1 to_II action_NN1 ,_, in_II other_JJ words_NN2 it_PPH1 is_VBZ possible_JJ to_TO learn_VVI while_CS sitting_VVG passively_RR in_II a_AT1 class-room_NN1 ._. 
Education_NN1 or_CC abstract_JJ learning_NN1 does_VDZ seem_VVI to_TO take_VVI the_AT form_NN1 mainly_RR of_IO symbolic_JJ modelling_NN1 and_CC the_AT relating_NN1 of_IO these_DD2 models_NN2 to_II reality_NN1 awaits_VVZ later_JJR practical_JJ experience_NN1 ._. 
The_AT great_JJ asset_NN1 of_IO symbolic_JJ modelling_NN1 is_VBZ just_RR this_DD1 ,_, learning_NN1 does_VDZ not_XX have_VHI to_TO depend_VVI entirely_RR on_II practice_NN1 and_CC it_PPH1 is_VBZ possible_JJ for_IF collective_JJ knowledge_NN1 to_TO accumulate_VVI ._. 
This_DD1 knowledge_NN1 is_VBZ communicated_VVN between_II people_NN by_II the_AT use_NN1 of_IO shared_JJ models_NN2 ._. 
Conversely_RR ,_, abstract_JJ communication_NN1 can_VM not_XX take_VVI place_NN1 without_IW the_AT development_NN1 of_IO appropriate_JJ models_NN2 ._. 
For_REX21 example_REX22 ,_, the_AT technical_JJ teacher_NN1 is_VBZ trying_VVG to_TO convey_VVI various_JJ models_NN2 to_II his_APPGE pupils_NN2 ,_, some_DD of_IO the_AT models_NN2 will_VM be_VBI physically_RR based_VVN as_CSA in_II describing_VVG particular_JJ machines_NN2 or_CC systems_NN2 and_CC some_DD will_VM be_VBI functionally_RR based_VVN as_CSA when_CS he_PPHS1 talks_VVZ about_II thermodynamics_NN1 or_CC communication_NN1 ._. 
What_DDQ the_AT teacher_NN1 is_VBZ trying_VVG to_TO do_VDI is_VBZ to_TO guide_VVI each_DD1 pupil_NN1 into_II developing_VVG a_AT1 set_NN1 of_IO mental_JJ models_NN2 which_DDQ have_VH0 been_VBN found_VVN by_II experience_NN1 or_CC experiment_NN1 to_TO be_VBI useful_JJ in_II understanding_VVG technical_JJ processes_NN2 ._. 
Having_VHG developed_VVN these_DD2 models_NN2 the_AT pupil_NN1 is_VBZ in_II a_AT1 position_NN1 to_TO communicate_VVI much_RR more_RGR readily_RR with_IW other_JJ technical_JJ people_NN who_PNQS can_VM manipulate_VVI similar_JJ models_NN2 ._. 
Conversely_RR ,_, this_DD1 communication_NN1 between_II specialists_NN2 will_VM be_VBI incomprehensible_JJ to_II those_DD2 who_PNQS do_VD0 not_XX have_VHI the_AT expertise_NN1 which_DDQ resides_VVZ in_II this_DD1 particular_JJ set_NN1 of_IO models_NN2 ._. 
Even_RR between_II technical_JJ peers_NN2 as_CSA in_II a_AT1 design_NN1 team_NN1 there_EX can_VM be_VBI difficulties_NN2 in_II communication_NN1 because_CS the_AT models_NN2 which_DDQ individuals_NN2 are_VBR using_VVG are_VBR not_XX identical_JJ ._. 
Debate_NN1 ,_, demonstration_NN1 and_CC other_JJ communications_NN2 take_VV0 place_NN1 until_CS a_AT1 common_JJ modelling_NN1 is_VBZ accepted_VVN ._. 
When_CS there_EX is_VBZ disagreement_NN1 ,_, there_EX is_VBZ much_DA1 to_TO be_VBI said_VVN for_IF retreating_VVG specifically_RR to_TO consider_VVI the_AT model_NN1 rather_II21 than_II22 the_AT problem_NN1 ._. 
Correspondingly_RR ,_, when_CS there_EX is_VBZ a_AT1 complex_JJ situation_NN1 to_TO discuss_VVI there_RL can_VM be_VBI considerable_JJ dividends_NN2 in_II attempting_VVG to_TO get_VVI an_AT1 agreed_JJ model_NN1 '_GE on_II the_AT table_NN1 '_GE before_II considering_VVG specific_JJ issues_NN2 ._. 
This_DD1 is_VBZ what_DDQ briefing_NN1 sessions_NNT2 are_VBR intended_VVN to_TO accomplish_VVI ._. 
This_DD1 approach_NN1 also_RR explains_VVZ why_RRQ engineers_NN2 and_CC ergonomists_NN2 sometimes_RT have_VH0 difficulties_NN2 in_II reaching_VVG agreement_NN1 ._. 
The_AT former_DA is_VBZ likely_JJ to_TO be_VBI using_VVG mechanismbased_JJ models_NN2 with_IW people_NN as_CSA ancillaries_NN2 while_CS the_AT ergonomist_NN1 will_VM be_VBI using_VVG models_NN2 of_IO people_NN with_IW mechanisms_NN2 as_CSA ancillaries_NN2 ._. 
For_IF good_JJ cooperation_NN1 it_PPH1 is_VBZ essential_JJ that_CST the_AT engineer_NN1 has_VHZ some_DD grasp_NN1 of_IO ergonomics_NN1 and_CC that_CST the_AT ergonomist_NN1 understands_VVZ at_RR21 least_RR22 in_II general_JJ terms_NN2 the_AT technical_JJ situation_NN1 in_II the_AT particular_JJ industry_NN1 ._. 
There_EX can_VM of_RR21 course_RR22 still_RR be_VBI disagreements_NN2 even_CS21 when_CS22 there_EX is_VBZ clear_JJ mutual_JJ understanding_NN1 because_CS underlying_JJ values_NN2 result_VV0 in_II the_AT assessment_NN1 of_IO very_RG different_JJ priorities_NN2 ._. 
In_II summary_NN1 ,_, communication_NN1 ,_, whether_CSW between_II a_AT1 person_NN1 and_CC the_AT physical_JJ world_NN1 or_CC between_II people_NN ,_, involves_VVZ each_DD1 person_NN1 in_II developing_VVG and_CC manipulating_VVG a_AT1 mental_JJ model_NN1 by_II interacting_VVG with_IW the_AT situation_NN1 ._. 
Modelling_VVG the_AT physical_JJ world_NN1 and_CC modelling_VVG other_JJ people_NN 's_GE models_NN2 share_VV0 the_AT same_DA developmental_JJ procedures_NN2 ._. 
Understanding_NN1 what_DDQ a_AT1 person_NN1 is_VBZ doing_VDG requires_VVZ an_AT1 appreciation_NN1 of_IO the_AT kind_NN1 and_CC content_NN1 of_IO the_AT models_NN2 that_CST that_DD1 person_NN1 holds_VVZ ._. 
Knowledge_NN1 Individual_NN1 differences_NN2 Capacities_NN2 ,_, abilities_NN2 and_CC aptitudes_NN2 It_PPH1 is_VBZ useful_JJ to_TO discriminate_VVI between_II a_AT1 capacity_NN1 which_DDQ is_VBZ a_AT1 natural_JJ endowment_NN1 and_CC an_AT1 ability_NN1 which_DDQ is_VBZ a_AT1 competence_NN1 to_TO act_VVI ._. 
A_AT1 capacity_NN1 relates_VVZ to_II an_AT1 ability_NN1 through_II an_AT1 intervening_JJ phase_NN1 of_IO education_NN1 ,_, training_NN1 and_CC experience_NN1 ._. 
Thus_RR an_AT1 ability_NN1 represents_VVZ what_DDQ a_AT1 person_NN1 can_VM do_VDI now_RT ,_, whereas_CS a_AT1 capacity_NN1 is_VBZ essentially_RR a_AT1 potential_NN1 ._. 
An_AT1 aptitude_NN1 is_VBZ demonstrated_VVN by_II success_NN1 in_II learning_VVG which_DDQ results_VVZ in_II the_AT acquisition_NN1 of_IO an_AT1 ability_NN1 ._. 
An_AT1 aptitude_NN1 is_VBZ therefore_RR a_AT1 capacity_NN1 plus_II an_AT1 inclination_NN1 or_CC interest_NN1 ._. 
Ability_NN1 and_CC skill_NN1 are_VBR often_RR used_VVN interchangeably_RR although_CS ability_NN1 is_VBZ the_AT wider_JJR term_NN1 ._. 
An_AT1 ability_NN1 is_VBZ made_VVN up_RP of_IO a_AT1 repertoire_NN1 of_IO skills_NN2 and_CC is_VBZ thus_RR a_AT1 higher_JJR level_JJ skill_NN1 ._. 
Ability_NN1 and_CC capacity_NN1 are_VBR often_RR confused_VVN for_IF several_DA2 reasons_NN2 ._. 
Human_JJ resources_NN2 might_VM be_VBI expressed_VVN in_II31 terms_II32 of_II33 either_DD1 since_CS capacities_NN2 can_VM be_VBI transformed_VVN into_II abilities_NN2 by_II training_NN1 ._. 
Strictly_RR we_PPIS2 can_VM only_RR measure_VVI abilities_NN2 but_CCB much_RR psychometric_JJ testing_NN1 aims_VVZ to_TO infer_VVI capacities_NN2 from_II the_AT measured_JJ abilities_NN2 ,_, e.g._REX intelligence_NN1 tests_NN2 ._. 
All_DB three_MC terms_NN2 are_VBR attributes_NN2 of_IO individuals_NN2 intended_VVD to_TO describe_VVI their_APPGE distinction_NN1 from_II other_JJ individuals_NN2 ._. 
All_DB are_VBR used_VVN loosely_RR because_CS there_EX are_VBR no_AT taxonomies_NN2 which_DDQ are_VBR either_RR comprehensive_JJ or_CC rigorous_JJ ._. 
That_REX21 is_REX22 ,_, it_PPH1 would_VM be_VBI unduly_RR ambitious_JJ to_TO claim_VVI to_TO be_VBI able_JK to_TO describe_VVI a_AT1 complete_JJ range_NN1 of_IO human_JJ abilities_NN2 and_CC the_AT descriptors_NN2 used_VVN for_IF particular_JJ abilities_NN2 are_VBR not_XX always_RR separable_JJ ._. 
The_AT same_DA is_VBZ true_JJ for_IF capacities_NN2 and_CC aptitudes_NN2 ._. 
The_AT best_RRT known_VVN attempt_NN1 to_TO provide_VVI a_AT1 comprehensive_JJ structure_NN1 of_IO human_JJ abilities_NN2 is_VBZ that_CST due_II21 to_II22 Guilford_NP1 (_( 1967_MC )_) ._. 
His_APPGE model_NN1 contains_VVZ about_RG 120_MC different_JJ abilities_NN2 ,_, it_PPH1 is_VBZ not_XX currently_RR very_RG popular_JJ with_IW psychometricians_NN2 ._. 
The_AT only_JJ unambiguous_JJ categorisations_NN2 of_IO people_NN are_VBR by_II physical_JJ size_NN1 ,_, age_NN1 and_CC sex_NN1 ._. 
None_PN of_IO these_DD2 is_VBZ uniquely_RR related_VVN to_II abilities_NN2 but_CCB nevertheless_RR age_NN1 and_CC sex_NN1 are_VBR useful_JJ parameters_NN2 ._. 
Age_VV0 in_RR21 particular_RR22 at_RR21 least_RR22 correlates_VVZ with_IW some_DD of_IO the_AT parameters_NN2 which_DDQ affect_VV0 choice_NN1 of_IO work_NN1 and_CC performance_NN1 at_II work_NN1 ._. 
Intelligence_NN1 and_CC personality_NN1 There_EX is_VBZ no_AT agreed_JJ definition_NN1 of_IO intelligence_NN1 although_CS a_AT1 century_NNT1 of_IO experience_NN1 has_VHZ accumulated_VVN in_II attempts_NN2 to_TO measure_VVI it_PPH1 (_( Friedman_NP1 et_RA21 al._RA22 ,_, 1981_MC )_) ._. 
Intelligence_NN1 defined_VVN as_CSA that_DD1 which_DDQ is_VBZ measured_VVN by_II intelligence_NN1 tests_NN2 is_VBZ obviously_RR circular_JJ and_CC also_RR variable_JJ as_II the_AT fashions_NN2 in_II intelligence_NN1 testing_NN1 change_NN1 ._. 
For_REX21 example_REX22 ,_, the_AT attempt_NN1 in_II the_AT past_JJ thirty_MC years_NNT2 to_TO incorporate_VVI more_RGR divergent_JJ factors_NN2 changes_VVZ the_AT emphasis_NN1 towards_II inductive_JJ and_CC creative_JJ abilities_NN2 ._. 
This_DD1 supplements_VVZ the_AT consideration_NN1 of_IO deductive_JJ and_CC logical_JJ abilities_NN2 measured_VVN by_II the_AT traditional_JJ convergent_JJ questions_NN2 for_IF which_DDQ there_EX are_VBR unique_JJ correct_JJ answers_NN2 ._. 
In_II31 spite_II32 of_II33 the_AT absence_NN1 of_IO a_AT1 sound_NN1 theory_NN1 ,_, the_AT concept_NN1 is_VBZ operationally_RR useful_JJ ._. 
Intelligence_NN1 is_VBZ a_AT1 descriptor_NN1 of_IO the_AT quality_NN1 of_IO mental_JJ functioning_NN1 ,_, the_AT ceiling_NN1 of_IO intellectual_JJ manipulation_NN1 to_II which_DDQ the_AT individual_NN1 can_VM rise_VVI ._. 
High_JJ achievers_NN2 in_II technically_RR demanding_VVG fields_NN2 are_VBR always_RR intelligent_JJ although_CS the_AT converse_NN1 is_VBZ not_XX true_JJ ._. 
That_REX21 is_REX22 ,_, there_EX are_VBR many_DA2 intelligent_JJ individuals_NN2 who_PNQS are_VBR not_XX high_JJ achievers_NN2 ._. 
It_PPH1 follows_VVZ that_CST a_AT1 particular_JJ score_NN1 from_II an_AT1 intelligence_NN1 appraisal_NN1 can_VM be_VBI a_AT1 useful_JJ cut-off_NN1 point_NN1 in_CS21 that_CS22 those_DD2 who_PNQS do_VD0 not_XX attain_VVI the_AT cut-off_NN1 should_VM not_XX be_VBI expected_VVN to_TO cope_VVI with_IW the_AT demands_NN2 of_IO the_AT particular_JJ task_NN1 ._. 
However_RR ,_, a_AT1 high_JJ score_NN1 does_VDZ not_XX necessarily_RR predict_VVI success_NN1 in_II a_AT1 high_JJ level_JJ job_NN1 ._. 
The_AT intelligence_NN1 test_NN1 can_VM be_VBI a_AT1 useful_JJ source_NN1 of_IO evidence_NN1 about_II individuals_NN2 who_PNQS are_VBR considered_VVN for_IF lower_JJR level_NN1 jobs_NN2 ._. 
For_IF more_RGR senior_JJ jobs_NN2 individuals_NN2 will_VM have_VHI already_RR demonstrated_VVN an_AT1 appropriate_JJ level_NN1 of_IO intelligence_NN1 by_II their_APPGE educational_JJ standards_NN2 and_CC successful_JJ work_NN1 experience_NN1 ._. 
In_II31 line_II32 with_II33 the_AT principles_NN2 of_IO defining_VVG the_AT relevant_JJ abilities_NN2 in_II31 terms_II32 of_II33 reliable_JJ test_NN1 measures_NN2 ,_, intelligence_NN1 can_VM be_VBI divided_VVN into_II verbal_JJ ability_NN1 ,_, arithmetical_JJ ability_NN1 ,_, reasoning_VVG ability_NN1 and_CC spatial_JJ ability_NN1 ._. 
For_IF more_RGR extensive_JJ discussion_NN1 see_VV0 Eysenck_NP1 (_( 1979_MC )_) ._. 
There_EX is_VBZ a_AT1 long_JJ established_JJ distinction_NN1 in_II psychology_NN1 between_II cognitive_JJ and_CC conative_JJ aspects_NN2 of_IO behaviour_NN1 ._. 
Cognition_NN1 is_VBZ to_TO do_VDI with_IW the_AT rational_JJ domain_NN1 :_: logic_NN1 ,_, reasoning_VVG and_CC problem_NN1 solving_VVG uncomplicated_JJ by_II irrational_JJ behaviour_NN1 ._. 
Conation_NN1 is_VBZ to_TO do_VDI with_IW the_AT emotional_JJ domain_NN1 :_: feeling_NN1 ,_, caring_VVG and_CC striving_VVG ._. 
Intelligence_NN1 is_VBZ connected_VVN with_IW cognition_NN1 but_CCB personality_NN1 incorporates_VVZ conation_NN1 ._. 
Thus_RR Freudian_JJ theory_NN1 is_VBZ regarded_VVN as_II a_AT1 personality_NN1 theory_NN1 ._. 
Clearly_RR if_CS we_PPIS2 wish_VV0 to_TO describe_VVI the_AT whole_JJ person_NN1 conative_JJ aspects_NN2 must_VM be_VBI included_VVN ._. 
Unfortunately_RR personality_NN1 testing_NN1 is_VBZ much_RR less_RGR well_RR developed_VVN than_CSN intelligence_NN1 testing_NN1 ._. 
The_AT best_RRT known_VVN personality_NN1 tests_NN2 are_VBR the_AT Minnesota_NP1 Multiphase_NP1 Personality_NN1 Inventory_NN1 (_( M.M.P.I._NP1 )_) ,_, Catell_NP1 's_GE test_NN1 (_( 16_MC P.F._NP1 )_) ,_, and_CC the_AT Eysenck_NN1 Personality_NN1 Inventory_NN1 (_( E.P.I._NP1 )_) ._. 
For_IF details_NN2 see_VV0 Kline_NP1 (_( 1976_MC )_) ._. 
These_DD2 are_VBR selfreport_NN1 inventories_NN2 where_RRQ the_AT testee_NN1 has_VHZ the_AT possibility_NN1 of_IO cheating_VVG in_II that_DD1 he_PPHS1 can_VM respond_VVI with_IW an_AT1 answer_NN1 which_DDQ he_PPHS1 considers_VVZ will_VM give_VVI him_PPHO1 a_AT1 good_JJ score_NN1 rather_II21 than_II22 providing_VVG a_AT1 completely_RR truthful_JJ one_PN1 ._. 
Such_DA manipulation_NN1 of_IO answers_NN2 is_VBZ less_RGR feasible_JJ with_IW projective_JJ tests_NN2 where_RRQ the_AT testee_NN1 is_VBZ asked_VVN to_TO respond_VVI to_II a_AT1 highly_RR ambiguous_JJ situation_NN1 and_CC his_APPGE response_NN1 is_VBZ presumed_VVN to_TO reflect_VVI his_APPGE personality_NN1 as_II31 well_II32 as_II33 the_AT situation_NN1 ._. 
The_AT presentation_NN1 might_VM be_VBI a_AT1 picture_NN1 (_( thematic_JJ apperception_NN1 test_NN1 )_) ,_, an_AT1 ink-blot_NN1 (_( Rorschach_NP1 test_NN1 )_) or_CC prose_NN1 (_( sentence_NN1 completion_NN1 test_NN1 )_) ._. 
The_AT difficulty_NN1 about_II using_VVG these_DD2 tests_NN2 is_VBZ how_RRQ to_TO score_VVI the_AT responses_NN2 with_IW any_DD reasonable_JJ hope_NN1 of_IO reliability_NN1 let_II21 alone_II22 validity_NN1 ._. 
There_EX are_VBR other_JJ tests_NN2 which_DDQ relate_VV0 indirectly_RR to_II personality_NN1 ,_, namely_REX interest_NN1 tests_NN2 ._. 
Here_RL the_AT testee_NN1 is_VBZ presented_VVN with_IW a_AT1 set_NN1 of_IO questions_NN2 or_CC checklists_NN2 which_DDQ steer_VV0 him_PPHO1 into_II trying_VVG to_TO think_VVI carefully_RR about_II his_APPGE own_DA interests_NN2 ._. 
The_AT best_RRT known_VVN ones_NN2 are_VBR the_AT Kuder_NN1 Preference_NN1 test_NN1 and_CC the_AT Strong-Campbell_NP1 interest_NN1 inventory_NN1 ._. 
They_PPHS2 are_VBR particularly_RR useful_JJ in_II occupational_JJ guidance_NN1 (_( Nelson-Jones_NP1 1982_MC )_) ._. 
Age_NN1 differences_NN2 The_AT extremes_NN2 of_IO the_AT age_NN1 range_NN1 ,_, children_NN2 and_CC old_JJ people_NN ,_, are_VBR outside_II the_AT scope_NN1 of_IO this_DD1 book_NN1 ._. 
The_AT working_JJ age_NN1 range_NN1 is_VBZ 15_MC to_II 65_MC years_NNT2 ._. 
This_DD1 is_VBZ not_XX to_TO suggest_VVI that_CST those_DD2 outside_II this_DD1 range_NN1 never_RR work_VV0 ,_, but_CCB rather_RR that_CST in_II advanced_JJ countries_NN2 gainful_JJ employment_NN1 is_VBZ considered_VVN to_TO be_VBI mainly_RR the_AT responsibility_NN1 of_IO those_DD2 in_II this_DD1 particular_JJ age_NN1 band_NN1 of_IO 50_MC years_NNT2 ._. 
This_DD1 band_NN1 is_VBZ currently_RR contracting_VVG even_RR further_RRR in_II European_JJ societies_NN2 ._. 
Because_II21 of_II22 the_AT rise_NN1 in_II unemployment_NN1 it_PPH1 is_VBZ now_RT becoming_VVG standard_JJ that_CST almost_RR all_DB those_DD2 in_II the_AT 1518_MC age_NN1 range_NN1 are_VBR in_II education_NN1 or_CC training_NN1 schemes_NN2 and_CC retirement_NN1 is_VBZ increasingly_RR common_JJ from_II 55_MC years_NNT2 upwards_RL ,_, particularly_RR from_II manufacturing_NN1 industry_NN1 ._. 
Nevertheless_RR ,_, from_II both_DB2 physiological_JJ and_CC psychological_JJ viewpoints_NN2 ,_, ageing_VVG is_VBZ regarded_VVN as_II a_AT1 continuous_JJ process_NN1 so_CS21 that_CS22 considerable_JJ changes_NN2 can_VM be_VBI expected_VVN between_II 1_MC1 8_MC and_CC 55_MC years_NNT2 ._. 
Using_VVG the_AT information_NN1 processing_NN1 model_NN1 of_IO receptor_NN1 ,_, central_JJ and_CC effector_NN1 processes_NN2 (_( Welford_NP1 ,_, 1958_MC ;_; Birren_NP1 and_CC Schaie_NP1 ,_, 1977_MC )_) ,_, changes_NN2 occur_VV0 in_II all_DB these_DD2 processes_NN2 ._. 
The_AT receptors_NN2 diminish_VV0 in_II efficiency_NN1 :_: there_EX are_VBR consistent_JJ changes_NN2 in_II visual_JJ acuity_NN1 and_CC changes_NN2 in_II sensitivity_NN1 to_TO light_VVI ,_, the_AT threshold_NN1 of_IO hearing_NN1 increases_VVZ particularly_RR for_IF higher_JJR frequencies_NN2 ._. 
The_AT effector_NN1 processes_NN2 become_VV0 slower_RRR and_CC less_RGR powerful_JJ but_CCB these_DD2 effects_NN2 are_VBR not_XX so_RG marked_JJ or_CC so_RG consistent_JJ ._. 
The_AT main_JJ change_NN1 in_II central_JJ processes_NN2 seems_VVZ to_TO be_VBI decreased_VVN short-term_JJ memory_NN1 which_DDQ results_VVZ in_II performance_NN1 which_DDQ is_VBZ less_RGR rapid_JJ and_CC more_RGR deliberate_JJ ;_; measured_JJ intelligence_NN1 falls_VVZ slightly_RR but_CCB not_XX very_RG much_DA1 within_II the_AT working_JJ age_NN1 range_NN1 ._. 
This_DD1 may_VM seem_VVI to_TO be_VBI a_AT1 gloomy_JJ picture_NN1 but_CCB it_PPH1 must_VM be_VBI noted_VVN that_CST ,_, in_II31 relation_II32 to_II33 work_NN1 ,_, age_NN1 is_VBZ not_XX a_AT1 large_JJ aspect_NN1 of_IO individual_JJ differences_NN2 compared_VVN with_IW natural_JJ endowment_NN1 ,_, and_CC that_DD1 increases_VVZ in_II ability_NN1 can_VM more_RRR than_CSN compensate_VV0 for_IF small_JJ decreases_NN2 in_II capacity_NN1 ._. 
Wellord_NP1 (_( 1979_MC )_) suggests_VVZ that_CST work_VV0 on_II the_AT shop-floor_NN1 is_VBZ likely_JJ to_TO peak_VVI in_II the_AT thirties_MC2 those_DD2 in_II their_APPGE twenties_MC2 lack_NN1 experience_NN1 and_CC social_JJ skills_NN2 ,_, those_DD2 in_II their_APPGE forties_MC2 are_VBR beginning_VVG to_TO notice_VVI the_AT effect_NN1 of_IO sensory_JJ changes_NN2 and_CC are_VBR less_RGR tolerant_JJ of_IO fast_JJ or_CC very_RG heavy_JJ physical_JJ work_NN1 ._. 
On_II the_AT other_JJ hand_NN1 ,_, from_II the_AT forties_MC2 onwards_RL there_EX is_VBZ likely_JJ to_TO be_VBI greater_JJR stability_NN1 in_II the_AT sense_NN1 that_CST individuals_NN2 are_VBR more_RRR settled_VVN in_II their_APPGE jobs_NN2 and_CC ambitions_NN2 and_CC are_VBR supported_VVN by_II less_RGR rapidly_RR changing_VVG domestic_JJ and_CC leisure_NN1 situations_NN2 ._. 
The_AT effectiveness_NN1 of_IO training_NN1 can_VM be_VBI maintained_VVN if_CS the_AT training_NN1 scheme_NN1 incorporates_VVZ features_NN2 such_II21 as_II22 smaller_JJR learning_NN1 steps_NN2 and_CC '_GE discovery_NN1 learning_NN1 '_GE where_CS the_AT trainee_NN1 proceeds_VVZ at_II his_APPGE own_DA pace_NN1 using_VVG his_APPGE own_DA strategies_NN2 (_( Belbin_NP1 1965_MC )_) ._. 
For_IF more_RGR senior_JJ positions_NN2 there_EX are_VBR more_RGR subtle_JJ attributes_NN2 such_II21 as_II22 self-knowledge_NN1 and_CC the_AT ability_NN1 to_TO see_VVI '_GE the_AT big_JJ picture_NN1 '_GE which_DDQ increase_VV0 with_IW age_NN1 ,_, these_DD2 are_VBR the_AT reasons_NN2 why_RRQ most_DAT institutions_NN2 and_CC societies_NN2 rely_VV0 on_II older_JJR leaders_NN2 (_( Singleton_NP1 ,_, 1983b_FO )_) ._. 
Sex_NN1 differences_NN2 There_EX is_VBZ surprisingly_RR little_JJ research_NN1 on_II the_AT differences_NN2 in_II work_NN1 performance_NN1 which_DDQ are_VBR traceable_JJ to_II sex_NN1 differences_NN2 ,_, and_CC the_AT situation_NN1 is_VBZ complicated_VVN in_II many_DA2 countries_NN2 by_II the_AT inclusion_NN1 of_IO sex_NN1 as_CSA one_MC1 of_IO the_AT variables_NN2 where_RRQ discrimination_NN1 is_VBZ legally_RR inadmissible_JJ ._. 
Incidentally_RR ,_, in_II this_DD1 book_NN1 '_GE man_NN1 '_GE ,_, '_" he_PPHS1 '_VBZ and_CC '_" him_PPHO1 '_" are_VBR used_VVN as_CSA generic_JJ terms_NN2 covering_VVG both_DB2 sexes_NN2 ._. 
There_EX can_VM be_VBI no_AT argument_NN1 that_CST ,_, on_II average_NN1 ,_, women_NN2 are_VBR physically_RR smaller_JJR than_CSN men_NN2 ,_, and_CC there_EX are_VBR other_JJ features_NN2 such_II21 as_II22 the_AT greater_JJR proportion_NN1 of_IO fatty_JJ tissue_NN1 which_DDQ give_VV0 men_NN2 the_AT advantage_NN1 in_II31 relation_II32 to_II33 tolerance_NN1 of_IO heat_NN1 stress_NN1 and_CC physical_JJ effort_NN1 involving_VVG fast_JJ or_CC heavy_JJ work_NN1 or_CC awkward_JJ posture_NN1 ._. 
On_II the_AT other_JJ hand_NN1 in_II Russia_NP1 ,_, for_REX21 example_REX22 ,_, where_RRQ so_RG many_DA2 males_NN2 were_VBDR lost_VVN in_II two_MC world_NN1 wars_NN2 women_NN2 do_VD0 do_VDI much_DA1 heavier_JJR work_NN1 than_CSN is_VBZ traditional_JJ in_II Western_JJ countries_NN2 ._. 
Similarly_RR there_RL seem_VV0 to_TO be_VBI many_DA2 cultures_NN2 in_II tropical_JJ countries_NN2 where_RRQ the_AT women_NN2 get_VV0 on_RP with_IW the_AT necessary_JJ work_NN1 while_CS the_AT men_NN2 sit_VV0 around_RP discussing_VVG matters_NN2 ._. 
There_RL appear_VV0 to_TO be_VBI no_AT important_JJ differences_NN2 in_II performance_NN1 on_II intelligence_NN1 tests_NN2 in_II the_AT working_JJ age_NN1 range_NN1 and_CC as_II the_AT influence_NN1 of_IO physical_JJ effort_NN1 in_II work_NN1 becomes_VVZ less_RGR important_JJ so_CS it_PPH1 is_VBZ more_RGR feasible_JJ that_CST jobs_NN2 can_VM be_VBI performed_VVN equally_RR well_RR by_II either_DD1 sex_NN1 ._. 
The_AT overall_JJ situation_NN1 was_VBDZ reviewed_VVN by_II Hoiberg_NP1 (_( 1982_MC )_) ._. 
Equal_JJ opportunity_NN1 legislation_NN1 exists_VVZ in_II most_DAT advanced_JJ countries_NN2 but_CCB this_DD1 is_VBZ not_XX yet_RR reflected_VVN in_II equal_JJ pay_NN1 rates_NN2 ._. 
The_AT average_JJ wage_NN1 of_IO women_NN2 workers_NN2 is_VBZ two-thirds_MF that_DD1 of_IO men_NN2 ._. 
Part-time_JJ work_NN1 seems_VVZ to_TO be_VBI a_AT1 prerogative_NN1 of_IO women_NN2 presumably_RR as_II a_AT1 consequence_NN1 of_IO their_APPGE central_JJ role_NN1 in_II the_AT home_NN1 ._. 
Educational_JJ opportunity_NN1 varies_VVZ ,_, depending_VVG mainly_RR on_II family_NN1 attitudes_NN2 ._. 
In_II some_DD cultures_NN2 sons_NN2 are_VBR given_VVN priority_NN1 ,_, others_NN2 give_VV0 daughters_NN2 priority_NN1 ,_, following_VVG the_AT McIver_NP1 principle_NN1 '_GE when_CS you_PPY educate_VV0 a_AT1 man_NN1 you_PPY educate_VV0 an_AT1 individual_NN1 :_: when_RRQ you_PPY educate_VV0 a_AT1 woman_NN1 you_PPY educate_VV0 a_AT1 whole_JJ family_NN1 '_GE ._. 
Ethics_NN ,_, cultural_JJ ,_, climatic_JJ and_CC economic_JJ differences_NN2 This_DD1 is_VBZ a_AT1 sensitive_JJ topic_NN1 on_II which_DDQ to_TO conduct_VVI research_NN1 or_CC establish_VV0 principles_NN2 with_IW the_AT consequence_NN1 that_CST ,_, in_II31 spite_II32 of_II33 the_AT extensive_JJ effort_NN1 (_( Triandis_NP1 et_RA21 al._RA22 ,_, 1980_MC )_) there_EX is_VBZ not_XX a_AT1 great_JJ deal_NN1 of_IO knowledge_NN1 established_VVN beyond_II argument_NN1 ._. 
Climate_NN1 and_CC economics_NN1 need_NN1 to_TO be_VBI included_VVN because_CS these_DD2 factors_NN2 may_VM well_RR determine_VVI features_NN2 which_DDQ at_II first_MD sight_NN1 might_VM be_VBI attributed_VVN to_II ethnic_JJ or_CC cultural_JJ factors_NN2 ._. 
Clearly_RR the_AT work_NN1 that_CST people_NN do_VD0 is_VBZ determined_VVN by_II the_AT level_NN1 of_IO technology_NN1 which_DDQ is_VBZ related_VVN to_II overall_JJ wealth_NN1 ._. 
Ways_NN2 of_IO working_VVG and_CC locations_NN2 of_IO work_NN1 are_VBR also_RR affected_VVN by_II climate_NN1 ._. 
For_REX21 example_REX22 ,_, in_II a_AT1 tropical_JJ country_NN1 shoes_NN2 may_VM still_RR be_VBI made_VVN in_II the_AT open_JJ air_NN1 by_II a_AT1 craftsman_NN1 who_PNQS uses_VVZ his_APPGE feet_NN2 as_II31 well_II32 as_II33 his_APPGE hands_NN2 to_TO hold_VVI and_CC manipulate_VVI materials_NN2 ._. 
In_II a_AT1 temperate_JJ country_NN1 shoes_NN2 are_VBR made_VVN in_II a_AT1 factory_NN1 by_II workers_NN2 who_PNQS are_VBR process_NN1 controllers_NN2 rather_II21 than_II22 craftsmen_NN2 ,_, and_CC they_PPHS2 touch_VV0 the_AT materials_NN2 only_RR when_CS loading_VVG or_CC unloading_VVG machines_NN2 ._. 
For_IF these_DD2 and_CC many_DA2 other_JJ reasons_NN2 the_AT practice_NN1 of_IO ergonomics_NN1 in_II developing_JJ countries_NN2 is_VBZ different_JJ from_II that_DD1 in_II advanced_JJ countries_NN2 (_( p._NNU 155_MC )_) ._. 
The_AT acquisition_NN1 of_IO skills_NN2 is_VBZ governed_VVN by_II the_AT current_JJ needs_NN2 of_IO particular_JJ societies_NN2 and_CC by_II the_AT adaptation_NN1 of_IO individuals_NN2 within_II the_AT societies_NN2 in_II which_DDQ they_PPHS2 happen_VV0 to_TO find_VVI themselves_PPX2 ._. 
Research_NN1 on_II the_AT influence_NN1 of_IO cultural_JJ factors_NN2 on_II intelligence_NN1 testing_NN1 and_CC test_VV0 results_NN2 have_VH0 been_VBN conducted_VVN on_II a_AT1 wide_JJ scale_NN1 and_CC the_AT results_NN2 are_VBR endlessly_RR discussed_VVN because_II21 of_II22 the_AT inextricable_JJ mixture_NN1 of_IO technical_JJ and_CC value_NN1 judgments_NN2 ._. 
As_CSA Crombach_NP1 puts_VVZ it_PPH1 in_II the_AT foreword_NN1 to_II Irvine_NP1 and_CC Berry_NP1 (_( 1981_MC )_) '_GE the_AT progress_NN1 is_VBZ as_RG much_DA1 in_II the_AT psychology_NN1 of_IO the_AT investigators_NN2 as_CSA in_II the_AT investigations_NN2 being_VBG reported_JJ '_GE ._. 
As_CSA in_II other_JJ fields_NN2 of_IO behavioural_JJ study_NN1 there_EX are_VBR three_MC phases_NN2 ._. 
In_II the_AT first_MD phase_NN1 techniques_NN2 and_CC theories_NN2 are_VBR developed_VVN in_II the_AT West_ND1 ._. 
In_II the_AT second_MD phase_NN1 Western_JJ practitioners_NN2 try_VV0 out_RP their_APPGE ideas_NN2 in_II other_JJ cultures_NN2 and_CC many_DA2 new_JJ insights_NN2 emerge_VV0 by_II comparisons_NN2 and_CC contrasts_NN2 ,_, in_RR21 particular_RR22 it_PPH1 becomes_VVZ clear_JJ that_CST some_DD of_IO the_AT principles_NN2 thought_VVD to_TO be_VBI valid_JJ for_IF '_GE man_NN1 '_GE turn_NN1 out_RP to_TO be_VBI valid_JJ only_RR for_IF man_NN1 in_II Western_JJ cultures_NN2 ._. 
In_II the_AT third_MD phase_NN1 scientists_NN2 from_II other_JJ cultures_NN2 acquire_VV0 these_DD2 concepts_NN2 ,_, develop_VV0 them_PPHO2 further_RRR in_II their_APPGE indigenous_JJ environment_NN1 and_CC provide_VV0 penetrating_JJ comments_NN2 on_II Western_JJ ideas_NN2 and_CC their_APPGE application_NN1 from_II an_AT1 external_JJ viewpoint_NN1 (_( Crombach_NP1 and_CC Drenth_NP1 ,_, 1972_MC )_) ._. 
The_AT dominant_JJ influence_NN1 of_IO culture_NN1 on_II the_AT direction_NN1 of_IO human_JJ development_NN1 implies_VVZ that_CST descriptions_NN2 of_IO human_JJ abilities_NN2 can_VM not_XX be_VBI context_NN1 free_JJ ._. 
Specific_JJ cultures_NN2 are_VBR themselves_PPX2 dynamic_JJ ,_, in_RR21 particular_RR22 they_PPHS2 change_VV0 under_II the_AT influence_NN1 of_IO technology_NN1 ._. 
Ergonomics_NN1 can_VM not_XX be_VBI simply_RR the_AT adaptation_NN1 of_IO technology_NN1 to_TO suit_VVI invariant_JJ properties_NN2 of_IO '_GE man_NN1 '_GE ,_, people_NN change_VV0 with_IW technology_NN1 ._. 
Learning_VVG Learning_NN1 has_VHZ been_VBN a_AT1 major_JJ topic_NN1 within_II academic_JJ psychology_NN1 for_IF the_AT past_JJ century_NNT1 or_CC so_RR ._. 
The_AT nineteenth_MD century_NNT1 work_NN1 of_IO Pavlov_NP1 on_II the_AT conditioned_JJ reflex_NN1 generated_VVD vain_JJ hopes_NN2 that_CST psychology_NN1 ,_, and_CC in_RR21 particular_RR22 learning_VVG ,_, might_VM be_VBI studied_VVN by_II a_AT1 rigorous_JJ methodology_NN1 closely_RR allied_VVN to_II physiology_NN1 ._. 
It_PPH1 was_VBDZ assumed_VVN that_CST all_DB learning_NN1 could_VM be_VBI reduced_VVN to_II a_AT1 series_NN of_IO conditioned_JJ reflexes_NN2 ._. 
There_EX was_VBDZ extensive_JJ research_NN1 in_II this_DD1 behaviourist_NN1 tradition_NN1 (_( Hilgard_NP1 and_CC Marquis_NN1 ,_, 1940_MC )_) mostly_RR on_II the_AT laboratory_NN1 rat_NN1 ._. 
So_RR called_VVN verbal_JJ learning_NN1 in_II man_NN1 was_VBDZ studied_VVN by_II a_AT1 similar_JJ process_NN1 of_IO scoring_VVG repetitive_JJ performance_NN1 ._. 
Reliance_NN1 on_II such_DA data_NN produced_VVD the_AT systematic_JJ behaviour_NN1 theories_NN2 of_IO Thorndike_NP1 ,_, Hull_NP1 and_CC Skinner_NP1 ._. 
There_EX was_VBDZ a_AT1 parallel_NN1 although_CS less_RGR popular_JJ theoretical_JJ development_NN1 based_VVN on_II Gestalt_NN1 psychology_NN1 which_DDQ resulted_VVD in_II the_AT field_NN1 theories_NN2 of_IO Lewin_NP1 ,_, Wheeler_NP1 and_CC Tolman_NP1 (_( Hilgard_NP1 ,_, 1948_MC )_) ._. 
There_EX were_VBDR many_DA2 attempts_NN2 to_TO devise_VVI taxonomies_NN2 of_IO learning_NN1 which_DDQ used_VVD particular_JJ theories_NN2 as_CSA descriptive_JJ of_IO different_JJ kinds_NN2 of_IO learning_NN1 (_( Melton_NP1 ,_, 1964_MC )_) ._. 
At_II this_DD1 stage_NN1 there_RL seemed_VVD to_TO be_VBI little_JJ connection_NN1 between_II the_AT vast_JJ experience_NN1 of_IO learning_VVG in_II practice_NN1 within_II educational_JJ and_CC training_NN1 systems_NN2 and_CC learning_NN1 as_CSA conceived_VVN by_II psychologists_NN2 on_II the_AT basis_NN1 of_IO laboratory_NN1 experiments_NN2 ._. 
The_AT psychologists_NN2 attempted_VVD to_TO polarise_VVI various_JJ issues_NN2 such_II21 as_II22 massed_JJ versus_II spaced_JJ learning_NN1 ,_, whole_NN1 versus_II part_NN1 learning_NN1 and_CC transfer_NN1 of_IO training_NN1 which_DDQ had_VHD some_DD face_NN1 validity_NN1 in_II appearing_VVG to_TO identify_VVI general_JJ principles_NN2 ,_, but_CCB in_II practice_NN1 it_PPH1 always_RR seemed_VVD that_CST the_AT generalities_NN2 vanished_VVD into_II the_AT enormous_JJ variety_NN1 of_IO specific_JJ issues_NN2 ._. 
The_AT answer_NN1 always_RR differed_VVN with_IW the_AT particular_JJ situation_NN1 ._. 
Gagne_NP1 (_( 1970_MC )_) attempted_VVD to_TO produce_VVI a_AT1 theory_NN1 which_DDQ was_VBDZ germane_JJ to_II educational_JJ problems_NN2 by_II switching_VVG the_AT emphasis_NN1 from_II categories_NN2 to_II conditions_NN2 of_IO learning_NN1 ._. 
The_AT deliberate_JJ attempt_NN1 to_TO link_VVI learning_VVG to_II the_AT design_NN1 of_IO instruction_NN1 provided_CS the_AT necessary_JJ discipline_NN1 to_TO treat_VVI learning_VVG as_II a_AT1 practical_JJ as_II31 well_II32 as_II33 a_AT1 theoretical_JJ issue_NN1 ._. 
The_AT eight_MC types_NN2 of_IO learning_NN1 which_DDQ Gagne_NP1 distinguishes_VVZ are_VBR shown_VVN in_II Table_NN1 2.2_MC ._. 
Gagne_NN1 also_RR separated_VVN four_MC phases_NN2 of_IO a_AT1 learning_NN1 sequence_NN1 ;_; apprehension_NN1 ,_, acquisition_NN1 ,_, storage_NN1 and_CC retrieval_NN1 ._. 
The_AT apprehension_NN1 phase_NN1 includes_VVZ attending_VVG and_CC perceiving_VVG ,_, that_DD1 is_VBZ accepting_VVG new_JJ information_NN1 ._. 
Acquisition_NN1 is_VBZ not_XX easy_JJ to_TO separate_VVI from_II either_RR apprehension_NN1 on_II one_MC1 side_NN1 or_CC storage_NN1 on_II the_AT other_JJ ,_, but_CCB it_PPH1 implies_VVZ that_DD1 learning_NN1 has_VHZ taken_VVN place_NN1 in_II that_DD1 something_PN1 new_JJ can_VM now_RT be_VBI done_VDN if_CS appropriate_JJ ._. 
The_AT distinction_NN1 from_II apprehension_NN1 is_VBZ necessary_JJ to_TO incorporate_VVI the_AT phenomenon_NN1 that_CST it_PPH1 is_VBZ possible_JJ to_TO understand_VVI a_AT1 situation_NN1 in_II one_MC1 sense_NN1 without_IW knowing_VVG what_DDQ to_TO do_VDI about_II it_PPH1 ._. 
Correspondingly_RR acquisition_NN1 is_VBZ different_JJ from_II storage_NN1 in_CS21 that_CS22 the_AT latter_DA implies_VVZ a_AT1 formal_JJ recording_NN1 possibly_RR in_II short-term_JJ or_CC possibly_RR in_II long-term_JJ memory_NN1 ._. 
Finally_RR retrieval_NN1 is_VBZ a_AT1 separate_JJ process_NN1 because_II21 of_II22 another_DD1 familiar_JJ phenomenon_NN1 that_CST it_PPH1 is_VBZ possible_JJ to_TO know_VVI something_PN1 ,_, that_DD1 is_VBZ it_PPH1 must_VM be_VBI in_II storage_NN1 ,_, but_CCB not_XX actually_RR succeed_VV0 in_II retrieving_VVG it_PPH1 at_II a_AT1 particular_JJ time_NNT1 ._. 
These_DD2 phases_NN2 and_CC the_AT difficulties_NN2 of_IO separating_VVG them_PPHO2 reflect_VV0 the_AT fact_NN1 that_CST mental_JJ processes_NN2 are_VBR not_XX subject_II21 to_II22 clearly_RR defined_VVN distinctions_NN2 and_CC boundaries_NN2 ._. 
In_II31 common_II32 with_II33 all_DB educational_JJ psychologists_NN2 Gagne_NP1 is_VBZ also_RR restricted_VVN by_II reliance_NN1 on_II evidence_NN1 which_DDQ comes_VVZ mostly_RR from_II laboratory_NN1 experiments_NN2 ,_, usually_RR on_II lower_JJR animals_NN2 ,_, with_IW all_DB the_AT limitations_NN2 and_CC artefacts_NN2 which_DDQ this_DD1 implies_VVZ ._. 
More_RGR subtly_RR he_PPHS1 is_VBZ also_RR restricted_VVN by_II attempting_VVG to_TO set_VVI the_AT knowledge_NN1 in_II another_DD1 artificial_JJ situation_NN1 ,_, the_AT educational_JJ process_NN1 of_IO sitting_VVG in_II classrooms_NN2 learning_VVG by_II rote_NN1 leavened_VVD by_II some_DD understanding_NN1 and_CC being_VBG examined_VVN and_CC tested_VVN in_II standardised_JJ situations_NN2 ._. 
Thomas_NP1 and_CC Harri-Augstein_NP1 (_( 1985_MC )_) attempt_VV0 a_AT1 more_RGR autonomous_JJ approach_NN1 to_II learning_VVG in_II two_MC senses_NN2 ._. 
That_REX21 is_REX22 ,_, learning_NN1 need_VM not_XX be_VBI restricted_VVN to_II the_AT orthodox_JJ educational_JJ system_NN1 and_CC also_RR that_DD1 learning_NN1 ,_, as_CSA a_AT1 process_NN1 ,_, is_VBZ essentially_RR self-centred_JJ ,_, and_CC self-organised_NN1 ._. 
This_DD1 approach_NN1 follows_VVZ the_AT tradition_NN1 of_IO Rogers_NP1 (_( 1951_MC )_) who_PNQS developed_VVD client-centred_JJ therapy_NN1 and_CC Kelly_NP1 (_( 1955_MC )_) who_PNQS developed_VVD personal_JJ construct_NN1 theory_NN1 ._. 
The_AT emphasis_NN1 is_VBZ on_II the_AT individual_NN1 who_PNQS inevitably_RR has_VHZ a_AT1 unique_JJ view_NN1 of_IO the_AT world_NN1 which_DDQ he_PPHS1 continuously_RR modifies_VVZ in_II41 the_II42 light_II43 of_II44 experience_NN1 ._. 
Each_DD1 view_NN1 of_IO the_AT world_NN1 can_VM be_VBI described_VVN using_VVG personal_JJ constructs_NN2 which_DDQ can_VM be_VBI elicited_VVN by_II the_AT use_NN1 of_IO a_AT1 Repertory_NN1 Grid_NN1 ._. 
The_AT individual_NN1 reflects_VVZ on_II his_APPGE own_DA experience_NN1 and_CC is_VBZ thus_RR continuously_RR involved_JJ in_II both_DB2 internal_JJ and_CC external_JJ conversations_NN2 ._. 
Learning_NN1 takes_VVZ place_NN1 as_II a_AT1 result_NN1 of_IO these_DD2 conversations_NN2 ._. 
Traditional_JJ distinctions_NN2 between_II teaching_NN1 ,_, training_NN1 and_CC therapy_NN1 disappear_VV0 ,_, so_RG also_RR does_VDZ the_AT conceptual_JJ distinction_NN1 between_II cognition_NN1 and_CC conation_NN1 ._. 
One_MC1 attractive_JJ aspect_NN1 of_IO this_DD1 theory_NN1 is_VBZ that_CST it_PPH1 highlights_VVZ the_AT way_NN1 in_II which_DDQ formal_JJ instruction_NN1 can_VM inhibit_VVI learning_VVG by_II not_XX allowing_VVG sufficient_JJ scope_NN1 for_IF self-expression_NN1 and_CC self-development_NN1 alienation_NN1 following_VVG submission_NN1 to_II being_VBG taught_VVN rather_II21 than_II22 learning_VVG how_RRQ to_TO learn_VVI ._. 
The_AT emphasis_NN1 on_II self_NN1 does_VDZ not_XX limit_VVI the_AT application_NN1 to_II individual_JJ activity_NN1 ,_, shared_JJ meaning_NN1 can_VM be_VBI negotiated_VVN and_CC developed_VVN within_II groups_NN2 ,_, this_DD1 is_VBZ group_NN1 learning_NN1 ._. 
Correspondingly_RR the_AT teacher_NN1 is_VBZ not_XX redundant_JJ ,_, a_AT1 competent_JJ teacher_NN1 is_VBZ a_AT1 learning_NN1 manager_NN1 and_CC so_RG also_RR is_VBZ every_AT1 parent_NN1 ,_, manager_NN1 or_CC counsellor_NN1 ,_, their_APPGE task_NN1 is_VBZ to_TO provide_VVI the_AT conditions_NN2 and_CC facilitate_VVI the_AT process_NN1 of_IO self-development_NN1 ._. 
If_CS learning_NN1 is_VBZ defined_VVN as_II the_AT improvement_NN1 of_IO specific_JJ performance_NN1 following_VVG experience_NN1 of_IO that_DD1 performance_NN1 then_RT organisations_NN2 as_II31 well_II32 as_II33 individuals_NN2 can_VM be_VBI said_VVN to_TO learn_VVI ._. 
Paradoxically_RR much_DA1 of_IO the_AT more_RGR abstract_JJ work_NN1 on_II the_AT mathematical_JJ theory_NN1 of_IO learning_VVG curves_NN2 has_VHZ its_APPGE application_NN1 at_RR21 least_RR22 in_II principle_NN1 in_II the_AT requirements_NN2 of_IO accountants_NN2 and_CC production_NN1 engineers_NN2 ._. 
The_AT process_NN1 of_IO making_VVG anything_PN1 from_II a_AT1 switch_NN1 to_II a_AT1 civil_JJ airliner_NN1 is_VBZ subject_II21 to_II22 improvements_NN2 in_II speed_NN1 ,_, quality_NN1 and_CC cost_NN1 reduction_NN1 which_DDQ follow_VV0 the_AT characteristic_JJ learning_NN1 curve_NN1 ._. 
It_PPH1 is_VBZ obviously_RR important_JJ to_II the_AT managers_NN2 of_IO such_DA organisations_NN2 to_TO be_VBI able_JK to_TO predict_VVI by_II how_RGQ much_DA1 the_AT process_NN1 will_VM improve_VVI after_II particular_JJ lengths_NN2 of_IO time_NNT1 and_CC numbers_NN2 of_IO products_NN2 made_VVD ._. 
Conversely_RR ,_, because_II21 of_II22 the_AT universal_JJ very_RG steep_JJ learning_NN1 curves_NN2 with_IW early_JJ experience_NN1 ,_, any_DD novel_JJ enterprise_NN1 is_VBZ bound_VVNK to_TO have_VHI extensive_JJ teething_NN1 troubles_NN2 ,_, which_DDQ should_VM be_VBI allowed_VVN for_IF in_RR21 general_RR22 even_CS21 though_CS22 they_PPHS2 are_VBR not_XX predictable_JJ in_RR21 particular_RR22 ._. 
Experiments_NN2 ,_, trials_NN2 ,_, prototypes_NN2 and_CC the_AT running_NN1 in_II parallel_NN1 of_IO old_JJ and_CC new_JJ systems_NN2 are_VBR all_DB valuable_JJ ,_, almost_RR essential_JJ procedures_NN2 when_RRQ something_PN1 radical_JJ is_VBZ being_VBG attempted_VVN on_II any_DD scale_NN1 from_II a_AT1 new_JJ car_NN1 suspension_NN1 to_II a_AT1 new_JJ educational_JJ system_NN1 ._. 
Technology_NN1 and_CC society_NN1 generally_RR is_VBZ continuously_RR in_II trouble_NN1 because_CS this_DD1 elementary_JJ principle_NN1 is_VBZ forgotten_VVN or_CC ignored_VVN by_II enthusiastic_JJ innovators_NN2 ._. 
Memory_NN1 and_CC thinking_VVG Thinking_NN1 is_VBZ essentially_RR an_AT1 internal_JJ activity_NN1 although_CS of_RR21 course_RR22 it_PPH1 is_VBZ stimulated_VVN and_CC aided_VVN by_II interaction_NN1 with_IW the_AT external_JJ world_NN1 including_II other_JJ people_NN ._. 
Since_CS it_PPH1 takes_VVZ place_NN1 '_GE inside_NN1 '_GE it_PPH1 must_VM be_VBI related_VVN to_II memory_NN1 ._. 
This_DD1 is_VBZ one_MC1 of_IO several_DA2 complications_NN2 of_IO the_AT simplistic_JJ view_NN1 that_CST memory_NN1 is_VBZ just_RR a_AT1 store_NN1 ._. 
Another_DD1 is_VBZ that_CST a_AT1 store_NN1 is_VBZ useless_JJ without_IW means_NN of_IO access_NN1 and_CC egress_NN1 ._. 
In_II other_JJ words_NN2 there_EX must_VM be_VBI processes_NN2 of_IO recording_NN1 and_CC retrieval_NN1 and_CC the_AT underlying_JJ mechanisms_NN2 must_VM be_VBI closely_RR integrated_VVN with_IW the_AT mechanism_NN1 of_IO the_AT store_NN1 ._. 
The_AT store_NN1 or_CC stores_NN2 are_VBR almost_RR certainly_RR active_JJ rather_II21 than_II22 passive_JJ records_NN2 of_IO events_NN2 and_CC knowledge_NN1 so_CS21 that_CS22 these_DD2 also_RR are_VBR best_RRT considered_VVN as_CSA processes_NN2 ._. 
Early_JJ studies_NN2 of_IO memory_NN1 by_II psychologists_NN2 concentrated_VVN on_II apparatus_NN1 such_II21 as_II22 the_AT memory_NN1 drum_NN1 which_DDQ was_VBDZ used_JJ to_II measure_NN1 the_AT ability_NN1 to_TO associate_VVI verbal_JJ items_NN2 ._. 
In_II the_AT pursuit_NN1 of_IO generality_NN1 these_DD2 items_NN2 were_VBDR often_RR nonsense_NN1 syllables_NN2 ._. 
This_DD1 is_VBZ another_DD1 example_NN1 of_IO the_AT way_NN1 in_II which_DDQ the_AT attempt_NN1 to_TO standardise_VVI human_JJ performance_NN1 can_VM negate_VVI the_AT purpose_NN1 of_IO study_NN1 ._. 
There_EX is_VBZ a_AT1 built-in_JJ assumption_NN1 that_CST memory_NN1 is_VBZ about_II association_NN1 and_CC a_AT1 removal_NN1 of_IO any_DD possibility_NN1 of_IO demonstrating_VVG that_DD1 memory_NN1 might_VM be_VBI dependent_JJ on_II meaning_NN1 ._. 
Other_JJ early_JJ studies_NN2 of_IO memory_NN1 attempted_VVN to_II measure_NN1 capacity_NN1 by_II data_NN such_II21 as_II22 the_AT length_NN1 of_IO a_AT1 number_NN1 series_NN which_DDQ could_VM be_VBI accurately_RR reproduced_VVN after_II one_MC1 presentation_NN1 ._. 
The_AT answer_NN1 turns_VVZ out_RP to_TO be_VBI about_RG seven_MC (_( Woodworth_NP1 ,_, 1938_MC )_) ._. 
These_DD2 studies_NN2 of_IO immediate_JJ memory_NN1 span_NN1 are_VBR of_IO more_DAR than_CSN historical_JJ interest_NN1 because_CS the_AT fact_NN1 that_CST there_EX is_VBZ such_DA a_AT1 severe_JJ limit_NN1 is_VBZ important_JJ in_II the_AT design_NN1 of_IO information_NN1 presentations_NN2 of_IO technical_JJ data_NN a_AT1 standard_JJ ergonomics_NN1 problem_NN1 ._. 
Other_JJ significant_JJ phenomena_NN2 which_DDQ have_VH0 emerged_VVN from_II such_DA studies_NN2 are_VBR that_RG simple_JJ reversals_NN2 of_IO the_AT numbers_NN2 are_VBR a_AT1 common_JJ form_NN1 of_IO error_NN1 ,_, accurate_JJ reproduction_NN1 is_VBZ facilitated_VVN by_II deliberate_JJ grouping_NN1 in_II twos_MC2 or_CC threes_MC2 and_CC the_AT ends_NN2 of_IO a_AT1 span_NN1 seem_VV0 to_TO be_VBI less_RGR prone_JJ to_II error_NN1 than_CSN the_AT middle_NN1 ._. 
With_IW the_AT advent_NN1 of_IO information_NN1 theory_NN1 (_( Attneave_NP1 ,_, 1959_MC ;_; Edwards_NP1 ,_, 1964_MC )_) other_JJ interesting_JJ issues_NN2 arose_VVD such_II21 as_II22 whether_CSW the_AT performance_NN1 of_IO the_AT store_NN1 could_VM better_RRR be_VBI measured_VVN in_II31 terms_II32 of_II33 bits_NN2 of_IO information_NN1 or_CC chunks_NN2 of_IO material_NN1 (_( the_AT bits-versus-chunks_NN2 controversy_NN1 (_( Miller_NP1 ,_, 1956_MC )_) )_) and_CC the_AT possibility_NN1 that_CST memory_NN1 processes_NN2 might_VM distinguish_VVI between_II content_NN1 and_CC order_NN1 ._. 
The_AT simple_JJ memory_NN1 span_NN1 measure_NN1 confounds_VVZ these_DD2 variables_NN2 ._. 
Clearly_RR there_EX is_VBZ more_RRR to_II memory_NN1 than_CSN the_AT reproduction_NN1 of_IO numbers_NN2 or_CC lists_NN2 and_CC another_DD1 distinction_NN1 which_DDQ has_VHZ arisen_VVN is_VBZ between_II episodic_JJ and_CC semantic_JJ memory_NN1 ._. 
The_AT former_DA is_VBZ concerned_JJ with_IW specific_JJ events_NN2 and_CC the_AT latter_DA is_VBZ relatively_RR context_NN1 free_JJ (_( Baddeley_NP1 ,_, 1976_MC )_) ._. 
A_AT1 parallel_JJ but_CCB not_XX identical_JJ distinction_NN1 is_VBZ between_II short-term_JJ and_CC long-term_JJ memory_NN1 ._. 
Short-term_JJ memory_NN1 has_VHZ capacity_NN1 limits_NN2 and_CC is_VBZ readily_RR purged_VVN ,_, it_PPH1 probably_RR keeps_VVZ a_AT1 record_NN1 of_IO the_AT current_JJ situation_NN1 ,_, whereas_CS the_AT long-term_JJ memory_NN1 is_VBZ the_AT repository_NN1 of_IO principles_NN2 and_CC strategies_NN2 ._. 
Both_DB2 these_DD2 distinctions_NN2 imply_VV0 that_DD1 registration_NN1 in_II storage_NN1 continues_VVZ long_RR past_II the_AT time_NNT1 of_IO reception_NN1 of_IO information_NN1 ._. 
Whether_CSW31 or_CSW32 not_CSW33 this_DD1 implies_VVZ shifting_VVG to_II different_JJ stores_NN2 is_VBZ not_XX known_VVN ._. 
In_II functional_JJ terms_NN2 there_RL do_VD0 seem_VVI to_TO be_VBI storage_NN1 facilities_NN2 relatively_RR near_II the_AT entry_NN1 channels_NN2 through_II the_AT senses_NN2 ,_, those_DD2 for_IF the_AT visual_JJ and_CC auditory_JJ systems_NN2 are_VBR called_VVN respectively_RR the_AT iconic_JJ store_NN1 and_CC the_AT echoic_JJ store_NN1 (_( Wickens_NP1 ,_, 1984_MC )_) ._. 
These_DD2 stores_NN2 have_VH0 available_JJ a_AT1 literal_JJ record_NN1 of_IO the_AT stimulus_NN1 so_CS21 that_CS22 the_AT observer_NN1 can_VM ,_, as_RR31 it_RR32 were_RR33 ,_, internally_RR inspect_VV0 them_PPHO2 but_CCB such_DA impressions_NN2 decay_VV0 very_RG rapidly_RR ,_, typically_RR in_II less_DAR than_CSN ten_MC seconds_NNT2 ._. 
In_II an_AT1 elegant_JJ series_NN of_IO experiments_NN2 Conrad_NP1 (_( 1964_MC )_) demonstrated_VVD that_CST in_II transposing_VVG visually_RR presented_VVN data_NN the_AT errors_NN2 are_VBR more_RGR likely_JJ to_TO be_VBI in_II numbers_NN2 or_CC letters_NN2 of_IO similar_JJ sound_NN1 rather_II21 than_II22 those_DD2 which_DDQ are_VBR of_IO similar_JJ appearance_NN1 ._. 
This_DD1 suggests_VVZ that_CST this_DD1 short-term_JJ store_NN1 is_VBZ auditorily_RR rather_II21 than_II22 visually_RR based_VVN even_CS21 when_CS22 the_AT task_NN1 is_VBZ visual-motor_NN1 ._. 
The_AT effect_NN1 diminishes_VVZ if_CS there_EX is_VBZ irrelevant_JJ articulatory_JJ activity_NN1 at_II the_AT time_NNT1 ,_, this_DD1 raises_VVZ the_AT possibility_NN1 that_CST there_EX may_VM be_VBI preoutput_NN1 stores_NN2 as_II31 well_II32 as_II33 post-input_JJ stores_NN2 ,_, almost_RR literally_RR memory_NN1 in_II the_AT fingers_NN2 ._. 
If_CS an_AT1 experienced_JJ operator_NN1 of_IO a_AT1 complex_JJ console_NN1 of_IO switches_NN2 is_VBZ asked_VVN where_CS a_AT1 particular_JJ switch_NN1 is_VBZ he_PPHS1 will_VM often_RR touch_VVI it_PPH1 and_CC check_VVI what_DDQ he_PPHS1 has_VHZ touched_VVN ,_, the_AT action_NN1 precedes_VVZ the_AT recall_NN1 and_CC recall_NN1 precedes_VVZ recognition_NN1 ._. 
The_AT distinction_NN1 between_II recall_NN1 and_CC recognition_NN1 is_VBZ clearly_RR an_AT1 important_JJ one_PN1 ,_, in_CS21 that_CS22 the_AT human_JJ memory_NN1 is_VBZ so_RG much_DA1 superior_JJ in_II the_AT latter_DA function_NN1 ._. 
We_PPIS2 may_VM be_VBI totally_RR unable_JK to_TO recall_VVI an_AT1 event_NN1 or_CC a_AT1 fact_NN1 but_CCB recognise_VV0 it_PPH1 and_CC all_DB its_APPGE context_NN1 immediately_RR if_CS it_PPH1 is_VBZ presented_VVN ._. 
Again_RT there_EX seems_VVZ to_TO be_VBI a_AT1 distinction_NN1 between_II what_DDQ and_CC when_RRQ ._. 
Any_DD busy_JJ person_NN1 will_VM recall_VVI that_CST he_PPHS1 has_VHZ a_AT1 particular_JJ engagement_NN1 but_CCB will_VM have_VHI only_RR a_AT1 sparse_JJ internal_JJ record_NN1 of_IO when_RRQ this_DD1 commitment_NN1 will_VM arise_VVI ,_, hence_RR the_AT importance_NN1 of_IO a_AT1 diary_NN1 ._. 
If_CS asked_VVN to_TO recall_VVI a_AT1 date_NN1 such_DA a_AT1 person_NN1 will_VM proceed_VVI by_II inference_NN1 rather_II21 than_II22 by_II a_AT1 direct_JJ introspective_JJ search_NN1 ,_, e.g._REX '_" it_PPH1 can_VM not_XX be_VBI next_MD week_NNT1 but_CCB it_PPH1 must_VM be_VBI within_II the_AT next_MD month_NNT1 '_GE or_CC '_" this_DD1 kind_NN1 of_IO event_NN1 is_VBZ always_RR on_II a_AT1 Tuesday_NPD1 '_GE and_RR31 so_RR32 on_RR33 ._. 
This_DD1 is_VBZ one_MC1 illustration_NN1 of_IO the_AT process_NN1 which_DDQ Bartlett_NP1 (_( 1932_MC )_) called_JJ '_GE turning_VVG round_RP on_II one_PN1 's_GE own_DA schemata_NN2 '_GE '_" I_PPIS1 am_VBM in_II this_DD1 state_NN1 therefore_RR this_DD1 must_VM be_VBI so_RR '_GE rather_II21 than_II22 the_AT direct_JJ retrieval_NN1 from_II a_AT1 store_NN1 ._. 
In_II Bartlett_NP1 's_GE view_NN1 long-term_JJ memory_NN1 involves_VVZ the_AT reconstruction_NN1 of_IO events_NN2 ,_, such_DA remembering_NN1 is_VBZ subject_II21 to_II22 bias_NN1 and_CC distortion_NN1 not_XX only_RR from_II idiosyncrasy_NN1 but_CCB also_RR from_II the_AT context_NN1 and_CC even_RR the_AT culture_NN1 ._. 
It_PPH1 is_VBZ in_II this_DD1 sense_NN1 that_CST memory_NN1 is_VBZ a_AT1 consequence_NN1 of_IO the_AT continuously_RR modified_JJ record_NN1 of_IO experience_NN1 (_( p._NNU 100_MC )_) rather_II21 than_II22 a_AT1 separate_JJ function_NN1 ._. 
The_AT analogy_NN1 of_IO the_AT ego_NN1 or_CC self_NN1 ,_, the_AT internal_JJ little_JJ man_NN1 consulting_VVG personal_JJ records_NN2 is_VBZ attractive_JJ but_CCB misleading_JJ ._. 
One_MC1 dubious_JJ consequence_NN1 is_VBZ that_CST the_AT short-term_JJ memory_NN1 ,_, of_IO limited_JJ capacity_NN1 compared_VVN with_IW the_AT virtually_RR infinite_JJ capacity_NN1 of_IO long-term_JJ memory_NN1 ,_, is_VBZ conceived_VVN as_II the_AT internal_JJ stage_NN1 on_II which_DDQ exhibits_VVZ from_II the_AT store_NN1 are_VBR manipulated_VVN ._. 
This_DD1 is_VBZ one_MC1 view_NN1 of_IO thinking_NN1 but_CCB again_RT it_PPH1 is_VBZ thinking_VVG restricted_VVN by_II the_AT limitations_NN2 of_IO the_AT laboratory_NN1 situation_NN1 where_RRQ the_AT problem_NN1 must_VM be_VBI easily_RR assimilated_VVN and_CC the_AT proposed_JJ solution_NN1 is_VBZ readily_RR measurable_JJ ._. 
Psychological_JJ research_NN1 on_II thinking_NN1 has_VHZ been_VBN the_AT province_NN1 of_IO the_AT field_NN1 theorists_NN2 ,_, in_RR21 particular_RR22 the_AT gestalt_NN1 psychologists_NN2 (_( Humphrey_NP1 ,_, 1951_MC )_) ._. 
There_EX was_VBDZ considerable_JJ debate_NN1 within_II this_DD1 school_NN1 about_II the_AT overlapping_JJ concepts_NN2 of_IO motive_NN1 ,_, determining_JJ tendency_NN1 and_CC set_VVD ._. 
Some_DD such_DA concept_NN1 is_VBZ required_VVN to_TO explain_VVI why_RRQ different_JJ individuals_NN2 reach_VV0 different_JJ solutions_NN2 in_II diagnosing_VVG and_CC providing_VVG remedies_NN2 for_IF particular_JJ situations_NN2 ._. 
These_DD2 ideas_NN2 have_VH0 recently_RR been_VBN revived_VVN by_II the_AT concept_NN1 of_IO '_GE mind-set_NN1 '_GE to_TO describe_VVI why_RRQ errors_NN2 are_VBR made_VVN in_II coping_VVG with_IW complex_JJ system_NN1 failures_NN2 ._. 
Craik_NP1 (_( 1943_MC )_) considered_VVD that_DD1 thinking_NN1 paralleled_VVD reality_NN1 in_II that_DD1 within_II the_AT mind_NN1 there_EX must_VM be_VBI a_AT1 model_NN1 of_IO reality_NN1 which_DDQ can_VM be_VBI manipulated_VVN independently_RR of_IO the_AT outside_JJ world_NN1 ._. 
The_AT advantages_NN2 of_IO such_DA a_AT1 mechanism_NN1 are_VBR clear_JJ ,_, it_PPH1 is_VBZ possible_JJ to_TO manipulate_VVI the_AT model_NN1 and_CC thus_RR understand_VV0 the_AT outside_JJ world_NN1 in_II the_AT sense_NN1 of_IO predicting_VVG what_DDQ will_VM happen_VVI without_IW the_AT potential_JJ costs_NN2 of_IO attempting_VVG to_TO manipulate_VVI the_AT real_JJ world_NN1 and_CC allowing_VVG things_NN2 to_TO happen_VVI ,_, some_DD of_IO which_DDQ might_VM be_VBI considered_VVN to_TO be_VBI unfortunate_JJ ._. 
Using_VVG technology_NN1 ,_, this_DD1 process_NN1 can_VM now_RT be_VBI partially_RR externalised_VVN in_II that_DD1 ,_, for_REX21 example_REX22 ,_, a_AT1 simulation_NN1 of_IO a_AT1 situation_NN1 can_VM be_VBI run_VVN in_II parallel_NN1 with_IW a_AT1 real_JJ situation_NN1 and_CC can_VM be_VBI manipulated_VVN independently_RR of_IO what_DDQ happens_VVZ in_II real_JJ time_NNT1 ._. 
Bartlett_NP1 (_( 1958_MC )_) regarded_VVD thinking_VVG as_II a_AT1 form_NN1 of_IO skill_NN1 in_II that_DD1 it_PPH1 has_VHZ the_AT characteristics_NN2 of_IO organising_VVG information_NN1 ._. 
A_AT1 situation_NN1 can_VM be_VBI structured_VVN and_CC comprehended_VVN so_BCL21 as_BCL22 to_TO indicate_VVI a_AT1 direction_NN1 for_IF proceeding_VVG ._. 
In_II technological_JJ situations_NN2 there_EX is_VBZ often_RR also_RR a_AT1 timing_NN1 characteristic_NN1 ,_, evidence_NN1 is_VBZ developing_JJ and_CC at_II some_DD point_NN1 in_II the_AT future_NN1 ,_, which_DDQ itself_PPX1 has_VHZ to_TO be_VBI determined_VVN ,_, something_PN1 will_VM have_VHI to_TO be_VBI done_VDN ._. 
One_MC1 attribute_NN1 of_IO thinking_VVG as_II31 opposed_II32 to_II33 perception_NN1 is_VBZ that_CST the_AT evidence_NN1 is_VBZ relatively_RR less_RGR complete_JJ ,_, gaps_NN2 have_VH0 to_TO be_VBI filled_VVN either_RR within_RL or_CC beyond_II the_AT available_JJ data_NN ._. 
This_DD1 is_VBZ achieved_VVN on_II the_AT basis_NN1 of_IO past_JJ experience_NN1 and_CC interests_NN2 ._. 
Inevitably_RR the_AT product_NN1 of_IO thinking_NN1 is_VBZ a_AT1 function_NN1 of_IO the_AT thinker_NN1 as_II31 well_II32 as_II33 of_IO the_AT situation_NN1 ._. 
Past_JJ experience_NN1 is_VBZ brought_VVN to_TO bear_VVI on_II a_AT1 new_JJ situation_NN1 by_II a_AT1 categorisation_NN1 ,_, a_AT1 process_NN1 regarded_VVN as_CSA central_JJ to_II thinking_VVG by_II Bruner_NP1 and_CC his_APPGE colleagues_NN2 (_( 1956_MC )_) ._. 
Classification_NN1 must_VM be_VBI a_AT1 function_NN1 not_XX only_RR of_IO the_AT situation_NN1 but_CCB also_RR of_IO the_AT existing_JJ internalised_JJ classes_NN2 and_CC their_APPGE relative_JJ accessibility_NN1 ._. 
Bruner_NP1 (_( 1957_MC )_) discusses_VVZ the_AT classical_JJ problem_NN1 of_IO determining_JJ tendency_NN1 as_58 '_GE perceptual_JJ readiness_NN1 '_GE and_CC notes_VVZ also_RR the_AT problem_NN1 that_CST the_AT first_MD classification_NN1 can_VM mask_VVI a_AT1 more_RGR appropriate_JJ classification_NN1 ._. 
This_DD1 relates_VVZ to_II a_AT1 currently_RR important_JJ limitation_NN1 in_II fault_NN1 diagnosis_NN1 for_IF technological_JJ systems_NN2 where_RRQ a_AT1 first_MD hypothesis_NN1 about_II the_AT cause_NN1 of_IO the_AT problem_NN1 can_VM inhibit_VVI flexibility_NN1 in_II considering_VVG other_JJ possible_JJ causes_NN2 ._. 
The_AT above_JJ ideas_NN2 were_VBDR generated_VVN mainly_RR on_II the_AT basis_NN1 of_IO experiments_NN2 and_CC it_PPH1 is_VBZ not_XX surprising_JJ that_CST many_DA2 of_IO the_AT key_JJ characteristics_NN2 of_IO thinking_VVG in_II real_JJ situations_NN2 were_VBDR not_XX given_VVN sufficient_JJ weight_NN1 ._. 
These_DD2 include_VV0 the_AT use_NN1 of_IO evidence_NN1 arising_VVG from_II the_AT absence_NN1 of_IO events_NN2 rather_II21 than_II22 their_APPGE presence_NN1 ,_, the_AT cost-effectiveness_JJ criterion_NN1 in_II pursuing_VVG evidence_NN1 and_CC reasoning_VVG processes_NN2 based_VVN on_II extensive_JJ experience_NN1 rather_II21 than_II22 intellectual_JJ analysis_NN1 ._. 
More_RGR recent_JJ work_NN1 on_II observation_NN1 of_IO ,_, rather_CS21 than_CS22 experiment_VVI with_IW thinking_NN1 (_( Johnson-Laird_NP1 and_CC Wason_NP1 ,_, 1977_MC )_) goes_VVZ some_DD way_NN1 to_II restoring_VVG the_AT balance_NN1 in_II appraising_VVG all_DB the_AT relevant_JJ parameters_NN2 in_II a_AT1 real_JJ situation_NN1 where_RRQ thinking_NN1 is_VBZ taking_VVG place_NN1 ._. 
There_EX is_VBZ also_RR a_AT1 dearth_NN1 of_IO evidence_NN1 about_II thinking_VVG by_II groups_NN2 ._. 
This_DD1 is_VBZ surprising_JJ in_II31 view_II32 of_II33 the_AT time_NNT1 which_DDQ people_NN spend_VV0 in_II committees_NN2 ,_, task_NN1 forces_NN2 and_CC the_AT like_JJ ._. 
There_EX is_VBZ experimental_JJ work_NN1 on_II issues_NN2 such_II21 as_II22 kinds_NN2 of_IO group_NN1 organisation_NN1 ,_, e.g._REX autocratic_JJ versus_II democratic_JJ versus_II laissez-faire_NN1 (_( Sherif_NP1 ,_, 1948_MC )_) and_CC on_II the_AT group_NN1 dynamics_NN of_IO people_NN interactions_NN2 (_( Lewin_NP1 ,_, 1935_MC )_) but_CCB little_RR work_VV0 on_II the_AT process_NN1 of_IO problem_NN1 solving_VVG by_II groups_NN2 ._. 
The_AT collective_JJ mind_NN1 in_II action_NN1 is_VBZ clearly_RR an_AT1 important_JJ topic_NN1 but_CCB it_PPH1 seems_VVZ to_TO be_VBI a_AT1 challenge_NN1 which_DDQ psychologists_NN2 have_VH0 not_XX yet_RR taken_VVN up_RP ._. 
It_PPH1 is_VBZ important_JJ in_II education_NN1 as_II31 well_II32 as_II33 in_II gainful_JJ employment_NN1 (_( Singleton_NP1 ,_, 1983a_FO )_) ._. 
Language_NN1 There_EX has_VHZ been_VBN extensive_JJ work_NN1 on_II the_AT psychology_NN1 of_IO language_NN1 (_( Campbell_NP1 and_CC Smith_NP1 ,_, 1976_MC ;_; Gerver_NP1 and_CC Sinaiko_NP1 ,_, 1978_MC )_) ,_, but_CCB with_IW a_AT1 greater_JJR emphasis_NN1 on_II language_NN1 as_II an_AT1 interpersonal_JJ communication_NN1 vehicle_NN1 rather_II21 than_II22 language_NN1 as_II a_AT1 supporter_NN1 of_IO thinking_NN1 ._. 
The_AT work_NN1 of_IO Piaget_NP1 (_( 1950_MC )_) and_CC Chomsky_NP1 (_( 1957_MC )_) is_VBZ essentially_RR about_II thinking_VVG and_CC language_NN1 or_CC psycholinguistics_NN2 ,_, but_CCB these_DD2 authors_NN2 did_VDD not_XX concern_VVI themselves_PPX2 with_IW the_AT level_NN1 of_IO problem_NN1 which_DDQ arises_VVZ when_RRQ ,_, for_REX21 example_REX22 ,_, a_AT1 physiologist_NN1 and_CC a_AT1 psychologist_NN1 attempt_NN1 to_TO exchange_VVI mutually_RR supportive_JJ ideas_NN2 ._. 
Herriot_NP1 (_( 1970_MC ,_, 1974_MC )_) ,_, however_RR ,_, makes_VVZ some_DD interesting_JJ suggestions_NN2 about_II the_AT relationship_NN1 between_II language_NN1 ,_, schema_NN1 ,_, strategies_NN2 and_CC deep_JJ structure_NN1 ._. 
As_CSA he_PPHS1 sees_VVZ it_PPH1 ,_, deep_JJ structure_NN1 is_VBZ represented_VVN in_II schemata_NN2 which_DDQ relate_VV0 non-linguistic_JJ and_CC linguistic_JJ thinking_NN1 ._. 
Language_NN1 and_CC indeed_RR behaviour_NN1 generally_RR is_VBZ necessarily_RR ordered_VVN and_CC is_VBZ represented_VVN internally_RR as_CSA strategies_NN2 ,_, schemata_NN2 are_VBR not_XX inherently_RR sequential_JJ and_CC thinking_NN1 can_VM thus_RR be_VBI concerned_JJ with_IW context_NN1 before_II the_AT constraint_NN1 of_IO achieving_VVG is_VBZ introduced_VVN in_BCL21 order_BCL22 to_TO generate_VVI an_AT1 output_NN1 ._. 
Thinking_NN1 regarded_VVN as_CSA internal_JJ manipulation_NN1 of_IO events_NN2 and_CC ideas_NN2 does_VDZ not_XX necessarily_RR depend_VVI on_II language_NN1 ,_, but_CCB if_CS it_PPH1 is_VBZ not_XX entirely_RR ego_NN1 orientated_VVN ,_, that_DD1 is_VBZ not_XX concentrated_VVN on_II the_AT relationship_NN1 of_IO the_AT person_NN1 to_II the_AT scheme_NN1 of_IO things_NN2 ,_, then_RT it_PPH1 usually_RR invokes_VVZ iconic_JJ representation_NN1 ._. 
Designers_NN2 of_IO computer_NN1 based_VVN support_NN1 for_IF thinking_VVG beyond_II the_AT level_NN1 of_IO merely_RR providing_VVG additional_JJ information_NN1 will_VM hopefully_RR begin_VVI to_II simultaneously_RR use_VV0 and_CC develop_VVI these_DD2 ideas_NN2 ._. 
Effective_JJ computer_NN1 support_NN1 must_VM be_VBI matched_VVN to_II human_JJ thinking_NN1 so_CS21 that_CS22 communication_NN1 is_VBZ readily_RR established_VVN and_CC yet_RR different_JJ in_II providing_VVG functions_NN2 which_DDQ supplement_VV0 human_JJ thinking_NN1 (_( p._NNU 233_MC )_) ._. 
Learning_NN1 and_CC memory_NN1 The_AT learner_NN1 must_VM have_VHI the_AT drive_NN1 to_TO learn_VVI and_CC he_PPHS1 must_VM also_RR have_VHI knowledge_NN1 of_IO the_AT results_NN2 of_IO his_APPGE activities._NNU 1_MC1 ._. 
Behaviour_NN1 at_II a_AT1 higher_JJR skilled_JJ level_NN1 is_VBZ characterised_VVN by_II selectivity_NN1 in_II choice_NN1 of_IO inputs_NN2 and_CC outputs_NN2 and_CC by_II increasing_JJ influence_NN1 of_IO the_AT past_NN1 and_CC the_AT future_NN1 rather_II21 than_II22 the_AT immediate_JJ situation._NNU 2_MC ._. 
Learning_NN1 is_VBZ an_AT1 activity_NN1 of_IO an_AT1 individual_JJ ,_, no_PN121 one_PN122 else_RR can_VM do_VDI it_PPH1 for_IF him_PPHO1 ._. 
Educators_NN2 and_CC trainers_NN2 can_VM do_VDI no_AT more_DAR than_CSN provide_VV0 the_AT conditions_NN2 ,_, the_AT content_NN1 and_CC the_AT materials._NNU 3_MC ._. 
Social_JJ skills_NN2 and_CC communication_NN1 generally_RR depend_VV0 on_II the_AT detection_NN1 and_CC definition_NN1 of_IO mutually_RR agreed_VVN internal_JJ models_NN2 of_IO reality._NNU 4_MC ._. 
The_AT human_JJ memory_NN1 ,_, in_II31 common_II32 with_II33 every_AT1 other_JJ store_NN1 ,_, has_VHZ to_TO be_VBI positively_RR consulted_VVN before_CS it_PPH1 will_VM function_VVI ._. 
This_DD1 is_VBZ not_XX a_AT1 limitation_NN1 ,_, it_PPH1 is_VBZ essential_JJ for_IF coherent_JJ behaviour_NN1 ,_, there_EX would_VM be_VBI chaos_NN1 if_CS material_NN1 emerged_VVD without_IW prompting_VVG ._. 
The_AT trigger_NN1 is_VBZ usually_RR some_DD external_JJ stimulus_NN1 ,_, not_XX necessarily_RR an_AT1 obvious_JJ one_PN1 ._. 
It_PPH1 might_VM be_VBI a_AT1 particular_JJ smell_NN1 ,_, a_AT1 particular_JJ melody_NN1 or_CC a_AT1 brief_JJ glimpse_NN1 of_IO a_AT1 person_NN1 resembling_VVG one_MC1 of_IO the_AT actors_NN2 in_II an_AT1 event_NN1 which_DDQ is_VBZ then_RT recalled_VVN ._. 
This_DD1 facility_NN1 for_IF associations_NN2 which_DDQ are_VBR neither_RR obvious_JJ nor_CC apparently_RR logical_JJ is_VBZ extremely_RR valuable_JJ in_II creative_JJ thinking_NN1 and_CC problem_NN1 solving_NN1 ._. 
The_AT converse_NN1 of_IO positively_RR trying_VVG to_TO recall_VVI some_DD fact_NN1 such_II21 as_II22 the_AT name_NN1 of_IO a_AT1 person_NN1 is_VBZ subject_II21 to_II22 curious_JJ blockages_NN2 which_DDQ are_VBR not_XX understood._NNU 5_MC ._. 
Given_VVN the_AT alternative_NN1 of_IO storage_NN1 internally_RR in_II the_AT mind_NN1 or_CC externally_RR in_II a_AT1 file_NN1 (_( paper-based_NN1 or_CC computer-based_JJ )_) external_JJ records_NN2 are_VBR much_RR superior_JJ for_IF literal_JJ reproductions_NN2 at_RR21 least_RR22 in_II western_JJ societies_NN2 (_( there_EX is_VBZ anecdotal_JJ evidence_NN1 concerning_II illiterate_JJ traders_NN2 in_II other_JJ cultures_NN2 who_PNQS seem_VV0 to_TO have_VHI remarkable_JJ memories_NN2 for_IF detailed_JJ facts_NN2 and_CC numbers_NN2 connected_VVN with_IW their_APPGE personal_JJ business_NN1 )_) ._. 
The_AT capacity_NN1 and_CC flexibility_NN1 of_IO desk-top_JJ computers_NN2 is_VBZ now_RT such_CS21 that_CS22 the_AT optimal_JJ sharing_NN1 of_IO processing_NN1 ,_, storage_NN1 and_CC presentation_NN1 of_IO material_NN1 between_II computer_NN1 and_CC operator_NN1 may_VM well_RR be_VBI quite_RG different_JJ from_II the_AT traditional_JJ combination_NN1 of_IO human_JJ memory_NN1 and_CC material_NN1 on_II paper_NN1 ._. 
This_DD1 topic_NN1 is_VBZ too_RG recent_JJ for_IF there_RL to_TO be_VBI many_DA2 guidelines_NN2 available_JJ but_II21 for_II22 a_AT1 particular_JJ topic_NN1 the_AT designer_NN1 can_VM assume_VVI that_CST he_PPHS1 need_VM not_XX be_VBI inhibited_VVN in_II allowing_VVG his_APPGE imagination_NN1 to_TO run_VVI to_II many_DA2 kinds_NN2 of_IO novel_JJ solutions._NNU 6_MC ._. 
There_EX is_VBZ a_AT1 considerable_JJ art_NN1 in_II developing_VVG the_AT most_RGT effective_JJ combination_NN1 of_IO external_JJ and_CC internal_JJ stores_NN2 and_CC reminders_NN2 which_DDQ every_AT1 highly_RR skilled_JJ person_NN1 deliberately_RR cultivates_VVZ ._. 
For_REX21 example_REX22 ,_, there_EX is_VBZ no_AT need_NN1 to_TO write_VVI in_II a_AT1 diary_NN1 '_GE check_NN1 in-tray_NN1 and_CC consult_VV0 secretary_NN1 '_GE ,_, these_DD2 actions_NN2 take_VV0 place_NN1 as_CSA routine_NN1 following_VVG arrival_NN1 at_II the_AT office_NN1 ._. 
On_II the_AT other_JJ hand_NN1 a_AT1 diary_NN1 entry_NN1 such_II21 as_II22 '_GE ring_NN1 X_ZZ1 '_GE is_VBZ effective_JJ and_CC if_CS the_AT entry_NN1 is_VBZ some_DD way_NN1 in_II the_AT future_NN1 it_PPH1 may_VM be_VBI necessary_JJ to_TO amplify_VVI with_IW a_AT1 trigger_NN1 of_IO the_AT form_NN1 '_GE ring_NN1 X_ZZ1 re_II Y_NP1 '_GE and_CC to_TO have_VHI easily_RR accessible_JJ some_DD factual_JJ data_NN such_II21 as_II22 the_AT X_ZZ1 telephone_NN1 number_NN1 and_CC some_DD data_NN re_II Y._NP1 In_II a_AT1 different_JJ context_NN1 a_AT1 car_NN1 driver_NN1 will_VM develop_VVI a_AT1 strategy_NN1 to_TO ensure_VVI that_CST he_PPHS1 does_VDZ not_XX run_VVI out_II21 of_II22 petrol_NN1 ,_, he_PPHS1 may_VM rely_VVI on_II a_AT1 light_NN1 which_DDQ appears_VVZ when_RRQ the_AT tank_NN1 is_VBZ nearly_RR empty_JJ or_CC he_PPHS1 may_VM calculate_VVI from_II his_APPGE expected_JJ travelling_NN1 that_CST he_PPHS1 need_VM not_XX concern_VVI himself_PPX1 about_II the_AT issue_NN1 until_CS at_RR21 least_RR22 the_AT next_MD weekend_NNT1 ,_, or_CC he_PPHS1 may_VM programme_NN1 himself_PPX1 to_TO react_VVI to_II the_AT fact_NN1 that_CST he_PPHS1 is_VBZ approaching_VVG a_AT1 particular_JJ garage_NN1 ._. 
This_DD1 self-programming_NN1 goes_VVZ on_RP continuously_RR with_IW an_AT1 implicit_JJ acknowledgment_NN1 of_IO the_AT need_NN1 for_IF triggers_NN2 and_CC the_AT relative_JJ advantages_NN2 of_IO various_JJ kinds_NN2 of_IO stores_NN2 and_CC stored_VVD materials._NNU 7_MC ._. 
This_DD1 self-organised_JJ work_NN1 design_NN1 has_VHZ its_APPGE parallel_NN1 in_II designing_VVG tasks_NN2 for_IF others_NN2 ._. 
In_II studying_VVG an_AT1 elaborate_JJ sequence_NN1 of_IO events_NN2 within_II a_AT1 task_NN1 the_AT designer_NN1 will_VM systematically_RR consider_VVI the_AT need_NN1 for_IF appropriate_JJ triggers_NN2 for_IF the_AT memory_NN1 at_II specific_JJ points_NN2 in_II the_AT task_NN1 ._. 
In_RR21 particular_RR22 he_PPHS1 will_VM never_RR rely_VVI on_II the_AT operator_NN1 spontaneously_RR remembering_VVG to_TO do_VDI something_PN1 which_DDQ has_VHZ no_AT natural_JJ place_NN1 in_II the_AT developing_JJ task_NN1 (_( p._NNU 56_MC )_) ._. 
8_MC ._. 
There_EX are_VBR at_RR21 least_RR22 three_MC and_CC probably_RR many_DA2 more_DAR levels_NN2 of_IO storage_NN1 ._. 
The_AT sensory_JJ stores_NN2 decay_VV0 very_RG rapidly_RR ,_, items_NN2 are_VBR lost_VVN in_II less_DAR than_CSN ten_MC seconds_NNT2 ._. 
The_AT short-term_JJ store_NN1 has_VHZ a_AT1 limit_NN1 of_IO about_RG twenty_MC seconds_NNT2 unless_CS there_EX is_VBZ opportunity_NN1 for_IF rehearsal_NN1 ,_, e.g._REX this_DD1 is_VBZ the_AT maximum_JJ time_NNT1 available_JJ between_II looking_VVG up_RP a_AT1 telephone_NN1 number_NN1 and_CC then_RT dialling_VVG it_PPH1 unless_CS the_AT operator_NN1 repeats_VVZ it_PPH1 to_II himself_PPX1 ._. 
Some_DD kinds_NN2 of_IO long-term_JJ memory_NN1 seem_VV0 to_TO endure_VVI indefinitely_RR even_CS21 though_CS22 they_PPHS2 have_VH0 apparently_RR been_VBN lost_VVN for_IF a_AT1 long_JJ time_NNT1 ,_, e.g._REX an_AT1 older_JJR person_NN1 may_VM find_VVI it_PPH1 easy_JJ to_TO recall_VVI childhood_NN1 events_NN2 with_IW great_JJ clarity_NN1 even_CS21 though_CS22 there_EX has_VHZ been_VBN no_AT use_NN1 of_IO the_AT material_NN1 for_IF fifty_MC or_CC sixty_MC years._NNU 9_MC ._. 
There_EX seems_VVZ to_TO be_VBI a_AT1 memory_NN1 for_IF elaborate_JJ patterns_NN2 and_CC sequences_NN2 which_DDQ takes_VVZ a_AT1 long_JJ time_NNT1 to_TO develop_VVI ._. 
For_REX21 example_REX22 a_AT1 chemist_NN1 will_VM learn_VVI about_II compounds_NN2 by_II laboriously_RR memorising_VVG as_II a_AT1 student_NN1 the_AT properties_NN2 of_IO each_DD1 one_PN1 separately_RR but_CCB eventually_RR sets_VVZ of_IO compounds_NN2 are_VBR perceived_VVN as_II a_AT1 pattern_NN1 and_CC thereafter_RT all_DB the_AT relevant_JJ material_NN1 is_VBZ readily_RR available_JJ because_CS it_PPH1 fits_VVZ together_RL neatly_RR ._. 
The_AT corollary_NN1 for_IF the_AT trainer_NN1 is_VBZ to_TO look_VVI for_IF patterns_NN2 which_DDQ exist_VV0 in_II complex_JJ material_NN1 and_CC introduce_VV0 the_AT trainee_NN1 to_II the_AT patterns_NN2 as_II31 well_II32 as_II33 to_II the_AT separate_JJ facts_NN2 ._. 
Similarly_RR an_AT1 information_NN1 presentation_NN1 will_VM be_VBI more_RGR readily_RR comprehended_VVN if_CS there_EX is_VBZ a_AT1 detectable_JJ structure_NN1 such_II21 as_II22 the_AT '_GE christmas_NNT1 tree_NN1 '_GE method_NN1 of_IO working_VVG through_II a_AT1 checklist._NNU 10_MC ._. 
Errors_NN2 in_II recall_NN1 can_VM be_VBI similar_JJ for_IF different_JJ individuals._NNU for_REX21 example_REX22 the_AT propensity_NN1 for_IF simple_JJ reversals_NN2 within_II a_AT1 number_NN1 sequence_NN1 ._. 
It_PPH1 follows_VVZ that_CST attempting_VVG to_TO reduce_VVI error_NN1 rates_NN2 by_II one_MC1 person_NN1 checking_VVG another_DD1 's_VBZ performance_NN1 or_CC automatically_RR comparing_VVG the_AT output_NN1 of_IO the_AT individuals_NN2 simultaneously_RR performing_VVG the_AT same_DA task_NN1 is_VBZ not_XX as_CSA effective_JJ as_CSA it_PPH1 would_VM be_VBI if_CSW errors_NN2 in_II the_AT sources_NN2 were_VBDR independent_JJ (_( Chapanis_NP1 et_RA21 al._RA22 ,_, 1949_MC )_) ._. 
Principles_NN2 ,_, methods_NN2 and_CC procedures_NN2 Interviewing_VVG An_AT1 interview_NN1 is_VBZ a_AT1 formal_JJ conversation_NN1 in_II which_DDQ there_EX is_VBZ a_AT1 non-reciprocal_JJ relationship_NN1 between_II the_AT parties_NN2 ._. 
It_PPH1 is_VBZ formal_JJ in_CS21 that_CS22 there_EX are_VBR purposes_NN2 which_DDQ define_VV0 the_AT reasons_NN2 why_RRQ the_AT transaction_NN1 is_VBZ taking_VVG place_NN1 ._. 
There_EX is_VBZ conversation_NN1 which_DDQ is_VBZ usually_RR face_NN1 to_II face_NN1 but_CCB may_VM sometimes_RT involve_VVI telecommunication_NN1 ._. 
It_PPH1 is_VBZ non-reciprocal_JJ in_CS21 that_CS22 the_AT two_MC parties_NN2 are_VBR never_RR equivalent_JJ ;_; one_PN1 is_VBZ the_AT interviewer_NN1 who_PNQS has_VHZ the_AT initiative_NN1 ,_, the_AT other_NN1 is_VBZ the_AT interviewee_NN1 ._. 
The_AT interviewing_JJ party_NN1 may_VM be_VBI a_AT1 group_NN1 facing_VVG one_MC1 interviewee_NN1 ,_, e.g._REX a_AT1 selection_NN1 board_NN1 ._. 
The_AT interviewed_JJ party_NN1 may_VM be_VBI a_AT1 group_NN1 facing_VVG one_MC1 interviewer_NN1 ,_, e.g._REX a_AT1 group_NN1 of_IO witnesses_NN2 facing_VVG a_AT1 reporter_NN1 ._. 
Any_DD transaction_NN1 involving_VVG two_MC groups_NN2 or_CC two_MC equivalent_JJ individuals_NN2 is_VBZ regarded_VVN as_II a_AT1 negotiation_NN1 rather_II21 than_II22 an_AT1 interview_NN1 ._. 
The_AT interview_NN1 can_VM be_VBI initiated_VVN by_II either_DD1 side_NN1 ,_, e.g._REX by_II the_AT interviewer_NN1 when_CS a_AT1 more_RGR senior_JJ person_NN1 calls_VVZ a_AT1 subordinate_JJ or_CC by_II the_AT interviewee_NN1 when_CS a_AT1 patient_NN1 calls_VVZ a_AT1 doctor_NN1 ._. 
The_AT information_NN1 transmission_NN1 will_VM inevitably_RR be_VBI two-way_JJ but_CCB the_AT main_JJ purpose_NN1 may_VM be_VBI transmission_NN1 from_II interviewer_NN1 to_II interviewee_NN1 as_CSA in_II an_AT1 appraisal_NN1 interview_NN1 ,_, from_II interviewee_NN1 to_II interviewer_NN1 as_CSA in_II an_AT1 opinion_NN1 survey_NN1 ,_, or_CC it_PPH1 may_VM change_VVI direction_NN1 during_II the_AT course_NN1 of_IO the_AT interview_NN1 as_CSA in_II a_AT1 patient-doctor_JJ interview_NN1 ._. 
In_II this_DD1 last_MD case_NN1 the_AT interviewee_NN1 begins_VVZ by_II providing_VVG information_NN1 which_DDQ facilitates_VVZ a_AT1 diagnosis_NN1 and_CC the_AT interviewer_NN1 thereafter_RT provides_VVZ information_NN1 about_II possible_JJ causes_NN2 and_CC remedies_NN2 ._. 
In_II31 view_II32 of_II33 the_AT universality_NN1 and_CC range_NN1 of_IO the_AT interview_NN1 situation_NN1 it_PPH1 is_VBZ not_XX surprising_JJ that_CST there_EX has_VHZ been_VBN extensive_JJ research_NN1 ,_, but_II21 for_II22 the_AT same_DA reasons_NN2 the_AT research_NN1 is_VBZ of_IO little_JJ operational_JJ consequence_NN1 ._. 
Checks_NN2 of_IO interview_NN1 effectiveness_NN1 by_II ,_, for_REX21 example_REX22 ,_, having_VHG the_AT same_DA list_NN1 of_IO candidates_NN2 ranked_VVN independently_RR by_II two_MC selection_NN1 boards_NN2 invariably_RR indicates_VVZ rather_RG poor_JJ consistency_NN1 ._. 
On_II the_AT other_JJ hand_NN1 no_AT manager_NN1 willingly_RR accepts_VVZ a_AT1 new_JJ member_NN1 of_IO staff_NN without_IW the_AT use_NN1 of_IO a_AT1 selection_NN1 interview_NN1 ,_, no_AT doctor_NN1 will_VM express_VVI a_AT1 confident_JJ diagnosis_NN1 without_IW an_AT1 interview_NN1 with_IW the_AT patient_NN1 ,_, and_CC no_AT counsellor_NN1 could_VM function_VVI without_IW meeting_VVG his_APPGE clients_NN2 face_NN1 to_II face_NN1 ._. 
The_AT key_NN1 to_II the_AT issue_NN1 is_VBZ that_CST interviews_NN2 except_CS in_II the_AT simplest_JJT case_NN1 of_IO surveys_NN2 ,_, to_TO be_VBI discussed_VVN later_RRR ,_, are_VBR not_XX about_II acquiring_VVG factual_JJ evidence_NN1 ._. 
This_DD1 is_VBZ best_RRT obtained_VVN by_II asking_VVG interviewees_NN2 to_TO complete_VVI standard_JJ forms_NN2 or_CC to_TO take_VVI tests_NN2 before_II or_CC between_II interviews_NN2 ._. 
Information_NN1 obtained_VVN during_II an_AT1 interview_NN1 is_VBZ about_II assessable_JJ but_CCB unquantifiable_JJ attributes_NN2 such_II21 as_II22 attitudes_NN2 ,_, motivation_NN1 ,_, reliability_NN1 ,_, integrity_NN1 ,_, social_JJ ease_NN1 and_RR31 so_RR32 on_RR33 ._. 
In_II skill_NN1 terminology_NN1 the_AT interviewer_NN1 uses_VVZ the_AT interview_NN1 to_TO create_VVI a_AT1 model_NN1 in_II his_APPGE mind_NN1 which_DDQ he_PPHS1 can_VM use_VVI to_TO predict_VVI the_AT behaviour_NN1 of_IO the_AT individual_JJ interviewee_NN1 in_II a_AT1 work_NN1 situation_NN1 ,_, a_AT1 stress_NN1 situation_NN1 ,_, an_AT1 illness_NN1 or_CC whatever_DDQV an_AT1 interview_NN1 is_VBZ about_RP ._. 
Obviously_RR he_PPHS1 can_VM create_VVI a_AT1 better_JJR model_NN1 if_CS he_PPHS1 knows_VVZ what_DDQ the_AT interviewee_NN1 looks_VVZ like_II ,_, how_RRQ he_PPHS1 dresses_VVZ ,_, talks_NN2 and_CC responds_VVZ non-verbally_RR ._. 
Equally_RR the_AT interviewee_NN1 forms_VVZ a_AT1 model_NN1 of_IO the_AT interviewer(s)_NN2 and_CC this_DD1 can_VM be_VBI a_AT1 considerable_JJ aid_NN1 to_II his_APPGE decision-making_NN1 about_II whether_CSW he_PPHS1 can_VM respect_VVI ,_, trust_VV0 ,_, work_VV0 with_IW or_CC tolerate_VV0 guidance_NN1 from_II the_AT interviewer_NN1 ._. 
This_DD1 interaction_NN1 may_VM or_CC may_VM not_XX achieve_VVI a_AT1 successful_JJ conclusion_NN1 for_IF both_DB2 sides_NN2 depending_II21 on_II22 their_APPGE level_NN1 of_IO skill_NN1 ._. 
Attempting_VVG to_TO do_VDI research_NN1 on_II the_AT interview_NN1 per_RR21 se_RR22 is_VBZ doomed_VVN to_II failure_NN1 because_CS the_AT skills_NN2 of_IO the_AT actors_NN2 will_VM dominate_VVI the_AT success_NN1 or_CC otherwise_RR of_IO the_AT proceedings_NN2 ._. 
It_PPH1 should_VM be_VBI remembered_VVN also_RR that_CST the_AT interview_NN1 is_VBZ only_RR one_MC1 incident_NN1 within_II a_AT1 series_NN of_IO communication_NN1 functions_NN2 which_DDQ aim_VV0 towards_II one_MC1 objective_NN1 ._. 
For_REX21 example_REX22 ,_, a_AT1 work_NN1 placement_NN1 involves_VVZ trawling_VVG for_IF candidates_NN2 ,_, testing_VVG and_CC formfilling_VVG and_CC preliminary_JJ sifts_VVZ before_II the_AT interview_NN1 followed_VVN by_II induction_NN1 and_CC training_NN1 after_II the_AT interview_NN1 ._. 
Those_DD2 responsible_JJ are_VBR interested_JJ in_II an_AT1 effective_JJ total_NN1 process_VV0 not_XX just_RR an_AT1 effective_JJ interview_NN1 and_CC all_DB the_AT stages_NN2 in_II the_AT process_NN1 interact_VV0 ._. 
For_IF these_DD2 reasons_NN2 it_PPH1 is_VBZ difficult_JJ to_TO generate_VVI principles_NN2 of_IO interviewing_VVG ,_, there_EX are_VBR always_RR alternative_JJ viewpoints_NN2 and_CC exceptions._NNU for_REX21 example_REX22 :_: 1_MC1 ._. 
Always_RR try_VV0 to_TO put_VVI the_AT interviewees_NN2 at_II ease_NN1 ._. 
For_IF senior_JJ posts_NN2 it_PPH1 can_VM be_VBI instructive_JJ to_TO do_VDI the_AT opposite_JJ to_TO see_VVI how_RGQ far_RR the_AT candidate_NN1 can_VM cope_VVI with_IW the_AT stress._NNU 2_MC ._. 
Always_RR ask_VV0 open-ended_JJ questions_NN2 ._. 
If_CS the_AT interviewee_NN1 is_VBZ very_RG nervous_JJ it_PPH1 can_VM help_VVI to_TO ask_VVI some_DD questions_NN2 which_DDQ can_VM readily_RR be_VBI answered_VVN with_IW a_AT1 yes_UH or_CC no_UH ,_, this_DD1 provides_VVZ the_AT opportunity_NN1 to_TO adjust_VVI the_AT tension._NNU 3_MC ._. 
Do_VD0 not_XX make_VVI jokes_NN2 ._. 
Sometimes_RT the_AT interviewee_NN1 exhibits_VVZ too_RG much_DA1 respect_NN1 creating_VVG a_AT1 communication_NN1 barrier_NN1 ,_, a_AT1 demonstration_NN1 that_CST the_AT interviewer_NN1 is_VBZ only_JJ human_NN1 by_II a_AT1 weak_JJ joke_NN1 can_VM remove_VVI this_DD1 barrier._NNU 4_MC ._. 
Always_RR structure_VV0 the_AT interview_NN1 to_TO ensure_VVI that_CST all_DB essential_JJ points_NN2 are_VBR covered_VVN ._. 
On_II the_AT contrary_NN1 a_AT1 free-wheeling_JJ interview_NN1 with_IW direction_NN1 changes_NN2 as_CSA key_JJ points_NN2 emerge_VV0 can_VM yield_VVI unexpected_JJ but_CCB valuable_JJ evidence._NNU 5_MC ._. 
Assess_VV0 the_AT interviewee_NN1 under_II various_JJ headings_NN2 to_TO obtain_VVI a_AT1 comparable_JJ profile_NN1 score_NN1 ._. 
Part_NN1 of_IO the_AT skill_NN1 of_IO the_AT interviewer_NN1 is_VBZ in_II extracting_VVG different_JJ salient_JJ points_NN2 from_II individuals_NN2 and_CC appropriately_RR weighting_VVG totally_RR disparate_JJ facets_NN2 ._. 
On_II the_AT other_JJ hand_NN1 it_PPH1 must_VM be_VBI acknowledged_VVN that_CST there_EX are_VBR many_DA2 bad_JJ interviews_NN2 and_CC ,_, as_CSA always_RR ,_, improvement_NN1 is_VBZ possible_JJ by_II design_NN1 ,_, consideration_NN1 of_IO procedures_NN2 and_CC training_NN1 ._. 
The_AT design_NN1 of_IO the_AT situation_NN1 and_CC the_AT process_NN1 should_VM adhere_VVI to_II standard_JJ practices_NN2 which_DDQ have_VH0 been_VBN found_VVN to_TO be_VBI helpful_JJ by_II experience_NN1 and_CC commonsense._NNU 1_MC1 ._. 
Obtain_VV0 all_DB the_AT relevant_JJ factual_JJ data_NN (_( biography_NN1 and_CC testscores_NN2 )_) before_II the_AT final_JJ interview._NNU 2_MC ._. 
Provide_VV0 a_AT1 waiting_NN1 room_NN1 which_DDQ has_VHZ accessible_JJ toilet_NN1 facilities_NN2 including_II mirrors._NNU 3_MC ._. 
The_AT interviewer_NN1 should_VM collect_VVI the_AT interviewee_NN1 ,_, not_XX have_VH0 him_PPHO1 sent_VVN for_IF from_II the_AT waiting_NN1 room._NN1 4_MC ._. 
Provide_VV0 the_AT interviewee_NN1 with_IW a_AT1 written_JJ job_NN1 aid_NN1 which_DDQ indicates_VVZ the_AT name_NN1 and_CC function_NN1 of_IO the_AT interviewer(s)._NNU 5_MC ._. 
The_AT relative_JJ positioning_NN1 of_IO the_AT two_MC main_JJ interactors_NN2 and_CC the_AT direction_NN1 of_IO lighting_NN1 are_VBR significant_JJ ._. 
The_AT obvious_58 '_GE third-degree_NN1 '_GE lighting_NN1 should_VM be_VBI avoided_VVN but_CCB not_XX being_VBG able_JK to_TO see_VVI the_AT interview_NN1 clearly_RR is_VBZ equally_RR deleterious_JJ ._. 
Face_NN1 to_II face_NN1 is_VBZ the_AT most_RGT formal_JJ ,_, side_NN1 by_II side_NN1 the_AT least_RGT formal_JJ ,_, seating_VVG at_II right_JJ angles_NN2 is_VBZ often_RR a_AT1 suitable_JJ compromise._NNU 6_MC ._. 
Provide_VV0 the_AT interviewee_NN1 with_IW opportunities_NN2 to_TO make_VVI points_NN2 which_DDQ have_VH0 not_XX been_VBN covered_VVN in_II questions_NN2 and_CC to_TO ask_VVI other_JJ questions_NN2 on_II matters_NN2 important_JJ to_II him_PPHO1 ._. 
This_DD1 is_VBZ not_XX mere_JJ courtesy_NN1 ,_, what_DDQ the_AT interviewee_NN1 regards_VVZ as_CSA important_JJ can_VM be_VBI very_RG revealing._NNU 7_MC ._. 
Provide_VV0 clear_JJ if_CS indirect_JJ indications_NN2 that_CST the_AT interview_NN1 is_VBZ ending._NNU 8_MC ._. 
Tell_VV0 the_AT interviewee_NN1 what_DDQ the_AT next_MD stage_NN1 in_II the_AT process_NN1 will_VM be_VBI and_CC when._NNU 9_MC ._. 
Escort_VV0 the_AT interviewee_NN1 at_RR21 least_RR22 to_II the_AT door_NN1 ,_, again_RT the_AT behaviour_NN1 at_II the_AT parting_NN1 point_NN1 can_VM be_VBI significant_JJ ._. 
In_II31 view_II32 of_II33 the_AT above_JJ discussion_NN1 training_NN1 of_IO interviewers_NN2 and_CC interviewees_NN2 must_VM necessarily_RR be_VBI based_VVN on_II principles_NN2 of_IO training_NN1 (_( p._NNU 121_MC )_) rather_II21 than_II22 principles_NN2 of_IO interviewing_VVG ._. 
Role_NN1 playing_VVG and_CC case_NN1 studies_NN2 are_VBR often_RR used_VVN and_CC they_PPHS2 can_VM be_VBI effective_JJ in_II reducing_VVG self-unease_NN1 (_( self-awareness_NN1 and_CC self-analysis_NN1 are_VBR necessary_JJ attributes_NN2 of_IO the_AT good_JJ interviewer_NN1 in_II action_NN1 )_) and_CC highlighting_VVG idiosyncratic_JJ features_NN2 such_II21 as_II22 mannerisms_NN2 and_CC biases_NN2 ._. 
The_AT most_RGT powerful_JJ tool_NN1 of_IO the_AT interview_NN1 trainer_NN1 is_VBZ the_AT closed_JJ circuit_NN1 television_NN1 system_NN1 ._. 
So_RR powerful_JJ that_CST it_PPH1 needs_VVZ to_TO be_VBI used_VVN circumspectly_RR to_TO avoid_VVI reducing_VVG self-confidence_NN1 ._. 
Normally_RR the_AT trainer_NN1 will_VM go_VVI through_II a_AT1 reproduced_JJ interview_NN1 and_CC discuss_VVI the_AT good_JJ and_CC bad_JJ points_NN2 which_DDQ are_VBR usually_RR clearly_RR evident_JJ ._. 
This_DD1 provides_VVZ salutary_JJ knowledge_NN1 of_IO results_NN2 of_IO the_AT interview_NN1 itself_PPX1 if_CS not_XX of_IO its_APPGE degree_NN1 of_IO success_NN1 in_II31 terms_II32 of_II33 a_AT1 real_JJ objective_NN1 ._. 
Randell_NP1 (_( 1978_MC )_) suggests_VVZ that_CST an_AT1 interviewing_NN1 at_II work_NN1 course_NN1 can_VM reasonably_RR take_VVI two_MC days_NNT2 covering_NN1 '_GE unfreezing_NN1 '_GE ,_, conceptual_JJ analysis_NN1 ,_, technique_NN1 development_NN1 and_CC practice_NN1 with_IW feedback_NN1 ._. 
Rutter_NP1 (_( 1979_MC )_) devised_VVD an_AT1 interview_NN1 training_NN1 programme_NN1 for_IF medical_JJ students_NN2 involving_VVG a_AT1 history_NN1 taking_VVG scheme_NN1 and_CC two_MC videotaped_VVD 15_MC minute_JJ diagnostic_JJ sessions_NNT2 one_MC1 week_NNT1 apart_RL ,_, with_IW discussion_NN1 feedback_NN1 based_VVN on_II a_AT1 nine-point_JJ method_NN1 of_IO scoring_VVG information_NN1 elicited_VVD ._. 
These_DD2 scores_NN2 were_VBDR also_RR used_VVN to_TO validate_VVI the_AT training_NN1 by_II comparing_VVG experimental_JJ and_CC control_NN1 groups_NN2 ._. 
Psychological_JJ testing_NN1 The_AT design_NN1 and_CC development_NN1 of_IO tests_NN2 is_VBZ a_AT1 well_NN1 established_VVN formal_JJ procedure_NN1 involving_VVG checking_VVG for_IF internal_JJ consistency_NN1 and_CC absence_NN1 of_IO ambiguity_NN1 ,_, efficiency_NN1 of_IO administration_NN1 and_CC marking_VVG procedures_NN2 and_CC the_AT production_NN1 of_IO norms_NN2 for_IF definitive_JJ populations_NN2 ._. 
There_EX is_VBZ a_AT1 comprehensive_JJ list_NN1 and_CC description_NN1 of_IO available_JJ tests_NN2 in_II the_AT '_GE Mental_JJ Measurement_NN1 Yearbook_NN1 '_GE which_DDQ is_VBZ updated_VVN at_II intervals_NN2 of_IO a_AT1 few_DA2 years_NNT2 ._. 
The_AT reliability_NN1 of_IO a_AT1 test_NN1 is_VBZ measured_VVN by_II correlation_NN1 between_II the_AT test_NN1 scores_NN2 ,_, obtained_VVN at_II two_MC different_JJ times_NNT2 ,_, between_II different_JJ forms_NN2 of_IO the_AT same_DA test_NN1 or_CC between_II samples_NN2 of_IO questions_NN2 in_II different_JJ parts_NN2 of_IO the_AT same_DA test_NN1 ._. 
The_AT interpretation_NN1 of_IO this_DD1 measure_NN1 of_IO consistency_NN1 is_VBZ not_XX as_RG straightforward_JJ as_CSA it_PPH1 seems_VVZ at_II first_MD sight_NN1 ._. 
For_REX21 example_REX22 ,_, it_PPH1 has_VHZ been_VBN pointed_VVN out_RP that_CST one_MC1 person_NN1 can_VM not_XX be_VBI asked_VVN the_AT same_DA question_NN1 twice_RR ,_, the_AT second_MD time_NNT1 he_PPHS1 is_VBZ not_XX the_AT same_DA person_NN1 because_CS he_PPHS1 has_VHZ already_RR been_VBN asked_VVN the_AT question_NN1 once_RR ._. 
The_AT validity_NN1 of_IO a_AT1 test_NN1 is_VBZ an_AT1 even_RR more_RGR complex_JJ concept_NN1 ._. 
It_PPH1 refers_VVZ in_RR21 general_RR22 to_II the_AT confidence_NN1 the_AT tester_NN1 can_VM attach_VVI to_II decisions_NN2 based_VVN on_II the_AT test_NN1 scores_NN2 ._. 
There_EX are_VBR at_RR21 least_RR22 three_MC kinds_NN2 of_IO validity_NN1 :_: construct_VV0 validity_NN1 which_DDQ refers_VVZ to_II the_AT degree_NN1 to_II which_DDQ the_AT test_NN1 seems_VVZ to_TO be_VBI based_VVN on_II psychological_JJ theory_NN1 ,_, content_JJ validity_NN1 which_DDQ describes_VVZ how_RRQ well_RR the_AT test_NN1 measures_NN2 what_DDQ it_PPH1 is_VBZ intended_VVN to_II measure_NN1 and_CC criterion_NN1 validity_NN1 which_DDQ indicates_VVZ its_APPGE value_NN1 as_II a_AT1 predictor_NN1 using_VVG as_CSA criteria_NN2 other_JJ measures_NN2 of_IO relevant_JJ performance_NN1 ._. 
The_AT problems_NN2 of_IO criterion_NN1 validity_NN1 nicely_RR illustrate_VV0 the_AT difficulty_NN1 of_IO finding_VVG any_DD solid_JJ foundation_NN1 on_II which_DDQ to_TO construct_VVI a_AT1 psychometric_JJ measure_NN1 ._. 
Suppose_VV0 that_CST the_AT purpose_NN1 of_IO a_AT1 particular_JJ test_NN1 is_VBZ to_TO predict_VVI success_NN1 in_II a_AT1 particular_JJ job_NN1 ._. 
Even_RR with_IW hindsight_NN1 this_DD1 is_VBZ not_XX easy_JJ to_TO determine_VVI ._. 
The_AT measure_NN1 of_IO success_NN1 in_II a_AT1 training_NN1 course_NN1 depends_VVZ on_II the_AT validity_NN1 of_IO the_AT training_NN1 course_NN1 itself_PPX1 ,_, supervisors_NN2 '_GE opinions_NN2 based_VVN on_II experience_NN1 of_IO job_NN1 performance_NN1 are_VBR subject_II21 to_II22 distortion_NN1 by_II various_JJ biases_NN2 and_CC measured_JJ performance_NN1 such_II21 as_II22 productivity_NN1 is_VBZ subject_II21 to_II22 many_DA2 vicissitudes_NN2 independent_JJ of_IO the_AT ability_NN1 of_IO the_AT producer_NN1 ._. 
Faced_VVN with_IW all_DB these_DD2 uncertainties_NN2 the_AT strategies_NN2 adopted_VVN in_II the_AT U.S.A._NP1 and_CC Europe_NP1 are_VBR in_RR21 general_RR22 different_JJ but_CCB usefully_RR complementary_JJ ._. 
The_AT American_JJ approach_NN1 is_VBZ to_TO be_VBI as_RG formal_JJ and_CC rigorous_JJ as_CSA possible_JJ with_IW insistence_NN1 on_II systematic_JJ sampling_NN1 ,_, correlating_VVG and_RR31 so_RR32 on_RR33 ._. 
The_AT European_JJ approach_NN1 is_VBZ less_RGR tidy_JJ and_CC more_RGR humanistic_JJ with_IW continuous_JJ questioning_NN1 of_IO philosophies_NN2 and_CC methodologies_NN2 ._. 
A_AT1 good_JJ example_NN1 of_IO the_AT latter_DA is_VBZ Heim_NP1 (_( 1970_MC )_) in_II which_DDQ intelligence_NN1 and_CC personality_NN1 testing_NN1 is_VBZ discussed_VVN in_II the_AT context_NN1 of_IO the_AT meaning_NN1 of_IO intelligence_NN1 ,_, creativity_NN1 ,_, personality_NN1 ,_, test_VV0 taking_VVG as_II a_AT1 skill_NN1 and_CC the_AT different_JJ but_CCB inseparable_JJ limitations_NN2 of_IO speed_NN1 and_CC accuracy_NN1 based_VVN measures_NN2 ._. 
For_IF further_JJR discussion_NN1 of_IO these_DD2 elusive_JJ topics_NN2 see_VV0 Super_JJ and_CC Bohn_NP1 (_( 1971_MC )_) ,_, Drenth_NP1 (_( 1978_MC )_) and_CC Jessup_NP1 and_CC Jessup_NP1 (_( 1975_MC )_) ._. 
The_AT aim_NN1 of_IO psychological_JJ measurement_NN1 is_VBZ optimal_JJ discrimination_NN1 between_II individuals_NN2 ,_, for_IF this_DD1 purpose_NN1 the_AT difficulty_NN1 of_IO the_AT test_NN1 should_VM match_VVI the_AT range_NN1 of_IO abilities_NN2 of_IO the_AT testees_NN2 ._. 
For_REX21 example_REX22 an_AT1 intelligence_NN1 test_NN1 may_VM be_VBI too_RG easy_JJ so_CS21 that_CS22 all_DB testees_NN2 have_VH0 almost_RR perfect_JJ scores_NN2 ,_, or_CC too_RG difficult_JJ in_II that_DD1 all_DB testees_NN2 have_VH0 very_RG low_JJ scores_NN2 ,_, in_II both_DB2 cases_NN2 discrimination_NN1 will_VM be_VBI poor_JJ ._. 
One_MC1 answer_NN1 to_II this_DD1 problem_NN1 is_VBZ tailored_JJ testing_NN1 in_II which_DDQ questions_NN2 are_VBR computer-based_JJ and_CC the_AT test_NN1 is_VBZ adaptive_JJ in_II focussing_VVG the_AT range_NN1 of_IO presented_JJ questions_NN2 at_II about_II the_AT level_NN1 of_IO success/failure_NN1 which_DDQ is_VBZ appropriate_JJ for_IF each_DD1 testee_NN1 ._. 
In_II this_DD1 way_NN1 discrimination_NN1 is_VBZ much_RR improved_VVN without_IW excessively_RR lengthening_VVG the_AT test_NN1 time_NNT1 (_( Killcross_NP1 and_CC Cassie_NP1 ,_, 1975_MC )_) ._. 
The_AT value_NN1 and_CC extent_NN1 of_IO the_AT use_NN1 of_IO tests_NN2 is_VBZ subject_II21 to_II22 other_JJ changes_NN2 in_II the_AT history_NN1 of_IO the_AT particular_JJ community_NN1 ._. 
Obviously_RR testing_VVG can_VM be_VBI extensively_RR utilised_VVN in_II war-time_NN1 when_CS many_DA2 people_NN are_VBR changing_JJ jobs_NN2 both_RR in_II military_JJ and_CC civilian_JJ life_NN1 ._. 
In_II peace-time_NN1 the_AT selection_NN1 ratio_NN1 ,_, the_AT ratio_NN1 of_IO applicants_NN2 to_II available_JJ jobs_NN2 is_VBZ a_AT1 key_JJ feature_NN1 ,_, there_EX tends_VVZ to_TO be_VBI more_DAR testing_NN1 in_II times_NNT2 of_IO economic_JJ depression_NN1 when_RRQ jobs_NN2 are_VBR scarce_JJ and_CC also_RR in_II post-war_JJ periods_NN2 when_RRQ there_EX is_VBZ extensive_JJ experience_NN1 of_IO using_VVG tests_NN2 ._. 
The_AT use_NN1 of_IO tests_NN2 is_VBZ not_XX ,_, of_RR21 course_RR22 ,_, confined_VVN to_II selection_NN1 procedures_NN2 ._. 
Indeed_RR there_EX is_VBZ currently_RR much_RR greater_JJR utilisation_NN1 in_II guidance_NN1 and_CC therapy_NN1 ._. 
Surveys_NN2 In_II31 common_II32 with_II33 tests_NN2 ,_, surveys_NN2 are_VBR required_VVN to_TO be_VBI as_RG reliable_JJ and_CC valid_JJ as_CSA is_VBZ feasible_JJ in_II the_AT circumstances_NN2 ._. 
Surveys_NN2 are_VBR however_RR different_JJ from_II tests_NN2 in_II their_APPGE objective_NN1 :_: a_AT1 test_NN1 is_VBZ usually_RR carried_VVN out_RP to_TO find_VVI out_RP about_II an_AT1 individual_JJ ,_, a_AT1 survey_NN1 is_VBZ carried_VVN out_RP to_TO find_VVI out_RP about_II an_AT1 issue_NN1 which_DDQ is_VBZ across_II people_NN ._. 
The_AT issue_NN1 itself_PPX1 must_VM be_VBI specified_VVN as_RG precisely_RR as_CSA possible_JJ usually_RR in_II31 terms_II32 of_II33 both_DB2 what_DDQ we_PPIS2 want_VV0 to_TO know_VVI and_CC why_RRQ we_PPIS2 want_VV0 to_TO know_VVI ._. 
'_" Why_RRQ '_" will_VM clarify_VVI '_" what_DDQ '_VBZ and_CC will_VM also_RR contribute_VVI to_II the_AT practical_JJ question_NN1 of_IO how_RGQ much_DA1 to_TO spend_VVI on_II finding_VVG out_RP ._. 
For_IF reasons_NN2 of_IO economy_NN1 the_AT population_NN1 of_IO individuals_NN2 approached_VVN is_VBZ usually_RR a_AT1 small_JJ sample_NN1 of_IO the_AT total_JJ relevant_JJ population_NN1 ._. 
The_AT size_NN1 of_IO the_AT sample_NN1 is_VBZ less_RGR important_JJ than_CSN its_APPGE structure_NN1 ._. 
The_AT first_MD rule_NN1 of_IO sampling_NN1 is_VBZ that_CST each_DD1 member_NN1 of_IO the_AT relevant_JJ population_NN1 must_VM have_VHI some_DD chance_NN1 of_IO being_VBG included_VVN ._. 
If_CS the_AT probability_NN1 of_IO being_VBG included_VVN is_VBZ equal_JJ for_IF each_DD1 member_NN1 of_IO the_AT relevant_JJ population_NN1 then_RT the_AT sample_NN1 is_VBZ said_VVN to_TO be_VBI a_AT1 random_JJ one_PN1 ._. 
Often_RR the_AT relevant_JJ population_NN1 is_VBZ stratified_VVN to_TO ensure_VVI that_CST the_AT sample_NN1 will_VM be_VBI more_RGR representative_JJ in_II certain_JJ respects._NNU for_REX21 example_REX22 a_AT1 survey_NN1 of_IO hospital_NN1 staff_NN would_VM not_XX usually_RR be_VBI carried_VVN out_RP by_II selecting_VVG names_NN2 at_RR21 random_RR22 from_II the_AT total_JJ staff_NN list_NN1 ,_, it_PPH1 might_VM concentrate_VVI on_II doctors_NN2 ,_, nurses_NN2 or_CC cleaners_NN2 only_RR ,_, or_CC might_VM sample_VVI medical_JJ ,_, paramedical_JJ ,_, administrative_JJ and_CC support_VV0 staff_NN in_II proportions_NN2 of_IO their_APPGE total_JJ numbers_NN2 depending_II21 on_II22 the_AT purpose_NN1 of_IO the_AT survey_NN1 ._. 
Sampling_NN1 might_VM also_RR be_VBI carried_VVN out_RP progressively_RR involving_VVG different_JJ stages_NN2 ._. 
For_REX21 example_REX22 a_AT1 survey_NN1 concerned_JJ with_IW the_AT whole_JJ National_JJ Health_NN1 Service_NN1 staff_NN might_VM begin_VVI by_II separating_VVG the_AT hospital_NN1 and_CC the_AT general_JJ practice_NN1 services_NN2 ,_, then_RT sample_VV0 key_JJ regions_NN2 of_IO the_AT country_NN1 ,_, separate_VV0 urban_JJ ,_, suburban_JJ and_CC rural_JJ services_NN2 and_CC then_RT select_VV0 within_II organisations_NN2 as_CSA mentioned_VVN above_RL ._. 
Sampling_NN1 might_VM also_RR involve_VVI time_NNT1 phasing_VVG as_CSA in_II attempting_VVG to_TO detect_VVI opinion_NN1 trends_NN2 leading_VVG up_II21 to_II22 a_AT1 general_JJ election_NN1 ._. 
It_PPH1 is_VBZ possible_JJ to_TO estimate_VVI sample_NN1 sizes_NN2 required_VVN if_CS the_AT tolerable_JJ error_NN1 is_VBZ known_VVN and_CC vice_RR21 versa_RR22 (_( Yates_NP1 1960_MC )_) ._. 
Data_NN may_VM be_VBI obtained_VVN purely_RR by_II observation_NN1 but_CCB usually_RR involve_VV0 asking_VVG questions_NN2 ._. 
The_AT design_NN1 of_IO questionnaires_NN2 is_VBZ itself_PPX1 an_AT1 art_NN1 with_IW certain_JJ ground_NN1 rules_NN2 ._. 
Clearly_RR the_AT questions_NN2 must_VM be_VBI such_CS21 that_CS22 the_AT relevant_JJ population_NN1 can_VM be_VBI expected_VVN to_TO understand_VVI them_PPHO2 and_CC to_TO make_VVI informed_JJ responses_NN2 ._. 
The_AT questions_NN2 must_VM avoid_VVI ambiguities_NN2 which_DDQ is_VBZ not_XX as_RG easy_JJ as_CSA it_PPH1 might_VM seem_VVI ,_, it_PPH1 is_VBZ desirable_JJ to_TO obtain_VVI several_DA2 opinions_NN2 about_II the_AT interpretation_NN1 of_IO each_DD1 question_NN1 from_II the_AT same_DA kind_NN1 of_IO people_NN as_CSA those_DD2 who_PNQS will_VM be_VBI in_II the_AT survey_NN1 ._. 
The_AT sequence_NN1 of_IO questions_NN2 may_VM bias_VVI the_AT answers_NN2 e.g._REX a_AT1 likely_JJ alternation_NN1 of_IO Yes/No_UH answers_NN2 is_VBZ more_RGR '_GE natural_JJ '_" than_CSN a_AT1 uniform_JJ series_NN of_IO Yes_UH or_CC No_AT answers_NN2 ._. 
The_AT style_NN1 of_IO the_AT question_NN1 can_VM also_RR be_VBI unintentionally_RR '_GE loaded_JJ '_GE towards_II a_AT1 particular_JJ response_NN1 ._. 
There_EX is_VBZ a_AT1 temptation_NN1 to_TO put_VVI in_II questions_NN2 which_DDQ will_VM check_VVI against_II each_PPX221 other_PPX222 but_CCB this_DD1 can_VM irritate_VVI the_AT responder_NN1 who_PNQS will_VM easily_RR detect_VVI redundancy_NN1 ._. 
There_EX is_VBZ also_RR the_AT temptation_NN1 to_TO make_VVI the_AT questionnaire_NN1 too_RG long_RR in_II the_AT hope_NN1 of_IO getting_VVG just_RR that_DD1 little_JJ bit_NN1 more_DAR information_NN1 ,_, this_DD1 can_VM more_RRR than_CSN defeat_VV0 its_APPGE object_NN1 by_II reducing_VVG the_AT response_NN1 rate_NN1 ._. 
A_AT1 new_JJ questionnaire_NN1 should_VM always_RR be_VBI piloted_VVN ,_, that_DD1 is_VBZ tried_VVN out_RP on_II a_AT1 small_JJ sample_NN1 ,_, before_CS it_PPH1 is_VBZ finalised_VVN ._. 
The_AT main_JJ factor_NN1 influencing_VVG response_NN1 rate_NN1 is_VBZ whether_CSW the_AT survey_NN1 is_VBZ postal_JJ or_CC personal_JJ ._. 
The_AT response_NN1 rate_NN1 to_II a_AT1 verbal_JJ questionnaire_NN1 can_VM easily_RR be_VBI 90%_NNU or_CC more_DAR but_CCB a_AT1 mailed_JJ questionnaire_NN1 can_VM have_VHI a_AT1 response_NN1 rate_NN1 as_RG low_JJ as_CSA 30%_NNU even_RR with_IW follow-up_JJ reminders_NN2 ._. 
A_AT1 low_JJ response_NN1 rate_NN1 is_VBZ serious_JJ particularly_RR if_CS there_EX is_VBZ reason_NN1 to_TO suspect_VVI that_CST persons_NN2 likely_JJ to_TO give_VVI particular_JJ kinds_NN2 of_IO answers_NN2 might_VM be_VBI less_RRR or_CC more_RGR likely_JJ to_TO respond_VVI than_CSN others_NN2 ._. 
Telephone_NN1 based_VVN surveys_NN2 are_VBR currently_RR popular_JJ as_II a_AT1 reasonable_JJ compromise_NN1 ,_, this_DD1 increases_VVZ the_AT speed_NN1 of_IO data_NN collection_NN1 rather_II21 than_II22 the_AT insight_NN1 which_DDQ is_VBZ revealed_VVN by_II personal_JJ interviews_NN2 ._. 
Large_JJ scale_NN1 impersonal_JJ surveys_NN2 can_VM be_VBI supplemented_VVN by_II more_RGR personally_RR based_VVN interviews_NN2 either_RR with_IW individuals_NN2 or_CC groups_NN2 ._. 
The_AT inference_NN1 from_II samples_NN2 may_VM be_VBI deductive_JJ or_CC inductive_JJ ._. 
Deductions_NN2 can_VM be_VBI made_VVN by_II statistical_JJ comparisons_NN2 of_IO samples_NN2 to_TO determine_VVI whether_CSW they_PPHS2 are_VBR from_II different_JJ populations_NN2 ._. 
Inferences_NN2 from_II samples_NN2 to_II populations_NN2 can_VM be_VBI made_VVN within_II quantitative_JJ confidence_NN1 limits_NN2 ._. 
Much_DA1 of_IO the_AT labour_NN1 which_DDQ used_VMK to_TO be_VBI involved_JJ in_II manipulating_VVG and_CC presenting_VVG data_NN can_VM now_RT be_VBI delegated_VVN to_II specialised_JJ computer_NN1 software_NN1 but_CCB the_AT basic_JJ issues_NN2 of_IO coding_NN1 and_CC structuring_NN1 data_NN still_RR depend_VV0 on_II the_AT skills_NN2 of_IO the_AT analyst_NN1 ._. 
The_AT survey_NN1 is_VBZ the_AT most_RGT extensively_RR used_JJ method_NN1 of_IO obtaining_VVG generalisations_NN2 about_II people_NN ._. 
It_PPH1 can_VM vary_VVI in_II precision_NN1 from_II quantitative_JJ anthropometric_JJ surveys_NN2 to_II attempts_NN2 to_TO describe_VVI the_AT attributes_NN2 of_IO products_NN2 which_DDQ particular_JJ users_NN2 prefer_VV0 ._. 
The_AT systematic_JJ survey_NN1 is_VBZ the_AT antidote_NN1 to_II excessive_JJ reliance_NN1 on_II personal_JJ experience_NN1 which_DDQ is_VBZ usually_RR biased_VVN by_II exposure_NN1 to_II idiosyncratic_JJ samples_NN2 and_CC by_II selective_JJ perception_NN1 ._. 
The_AT required_JJ systematic_JJ process_NN1 is_VBZ summarised_VVN in_II Table_NN1 2.3_MC ._. 
Task_NN1 training_VVG The_AT distinction_NN1 between_II task_NN1 training_NN1 and_CC skill_NN1 training_NN1 is_VBZ one_MC1 of_IO degree_NN1 rather_II21 than_II22 kind_NN1 ._. 
In_II task_NN1 training_VVG the_AT objective_NN1 is_VBZ to_TO guide_VVI the_AT trainee_NN1 into_II following_VVG rules_NN2 and_CC essentially_RR to_TO make_VVI the_AT performance_NN1 more_RGR automatic_JJ ._. 
In_II skill_NN1 training_VVG the_AT opposite_NN1 can_VM apply_VVI ,_, the_AT trainee_NN1 is_VBZ persuaded_VVN to_TO be_VBI flexible_JJ and_CC to_TO orient_VVI himself_PPX1 towards_II the_AT end_NN1 rather_II21 than_II22 the_AT means_NN ._. 
The_AT difference_NN1 between_II the_AT two_MC kinds_NN2 of_IO training_NN1 is_VBZ not_XX as_RG great_JJ as_CSA would_VM appear_VVI at_II first_MD sight_NN1 because_CS it_PPH1 turns_VVZ out_RP that_DD1 task_NN1 training_NN1 has_VHZ in_II31 common_II32 with_II33 skill_NN1 training_VVG an_AT1 emphasis_NN1 on_II the_AT perceptual_JJ side_NN1 of_IO human_JJ functioning_NN1 ._. 
Even_RR in_II what_DDQ appear_VV0 to_TO be_VBI straightforward_JJ motor_NN1 skills_NN2 the_AT changes_NN2 in_II learning_NN1 are_VBR associated_VVN with_IW greater_JJR selectivity_NN1 and_CC more_RGR economical_JJ use_NN1 of_IO the_AT evidence_NN1 needed_VVD to_TO guide_VVI performance_NN1 ._. 
These_DD2 distinctions_NN2 are_VBR summarised_VVN in_II Table_NN1 2.4_MC ._. 
Task_NN1 training_NN1 is_VBZ often_RR called_VVN operator_NN1 training_NN1 or_CC industrial_JJ training_NN1 ._. 
The_AT essential_JJ principles_NN2 are_VBR :_: 1_MC1 ._. 
The_AT trainee_NN1 must_VM wish_VVI to_TO learn_VVI ,_, nothing_PN1 can_VM be_VBI achieved_VVN unless_CS the_AT trainee_NN1 is_VBZ adequately_RR motivated._NNU 2_MC ._. 
The_AT learning_NN1 must_VM be_VBI steered_VVN by_II adequate_JJ knowledge_NN1 of_IO performance_NN1 ._. 
The_AT behavioural_JJ characteristic_NN1 which_DDQ facilitates_VVZ both_RR of_IO these_DD2 requirements_NN2 is_VBZ knowledge_NN1 of_IO results_NN2 ._. 
This_DD1 is_VBZ the_AT most_RGT potent_JJ and_CC consistent_JJ performance_NN1 shaping_NN1 factor_NN1 ever_RR uncovered_VVD by_II psychologists_NN2 ._. 
It_PPH1 simultaneously_RR promotes_VVZ motivation_NN1 and_CC performance_NN1 ._. 
Knowledge_NN1 of_IO how_RGQ well_RR one_PN1 is_VBZ doing_VDG will_NN1 not_XX provide_VVI the_AT basic_JJ motivation_NN1 in_CS21 that_CS22 the_AT performer_NN1 must_VM care_VVI about_II his_APPGE performance_NN1 but_CCB if_CS this_DD1 is_VBZ established_VVN ,_, knowledge_NN1 of_IO performance_NN1 is_VBZ a_AT1 most_RGT vigorous_JJ factor_NN1 in_II developing_VVG and_CC maintaining_VVG the_AT will_NN1 to_TO perform_VVI ._. 
Carmichael_NP1 and_CC Dearborn_NP1 (_( 1950_MC )_) demonstrated_VVD that_CST continuous_JJ reading_NN1 was_VBDZ likely_JJ to_TO result_VVI in_II increased_JJ failure_NN1 of_IO concentration_NN1 within_II an_AT1 hour_NNT1 ,_, but_CCB if_CS the_AT performance_NN1 of_IO the_AT reader_NN1 was_VBDZ checked_VVN and_CC confirmed_VVN by_II asking_VVG questions_NN2 at_II half-hour_NNT1 intervals_NN2 then_RT performance_NN1 could_VM continue_VVI for_IF six_MC to_II eight_MC hours_NNT2 without_IW signs_NN2 of_IO fatigue_NN1 ._. 
Mackworth_NP1 (_( 1950_MC )_) ,_, within_II his_APPGE classical_JJ studies_NN2 of_IO vigilance_NN1 ,_, showed_VVD that_CST without_IW knowledge_NN1 of_IO results_NN2 the_AT proportion_NN1 of_IO detected_JJ signals_NN2 decreased_VVN in_II succeeding_JJ half-hours_NNT2 compared_VVN with_IW the_AT first_MD half-hour_NNT1 ,_, but_II21 for_II22 subjects_NN2 given_VVN knowledge_NN1 of_IO results_NN2 there_EX was_VBDZ no_AT deterioration_NN1 compared_VVN with_IW the_AT first_MD half-hour_NNT1 through_II the_AT full_JJ two_MC hours_NNT2 of_IO the_AT study_NN1 ._. 
Correspondingly_RR the_AT effectiveness_NN1 of_IO performance_NN1 will_VM improve_VVI with_IW knowledge_NN1 of_IO performance_NN1 ._. 
This_DD1 is_VBZ as_RG much_RR a_AT1 logical_JJ as_CSA a_AT1 psychological_JJ principle_NN1 ._. 
Clearly_RR if_CS a_AT1 person_NN1 has_VHZ no_AT knowledge_NN1 of_IO the_AT success_NN1 of_IO performance_NN1 the_AT performance_NN1 can_VM not_XX improve_VVI because_CS there_EX can_VM be_VBI no_AT guidelines_NN2 to_TO steer_VVI the_AT improvement_NN1 ._. 
There_EX have_VH0 been_VBN many_DA2 experiments_NN2 demonstrating_VVG the_AT validity_NN1 of_IO this_DD1 principle_NN1 and_CC exploring_VVG detailed_JJ variables_NN2 such_II21 as_II22 the_AT timing_NN1 and_CC quality_NN1 of_IO feedback_NN1 ._. 
For_IF details_NN2 see_VV0 Welford_NP1 (_( 1968_MC )_) ,_, Bilodeau_NP1 (_( 1969_MC )_) ,_, Annett_NP1 (_( 1969_MC )_) ._. 
Miller_NP1 et_RA21 al._RA22 (_( 1960_MC )_) formalise_VV0 it_PPH1 into_II what_DDQ they_PPHS2 call_VV0 the_AT TOTE_NN1 principle_NN1 (_( Test_VV0 Operate_VV0 Test_NN1 Exit_NN1 )_) ._. 
The_AT first_MD test_NN1 is_VBZ a_AT1 review_NN1 of_IO the_AT situation_NN1 ,_, operate_VV0 is_VBZ the_AT action_NN1 which_DDQ follows_VVZ ,_, the_AT second_MD test_NN1 is_VBZ a_AT1 check_NN1 as_II21 to_II22 whether_CSW31 or_CSW32 not_CSW33 the_AT desired_JJ result_NN1 has_VHZ been_VBN achieved_VVN and_CC this_DD1 is_VBZ followed_VVN either_RR by_II another_DD1 operation_NN1 or_CC by_II an_AT1 exit_NN1 if_CS the_AT desired_JJ result_NN1 has_VHZ been_VBN achieved_VVN ._. 
The_AT TOTE_NN1 is_VBZ regarded_VVN as_II a_AT1 fundamental_JJ unit_NN1 of_IO behaviour_NN1 ._. 
Broadly_RR speaking_VVG the_AT more_RGR immediate_JJ the_AT feedback_NN1 the_AT more_RGR effective_JJ it_PPH1 is_VBZ except_CS21 that_CS22 there_EX comes_VVZ a_AT1 point_NN1 at_II which_DDQ ,_, to_TO use_VVI Miller_NP1 's_GE (_( 1953_MC )_) distinction_NN1 ,_, learning_VVG feedback_NN1 becomes_VVZ action_NN1 feedback_NN1 ,_, the_AT latter_DA improves_VVZ the_AT current_JJ response_NN1 whereas_CS the_AT former_DA improves_VVZ succeeding_JJ responses_NN2 ._. 
There_EX is_VBZ a_AT1 risk_NN1 that_CST what_DDQ is_VBZ intended_VVN to_TO be_VBI an_AT1 aid_NN1 only_RR during_II training_NN1 can_VM become_VVI an_AT1 undesirable_JJ crutch_NN1 in_II that_DD1 performance_NN1 comes_VVZ to_TO depend_VVI on_II it_PPH1 but_CCB this_DD1 is_VBZ rare_JJ and_CC can_VM be_VBI avoided_VVN by_II using_VVG a_AT1 suitable_JJ time_NNT1 delay_NN1 ,_, thus_RR ensuring_VVG that_CST it_PPH1 is_VBZ really_RR learning_VVG and_CC not_XX action_NN1 feedback_NN1 ._. 
The_AT accuracy_NN1 of_IO the_AT feedback_NN1 need_VM not_XX be_VBI greater_JJR than_CSN the_AT discrimination_NN1 ability_NN1 of_IO the_AT trainee_NN1 but_CCB equally_RR its_APPGE value_NN1 will_VM diminish_VVI if_CSW it_PPH1 is_VBZ too_RG approximate_JJ ._. 
Feedback_NN1 of_IO the_AT discrepancy_NN1 between_II desirable_JJ and_CC achieved_VVN performance_NN1 is_VBZ superior_JJ to_II feedback_NN1 of_IO absolute_JJ performance_NN1 ._. 
Holding_NP1 (_( 1965_MC )_) distinguished_VVD between_II successive_JJ sub-classifications_NN2 of_IO feedback_NN1 into_II intrinsic/artificial_JJ ,_, concurrent/terminal_JJ ,_, immediate/delayed_JJ ,_, non-verbal/verbal_JJ ,_, separate/accumulated_JJ ._. 
The_AT superior_JJ value_NN1 of_IO direct_JJ ,_, rapid_JJ ,_, unambiguous_JJ feedback_NN1 dominates_VVZ the_AT choice_NN1 of_IO length_NN1 and_CC content_NN1 of_IO learning_VVG periods_NN2 ._. 
There_EX was_VBDZ an_AT1 extended_JJ controversy_NN1 between_II supporters_NN2 of_IO part_NN1 and_CC whole_JJ learning_NN1 (_( Blum_NP1 and_CC Naylor_NP1 1968_MC )_) ._. 
The_AT advantage_NN1 of_IO whole_JJ learning_NN1 is_VBZ that_CST the_AT connections_NN2 between_II the_AT parts_NN2 are_VBR also_RR learned_VVN simultaneously_RR ._. 
However_RRQV the_AT advantage_NN1 of_IO part_NN1 learning_NN1 is_VBZ that_CST the_AT feedback_NN1 can_VM be_VBI of_IO much_DA1 higher_JJR quality_NN1 ._. 
An_AT1 excellent_JJ compromise_NN1 is_VBZ the_AT progressive-part_JJ method_NN1 (_( Seymour_NP1 ,_, 1966_MC )_) in_II which_DDQ parts_NN2 are_VBR learned_VVN separately_RR but_CCB combined_VVD in_II groups_NN2 within_II a_AT1 tree-like_JJ structure_NN1 which_DDQ converges_VVZ on_II the_AT total_JJ task_NN1 ._. 
See_VV0 ,_, for_REX21 example_REX22 ,_, Singleton_NP1 (_( 1959_MC )_) ,_, King_NP1 (_( 1964_MC )_) ._. 
The_AT identification_NN1 of_IO the_AT sub-tasks_NN2 which_DDQ are_VBR appropriate_JJ for_IF intensive_JJ training_NN1 with_IW feedback_NN1 is_VBZ achieved_VVN by_II task_NN1 analysis_NN1 ._. 
Unfortunately_RR there_EX is_VBZ confusion_NN1 in_II the_AT literature_NN1 and_CC the_AT required_JJ procedures_NN2 may_VM be_VBI referred_VVN to_II as_RG either_RR skills_NN2 analysis_NN1 or_CC task_NN1 analysis_NN1 (_( Seymour_NP1 1968_MC ,_, Singer_NP1 and_CC Ramsden_NP1 1969_MC ,_, Miller_NP1 1962_MC )_) ._. 
In_II the_AT terminology_NN1 used_VVN in_II this_DD1 book_NN1 task_NN1 analysis_NN1 is_VBZ the_AT correct_JJ description_NN1 of_IO this_DD1 activity_NN1 ._. 
It_PPH1 will_VM be_VBI evident_JJ from_II the_AT dates_NN2 of_IO most_DAT of_IO these_DD2 references_NN2 that_CST this_DD1 kind_NN1 of_IO training_NN1 and_CC the_AT supporting_JJ research_NN1 flourished_VVD in_II the_AT 1960s_MC2 ._. 
The_AT need_NN1 for_IF it_PPH1 has_VHZ reduced_VVN but_CCB has_VHZ not_XX vanished_VVN over_II the_AT past_JJ twenty_MC years_NNT2 ._. 
Technology_NN1 has_VHZ shifted_VVN the_AT general_JJ allocation_NN1 of_IO function_NN1 slightly_RR both_RR in_II industry_NN1 and_CC in_II defence_NN1 ._. 
Many_DA2 processes_NN2 have_VH0 changed_VVN so_CS21 that_CS22 there_EX is_VBZ less_RGR direct_JJ human_JJ involvement_NN1 in_II the_AT production_NN1 cycle_NN1 ,_, e.g._REX metal_NN1 working_VVG ,_, highly_RR repetitive_JJ cycles_NN2 can_VM be_VBI conducted_VVN by_II robots_NN2 and_CC similar_JJ devices_NN2 ,_, e.g._REX in_II car_NN1 assemblies_NN2 ,_, and_CC the_AT human_JJ operator_NN1 gets_VVZ better_JJR support_NN1 even_CS21 when_CS22 still_RR involved_VVN directly_RR ,_, e.g._REX the_AT word_NN1 processor_NN1 as_II a_AT1 substitute_NN1 for_IF the_AT typewriter_NN1 ._. 
Nevertheless_RR within_II most_DAT jobs_NN2 there_EX are_VBR at_RR21 least_RR22 some_DD tasks_NN2 which_DDQ are_VBR amenable_JJ to_II this_DD1 kind_NN1 of_IO training_NN1 and_CC the_AT benefits_NN2 are_VBR considerable_JJ ._. 
If_CS task_NN1 training_NN1 is_VBZ neglected_VVN the_AT larger_JJR job_NN1 may_VM be_VBI interfered_VVN with_IW ,_, e.g._REX the_AT manager_NN1 attempting_VVG to_TO use_VVI a_AT1 personal_JJ computer_NN1 with_IW inadequate_JJ key-board_NN1 and_CC data_NN search_NN1 performance_NN1 ._. 
Key-board_NN1 manipulation_NN1 is_VBZ a_AT1 skill_NN1 relevant_JJ to_II many_DA2 tasks_NN2 and_CC is_VBZ typical_JJ of_IO psycho-motor_NN1 skills_NN2 in_CS21 that_CS22 the_AT perceptual_JJ elements_NN2 of_IO identify_VV0 and_CC select_VV0 dominate_VV0 the_AT motor_NN1 element_NN1 of_IO actual_JJ key_NN1 pressing_VVG ._. 
As_CSA mentioned_VVN earlier_JJR improvements_NN2 in_II speed_NN1 and_CC accuracy_NN1 result_NN1 from_II changes_NN2 in_II the_AT control_NN1 of_IO performance_NN1 ._. 
Skill_NN1 training_VVG The_AT simplest_JJT criterion_NN1 for_IF the_AT distinction_NN1 between_II a_AT1 skill_NN1 and_CC a_AT1 task_NN1 is_VBZ that_CST a_AT1 skill_NN1 description_NN1 is_VBZ susceptible_JJ to_II individual_JJ differences_NN2 but_CCB a_AT1 task_NN1 description_NN1 is_VBZ not_XX ._. 
Skill_NN1 implies_VVZ idiosyncratic_JJ performance_NN1 and_CC as_CSA such_DA can_VM transfer_VVI between_II many_DA2 tasks_NN2 whereas_CS a_AT1 task_NN1 meets_VVZ a_AT1 particular_JJ requirement_NN1 within_II a_AT1 system_NN1 activity_NN1 ._. 
Thus_RR it_PPH1 follows_VVZ that_DD1 skill_NN1 training_NN1 is_VBZ more_RGR generalised_JJ and_CC generalisable_JJ and_CC is_VBZ better_RRR fitted_VVN to_II the_AT overall_JJ role_NN1 of_IO human_JJ operators_NN2 ._. 
Education_NN1 is_VBZ the_AT ultimate_JJ form_NN1 of_IO skill_NN1 training_NN1 where_CS no_AT attempt_NN1 is_VBZ made_VVN to_TO specify_VVI the_AT particular_JJ purposes_NN2 for_IF which_DDQ the_AT skills_NN2 might_VM be_VBI utilised_VVN ._. 
This_DD1 limits_VVZ the_AT potential_JJ rigour_NN1 of_IO design_NN1 because_CS the_AT anchor_NN1 of_IO skill_NN1 training_NN1 is_VBZ the_AT specification_NN1 of_IO the_AT objectives_NN2 ._. 
Incidentally_RR this_DD1 accounts_VVZ for_IF the_AT interminable_JJ debate_NN1 about_II education_NN1 ,_, since_CS objectives_NN2 are_VBR not_XX specifiable_JJ the_AT content_NN1 can_VM only_RR emerge_VVI as_II a_AT1 consensus_NN1 within_II the_AT current_JJ zeitgeist_NN1 ._. 
Skill_NN1 descriptions_NN2 are_VBR generalisable_JJ in_II that_DD1 human_JJ operators_NN2 have_VH0 characteristic_JJ abilities_NN2 and_CC limitations_NN2 and_CC therefore_RR have_VH0 tendencies_NN2 to_TO perform_VVI in_II the_AT same_DA way_NN1 ._. 
Differences_NN2 in_II level_NN1 of_IO skill_NN1 are_VBR partly_RR but_CCB not_XX wholly_RR attributable_JJ to_II different_JJ locations_NN2 on_II a_AT1 learning_NN1 curve_NN1 which_DDQ has_VHZ some_DD uniformity_NN1 for_IF that_DD1 particular_JJ skill_NN1 ._. 
Skills_NN2 can_VM not_XX be_VBI transferred_VVN directly_RR from_II a_AT1 trainer_NN1 to_II a_AT1 trainee_NN1 ,_, the_AT function_NN1 of_IO the_AT trainer_NN1 is_VBZ to_TO provide_VVI conditions_NN2 and_CC guidelines_NN2 which_DDQ will_VM facilitate_VVI learning_NN1 ._. 
To_TO do_VDI this_DD1 the_AT trainer_NN1 must_VM have_VHI a_AT1 coherent_JJ model_NN1 of_IO the_AT form_NN1 of_IO the_AT skill_NN1 ,_, this_DD1 is_VBZ attained_VVN by_II skills_NN2 analysis_NN1 ._. 
Inevitably_RR skills_NN2 analysis_NN1 is_VBZ more_RGR general_JJ and_CC less_RGR definitive_JJ than_CSN task_NN1 analysis_NN1 although_CS many_DA2 of_IO the_AT same_DA procedures_NN2 for_IF extracting_VVG evidence_NN1 might_VM be_VBI used_VVN ._. 
Skills_NN2 analysis_NN1 may_VM also_RR involve_VVI experiments_NN2 to_TO study_VVI more_RGR closely_RR how_RRQ the_AT required_JJ objective_NN1 is_VBZ achieved_VVN (_( Drury_NP1 and_CC Fox_NP1 ,_, 1975_MC ,_, Singleton_NP1 ,_, 1978_MC )_) ._. 
It_PPH1 requires_VVZ a_AT1 broader_JJR approach_NN1 than_CSN task_NN1 analysis_NN1 in_II that_DD1 it_PPH1 often_RR involves_VVZ tracing_VVG the_AT acquisition_NN1 of_IO the_AT skill_NN1 starting_VVG from_II the_AT kind_NN1 of_IO persons_NN2 who_PNQS undertake_VV0 training_NN1 (_( the_AT selection_NN1 criteria_NN2 )_) through_II the_AT training_NN1 procedures_NN2 to_II the_AT end_NN1 product_NN1 (_( the_AT training_NN1 success_NN1 criteria_NN2 )_) ._. 
Such_DA training_NN1 often_RR has_VHZ an_AT1 emphasis_NN1 on_II features_NN2 such_II21 as_II22 style_NN1 and_CC quality_NN1 rather_II21 than_II22 mere_JJ speed_NN1 of_IO activity_NN1 ._. 
This_DD1 can_VM extend_VVI beyond_II skill_NN1 training_NN1 to_II attitude_NN1 training_NN1 (_( see_VV0 below_RL )_) ._. 
These_DD2 differences_NN2 are_VBR summarised_VVN in_II Table_NN1 2.5_MC ._. 
There_EX is_VBZ emphasis_NN1 on_II the_AT end_NN1 purpose_NN1 or_CC objective_NN1 with_IW relatively_RR less_DAR attention_NN1 to_II the_AT means_NN ,_, partly_RR so_BCL21 as_BCL22 to_TO allow_VVI for_IF individual_JJ differences_NN2 and_CC partly_RR because_CS the_AT evidence_NN1 accumulating_VVG in_II particular_JJ cases_NN2 may_VM change_VVI the_AT direction_NN1 of_IO progress_NN1 ._. 
For_IF this_DD1 reason_NN1 skill_NN1 training_NN1 is_VBZ sometimes_RT called_VVN strategic_JJ training_NN1 ._. 
Such_DA activities_NN2 are_VBR found_VVN in_II the_AT broad_JJ range_NN1 of_IO tasks_NN2 concerned_JJ with_IW diagnosis_NN1 ._. 
These_DD2 can_VM vary_VVI from_II dealing_VVG with_IW faults_NN2 in_II equipment_NN1 (_( Tilley_NP1 ,_, 1967_MC )_) to_II dealing_VVG with_IW patients_NN2 in_II a_AT1 surgery_NN1 or_CC clinic_NN1 (_( Rutter_NP1 ,_, 1979_MC )_) ._. 
In_II all_DB cases_NN2 although_CS the_AT reason_NN1 for_IF the_AT activity_NN1 is_VBZ clear_RR cut_VVN the_AT means_NN of_IO achieving_VVG the_AT desired_JJ end_NN1 vary_VV0 widely_RR in_II31 terms_II32 of_II33 the_AT path_NN1 taken_VVN and_CC the_AT time_NNT1 required_VVN ._. 
The_AT medical_JJ interview_NN1 has_VHZ much_RR in_II31 common_II32 with_II33 counselling_NN1 (_( Joanning_NP1 et_RA21 al._RA22 ,_, 1979_MC )_) and_CC occupational_JJ guidance_NN1 (_( Davis_NP1 and_CC Shackleton_NP1 ,_, 1975_MC )_) ._. 
Medical_JJ diagnosis_NN1 involves_VVZ social_JJ skills_NN2 (_( Melhuish_NN1 ,_, 1979_MC )_) but_CCB as_CSA discussed_VVN earlier_RRR the_AT basis_NN1 and_CC development_NN1 of_IO these_DD2 skills_NN2 is_VBZ not_XX dissimilar_JJ from_II other_JJ cognitive_JJ skills_NN2 and_CC correspondingly_RR the_AT training_NN1 can_VM follow_VVI the_AT same_DA principles_NN2 (_( Singleton_NP1 et_RA21 al._RA22 ,_, 1980_MC ;_; Argyle_NP1 ,_, 1981_MC )_) ._. 
Attitude_NN1 training_NN1 Attitudes_NN2 are_VBR much_RR more_RGR difficult_JJ to_TO change_VVI than_CSN are_VBR skills_NN2 and_CC there_EX can_VM be_VBI ambiguity_NN1 about_II what_DDQ constitutes_VVZ an_AT1 improvement_NN1 ._. 
Attitudes_NN2 involve_VV0 values_NN2 which_DDQ vary_VV0 between_II individuals_NN2 ,_, societies_NN2 and_CC cultures_NN2 ._. 
For_REX21 example_REX22 '_GE brain_NN1 washing_NN1 '_GE is_VBZ a_AT1 form_NN1 of_IO attitude_NN1 training_NN1 which_DDQ attempts_VVZ to_TO change_VVI the_AT beliefs_NN2 and_CC values_NN2 acquired_VVN within_II a_AT1 particular_JJ culture_NN1 (_( Biderman_NP1 ,_, 1967_MC )_) ._. 
The_AT extreme_JJ techniques_NN2 of_IO isolation_NN1 ,_, starvation_NN1 and_CC other_JJ forms_NN2 of_IO stress_NN1 induction_NN1 give_VV0 some_DD indication_NN1 of_IO the_AT pressures_NN2 required_VVN to_TO positively_RR change_VVI attitudes_NN2 ._. 
Generation_NN1 of_IO standard_JJ useful_JJ attitudes_NN2 has_VHZ always_RR been_VBN one_MC1 of_IO the_AT main_JJ purposes_NN2 of_IO military_JJ training_NN1 ._. 
The_AT objective_NN1 is_VBZ to_TO cultivate_VVI the_AT willingness_NN1 to_TO accept_VVI or_CC ignore_VVI personal_JJ risk_NN1 (_( Page_NN1 ,_, 1987_MC )_) ._. 
In_II the_AT civilian_JJ context_NN1 the_AT purposes_NN2 of_IO attitude_NN1 training_NN1 are_VBR to_TO do_VDI with_IW care_NN1 about_II quality_NN1 and_CC safety_NN1 ._. 
Apprenticeship_NN1 training_NN1 is_VBZ essentially_RR about_II ensuring_VVG standards_NN2 of_IO workmanship_NN1 and_CC characteristically_RR it_PPH1 appears_VVZ at_II first_MD sight_NN1 to_TO take_VVI an_AT1 unconscionably_RR long_JJ time_NNT1 ._. 
A_AT1 common_JJ fallacy_NN1 is_VBZ the_AT attempt_NN1 to_TO assess_VVI apprenticeship_NN1 schemes_NN2 in_II31 terms_II32 of_II33 task_NN1 and_CC skill_NN1 training_NN1 ._. 
Safety_NN1 training_NN1 is_VBZ also_RR about_II attitudes_NN2 and_CC such_DA schemes_NN2 rarely_RR have_VH0 the_AT hoped_VVN for_IF success_NN1 because_CS the_AT difficulty_NN1 and_CC time_NNT1 required_VVN are_VBR invariably_RR underestimated_VVN ._. 
This_DD1 is_VBZ also_RR the_AT reason_NN1 why_RRQ road_NN1 accidents_NN2 are_VBR so_RG difficult_JJ to_TO approach_VVI by_II training_NN1 ,_, safety_NN1 on_II the_AT road_NN1 is_VBZ much_DA1 more_DAR to_TO do_VDI with_IW attitudes_NN2 than_CSN with_IW driving_JJ skill_NN1 (_( Parry_NP1 ,_, 1968_MC )_) ._. 
In_II summary_NN1 ,_, we_PPIS2 have_VH0 no_AT useful_JJ theory_NN1 about_II the_AT design_NN1 of_IO attitude_NN1 training_NN1 and_CC success_NN1 in_II practice_NN1 is_VBZ based_VVN on_II indirect_JJ traditional_JJ procedures_NN2 ._. 
Skills_NN2 analysis_NN1 It_PPH1 will_VM be_VBI appreciated_VVN from_II the_AT earlier_JJR sections_NN2 of_IO this_DD1 chapter_NN1 that_CST skills_NN2 analysis_NN1 is_VBZ not_XX reducible_JJ to_II simple_JJ procedures_NN2 or_CC recipes_NN2 ._. 
In_II principle_NN1 it_PPH1 is_VBZ impossible_JJ because_CS skills_NN2 are_VBR by_II their_APPGE nature_NN1 totally_RR integrated_VVN and_CC interactive_JJ so_CS21 that_CS22 they_PPHS2 can_VM not_XX meaningfully_RR be_VBI separated_VVN into_II independent_JJ parts_NN2 ._. 
Nevertheless_RR ,_, as_CSA in_II many_DA2 other_JJ situations_NN2 the_AT analyst_NN1 ,_, himself_PPX1 a_AT1 skilled_JJ performer_NN1 ,_, has_VHZ some_DD success_NN1 in_II practice_NN1 ._. 
A_AT1 skill_NN1 description_NN1 relates_VVZ to_II how_RRQ a_AT1 task_NN1 is_VBZ performed_VVN and_CC what_DDQ is_VBZ achieved_VVN rather_II21 than_II22 what_DDQ actions_NN2 are_VBR taken_VVN ._. 
The_AT reference_NN1 is_VBZ to_II the_AT end_NN1 and_CC the_AT means_NN is_VBZ described_VVN in_II person_NN1 terms_NN2 rather_II21 than_II22 task_NN1 terms_NN2 ._. 
This_DD1 is_VBZ because_CS the_AT end_NN1 is_VBZ more_RGR consistent_JJ than_CSN the_AT means_NN ._. 
Although_CS there_EX may_VM be_VBI considerable_JJ idiosyncrasy_NN1 in_II the_AT actions_NN2 the_AT situation_NN1 is_VBZ not_XX anarchical_JJ ._. 
The_AT human_JJ operator_NN1 has_VHZ characteristic_JJ ways_NN2 of_IO doing_VDG things_NN2 and_CC detection_NN1 of_IO these_DD2 is_VBZ one_MC1 aspect_NN1 of_IO the_AT skill_NN1 of_IO the_AT skills_NN2 analyst_NN1 ._. 
There_EX are_VBR differences_NN2 in_II skills_NN2 analysis_NN1 procedure_NN1 depending_II21 on_II22 the_AT kind_NN1 of_IO skill_NN1 ._. 
For_IF the_AT skills_NN2 of_IO interacting_VVG with_IW the_AT physical_JJ world_NN1 the_AT procedure_NN1 summarised_VVN in_II Table_NN1 2.6_MC is_VBZ appropriate_JJ ._. 
This_DD1 involves_VVZ observation_NN1 of_IO the_AT skill_NN1 in_II practice_NN1 and_CC during_II training_NN1 and_CC discussion_NN1 with_IW practitioners_NN2 and_CC trainers_NN2 ._. 
There_EX are_VBR useful_JJ ways_NN2 of_IO focusing_VVG such_DA observation_NN1 by_II contrasting_VVG good/poor_JJ performers_NN2 and_CC performers_NN2 ._. 
Discussion_NN1 with_IW practitioners_NN2 can_VM be_VBI focused_VVN by_II asking_VVG them_PPHO2 to_TO talk_VVI while_CS performing_VVG and_CC by_II jointly_RR discussing_VVG performances_NN2 observed_VVN on_II film_NN1 or_CC tape_NN1 ._. 
For_IF management_NN1 skills_NN2 there_EX is_VBZ greater_JJR emphasis_NN1 on_II the_AT objectives_NN2 and_CC how_RRQ they_PPHS2 are_VBR arrived_VVN at_II ._. 
Objectives_NN2 in_II an_AT1 organisational_JJ context_NN1 are_VBR subject_II21 to_II22 many_DA2 constraints_NN2 ._. 
Some_DD such_II21 as_II22 financial_JJ resources_NN2 are_VBR easily_RR specifiable_JJ ,_, others_NN2 such_II21 as_II22 not_XX contravening_VVG the_AT mores_NN2 of_IO the_AT organisation_NN1 are_VBR more_RGR elusive_JJ but_CCB a_AT1 key_JJ aspect_NN1 of_IO these_DD2 skills_NN2 is_VBZ sensitivity_NN1 to_II limitations_NN2 and_CC obstacles_NN2 as_II31 well_II32 as_II33 positive_JJ assets_NN2 (_( Singleton_NP1 ,_, 1981_MC )_) ._. 
The_AT variety_NN1 of_IO management_NN1 tasks_NN2 is_VBZ often_RR so_RG great_JJ as_CSA to_TO warrant_VVI a_AT1 task_NN1 analysis_NN1 with_IW separate_JJ skills_NN2 analyses_NN2 of_IO particular_JJ tasks_NN2 or_CC groups_NN2 of_IO tasks_NN2 ._. 
At_II this_DD1 level_NN1 the_AT practitioner_NN1 is_VBZ often_RR the_AT conscious_JJ monitor_NN1 of_IO the_AT practice_NN1 and_CC facility_NN1 in_II self-monitoring_NN1 is_VBZ a_AT1 useful_JJ indicator_NN1 of_IO skill_NN1 ._. 
Social_JJ skills_NN2 can_VM involve_VVI not_XX only_RR self-monitoring_JJ but_CCB also_RR monitoring_VVG of_IO what_DDQ another_DD1 person_NN1 is_VBZ thinking_VVG as_II31 well_II32 as_II33 doing_VDG ._. 
For_REX21 example_REX22 ,_, analysing_VVG a_AT1 transaction_NN1 between_II two_MC skilled_JJ negotiators_NN2 requires_VVZ the_AT study_NN1 of_IO the_AT overt_JJ interaction_NN1 and_CC the_AT identification_NN1 of_IO what_DDQ each_DD1 one_PN1 is_VBZ thinking_VVG about_II what_DDQ he_PPHS1 himself_PPX1 is_VBZ doing_VDG and_CC what_DDQ his_APPGE opponent_NN1 is_VBZ probably_RR thinking_VVG about_II in_II the_AT context_NN1 of_IO what_DDQ he_PPHS1 is_VBZ saying_VVG (_( Singleton_NP1 ,_, 1983a_FO )_) ._. 
There_EX are_VBR no_AT standard_JJ formats_NN2 for_IF skill_NN1 descriptions_NN2 but_CCB usually_RR they_PPHS2 can_VM be_VBI separated_VVN into_II two_MC parts_NN2 :_: the_AT performance_NN1 and_CC the_AT antecedents_NN2 to_II the_AT performance_NN1 ._. 
That_DD1 is_VBZ respectively_RR the_AT key_JJ aspects_NN2 of_IO behaviour_NN1 which_DDQ contribute_VV0 to_II success_NN1 and_CC the_AT kind_NN1 of_IO education_NN1 ,_, training_NN1 and_CC experience_VV0 normally_RR required_VVN ._. 
At_II high_JJ levels_NN2 of_IO idiosyncratic_JJ skill_NN1 (_( flair_NN1 see_VV0 p._NNU 245_MC )_) analysis_NN1 is_VBZ particularly_RR difficult_JJ because_CS the_AT practitioner_NN1 may_VM have_VHI little_DA1 conscious_JJ awareness_NN1 of_IO how_RRQ or_CC why_RRQ he_PPHS1 achieves_VVZ unusual_JJ success_NN1 ._. 
In_II fact_NN1 it_PPH1 almost_RR seems_VVZ to_TO be_VBI a_AT1 condition_NN1 of_IO such_DA performance_NN1 that_CST the_AT exponent_NN1 must_VM not_XX proceed_VVI logically_RR but_CCB must_VM temporarily_RR inhibit_VVI his_APPGE conscious_JJ critical_JJ faculties_NN2 and_CC accept_VVI control_NN1 by_II intuition_NN1 ._. 
This_DD1 has_VHZ been_VBN graphically_RR described_VVN as_II '_GE switching_NN1 on_RP the_AT autopilot_NN1 '_GE (_( Drasdo_NP1 ,_, 1979_MC )_) ._. 
The_AT commonsense_JJ view_NN1 that_CST to_TO proceed_VVI with_IW care_NN1 is_VBZ to_TO proceed_VVI slowly_RR can_VM also_RR be_VBI reversed_VVN in_II high_JJ level_JJ skills_NN2 ,_, there_EX are_VBR instances_NN2 where_RRQ speed_NN1 seems_VVZ to_TO be_VBI an_AT1 essential_JJ accompaniment_NN1 of_IO delicate_JJ discrimination_NN1 (_( Lacy_NP1 ,_, 1978_MC )_) ._. 
Thus_RR ,_, the_AT observer_NN1 can_VM not_XX simplify_VVI his_APPGE task_NN1 by_II asking_VVG the_AT practitioner_NN1 to_TO go_VVI more_RGR slowly_RR nor_CC can_VM he_PPHS1 rely_VVI on_II the_AT introspection_NN1 of_IO the_AT skilled_JJ performer_NN1 ._. 
Skill_NN1 is_VBZ demonstrated_VVN by_II persistent_JJ and_CC efficient_JJ pursuit_NN1 of_IO an_AT1 objective_NN1 and_CC the_AT skill_NN1 can_VM usually_RR be_VBI understood_VVN although_CS not_XX necessarily_RR written_VVN down_RP with_IW any_DD great_JJ precision_NN1 in_II31 terms_II32 of_II33 a_AT1 goal_NN1 and_CC the_AT path_NN1 towards_II that_DD1 goal_NN1 ._. 
The_AT path_NN1 is_VBZ generated_VVN by_II navigating_VVG through_II a_AT1 conceptual_JJ map_NN1 containing_VVG landmarks_NN2 and_CC decision_NN1 points_NN2 (_( key_JJ features_NN2 of_IO the_AT skill_NN1 )_) and_CC by_II the_AT avoidance_NN1 of_IO obstacles_NN2 and_CC misleading_JJ features_NN2 which_DDQ have_VH0 been_VBN sensitively_RR detected_VVN ._. 
Applications_NN2 Selection_NN1 and_CC guidance_NN1 These_DD2 processes_NN2 are_VBR variations_NN2 on_II the_AT general_JJ theme_NN1 of_IO matching_VVG a_AT1 worker_NN1 to_II an_AT1 appropriate_JJ job_NN1 ._. 
In_II the_AT case_NN1 of_IO selection_NN1 the_AT given_JJ point_NN1 is_VBZ the_AT job_NN1 and_CC the_AT population_NN1 is_VBZ searched_VVN to_TO find_VVI the_AT most_RGT appropriate_JJ worker_NN1 ,_, in_II the_AT case_NN1 of_IO guidance_NN1 one_MC1 worker_NN1 is_VBZ the_AT starting_NN1 point_NN1 and_CC the_AT range_NN1 of_IO jobs_NN2 is_VBZ searched_VVN to_TO identify_VVI the_AT best_JJT one_PN1 ._. 
The_AT two_MC complementary_JJ processes_NN2 are_VBR shown_VVN in_II Fig._NN1 2._MC 1_MC1 ._. 
They_PPHS2 can_VM usefully_RR be_VBI considered_VVN together_RL because_CS they_PPHS2 are_VBR similar_JJ and_CC interactive_JJ ._. 
Thus_RR ,_, in_II the_AT selection_NN1 situation_NN1 the_AT process_NN1 involves_VVZ not_XX only_RR analysing_VVG and_CC describing_VVG the_AT job_NN1 but_CCB also_RR considering_II the_AT availability_NN1 of_IO potentially_RR appropriate_JJ workers_NN2 ._. 
In_II the_AT guidance_NN1 situation_NN1 the_AT process_NN1 involves_VVZ analysing_VVG and_CC describing_VVG the_AT worker_NN1 and_CC consideration_NN1 of_IO the_AT availability_NN1 of_IO suitable_JJ jobs_NN2 ._. 
At_II the_AT point_NN1 of_IO a_AT1 successful_JJ match_NN1 the_AT worker_NN1 is_VBZ described_VVN in_II31 terms_II32 of_II33 the_AT kinds_NN2 of_IO job_NN1 he_PPHS1 could_VM do_VDI and_CC the_AT job_NN1 is_VBZ described_VVN in_II31 terms_II32 of_II33 the_AT kind_NN1 of_IO worker_NN1 needed_VVD to_TO do_VDI it_PPH1 ,_, Table_NN1 2.7_MC ._. 
For_IF most_DAT people_NN and_CC jobs_NN2 the_AT whole_JJ process_NN1 takes_VVZ place_NN1 within_II a_AT1 localised_JJ community_NN1 ._. 
For_IF the_AT highest_JJT level_JJ jobs_NN2 a_AT1 whole_JJ country_NN1 or_CC even_RR an_AT1 international_JJ community_NN1 might_VM be_VBI considered_VVN ,_, but_CCB in_II European_JJ countries_NN2 most_DAT workers_NN2 attempt_VV0 to_TO find_VVI jobs_NN2 which_DDQ do_VD0 not_XX require_VVI either_RR moving_VVG house_NN1 or_CC excessive_JJ travelling_NN1 ,_, and_CC such_DA proximity_NN1 has_VHZ corresponding_JJ advantages_NN2 for_IF the_AT potential_JJ employers_NN2 ._. 
Thus_RR ,_, the_AT selection_NN1 process_NN1 involves_VVZ describing_VVG the_AT job_NN1 first_MD by_II analysis_NN1 (_( task_NN1 and_CC skills_NN2 analysis_NN1 )_) and_CC then_RT the_AT translation_NN1 of_IO these_DD2 data_NN into_II worker_NN1 relevant_JJ terminology_NN1 ._. 
Consideration_NN1 of_IO the_AT potential_JJ worker_NN1 availability_NN1 may_VM lead_VVI to_II a_AT1 redesign_NN1 of_IO the_AT job_NN1 either_RR by_II the_AT use_NN1 of_IO a_AT1 different_JJ task_NN1 combination_NN1 or_CC by_II introducing_VVG different_JJ technology_NN1 ._. 
It_PPH1 is_VBZ then_RT necessary_JJ to_TO communicate_VVI with_IW the_AT market_NN1 by_II publicising_VVG the_AT available_JJ job_NN1 usually_RR by_II advertising_NN1 ._. 
This_DD1 is_VBZ itself_PPX1 an_AT1 important_JJ stage_NN1 in_II the_AT process_NN1 because_CS a_AT1 well_NN1 prepared_JJ advertisement_NN1 will_VM enable_VVI the_AT recipients_NN2 to_TO engage_VVI in_II self_NN1 selection_NN1 which_DDQ does_VDZ not_XX ,_, at_II this_DD1 stage_NN1 ,_, involve_VV0 further_JJR selector_NN1 resources_NN2 ._. 
To_II this_DD1 end_NN1 it_PPH1 is_VBZ useful_JJ to_TO have_VHI a_AT1 multi-stage_JJ process_NN1 as_CSA shown_VVN in_II Fig._NN1 2.2_MC ._. 
Having_VHG developed_VVN some_DD interest_NN1 on_II the_AT basis_NN1 of_IO a_AT1 necessarily_RR brief_JJ advertisement_NN1 a_AT1 potential_JJ candidate_NN1 can_VM apply_VVI for_IF further_RRR written_VVN details_NN2 which_DDQ should_VM contain_VVI a_AT1 comprehensive_JJ description_NN1 of_IO the_AT job_NN1 ,_, the_AT task_NN1 and_CC skill_NN1 content_NN1 ,_, the_AT responsibilities_NN2 ,_, the_AT salary_NN1 and_CC the_AT details_NN2 of_IO the_AT organisation_NN1 including_II its_APPGE history_NN1 and_CC anticipated_JJ future_NN1 ,_, and_CC an_AT1 application_NN1 form_NN1 ._. 
A_AT1 name_NN1 with_IW job_NN1 title_NN1 and_CC telephone_NN1 number_NN1 should_VM be_VBI included_VVN so_CS21 that_CS22 informal_JJ interaction_NN1 and_CC discussion_NN1 of_IO details_NN2 of_IO particular_JJ interest_NN1 to_II the_AT candidate_NN1 can_VM take_VVI place_NN1 before_II the_AT commitment_NN1 to_II transmission_NN1 of_IO the_AT application_NN1 form_NN1 ._. 
All_DB this_DD1 can_VM be_VBI done_VDN at_II minimal_JJ cost_NN1 ._. 
If_CS the_AT job_NN1 description_NN1 has_VHZ been_VBN properly_RR constructed_VVN there_RL should_VM not_XX be_VBI an_AT1 excessive_JJ number_NN1 of_IO applicants_NN2 so_CS21 that_CS22 the_AT next_MD stage_NN1 of_IO a_AT1 paper_NN1 sift_VV0 is_VBZ also_RR economical_JJ ._. 
There_RL then_RT follow_VV0 the_AT more_RGR expensive_JJ stages_NN2 of_IO final_JJ selection_NN1 which_DDQ may_VM involve_VVI testing_NN1 and_CC interviewing_VVG as_CSA described_VVN earlier_RRR ._. 
The_AT choice_NN1 of_IO the_AT interviewers_NN2 and_CC the_AT interview_NN1 process_NN1 depends_VVZ on_II the_AT particular_JJ job_NN1 ._. 
At_II one_MC1 extreme_JJ it_PPH1 may_VM be_VBI one_MC1 company_NN1 representative_NN1 ,_, at_II the_AT other_JJ extreme_NN1 there_EX may_VM be_VBI a_AT1 series_NN of_IO interview_NN1 boards_NN2 ._. 
The_AT interview_NN1 board_NN1 can_VM have_VHI covert_JJ purposes_NN2 where_RRQ the_AT senior_JJ person_NN1 who_PNQS is_VBZ the_AT chairman_NN1 of_IO the_AT board_NN1 will_VM use_VVI the_AT opportunity_NN1 to_TO orientate_VVI the_AT precise_JJ expectations_NN2 from_II the_AT post_NN1 to_TO be_VBI filled_VVN including_II settling_VVG differences_NN2 of_IO opinion_NN1 between_II his_APPGE subordinates_NN2 who_PNQS are_VBR also_RR members_NN2 of_IO the_AT board_NN1 ._. 
Ideally_RR this_DD1 should_VM be_VBI done_VDN before_II candidates_NN2 are_VBR interviewed_VVN but_CCB it_PPH1 can_VM happen_VVI that_CST differences_NN2 in_II preferences_NN2 for_IF candidates_NN2 reveal_VV0 different_JJ opinions_NN2 between_II board_NN1 members_NN2 which_DDQ the_AT chairman_NN1 can_VM detect_VVI and_CC deal_VVI with_IW ._. 
Guidance_NN1 also_RR involves_VVZ testing_NN1 and_CC interviewing_VVG but_CCB this_DD1 is_VBZ invariably_RR a_AT1 two_MC person_NN1 situation_NN1 of_IO a_AT1 counsellor_NN1 and_CC client_NN1 ._. 
The_AT problem_NN1 is_VBZ that_CST most_DAT clients_NN2 have_VH0 only_RR the_AT vaguest_JJT ,_, undefined_JJ ideas_NN2 about_II the_AT most_RGT suitable_JJ choice_NN1 and_CC direction_NN1 of_IO career_NN1 ._. 
The_AT counsellor_NN1 can_VM help_VVI by_II identifying_VVG the_AT client_NN1 's_GE jobrelevant_JJ characteristics_NN2 and_CC by_II contributing_VVG his_APPGE knowledge_NN1 about_II occupations_NN2 (_( Fig._NN1 2.3_MC ._. )_) ._. 
The_AT former_DA may_VM be_VBI supported_VVN by_II testing_VVG although_CS test_NN1 results_NN2 are_VBR essentially_RR evidence_NN1 to_TO enable_VVI the_AT individual_JJ to_TO clarify_VVI his_APPGE own_DA self_NN1 concept_NN1 ._. 
The_AT latter_DA may_VM start_VVI from_II national_JJ classifications_NN2 of_IO occupations_NN2 such_II21 as_II22 the_AT American_JJ Dictionary_NN1 of_IO Occupational_JJ Titles_NN2 (_( DOT_NN1 )_) and_CC the_AT British_JJ Classification_NN1 of_IO Occupations_NN2 and_CC Dictionary_NN1 of_IO Occupational_JJ Titles_NN2 (_( CODOT_NP1 )_) ,_, but_CCB the_AT counsellor_NN1 's_GE suggestions_NN2 are_VBR likely_JJ to_TO converge_VVI very_RG rapidly_RR into_II a_AT1 more_RGR comprehensible_JJ repertoire_NN1 of_IO possibilities_NN2 using_VVG evidence_NN1 about_II the_AT particular_JJ client_NN1 (_( Singleton_NP1 ,_, 1975_MC )_) ._. 
This_DD1 process_NN1 can_VM be_VBI supported_VVN by_II a_AT1 computer_NN1 with_IW which_DDQ the_AT client_NN1 may_VM interact_VVI alone_JJ or_CC it_PPH1 may_VM be_VBI used_VVN by_II the_AT counsellor_NN1 as_II a_AT1 database_NN1 and_CC prompter_NN1 ._. 
A_AT1 guidance_NN1 episode_NN1 necessarily_RR takes_VVZ place_NN1 at_II one_MC1 point_NN1 in_II time_NNT1 within_II the_AT developing_JJ skills_NN2 and_CC experience_NN1 of_IO the_AT client_NN1 ._. 
To_TO emphasise_VVI the_AT continuous_JJ nature_NN1 of_IO career_NN1 development_NN1 and_CC the_AT changing_JJ aspirations_NN2 of_IO people_NN at_II different_JJ ages_NN2 Super_NN1 has_VHZ proposed_VVN a_AT1 division_NN1 into_II five_MC stages_NN2 :_: Growth_NN1 (_( 014_MC years_NNT2 )_) ;_; Exploration_NN1 (_( 1524_MC years_NNT2 )_) ;_; Establishment_NN1 (_( 2544_MC )_) ;_; Maintenance_NN1 (_( 4564_MC years_NNT2 )_) ;_; and_CC Decline_NN1 (_( 65_MC onwards_RL )_) (_( Super_JJ and_CC Bohn_NP1 ,_, 1971_MC )_) ._. 
Placement_NN1 Placement_NN1 is_VBZ a_AT1 mixture_NN1 of_IO selection_NN1 and_CC guidance_NN1 ,_, a_AT1 process_NN1 of_IO mutual_JJ matching_NN1 takes_VVZ place_NN1 within_II a_AT1 known_JJ range_NN1 of_IO persons_NN2 and_CC jobs_NN2 ._. 
The_AT problem_NN1 arises_VVZ when_RRQ a_AT1 batch_NN1 of_IO recruits_NN2 enter_VV0 military_JJ service_NN1 or_CC when_CS a_AT1 large_JJ company_NN1 takes_VVZ on_RP a_AT1 new_JJ set_NN1 of_IO graduates_NN2 ._. 
It_PPH1 is_VBZ one_MC1 application_NN1 of_IO psychometrics_NN2 to_II man-power_NN1 planning_NN1 (_( see_VV0 previous_JJ chapter_NN1 )_) ._. 
It_PPH1 becomes_VVZ of_IO particular_JJ significance_NN1 within_II the_AT currently_RR fashionable_JJ company_NN1 policy_NN1 of_IO separating_JJ core_NN1 and_CC peripheral_JJ employees_NN2 ._. 
Given_VVN the_AT vagaries_NN2 of_IO the_AT market_NN1 and_CC rapid_JJ changes_NN2 in_II processes_NN2 and_CC products_NN2 stimulated_VVN by_II changing_JJ technology_NN1 the_AT strategy_NN1 has_VHZ evolved_VVN of_IO taking_VVG on_RP many_DA2 employees_NN2 for_IF a_AT1 short_JJ term_NN1 only_RR ._. 
These_DD2 may_VM be_VBI production_NN1 workers_NN2 but_CCB they_PPHS2 may_VM also_RR be_VBI senior_JJ people_NN ;_; managers_NN2 hired_VVN for_IF a_AT1 fixed_JJ term_NN1 and_CC technologists_NN2 and_CC others_NN2 used_VVN as_CSA consultants_NN2 ._. 
The_AT placement_NN1 task_NN1 is_VBZ to_TO describe_VVI the_AT requirements_NN2 and_CC the_AT appropriate_JJ sources_NN2 of_IO individuals_NN2 with_IW the_AT relevant_JJ skills_NN2 (_( Fig._NN1 2.1_MC )_) ._. 
For_IF the_AT core_NN1 workers_NN2 who_PNQS are_VBR permanent_JJ staff_NN again_RT there_EX may_VM well_RR be_VBI a_AT1 mixture_NN1 of_IO people_NN at_II all_DB levels_NN2 and_CC here_RL there_EX is_VBZ more_DAR emphasis_NN1 on_II career_NN1 progression_NN1 and_CC job_NN1 satisfaction_NN1 ._. 
Core_NN1 employees_NN2 are_VBR given_VVN written_JJ annual_JJ assessments_NN2 which_DDQ can_VM be_VBI discussed_VVN with_IW the_AT immediate_JJ senior_NN1 who_PNQS is_VBZ probably_RR the_AT writer_NN1 of_IO the_AT assessment_NN1 ._. 
For_IF this_DD1 purpose_NN1 he_PPHS1 is_VBZ provided_VVN with_IW a_AT1 well-structured_JJ form_NN1 by_II the_AT personnel_NN2 department_NN1 who_PNQS will_VM also_RR advise_VVI on_II the_AT timely_JJ use_NN1 of_IO in-house_JJ or_CC external_JJ courses_NN2 to_TO extend_VVI the_AT range_NN1 of_IO skills_NN2 of_IO a_AT1 particular_JJ employee_NN1 ._. 
By_II contrast_NN1 the_AT peripheral_JJ employee_NN1 is_VBZ judged_VVN entirely_RR on_II his_APPGE past_JJ record_NN1 or_CC that_DD1 of_IO the_AT consultant_NN1 company_NN1 which_DDQ employs_VVZ him_PPHO1 on_II a_AT1 semi-permanent_JJ basis_NN1 ._. 
He_PPHS1 is_VBZ hired_VVN to_TO undertake_VVI a_AT1 specific_JJ task_NN1 without_IW reference_NN1 to_II longer_JJR term_NN1 features_NN2 such_II21 as_II22 job_NN1 satisfaction_NN1 or_CC career_NN1 development_NN1 ._. 
The_AT peripheral_JJ employee_NN1 will_VM be_VBI compensated_VVN for_IF his_APPGE disadvantages_NN2 by_II a_AT1 much_RR greater_JJR pay_NN1 rate_NN1 per_II hour_NNT1 and_CC the_AT company_NN1 gains_NN2 by_II reduced_JJ overheads_NN2 and_CC greater_JJR work-force_NN1 flexibility_NN1 ._. 
The_AT whole_JJ strategy_NN1 works_VVZ very_RG well_RR for_IF younger_JJR workers_NN2 with_IW well_RR documented_VVN training_NN1 and_CC experience_NN1 ._. 
This_DD1 reinforces_VVZ the_AT view_NN1 ,_, developed_VVN in_II the_AT previous_JJ chapter_NN1 ,_, that_DD1 manufacturing_NN1 industry_NN1 in_RR21 particular_RR22 is_VBZ following_VVG the_AT Armed_JJ Forces_NN2 in_II relying_VVG more_RRR and_CC more_RRR on_II fit_JJ ,_, skilled_JJ ,_, mobile_JJ workers_NN2 ._. 
Psychometrically_RR the_AT problem_NN1 is_VBZ to_TO develop_VVI appropriate_JJ descriptive_JJ taxonomies_NN2 so_CS21 that_CS22 a_AT1 person_NN1 's_GE actual_JJ or_CC potential_JJ contribution_NN1 to_II an_AT1 organisation_NN1 is_VBZ succinctly_RR expressible_JJ ._. 
These_DD2 remain_VV0 primitive_NN1 in_II that_DD1 ,_, on_II the_AT whole_NN1 ,_, non-technical_JJ English_NN1 is_VBZ used_VVN with_IW all_DB the_AT possibilities_NN2 of_IO ambiguity_NN1 and_CC communication_NN1 at_II cross_NN1 purposes_NN2 which_DDQ this_DD1 implies_VVZ ._. 
The_AT accountants_NN2 are_VBR ahead_II21 of_II22 the_AT psychologists_NN2 in_II developing_JJ ideas_NN2 such_II21 as_II22 profit_NN1 centres_VVZ applicable_JJ to_II small_JJ groups_NN2 or_CC even_RR to_II individuals_NN2 ._. 
The_AT increased_JJ awareness_NN1 of_IO the_AT importance_NN1 of_IO the_AT individual_JJ worker_NN1 to_TO profit_VVI and_CC success_NN1 generally_RR ,_, particularly_RR at_II higher_JJR levels_NN2 in_II the_AT organisation_NN1 ,_, has_VHZ stimulated_VVN the_AT growth_NN1 of_IO a_AT1 specialist_NN1 placement_NN1 profession_NN1 colloquially_RR known_VVN as_II the_AT head_NN1 hunters_NN2 ._. 
These_DD2 are_VBR companies_NN2 which_DDQ specialise_VV0 in_II assisting_VVG a_AT1 client_NN1 in_II clarifying_VVG what_DDQ kind_NN1 of_IO person_NN1 they_PPHS2 need_VV0 and_CC how_RRQ to_TO locate_VVI him_PPHO1 within_II the_AT potentially_RR suitable_JJ worker_NN1 population_NN1 ._. 
They_PPHS2 may_VM also_RR start_VVI with_IW an_AT1 individual_JJ and_CC search_NN1 for_IF a_AT1 location_NN1 ._. 
This_DD1 also_RR is_VBZ done_VDN mainly_RR by_II interview_NN1 although_CS some_DD use_NN1 is_VBZ made_VVN of_IO psychometric_JJ tests_NN2 ,_, profiles_NN2 and_CC rating_VVG scales_NN2 ._. 
The_AT design_NN1 of_IO training_NN1 schemes_NN2 Designing_VVG and_CC conducting_VVG training_NN1 schemes_NN2 is_VBZ expensive_JJ and_CC is_VBZ not_XX undertaken_VVN without_IW good_JJ reasons_NN2 ._. 
Among_II possible_JJ reasons_NN2 are_VBR :_: 1_MC1 ._. 
An_AT1 inadequate_JJ reservoir_NN1 of_IO competent_JJ workers_NN2 for_IF particular_JJ tasks_NN2 2_MC ._. 
A_AT1 workforce_NN1 sufficient_JJ in_II numbers_NN2 or_CC supply_NN1 but_CCB not_XX in_II skill_NN1 level_NN1 as_CSA evidenced_VVN usually_RR by_II quality_NN1 of_IO work_NN1 and_CC less_RGR frequently_RR by_II failures_NN2 to_TO meet_VVI production_NN1 targets_NN2 ,_, danger_NN1 to_II people_NN and_CC damage_NN1 to_II equipment_NN1 3_MC ._. 
Changes_NN2 in_II technology_NN1 which_DDQ result_VV0 in_II changes_NN2 in_II required_JJ skills_NN2 4_MC ._. 
An_AT1 organisational_JJ commitment_NN1 to_II continuous_JJ improvement_NN1 of_IO the_AT skills_NN2 of_IO members_NN2 5_MC ._. 
To_TO meet_VVI statutory_JJ requirements_NN2 in_II certain_JJ dangerous_JJ industries_NN2 and_CC services_NN2 6_MC ._. 
As_II a_AT1 service_NN1 to_II customers_NN2 buying_VVG equipment_NN1 7_MC ._. 
As_II a_AT1 service_NN1 to_II the_AT community_NN1 paid_VVN for_IF by_II public_JJ funds_NN2 The_AT remit_NN1 of_IO the_AT training_NN1 scheme_NN1 and_CC those_DD2 responsible_JJ for_IF it_PPH1 may_VM end_VVI at_II the_AT transition_NN1 point_NN1 to_II operational_JJ activity_NN1 or_CC may_VM continue_VVI in_II those_DD2 periods_NN2 of_IO work_NN1 regarded_VVN as_II a_AT1 continuation_NN1 of_IO training_NN1 and_CC supervised_VVN as_II such_DA ._. 
In_II either_DD1 case_NN1 there_EX needs_VVZ to_TO be_VBI close_JJ liaison_NN1 between_II those_DD2 responsible_JJ for_IF training_NN1 and_CC those_DD2 responsible_JJ for_IF operations_NN2 ._. 
On_II the_AT other_JJ hand_NN1 training_NN1 is_VBZ always_RR vulnerable_JJ because_CS the_AT benefits_NN2 are_VBR long-term_JJ and_CC it_PPH1 often_RR needs_VVZ protection_NN1 from_II the_AT demands_NN2 of_IO management_NN1 and_CC operations_NN2 where_CS there_EX are_VBR other_JJ priorities_NN2 ._. 
The_AT simplest_JJT protective_JJ barrier_NN1 is_VBZ a_AT1 geographical_JJ one_PN1 ,_, namely_REX to_TO conduct_VVI the_AT training_NN1 away_II21 from_II22 other_JJ centres_NN2 of_IO activity_NN1 within_II the_AT organisation_NN1 ._. 
Sometimes_RT a_AT1 separate_JJ room_NN1 is_VBZ sufficient_JJ ,_, in_II other_JJ situations_NN2 a_AT1 different_JJ part_NN1 of_IO the_AT country_NN1 may_VM be_VBI chosen_VVN to_TO provide_VVI adequate_JJ isolation_NN1 ._. 
The_AT essential_JJ vulnerability_NN1 reinforces_VVZ the_AT requirement_NN1 that_CST the_AT starting_NN1 point_NN1 of_IO design_NN1 should_VM be_VBI a_AT1 clarification_NN1 of_IO objectives_NN2 followed_VVN by_II a_AT1 consideration_NN1 of_IO the_AT criteria_NN2 of_IO assessment_NN1 that_CST the_AT objectives_NN2 have_VH0 been_VBN achieved_VVN ._. 
None_PN of_IO this_DD1 need_VM be_VBI numerical_JJ ,_, sometimes_RT numbers_NN2 are_VBR used_VVN to_TO provide_VVI a_AT1 pseudo_JJ precision_NN1 which_DDQ can_VM be_VBI counterproductive_JJ because_CS the_AT validity_NN1 of_IO the_AT numbers_NN2 can_VM so_RR easily_RR be_VBI questioned_VVN ._. 
Precise_JJ verbal_JJ statements_NN2 and_CC descriptions_NN2 avoid_VV0 this_DD1 pitfall_NN1 ._. 
The_AT sensitivity_NN1 of_IO training_NN1 regimes_NN2 to_II external_JJ pressures_NN2 is_VBZ demonstrated_VVN by_II the_AT erratic_JJ interest_NN1 and_CC activity_NN1 in_II this_DD1 area_NN1 observable_JJ at_II the_AT national_JJ level_NN1 ._. 
Inevitably_RR there_EX was_VBDZ a_AT1 burst_NN1 of_IO activity_NN1 during_II and_CC immediately_RR after_II World_NN1 War_NN1 II_MC as_CSA shown_VVN for_REX21 example_REX22 by_II military_JJ research_NN1 and_CC development_NN1 (_( Wolfie_NP1 ,_, 1951_MC )_) and_CC by_II the_AT '_GE Training_NN1 within_II Industry_NN1 '_GE (_( TWI_NP1 )_) movement_NN1 (_( War_NN1 Man-power_NN1 Commission_NN1 ,_, 1945_MC )_) ._. 
Although_CS research_NN1 continued_VVD the_AT next_MD burst_NN1 of_IO application_NN1 in_II the_AT U.K._NP1 took_VVD place_NN1 following_VVG the_AT Industrial_JJ Training_NN1 Act_NN1 of_IO 1964_MC (_( Robinson_NP1 and_CC Barnes_NP1 ,_, 1968_MC ,_, Barber_NP1 1968_MC )_) ._. 
The_AT Act_NN1 concentrated_VVN on_II training_NN1 oriented_VVD by_II industry_NN1 ,_, the_AT other_JJ possibilities_NN2 considered_VVN were_VBDR occupations_NN2 and_CC geographical_JJ regions_NN2 ._. 
It_PPH1 resulted_VVD in_II the_AT creation_NN1 of_IO a_AT1 Central_JJ Training_NN1 Council_NN1 and_CC a_AT1 comprehensive_JJ range_NN1 of_IO Industrial_JJ Training_NN1 Boards_NN2 ._. 
Each_DD1 Board_NN1 was_VBDZ financed_VVN by_II a_AT1 levy_NN1 on_II the_AT relevant_JJ industry_NN1 ._. 
Not_XX surprisingly_RR this_DD1 created_VVD a_AT1 demand_NN1 for_IF experienced_JJ trainer_NN1 manpower_NN1 which_DDQ could_VM not_XX be_VBI met_VVN ,_, there_EX was_VBDZ some_DD disillusion_VV0 and_CC retrenchment_NN1 in_II the_AT 1970s_MC2 ._. 
In_II the_AT 1980s_MC2 there_EX has_VHZ been_VBN another_DD1 resurgence_NN1 of_IO activity_NN1 following_VVG the_AT realisation_NN1 that_CST the_AT country_NN1 is_VBZ simultaneously_RR suffering_VVG from_II a_AT1 high_JJ rate_NN1 of_IO unemployment_NN1 and_CC a_AT1 shortage_NN1 of_IO workers_NN2 with_IW specific_JJ skills_NN2 ._. 
Extensive_JJ government_NN1 resources_NN2 are_VBR channelled_VVN by_II the_AT Department_NN1 of_IO Employment_NN1 through_II the_AT Training_NN1 Commission_NN1 into_II the_AT Youth_NN1 Training_NN1 Schemes_NN2 ,_, job_NN1 training_NN1 ,_, skill_NN1 training_NN1 and_RR31 so_RR32 on_RR33 ._. 
The_AT objectives_NN2 and_CC criteria_NN2 of_IO success_NN1 of_IO any_DD training_NN1 scheme_NN1 are_VBR best_RRT described_VVN in_II system_NN1 terms_NN2 ._. 
The_AT next_MD step_NN1 is_VBZ to_TO translate_VVI these_DD2 into_II a_AT1 person_NN1 oriented_VVD description_NN1 of_IO what_DDQ the_AT successful_JJ scheme_NN1 graduate_NN1 will_VM have_VHI acquired_VVN ._. 
This_DD1 is_VBZ more_DAR than_CSN skills_NN2 because_CS the_AT total_JJ expertise_NN1 will_VM include_VVI also_RR rules_NN2 ,_, knowledge_NN1 and_CC contextual_JJ information_NN1 ._. 
This_DD1 last_MD will_VM vary_VVI from_II some_DD acquaintance_NN1 with_IW the_AT parent_NN1 company_NN1 to_II the_AT basic_JJ technology_NN1 behind_II the_AT tasks_NN2 ._. 
Together_RL these_DD2 make_VV0 up_RP the_AT content_NN1 or_CC syllabus_NN1 of_IO the_AT course_NN1 ._. 
Decisions_NN2 are_VBR then_RT needed_VVN on_II how_RRQ to_TO train_VVI ,_, which_DDQ will_VM include_VVI whether_CSW or_CC which_DDQ parts_NN2 should_VM be_VBI on-line_JJ or_CC off-line_JJ ,_, whether_CSW the_AT operator_NN1 is_VBZ required_VVN to_TO function_VVI in_II a_AT1 mainly_RR programmed_VVN (_( i.e._REX rule-following_NN1 )_) mode_NN1 and_CC how_RGQ far_RR he_PPHS1 may_VM need_VVI to_TO function_VVI in_II a_AT1 conceptual_JJ (_( i.e._REX actions_NN2 based_VVN on_II understanding_NN1 )_) mode_NN1 ._. 
Consideration_NN1 will_VM be_VBI given_VVN to_II the_AT use_NN1 of_IO training_NN1 aids_NN2 such_II21 as_II22 technical_JJ notes_NN2 ,_, schematic_JJ diagrams_NN2 ,_, video_NN1 tapes_NN2 ,_, closed_JJ circuit_NN1 television_NN1 and_CC simulators_NN2 ._. 
The_AT most_RGT important_JJ training_NN1 aids_NN2 are_VBR the_AT instructors_NN2 ,_, the_AT selection_NN1 and_CC training_NN1 of_IO these_DD2 is_VBZ a_AT1 vital_JJ secondary_JJ scheme_NN1 supporting_VVG the_AT primary_JJ scheme_NN1 ._. 
These_DD2 many_DA2 facets_NN2 of_IO training_NN1 scheme_NN1 design_NN1 are_VBR shown_VVN in_II Table_NN1 2.8_MC ._. 
Programmed_JJ instruction_NN1 The_AT origins_NN2 of_IO this_DD1 movement_NN1 are_VBR in_II the_AT teaching_NN1 machines_NN2 first_MD developed_VVN systematically_RR about_RG 1960_MC ._. 
These_DD2 consisted_VVN of_IO film_NN1 strips_VVZ with_IW associated_JJ projection_NN1 devices_NN2 and_CC control_NN1 panels_NN2 which_DDQ enabled_VVD the_AT student_NN1 to_TO examine_VVI a_AT1 particular_JJ screen_NN1 presentation_NN1 and_CC respond_VVI by_II moving_VVG to_II another_DD1 frame_NN1 ._. 
The_AT succeeding_JJ frame_NN1 might_VM take_VVI up_RP another_DD1 topic_NN1 or_CC might_VM contain_VVI answers_NN2 and_CC comments_NN2 on_II questions_NN2 posed_VVN on_II the_AT previous_JJ one_PN1 ._. 
There_EX was_VBDZ some_DD scope_NN1 for_IF interaction_NN1 in_CS21 that_CS22 the_AT series_NN of_IO presentations_NN2 was_VBDZ determined_VVN by_II the_AT student_NN1 's_GE choice_NN1 of_IO responses_NN2 ._. 
If_CS the_AT student_NN1 demonstrated_VVN by_II his_APPGE choices_NN2 that_CST he_PPHS1 did_VDD not_XX fully_RR understand_VVI a_AT1 particular_JJ point_NN1 then_RT the_AT programme_NN1 could_VM send_VVI him_PPHO1 round_RP an_AT1 additional_JJ explanatory_JJ loop_NN1 ._. 
This_DD1 was_VBDZ called_VVN a_AT1 branching_JJ programme_NN1 as_CSA distinct_JJ from_II a_AT1 linear_JJ programme_NN1 which_DDQ contained_VVD no_AT loops_NN2 ._. 
It_PPH1 will_VM be_VBI appreciated_VVN that_CST this_DD1 technique_NN1 of_IO automated_JJ teaching_NN1 seemed_VVD to_TO have_VHI enormous_JJ potential_NN1 ._. 
Classroom_NN1 teaching_NN1 is_VBZ inherently_RR skilled_JJ man-power_NN1 intensive_JJ ._. 
There_EX are_VBR obvious_JJ benefits_NN2 in_II allowing_VVG each_DD1 student_NN1 to_TO go_VVI at_II his_APPGE own_DA pace_NN1 ._. 
It_PPH1 is_VBZ not_XX surprising_JJ that_CST teaching_VVG machines_NN2 had_VHD considerable_JJ appeal_NN1 to_II the_AT military_JJ and_CC to_II large_JJ scale_NN1 industry_NN1 ._. 
Some_DD years_NNT2 of_IO intensive_JJ research_NN1 and_CC development_NN1 resulted_VVN in_II a_AT1 more_RGR realistic_JJ view_NN1 (_( Glaser_NP1 ,_, 1965_MC ;_; Wallis_NP1 et_RA21 al._RA22 ,_, 1966_MC ,_, Kay_NP1 et_RA21 al._RA22 ,_, 1968_MC )_) ._. 
It_PPH1 became_VVD clear_JJ that_CST the_AT quality_NN1 of_IO the_AT programme_NN1 was_VBDZ the_AT key_NN1 to_II degree_NN1 of_IO success_NN1 ._. 
The_AT machine_NN1 itself_PPX1 and_CC its_APPGE style_NN1 of_IO operation_NN1 was_VBDZ incidental_JJ ,_, in_II fact_NN1 it_PPH1 was_VBDZ possible_JJ to_TO achieve_VVI the_AT same_DA procedure_NN1 if_CS not_XX quite_RG the_AT same_DA discipline_NN1 on_II the_AT student_NN1 by_II using_VVG programmed_JJ books_NN2 with_IW directional_JJ references_NN2 to_II other_JJ pages_NN2 at_II the_AT end_NN1 of_IO each_DD1 page_NN1 ._. 
If_CS a_AT1 well-structured_JJ book_NN1 is_VBZ the_AT answer_NN1 then_RT we_PPIS2 have_VH0 gone_VVN full-circle_JJ and_CC back_RP to_II the_AT benefits_NN2 of_IO a_AT1 systematic_JJ text-book_NN1 ._. 
In_II research_NN1 terms_NN2 the_AT study_NN1 of_IO programmed_JJ instruction_NN1 was_VBDZ instrumental_JJ in_II encouraging_VVG a_AT1 more_DAR systems_NN2 view_NN1 of_IO the_AT teaching/training_NN1 process_NN1 with_IW associated_JJ trends_NN2 towards_II greater_JJR consideration_NN1 of_IO objectives_NN2 ,_, task_NN1 analysis_NN1 ,_, cost/_VV0 benefits_NN2 and_RR31 so_RR32 on_RR33 ._. 
Correspondingly_RR from_II a_AT1 practical_JJ training_NN1 viewpoint_NN1 there_RL developed_VVD a_AT1 more_RGR systematic_JJ approach_NN1 to_II taxonomies_NN2 of_IO training_NN1 and_CC of_IO instructional_JJ methods_NN2 together_RL with_IW their_APPGE inter-relationships_NN2 ._. 
Tables_NN2 2.9_MC and_CC 2.10_MC are_VBR examples_NN2 from_II an_AT1 overview_NN1 of_IO military_JJ training_NN1 ._. 
Regarded_VVN in_II systems_NN2 terms_NN2 ,_, programmed_VVD instruction_NN1 can_VM not_XX be_VBI an_AT1 isolated_JJ continuously_RR developing_JJ activity_NN1 because_CS it_PPH1 depends_VVZ on_II the_AT skills_NN2 of_IO the_AT programme_NN1 writer_NN1 and_CC these_DD2 skills_NN2 can_VM only_RR be_VBI developed_VVN on_II the_AT basis_NN1 of_IO experience_NN1 in_II the_AT classroom_NN1 ._. 
On_II the_AT other_JJ hand_NN1 teaching_NN1 machines_NN2 are_VBR one_MC1 way_NN1 of_IO utilising_VVG the_AT skilled_JJ teacher_NN1 on_II a_AT1 larger_JJR scale_NN1 than_CSN his_APPGE personal_JJ activity_NN1 in_II the_AT classroom_NN1 ._. 
There_EX is_VBZ a_AT1 different_JJ form_NN1 of_IO automatic_JJ teaching_NN1 device_NN1 called_VVN a_AT1 pacing_VVG machine_NN1 which_DDQ can_VM facilitate_VVI the_AT development_NN1 of_IO motor_NN1 skills_NN2 ._. 
It_PPH1 consists_VVZ of_IO a_AT1 machine_NN1 which_DDQ emits_VVZ bleeps_NN2 at_II timed_JJ intervals_NN2 ._. 
The_AT intervals_NN2 are_VBR predetermined_VVN by_II the_AT elements_NN2 of_IO a_AT1 motor_NN1 task_NN1 or_CC more_RGR simply_RR by_II the_AT target_NN1 cycle_NN1 time_NNT1 of_IO a_AT1 task_NN1 ._. 
The_AT trainee_NN1 performs_VVZ his_APPGE task_NN1 and_CC tries_VVZ to_TO keep_VVI in_II phase_NN1 with_IW the_AT bleeps_NN2 which_DDQ are_VBR intended_VVN to_TO pace_VVI his_APPGE performance_NN1 ._. 
The_AT required_JJ rate_NN1 of_IO work_NN1 can_VM be_VBI increased_VVN by_II shortening_VVG the_AT time_NNT1 intervals_NN2 ._. 
The_AT second_MD main_JJ phase_NN1 of_IO programmed_JJ instruction_NN1 became_VVD feasible_JJ with_IW the_AT development_NN1 of_IO low_JJ cost_NN1 computing_NN1 ._. 
Computer_NN1 aided_VVD instruction_NN1 (_( C.A.I._NP1 )_) strictly_RR should_VM cover_VVI other_JJ techniques_NN2 such_II21 as_II22 simulation_NN1 and_CC computer_NN1 based_VVN procedures_NN2 but_CCB it_PPH1 is_VBZ usually_RR intended_VVN to_TO mean_VVI a_AT1 situation_NN1 where_RRQ a_AT1 student_NN1 sits_VVZ in_II31 front_II32 of_II33 a_AT1 screen_NN1 on_II which_DDQ the_AT presented_JJ formats_NN2 relate_VV0 to_II his_APPGE developing_JJ cognitive_JJ activity_NN1 as_CSA expressed_VVN by_II his_APPGE manipulations_NN2 of_IO the_AT associated_JJ key-board_NN1 ._. 
Even_RR with_IW this_DD1 restricted_JJ interface_NN1 there_EX is_VBZ enormous_JJ flexibility_NN1 and_CC the_AT training_NN1 tasks_NN2 can_VM vary_VVI from_II reading_VVG and_CC simple_JJ arithmetic_NN1 to_II diagnosing_VVG faults_NN2 in_II the_AT complex_JJ plant_NN1 used_VVN in_II process_NN1 industries_NN2 ._. 
The_AT use_NN1 of_IO computer_NN1 aided_VVD instruction_NN1 in_II primary_JJ schools_NN2 has_VHZ created_VVN a_AT1 new_JJ generation_NN1 of_IO what_DDQ have_VH0 been_VBN called_VVN '_GE television_NN1 children_NN2 '_GE ._. 
They_PPHS2 regard_VV0 the_AT screen/keyboard_NN1 interface_NN1 as_II no_AT more_RGR unnatural_JJ than_CSN a_AT1 book_NN1 is_VBZ to_II earlier_JJR generations_NN2 ._. 
This_DD1 has_VHZ far_RR reaching_VVG consequences_NN2 at_II the_AT cultural_JJ level_NN1 not_XX only_RR for_IF learning_VVG but_CCB also_RR for_IF the_AT design_NN1 of_IO jobs_NN2 and_CC even_RR for_IF leisure_NN1 pursuits_NN2 which_DDQ increasingly_RR depend_VV0 on_II the_AT same_DA kind_NN1 of_IO interface_NN1 ._. 
Many_DA2 of_IO the_AT earlier_JJR forms_NN2 of_IO computer_NN1 aided_VVD instructions_NN2 used_VVD a_AT1 central_JJ computer_NN1 facility_NN1 and_CC a_AT1 set_NN1 of_IO work-stations_NN2 where_RRQ a_AT1 whole_JJ class_NN1 of_IO trainees_NN2 could_VM function_VVI simultaneously_RR ._. 
The_AT development_NN1 of_IO micro-computers_NN2 resulted_VVN in_II the_AT use_NN1 of_IO more_RGR isolated_JJ dedicated_JJ systems_NN2 for_IF just_RR one_MC1 trainee_NN1 ._. 
In_II either_DD1 case_NN1 it_PPH1 is_VBZ feasible_JJ to_TO collect_VVI data_NN about_II a_AT1 trainee_NN1 's_GE performance_NN1 and_CC modify_VV0 the_AT presented_JJ information_NN1 accordingly_RR ._. 
It_PPH1 is_VBZ also_RR possible_JJ to_TO collect_VVI learning_VVG data_NN and_CC feed_VVI it_PPH1 to_II an_AT1 instructor_NN1 either_RR on-line_JJ or_CC off-line_JJ ._. 
The_AT widespread_JJ use_NN1 of_IO computer_NN1 based_VVN learning_NN1 and_CC testing_VVG situations_NN2 has_VHZ stimulated_VVN the_AT development_NN1 of_IO '_GE student_NN1 modelling_NN1 '_GE ._. 
All_DB the_AT data_NN about_II one_MC1 student_NN1 is_VBZ collected_VVN into_II one_MC1 bank_NN1 which_DDQ changes_VVZ dynamically_RR with_IW his_APPGE learning_NN1 achievements_NN2 (_( and_CC failures_NN2 )_) ._. 
In_II this_DD1 way_NN1 a_AT1 student_NN1 model_NN1 containing_VVG a_AT1 profile_NN1 of_IO attainment_NN1 together_RL with_IW a_AT1 history_NN1 of_IO progress_NN1 to_II date_NN1 can_VM be_VBI made_VVN available_JJ to_II the_AT trainer_NN1 and_CC to_II the_AT trainee_NN1 ._. 
However_RR ,_, communication_NN1 links_VVZ between_II the_AT trainee_NN1 and_CC the_AT trainer_NN1 via_II a_AT1 computer_NN1 are_VBR not_XX a_AT1 substitute_NN1 for_IF the_AT two-way_JJ conversation_NN1 and_CC observation_NN1 which_DDQ normally_RR takes_VVZ place_NN1 in_II a_AT1 class-room_NN1 ._. 
Computer_NN1 programmes_NN2 are_VBR notoriously_RR literal_JJ in_II their_APPGE requirement_NN1 for_IF and_CC response_NN1 to_II operator_NN1 responses_NN2 ._. 
Trainee-computer_JJ communication_NN1 failures_NN2 for_IF very_RG simple_JJ reasons_NN2 can_VM lead_VVI to_II a_AT1 complete_JJ hiatus_NN1 unless_CS they_PPHS2 are_VBR detected_VVN and_CC restored_VVN by_II an_AT1 experienced_JJ trainer_NN1 who_PNQS can_VM explain_VVI to_II the_AT trainee_NN1 why_RRQ the_AT system_NN1 is_VBZ failing_VVG to_TO respond_VVI adequately_RR ._. 
The_AT third_MD phase_NN1 of_IO programmed_JJ instruction_NN1 called_VVN Tutorial_NN1 Expert_NN1 Systems_NN2 (_( TES_NP1 )_) involves_VVZ artificial_JJ intelligence_NN1 (_( see_VV0 p._NNU 234_MC )_) ._. 
To_II a_AT1 trainee_NN1 at_II the_AT interface_NN1 this_DD1 may_VM not_XX seem_VVI very_RG different_JJ from_II a_AT1 teaching_NN1 machine_NN1 or_CC computer_NN1 aided_VVD instruction_NN1 but_CCB the_AT logic_NN1 or_CC architecture_NN1 of_IO the_AT driving_JJ system_NN1 is_VBZ different_JJ so_CS21 that_CS22 even_RR more_DAR flexibility_NN1 is_VBZ available_JJ ._. 
Instead_II21 of_II22 responding_VVG directly_RR by_II logical_JJ rules_NN2 and_CC paths_NN2 which_DDQ have_VH0 been_VBN envisaged_VVN and_CC stored_VVN by_II the_AT programmer_NN1 an_AT1 expert_NN1 system_NN1 training_NN1 programme_NN1 contains_VVZ a_AT1 knowledge_NN1 base_NN1 and_CC an_AT1 inference_NN1 engine_NN1 which_DDQ can_VM consult_VVI the_AT knowledge_NN1 base_NN1 and_CC respond_VVI more_RGR adaptively_RR to_II the_AT idiosyncratic_JJ needs_NN2 of_IO the_AT trainee_NN1 ._. 
It_PPH1 can_VM also_RR explain_VVI why_RRQ it_PPH1 is_VBZ proposing_VVG a_AT1 certain_JJ strategy_NN1 and_CC why_RRQ the_AT detected_JJ strategy_NN1 of_IO the_AT trainee_NN1 is_VBZ appropriate_JJ or_CC not_XX ,_, and_CC ,_, if_CS not_XX ,_, why_RRQ not_XX ._. 
From_II the_AT user_NN1 's_GE point_NN1 of_IO view_NN1 these_DD2 systems_NN2 are_VBR usually_RR menu_NN1 driven_VVN ,_, that_DD1 is_VBZ the_AT operator_NN1 can_VM select_VVI his_APPGE path_NN1 of_IO consultation_NN1 by_II choices_NN2 within_II ranges_NN2 of_IO possible_JJ choices_NN2 which_DDQ are_VBR presented_VVN to_II him_PPHO1 ._. 
Technically_RR the_AT task_NN1 of_IO the_AT programme_NN1 designer_NN1 is_VBZ made_VVN easier_RRR by_II the_AT use_NN1 of_IO training_NN1 skills_NN2 and_CC declarative_JJ programming_NN1 languages_NN2 ._. 
A_AT1 training_NN1 shell_NN1 is_VBZ a_AT1 generalised_JJ tutorial_NN1 system_NN1 which_DDQ can_VM operate_VVI with_IW a_AT1 variety_NN1 of_IO knowledge_NN1 bases_NN2 ._. 
A_AT1 declarative_JJ programming_NN1 language_NN1 is_VBZ one_PN1 which_DDQ can_VM accept_VVI statements_NN2 of_IO relationships_NN2 or_CC rules_NN2 for_IF relationships_NN2 contrasting_VVG with_IW more_RGR traditional_JJ languages_NN2 which_DDQ encompass_VV0 only_RR step_VV0 by_II step_NN1 logic_NN1 ._. 
It_PPH1 will_VM be_VBI appreciated_VVN that_CST this_DD1 rapidly_RR developing_JJ field_NN1 of_IO expertise_NN1 contains_VVZ extensive_JJ new_JJ jargon_NN1 ._. 
At_II this_DD1 stage_NN1 the_AT jargon_NN1 is_VBZ an_AT1 obstacle_NN1 in_II that_DD1 anyone_PN1 wishing_VVG to_TO find_VVI out_RP about_II the_AT field_NN1 has_VHZ first_MD to_TO interpret_VVI the_AT jargon_NN1 ._. 
This_DD1 is_VBZ doubly_RR difficult_JJ in_CS21 that_CS22 there_EX is_VBZ much_DA1 overlap_NN1 in_II terminology_NN1 and_CC concepts_NN2 and_CC specialists_NN2 are_VBR not_XX consistent_JJ with_IW each_PPX221 other_PPX222 in_II the_AT use_NN1 of_IO these_DD2 new_JJ terms_NN2 ._. 
No_RR21 doubt_RR22 the_AT field_NN1 will_VM eventually_RR clarify_VVI and_CC mature_VVI and_CC the_AT terminology_NN1 will_VM be_VBI designed_VVN with_IW precision_NN1 so_CS21 that_CS22 meaningful_JJ concepts_NN2 ,_, tools_NN2 and_CC methods_NN2 are_VBR unambiguously_RR clarified_VVN and_CC distinguished_JJ but_CCB this_DD1 has_VHZ not_XX yet_RR happened_VVN ._. 
From_II a_AT1 behavioural_JJ standpoint_NN1 the_AT issues_NN2 are_VBR the_AT same_DA as_CSA in_II any_DD other_JJ field_NN1 where_CS technology_NN1 is_VBZ simultaneously_RR providing_VVG many_DA2 new_JJ facilities_NN2 for_IF supporting_VVG and_CC measuring_VVG human_JJ performance._NNU 1_MC1 ._. 
Technology_NN1 provides_VVZ trainer_NN1 aids_NN2 not_XX trainer_NN1 substitutes_NN2 ._. 
Thus_RR computer_NN1 assisted_VVD instruction_NN1 (_( CAI_NP1 )_) is_VBZ more_RGR aptly_RR descriptive_JJ than_CSN computer_NN1 based_VVN training_NN1 (_( CBT_NP1 )_) ._. 
2_MC ._. 
Technology_NN1 enforces_VVZ rigorous_JJ thinking_NN1 to_II the_AT point_NN1 of_IO revealing_VVG embarrassing_JJ gaps_NN2 in_II learning_NN1 ,_, teaching_VVG and_CC training_NN1 theory_NN1 ._. 
On_II the_AT other_JJ hand_NN1 technology_NN1 also_RR opens_VVZ up_RP new_JJ possibilities_NN2 for_IF monitoring_VVG and_CC measurement_NN1 which_DDQ should_VM support_VVI the_AT development_NN1 of_IO better_JJR basic_JJ theory._NNU 3_MC ._. 
It_PPH1 is_VBZ essential_JJ to_TO develop_VVI the_AT basic_JJ taxonomies_NN2 behind_II the_AT learning_NN1 situation._NNU for_REX21 example_REX22 any_DD diagnostic_JJ task_NN1 can_VM be_VBI aided_VVN by_II a_AT1 taxonomy_NN1 of_IO symptoms_NN2 and_CC a_AT1 taxonomy_NN1 of_IO causes_NN2 together_RL with_IW connections_NN2 between_II them._NNU 4_MC ._. 
The_AT need_NN1 for_IF interdisciplinary_JJ approaches_NN2 is_VBZ reinforced_VVN but_CCB the_AT abiding_JJ difficulties_NN2 of_IO interdisciplinary_JJ communications_NN2 remain_VV0 at_II every_AT1 level_NN1 from_II different_JJ values_NN2 and_CC concepts_NN2 to_II different_JJ terminologies_NN2 ._. 
Communication_NN1 between_II information_NN1 technologists_NN2 and_CC behavioural_JJ specialists_NN2 is_VBZ a_AT1 continuous_JJ struggle_NN1 which_DDQ can_VM eventually_RR be_VBI rewarding._NNU 5_MC ._. 
The_AT design_NN1 of_IO the_AT man-machine_JJ interface_NN1 (_( MMI_MC )_) or_CC the_AT humancomputer_NN1 interface_NN1 (_( HCI_NP1 )_) or_CC more_RGR simply_RR human_JJ interfaces_NN2 (_( HI_UH )_) remains_VVZ one_MC1 of_IO the_AT most_RGT difficult_JJ design_NN1 problems_NN2 but_CCB a_AT1 crucial_JJ one_PN1 in_II that_DD1 poorly_RR designed_VVN interfaces_NN2 will_VM wreck_VVI the_AT performance_NN1 of_IO any_DD system._NNU 6_MC ._. 
Evaluation_NN1 is_VBZ an_AT1 essential_JJ procedure_NN1 within_II the_AT implementation_NN1 of_IO any_DD new_JJ system._NNU for_IF training_NN1 systems_NN2 this_DD1 can_VM be_VBI very_RG expensive_JJ because_II21 of_II22 the_AT requirements_NN2 to_TO monitor_VVI the_AT learning_NN1 process_NN1 and_CC compare_VVI procedures_NN2 which_DDQ are_VBR anyway_RR never_RR completely_RR comparable_JJ ._. 
Apparently_RR extraneous_JJ variables_NN2 such_II21 as_II22 trainee_NN1 motivation_NN1 and_CC trainer_NN1 expertise_NN1 continue_VV0 to_TO dominate_VVI other_JJ factors_NN2 such_II21 as_II22 differences_NN2 in_II technology_NN1 and_CC differences_NN2 in_II learning_VVG tasks._NNU 7_MC ._. 
Pedagogically_RR the_AT need_NN1 to_TO be_VBI much_RR clearer_JJR about_II what_DDQ is_VBZ being_VBG taught_VVN and_CC why_RRQ is_VBZ a_AT1 mixed_JJ blessing_NN1 ._. 
The_AT formal_JJ discipline_NN1 can_VM sometimes_RT tidy_VVI up_RP muddled_JJ thinking_NN1 but_CCB at_II other_JJ times_NNT2 it_PPH1 can_VM interfere_VVI with_IW the_AT creatively_RR developing_JJ interaction_NN1 between_II trainer_NN1 and_CC trainee_NN1 ._. 
In_RR21 general_RR22 ,_, programmed_VVD instruction_NN1 is_VBZ most_RGT useful_JJ for_IF tasks_NN2 which_DDQ can_VM be_VBI comprehensively_RR specified_VVN ._. 
This_DD1 implies_VVZ tasks_NN2 based_VVN on_II rules_NN2 for_REX21 example_REX22 arithmetic_NN1 ,_, or_CC on_II logic_NN1 ,_, for_REX21 example_REX22 fault_NN1 finding_NN1 ._. 
The_AT use_NN1 of_IO simulators_NN2 When_RRQ serious_JJ consequences_NN2 can_VM follow_VVI from_II human_JJ errors_NN2 ,_, e.g._REX in_II flying_VVG an_AT1 aircraft_NN ,_, or_CC when_CS on-line_JJ operation_NN1 is_VBZ too_RG expensive_JJ to_TO be_VBI trusted_VVN to_II the_AT hands_NN2 of_IO trainees_NN2 ,_, e.g._REX in_II process_NN1 control_NN1 ,_, there_EX is_VBZ obviously_RR a_AT1 case_NN1 for_IF providing_VVG training_NN1 devices_NN2 which_DDQ simulate_VV0 the_AT performance_NN1 of_IO on-line_JJ systems_NN2 ._. 
In_II this_DD1 way_NN1 risks_NN2 and_CC costs_NN2 are_VBR reduced_VVN ,_, the_AT performance_NN1 of_IO trainees_NN2 is_VBZ more_RGR easily_RR measured_VVN and_CC the_AT presented_JJ situation_NN1 is_VBZ precisely_RR controlled_VVN by_II the_AT trainers_NN2 ._. 
It_PPH1 is_VBZ feasible_JJ to_TO provide_VVI adequate_JJ exposure_NN1 to_II events_NN2 which_DDQ in_II practice_NN1 might_VM be_VBI rare_JJ but_CCB very_RG serious_JJ ._. 
High_JJ fidelity_NN1 simulation_NN1 is_VBZ an_AT1 interesting_JJ challenge_NN1 to_II technological_JJ design_NN1 ._. 
Simulators_NN2 can_VM provide_VVI demonstrations_NN2 which_DDQ always_RR impress_VV0 visitors_NN2 ._. 
With_IW all_DB these_DD2 advantages_NN2 it_PPH1 is_VBZ not_XX surprising_JJ that_CST a_AT1 great_JJ deal_NN1 of_IO effort_NN1 and_CC resources_NN2 go_VV0 into_II the_AT provision_NN1 of_IO simulators_NN2 for_IF high_JJ technology_NN1 industry_NN1 ._. 
Paradoxically_RR the_AT more_RRR advanced_VVD the_AT technology_NN1 the_AT easier_JJR it_PPH1 is_VBZ to_TO provide_VVI good_JJ simulation_NN1 ._. 
For_REX21 example_REX22 ,_, a_AT1 process_NN1 control_NN1 plant_NN1 which_DDQ consists_VVZ of_IO dials_NN2 ,_, charts_NN2 and_CC visual_JJ display_NN1 units_NN2 responding_VVG to_II activation_NN1 of_IO switches_NN2 is_VBZ much_RR easier_JJR to_TO simulate_VVI than_CSN ,_, say_VV0 ,_, an_AT1 opponent_NN1 in_II a_AT1 game_NN1 of_IO tennis_NN1 ._. 
The_AT perfect_JJ simulation_NN1 which_DDQ has_VHZ been_VBN suggested_VVN but_CCB not_XX yet_RR implemented_VVN in_II process_NN1 control_NN1 ,_, power_NN1 generation_NN1 and_CC air_NN1 traffic_NN1 control_NN1 would_VM be_VBI to_TO have_VHI two_MC identical_JJ control_NN1 rooms_NN2 and_CC two_MC crews_NN2 coming_VVG on_II duty_NN1 ._. 
One_MC1 crew_NN1 would_VM control_VVI a_AT1 real_JJ system_NN1 and_CC the_AT other_NN1 would_VM think_VVI they_PPHS2 were_VBDR so_RR doing_VDG but_CCB would_VM in_II fact_NN1 be_VBI in_II a_AT1 control_NN1 room_NN1 driven_VVN by_II software_NN1 ._. 
This_DD1 seems_VVZ to_TO be_VBI the_AT only_JJ way_NN1 of_IO avoiding_VVG the_AT main_JJ snag_NN1 of_IO simulation_NN1 ,_, namely_REX that_CST the_AT trainee_NN1 is_VBZ aware_JJ that_CST his_APPGE performance_NN1 is_VBZ not_XX important_JJ in_II that_DD1 reality_NN1 out_RP there_RL is_VBZ not_XX changing_VVG as_II a_AT1 consequence_NN1 of_IO his_APPGE actions_NN2 ._. 
However_RR ,_, he_PPHS1 will_VM always_RR know_VVI that_CST his_APPGE performance_NN1 on_II a_AT1 simulator_NN1 is_VBZ being_VBG assessed_VVN and_CC ,_, except_II21 for_II22 the_AT business_NN1 of_IO risks_NN2 ,_, he_PPHS1 may_VM well_RR take_VVI more_DAR care_NN1 than_CSN he_PPHS1 would_VM in_II a_AT1 real_JJ plant_NN1 ._. 
In_II many_DA2 if_CS not_XX most_DAT industries_NN2 where_RRQ simulators_NN2 are_VBR used_VVN the_AT benefits_NN2 to_II training_NN1 are_VBR not_XX confined_VVN to_II dynamic_JJ system_NN1 control_NN1 and_CC fault_NN1 diagnosis_NN1 ._. 
The_AT control_NN1 function_NN1 is_VBZ exercised_VVN by_II a_AT1 team_NN1 and_CC the_AT efficient_JJ interaction_NN1 between_II the_AT team_NN1 members_NN2 is_VBZ also_RR subject_II21 to_II22 improvement_NN1 with_IW practice_NN1 (_( see_VV0 p._NNU 95_MC )_) ._. 
Transfer_NN1 of_IO training_NN1 from_II a_AT1 simulator_NN1 to_II a_AT1 real_JJ situation_NN1 is_VBZ never_RR complete_JJ and_CC does_VDZ not_XX necessarily_RR increase_VVI with_IW degree_NN1 of_IO fidelity_NN1 ._. 
Simple_JJ simulations_NN2 can_VM be_VBI as_RG effective_JJ for_IF training_NN1 purposes_NN2 as_RG more_RGR elaborate_JJ ones_NN2 and_CC can_VM certainly_RR be_VBI more_RRR cost_VV0 effective_JJ ._. 
Degree_NN1 of_IO transfer_NN1 is_VBZ not_XX easy_JJ to_TO measure_VVI and_CC needs_VVZ to_TO be_VBI carefully_RR defined_VVN ._. 
For_REX21 example_REX22 ,_, in_II training_NN1 manually_RR guided_JJ missile_NN1 operators_NN2 the_AT degree_NN1 of_IO transfer_NN1 is_VBZ appropriately_RR measured_VVN by_II '_GE first_MD shot_NN1 '_GE success_NN1 whereas_CS in_II training_NN1 and_CC retraining_VVG flight_NN1 deck_NN1 crew_NN1 the_AT long_JJ term_NN1 contribution_NN1 to_II safety_NN1 is_VBZ the_AT appropriate_JJ measure_NN1 ._. 
Gagne_NP1 (_( 1962_MC )_) provides_VVZ an_AT1 excellent_JJ review_NN1 of_IO earlier_JJR work_NN1 in_II this_DD1 field_NN1 ._. 
More_RGR recent_JJ experience_NN1 is_VBZ reviewed_VVN in_II Stammers_NP1 (_( 1983_MC )_) ._. 
For_IF details_NN2 of_IO experimental_JJ studies_NN2 using_VVG large_JJ scale_NN1 defence_NN1 simulations_NN2 see_VV0 Parsons_NP1 (_( 1972_MC )_) ._. 
Moraal_JJ and_CC Kraiss_NP1 (_( 1981_MC )_) contains_VVZ chapters_NN2 dealing_VVG with_IW simulations_NN2 of_IO a_AT1 ship_NN1 entering_VVG harbour_NN1 ,_, car_NN1 driving_VVG ,_, tank_NN1 driving_VVG ,_, the_AT flight_NN1 deck_NN1 and_CC air_NN1 traffic_NN1 control_NN1 ._. 
MSC_NP1 (_( 1986_MC )_) reviews_VVZ the_AT current_JJ use_NN1 of_IO simulators_NN2 in_II twenty_MC U.K._NP1 industries_NN2 ._. 
As_II a_AT1 research_NN1 tool_NN1 the_AT simulator_NN1 provides_VVZ a_AT1 happy_JJ medium_NN1 between_II the_AT precision_NN1 of_IO laboratory_NN1 studies_NN2 and_CC the_AT realism_NN1 of_IO field_NN1 studies_NN2 ._. 
It_PPH1 is_VBZ not_XX widely_RR used_VVN for_IF research_NN1 outside_II the_AT military_JJ because_II21 of_II22 the_AT cost_NN1 of_IO high_JJ fidelity_NN1 simulator_NN1 time_NNT1 ._. 
A_AT1 complex_JJ dedicated_JJ simulator_NN1 can_VM cost_VVI several_DA2 million_NNO pounds_NN2 and_CC it_PPH1 needs_VVZ its_APPGE own_DA crew_NN1 of_IO skilled_JJ operators_NN2 ._. 
On_II the_AT other_JJ hand_NN1 standard_NN1 micro-computers_NN2 have_VH0 considerable_JJ potentiality_NN1 for_IF quite_RG elaborate_JJ simulation_NN1 and_CC effective_JJ simulation_NN1 training_NN1 on_II procedures_NN2 may_VM only_RR require_VVI simple_JJ static_JJ mock-ups_NN2 ._. 
Simulator_NN1 development_NN1 has_VHZ been_VBN driven_VVN by_II technology_NN1 rather_II21 than_II22 by_II the_AT behavioural_JJ sciences_NN2 with_IW the_AT standard_JJ result_NN1 that_CST there_EX is_VBZ a_AT1 high_JJ reliance_NN1 on_II face_NN1 validity_NN1 with_IW relatively_RR little_JJ resource_NN1 devoted_VVD to_II systematic_JJ evaluation_NN1 ._. 
Key_JJ features_NN2 such_II21 as_II22 the_AT timing_NN1 and_CC extent_NN1 of_IO simulator_NN1 usage_NN1 are_VBR based_VVN on_II experience_NN1 in_II particular_JJ industries_NN2 rather_II21 than_II22 on_II more_RGR formal_JJ evidence_NN1 ._. 
The_AT ergonomics_NN1 approach_NN1 to_II their_APPGE use_NN1 is_VBZ shown_VVN in_II Fig._NN1 2.4_MC but_CCB it_PPH1 must_VM be_VBI admitted_VVN that_CST this_DD1 is_VBZ as_RR21 yet_RR22 rarely_RR followed_VVN in_II practice_NN1 ._. 
Simulation_NN1 should_VM be_VBI regarded_VVN as_II one_MC1 tool_NN1 within_II the_AT repertoire_NN1 of_IO the_AT training_NN1 specialist_NN1 ._. 
There_EX are_VBR other_JJ uses_NN2 of_IO simulators_NN2 ._. 
They_PPHS2 can_VM be_VBI used_VVN for_IF assessment_NN1 independently_RR of_IO training_NN1 ._. 
Data_NN collected_VVN during_II simulator_NN1 trials_NN2 is_VBZ a_AT1 useful_JJ source_NN1 of_IO risk_NN1 and_CC reliability_NN1 data_NN ._. 
In_II the_AT nuclear_JJ power_NN1 plant_NN1 design_NN1 they_PPHS2 are_VBR also_RR used_VVN as_II the_AT final_JJ stage_NN1 of_IO pre-construction_JJ design_NN1 evaluation_NN1 (_( Williams_NP1 and_CC Story_NN1 ,_, 1987_MC )_) ._. 
They_PPHS2 can_VM also_RR be_VBI used_VVN as_II a_AT1 resource_NN1 for_IF checking_VVG operating_NN1 instructions_NN2 and_CC for_IF conducting_VVG detailed_JJ task_NN1 analyses_NN2 ._. 
For_IF these_DD2 purposes_NN2 the_AT simulator_NN1 must_VM be_VBI available_JJ before_II the_AT main_JJ control_NN1 room_NN1 is_VBZ constructed_VVN ._. 
The_AT full_JJ range_NN1 of_IO potential_JJ simulator_NN1 usage_NN1 is_VBZ summarised_VVN in_II Table_NN1 2.11_MC ._. 
