人机工程学案例分析

BADDESIGNOFHUMANFACTORSBADDESIGNOFHUMANFACTORSHerelistssomedesigncaseswhichrequireconsideringhumanfactors.Byanalyzingtheinconvenienceandconfusionstheygiveriseto,wemanagetohelpstudentstounderstandhumanfactorsthoroughly.BADDESIGNOFHUMANFACTORSWhichSideDoYouUseforCutting?Thisisaniceattractiveknife.Justoneproblem.Whichsidedoyouuseforcutting?Althoughyoucantellwhichendisthehandleandwhichendistheblade,itisn'tclearwhichsideofthebladecuts.DesignsuggestionTheshapeofanobjectshouldrevealhowitistobeused.BADDESIGNOFHUMANFACTORSSmoothasGlassThispictureshowsthehotwatercontrolknobonthebathroomsinkinafancyhotel.Youcantellit'safancyhotelbecauseithasamarblesinkanddesignerknobs.Unfortunately,thedesignerdidn'thavepeopletrytoturntheknobswithsoapontheirhandsbecausetheknobsareaboutassmoothasglassandalmostimpossibletoturn.DesignsuggestionAwell-designedobjectcanbedesignedtobothlookgoodandbeeasytouse.BADDESIGNOFHUMANFACTORSHowdoyouunlockthedoor?Thispictureshowsthelocksonourfrontdoor.Tounlockthedeadboltlock(above),youturnthekeytotheright.Tounlockthedoorknoblock(below),youturnthekeytotheleft!That'sprettyconfusing!Icheckedafewotherdoors,andthisseemstobethewaytheyworktoo.Iwouldhopetheydon'tallworklikethis!DesignsuggestionControlsthathavethesamefunctionshouldbeoperatedinthesameway.Forexample,bothlocksshouldbeunlockedbyturningthekeyinthesamedirection.Thisisanexampleofwhatismeantinhumanfactorsbyconsistencyindesign.BADDESIGNOFHUMANFACTORSGuessWhichSwitchControlstheProjectorScreen?Thispictureshowsaprojectorscreeninaconferenceroom.Thewhitescreenisloweredfromtheceilinginfrontofablackboard.Totherightofthescreenaresomeelectricalswitches.Guesswhichswitchraisesandlowersthescreen?Theswitchnexttothescreen?No,it'stheswitchfarthestawayfromthescreen!DesignsuggestionPlaceacontrolnexttothedeviceitcontrols.projectorscreenBADDESIGNOFHUMANFACTORSWhat'sintheBottle?Hereisanotherexampleofmanufacturerspackagingdifferentstuffinnearlyidenticalbottles.Theexampleshowstwobottlescontainingdifferentdosesofinsulinfortreatingdiabetes.Inthiscase,theconsequencesofchoosingthewrongbottlearemuchmoreserious.Youcouldendupinthehospital.ThebottleontheleftcontainsInsulinR(forRegularInsulin).RegularInsulinactsrelativelyfast(overa4to6hourperiod)andisgenerallymeanttobetakenbeforeameal.ThebottleontherightcontainsInsulinN(forNPHInsulin).NPHInsulinactsoverabroaderspanoftimeandmoreslowly(e.g.,a12to18hourperiod)andismeanttobetakengenerallyonceortwiceduringa24hourperiodtokeepadiabetics'bloodglucosefromrisingsignificantly.ManydiabeticsuseR(regular)insulininconjunctionwithNorsomeotherlong-actinginsulin.TheconsequencesofaccidentallytakingInsulinRinsteadofInsulinNatbedtimewouldbeseriousbecauseyoucouldenduphavingahypoglycemicreactionduringthemiddleofthenight(i.e.,extremelylowbloodglucoselevels).Thus,choosingthewronginsulincouldbeaveryseriousandpossiblydeadlymistake.DesignsuggestionThingsthatneedtobedistinguishedfromeachothershoulddifferbymorethanjustasinglefeature.Forexample,thebottlescouldhavedifferentshapesandsizestomakethemmoredistinguishable.BADDESIGNOFHUMANFACTORSMechanicalPencilsTheeraserisunderacap(shownremoved).IfyoumakealotmistakeslikeIdo,youwillbeconstantlytakingthecapoffthepencil,holdingitwithonehand,erasing(noticethetinylittleeraser),andpushingthecapbackon.Whenyoupushthecapbackonitwillcausethepencilleadtoadvanceonestepoutofthepencil.Youwillhavetoplaywiththepenciltogettheleadbackin.Eventually,youwilllosethecap.Whydoesthispencilhaveacap?Apparently,peoplethoughtitlookedbetterwithacap;cleanerlines;nounsightlyerasertoremindyouofyourerrors.Herearetwomechanicalpencils.Theoneabovehassomeprettyannoyingfeatures.Thepencilbelowdoesn'thavetheseproblems.Itdoesn'thaveacap.Ithasanicebigeraserandtheleadisnotadvancedbypressingontheeraser.Instead,thereisaleadadvancebuttonjustabovewhereIholdthepencilwhenwriting.(Although,thismaybeaproblemforpeoplewhogripthepencilhigherupthebarrelthanIdo!)DesignsuggestionDon'taddanextrasteptoataskforthesakeofaesthetics.Don'thavethesameaction(pushingonthecap)dotwodifferentthings:attachingthecapandadvancingthelead.BADDESIGNOFHUMANFACTORSHowFastAmIGoing?ForalongtimeIcaughtmyselfmistakingthetachometerforthespeedometer.OnemightthinkthatIcouldbreakthishabitprettyeasily.Whywasthissuchadifficulthabittobreak?AtfirstIthoughtthattheproblemwasthatinoneofourcars,thespeedometerwasontheright(A)andontheothercar,itwasontheleft(B).Butasseveralreaderspointedout,thespeedometerandtachometeronthecarbelowhavethesamenumericscale.Soifagaugeshows30,doesitindicate30milesperhour,or3000revolutionsperminute?Thegaugeabovedoesn'thavethatproblem.Whenyouhaveseveralsimilardisplaysclosetogetherandlinedup,peoplewillconfusethemwitheachother.Thisisespeciallytruewhendisplayswithnumericscaleshavethesameincrements.Thesedisplaysshouldbemademoredistinctivebymakingthenumericscaleincrementsdifferent.DesignsuggestionABBADDESIGNOFHUMANFACTORSStoveTopControlsThisistheobligatorystovetopcontrolexamplethatprobablyappearsineverybookonhumanfactorsdesigntoillustratebaddesign.Theproblemisthatitisdifficulttotellwhichcontrolgoe