人因工程学.docx

人因工程学.docx

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人因工程学

HUMANFACTORSANDSYSTEMS

Inthebygonemillenniaourancestorslivedinanessentially“natural”environmentinwhichtheirexistencevirtuallydependedonwhattheycoulddodirectlywiththeirhands（asinobtainingfood）andwiththeirfeet（asinchasingprey,gettingtofoodsources,andescapingfrompredators）.Overthecenturiestheydevelopedsimpletoolsandutensils,andtheyconstructedshelterforthemselvestoaidintheprocessofkeepingaliveandmakinglifemoretolerable.

Thehumanracehascomealongwayfromthedaysofprimitivelifetothepresentwithourtremendousarrayofproductsandfacilitiesthathavebeenmadepossiblewithcurrenttechnology,includingphysicalaccoutrementsandfacilitiesthatsimplycouldnothavebeenimaginedbyourancestorsintheirwildestdreams.Inmanycivilizationsofourpresentworld,themajorityofthe“things”peopleusearemadebypeople.Eventhoseengagedinactivitiesclosetonature—fishing,farming,camping-usemanysuchdevices.

Thecurrentinterestinhumanfactorsarisesfromthefactthattechnologicaldevelopmentshavefocusedattention（insomecasesdramatically）ontheneedtoconsiderhumanbeingsinsuchdevelopments.Haveyoueverusedatool,device,appliance,ormachineandsaidtoyourself,“Whatadumbwaytodesignthis;itissohardtouse!

Ifonlytheyhaddonethisorthat,usingitwouldbesomucheasier.”Ifyouhavehadsuchexperiences,youhavealreadybeguntothinkintermsofhumanfactorsconsiderationsinthedesignofthingspeopleuse.Norman（1988）,inanentertainingbook,providesnumerousexamplesofeverydaythingsthatwerenotdesignedfromahumanfactorsperspective,includingsingle-controlshowerfaucets,videocassetterecorders,andstove-topcontrols.Inasense,thegoalofhumanfactorsistoguidetheapplicationsoftechnologyinthedirectionofbenefitinghumanity.Thistextoffersanoverviewofthehumanfactorsfield;itsvarioussectionsandchaptersdealwithsomeofthemoreimportantaspectsofthefieldastheyapplytosuchobjectives.

HUMANFACTORSDEFINED

Beforeattemptingtodefinehumanfactors,weshouldsayawordaboutterms.HumanfactorsisthetermusedintheUnitedStatesandafewothercountries.Thetermergonomics,althoughusedintheUnitedStates,ismoreprevalentinEuropeandtherestoftheworld.Somepeoplehavetriedtodistinguishbetweenthetwo,butwebelievethatanydistinctionsarearbitraryandthat,forallpracticalpurposes,thetermsaresynonymous.Anothertermthatisoccasionallyseen（especiallywithintheU.S.military）ishumanengineering.However,thistermislessfavoredbytheprofession,anditsuseiswaning.Finally,thetermengineeringpsychologyisusedbysomepsychologistsintheUnitedStates.Somehavedistinguishedengineeringpsychology,asinvolvingbasicresearchonhumancapabilitiesandlimitations,fromhumanfactors,whichismoreconcernedwiththeapplicationoftheinformationtothedesignofthings.Sufficeittosay,noteveryonewouldagreewithsuchadistinction.

Weapproachthedefinitionofhumanfactorsintermsofitsfocus,objectives,andapproach.

FocusofHumanFactors

Humanfactorsfocusesonhumanbeingsandtheirinteractionwithproducts,equipment,facilities,procedures,andenvironmentsusedinworkandeverydayliving.Theemphasisisonhumanbeings（asopposedtoengineering,wheretheemphasisismoreonstrictlytechnicalengineeringconsiderations）andhowthedesignofthingsinfluencespeople.Humanfactors,then,seekstochangethethingspeopleuseandtheenvironmentsinwhichtheyusethesethingstobettermatchthecapabilities,limitations,andneedsofpeople.

ObjectivesofHumanFactors

Humanfactorshastwomajorobjectives.Thefirstistoenhancetheeffectivenessandefficiencywithwhichworkandotheractivitiesarecarriedout.Includedherewouldbesuchthingsasincreasedconvenienceofuse,reducederrors,andincreasedproductivity.Thesecondobjectiveistoenhancecertaindesirablehumanvalues,includingimprovedsafety,reducedfatigueandstress,increasedcomfort,greateruseracceptance,increasedjobsatisfaction,andimprovedqualityoflife.Itmayseemlikeatallordertoenhanceallthesevariedobjectives,butasChapanis（1983）pointsout,twothingshelpus.First,onlyasubsetoftheobjectivesaregenerallyofhighestimportanceinaspecificapplication.Second,theobjectivesareusuallycorrelated.Forexample,amachineorproductthatistheresultofhumanfactorstechnologyusuallynotonlyissafer,butalsoiseasiertouse,resultsinlessfatigue,andismoresatisfyingtotheuser.

ApproachofHumanFactors

Theapproachofhumanfactorsisthesystematicapplicationofrelevantinformationabouthumancapabilities,limitations,characteristics,behavior,andmotivationtothedesignofthingsandprocedurespeopleuseandtheenvironmentsinwhichtheyusethem.Thisinvolvesscientificinvestigationstodiscoverrelevantinformationabouthumansandtheirresponsestothings,environments,etc.Thisinformationservesasthebasisformakingdesignrecommendationsandforpredictingtheprobableeffectsofvariousdesignalternatives.Thehumanfactorsapproachalsoinvolvestheevaluationofthethingswedesigntoensurethattheysatisfytheirintendedobjectives.Althoughnoshortcatchphrasecanadequatelycharacterizethescopeofthehumanfactorsfield,suchexpressionsasdesigningforhumanuseandoptimizingworkingandlivingconditionsgiveapartialimpressionofwhathumanfactorsisabout.Forthosewhowouldlikeaconcisedefinitionofhumanfactorswhichcombinestheessentialelementsoffocus,objectives,andapproachdiscussedabove,wepresentthefollowingdefinition,modifiedslightlyfromChapanis（1985）:

Humanfactorsdiscoversandappliesinformationabouthumanbehavior,abilities,limitations,andothercharacteristicstothedesignoftools,machines,systems,tasks,jobs,andenvironmentsforproductive,safe,comfortable,andeffectivehumanuse.

Discussion

Thereareseveralmoreorlessestablisheddoctrinesthatcharacterizethehumanfactorsprofessionandthattogetherdistinguishitfromotherappliedfields:

•Commitmenttotheideathatthings,machines,etc.arebuilttoservehumansandmustbedesignedalwayswiththeuserinmind

•Recognitionofindividualdifferencesinhumancapabilitiesandlimitationsandanappreciationfortheirdesignimplications

•Convictionthatthedesignofthings,procedures,etc.influenceshumanbehaviorandwell-being•Emphasisonempiricaldataandevaluationinthedesignprocess

•Relianceonthescientificmethodandtheuseofobjectivedatatotesthypothesesandgeneratebasicdataabouthumanbehavior

•Commitmenttoasystemsorientationandarecognitionthatthings,procedures,environments,andpeopledonotexistinisolation

Wewouldberemissifwedidnotatleastmentionwhathumanfactorsisnot.Alltoooften,whenpeopleareaskedwhathumanfactorsis,theyrespondbysayingwhatitisnot.Thefollowingarethreethingshumanfactorsisnot.

Humanfactorsisnotjustapplyingchecklistsantiguidelines.lobesure,humanfactorspeopledevelopandusechecklistsandguidelines,however,suchaidsareonlypartoftheworkofhumanfactors.Thereisnotachecklistorguidelineinexistencetodaythat,ifitwereblindlyapplied,wouldensureagoodhumanfactorsproduct.Trade-offs,considerationsofthespecificapplication,andeducatedopinionsarethingsthatcannotbecapturedbyachecklistorguidelinebutareallimportantindesigningforhumanuse.

Humanfactorsisnotusingoneselfasthemodelfordesigningthings.Justbecauseasetofinstructionsmakessensetoanengineer,thereisnoguaranteeotherswillunderstandthem.Justbecauseadesignercanreachallthecontrolsonamachine,thatisnoguaranteethateveryoneelsewillbeabletooso.Humanfactorsrecognizesindividualdifferencesandtheneedtoconsidertheuniquecharacteristicsofuserpopulationsindesigningthingstortheiruse.Simplybeingahumanbeingdoesnotmakeapersonaqualifiedhumanactorsspecialist.

Humanfactorsisnotjustcommonsense.Tosomeextent,useofcommonsensewouldimproveadesign,buthumanfactorsismorethanjustthat.Knowinghowlargetomakelettersonasigntobereadataspecificdistanceorselectinganaudiblewarningthatcanbeheardanddistinguishedfromotheralarmsisnotdeterminedbysimplecommonsense.Knowinghowlongitwilltakepilotstorespondtoawarninglightorbuzzerisalsonotjustcommonsense.Giventhenumberofhumanfactorsdeficienciesinthethingsweuse,ifhumanfactorsisbasedonjustcommonsense,thenwemustconcludethatcommonsenseisnotverycommon.

AHISTORYOFHUMANFACTORS

Tounderstandhumanfactors,itisimportanttoknowfromwherethedisciplinecame.Itisnotpossible,however,topresentmorethanjustabriefoverviewofthemajorhumanfactorsdevelopments.WehavechosentoconcentrateondevelopmentsintheUnitedStates,butseveralsourcestracethehistoryinothercountries[see,forexample,EdholmandMurrell（1973）,Singleton（1982）,andWeiford（1976）].

EarlyHistory

Itcouldbesaidthathumanfactorsstartedwhenearlyhumansfirstfashionedsimpletoolsandutensils.Suchanassertion,however,mightbealittlepresumptuous.Thedevelopmentofthehumanfactorsfieldhasbeeninextricablyintertwinedwithdevelopmentsintechnologyandassuchhaditsbeginningintheindustrialrevolutionofthelate1800sandearly1900s.Itwasduringtheearly1900s,forexample,thatFrankandLillianGilbrethbegantheirworkinmotionstudyandshopmanagement.TheGilbreths’workcanbeconsideredas