Chronopsychological learning effects of rapidly-rotating shift work on day-shift attention PDF
Preview Chronopsychological learning effects of rapidly-rotating shift work on day-shift attention
CHRONOPSYCHOLOGICALLEARNINGEFFECTS OFRAPIDLY-ROTATINGSHIFTWORK ONDAY-SHIFTATTENTION By RAYMONM.MCADARAGH ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL OFTHEUNIVERSITYOFFLORIDAINPARTIALFULLFILLMENT OFTHEREQUIREMENTSFORTHEDEGREEOF DOCTOROFPHILOSOPHY UNIVERSITYOFFLORIDA 1999 ACKNOWLEDGMENTS MymostsincereappreciationgoestoDr.LeeMullally,thechair ofmydissertationcommittee,forhisscholarlysupportandguidance inthepreparationofthismanuscript. Despitehisbusyschedule,he spentagreatdealoftimereadingdraftsofmydissertationand providingmewithvaluableandtimelyfeedback. Hewasavery supportiveandencouragingadvisor. IwouldalsoliketothankDr.EdwardWolfeforhistimeand effortinprovidingmewiththeguidanceandhelpthatIneededin thedataanalysisportionofthisstudy. Hecontributedmanyhours ofresearchandguidancesothatthecorrectanalysisprocedures wouldbeusedtodescribethedatainalogicalandmeaningfulway. Myappreciationalsogoesouttomyothercommitteemembers fortheirinputandsupport. Dr.SebastianFoti,Dr.LarryLoesch,and Dr.JeffHurtwerealwaystherewhenIneededthem. Finally,Iwouldliketothankmywife,Carol,whowasalways helpfulandsupportive,andmytwosons,JeffreyandEric,who,with theirmother,wereverypatientandunderstandingofmybusy scheduleatschoolandatwork. Iplantospendmuchmoretime withthemfromnowon. ii 88 TABLEOFCONTENTS Page ACKNOWLEDGMENTS ii ABSTRACT v CHAPTERS 1 INTRODUCTION 1 StatementoftheProblem 4 NeedfortheStudy 5 NullHypotheses 10 Limitations 12 Delimitations 13 Assumptions 16 Summary 17 2 RELATEDLITERATURE 1 OrcadianRhythms 1 OrcadianDysrhythmia. 27 Shiftwork. 37 Overview 37 WorkSchedules 38 Sleepiness 42 Performance 53 OrcadianRhythmsandLearning 57 Summary. 69 3 METHODOLOGY. 70 Participants 70 Instruments 70 Mi 111 Materials/Apparatus 72 Design 73 Procedure. 74 NullHypotheses 75 Variables 77 DataAnalysis 77 Summary 80 4 RESEARCHFINDINGS 8 Results 81 Hypothesis1 8 Hypothesis2 8 Hypothesis3 82 Hypothesis4 82 Hypothesis5 83 Hypothesis6 83 Hypothesis7 84 AttentionAllocation 84 LearningCurveComparisons 87 5 CONCLUSION 98 Introduction 98 Discussion 101 Implications. 109 Theoretical 109 PracticaL Ill Recommendations 112 REFERENCES 118 BIOGRAPHICALSKETCH 125 IV AbstractofDissertationPresentedtotheGraduateSchool OftheUniversityofFloridainPartialFulfillmentofthe RequirementsfortheDegreeofDoctorofPhilosophy CHRONOPSYCHOLOGICALLEARNINGEFFECTS OFRAPIDLY-ROTATINGSHIFTWORK ONDAY-SHIFTATTENTION By RaymonM.McAdaragh May1999 Chairman:LeeMullally,Ph.D. MajorDepartment:InstructionandCurriculum Thepurposeofthisstudywastodetermineifanobjectively- measurableday-shiftattentiondecrementorlearningdeficiency existsamongrapidly-rotatingshiftworkers. Researchusing subjectiveratingscalesindicatesthatthistypeofshiftworkis associatedwithalackofalertnessduringday-shifthours. An attentiondecrementmaycauselearningdeficienciesduringday-shift trainingsessions,orproblemswithdynamicsituationawarenesson thejob. Forthisstudy,37airtrafficcontrollers(agedunder46years) wererecruitedfromtheJacksonvilleAirRouteTrafficControlCenter asvolunteerparticipants.Group1consistedof18rapidly-rotating v three-shiftworkers(15male/3female),andGroup2consistedof19 day/eveningtwo-shiftworkers(16male/3female). Eachparticipantcompleted25sessionsontheNovaScan computer-basedperformancetesttodeterminetwobaseline measuresofattentionallocation(oneduringaspatial-visualization taskandtheotherduringatrackingtask).Themeanbaseline measuresforthegroupswerecomparedusingt-tests.Themean learningcurvesforthegroupswerecomparedonfivevariables (attentionallocationduringthespatial-visualizationtask,attention allocationduringthetrackingtask,responseflexibilityinswitching resources,non-transitionreactiontospatialvisualization,and trackingerrorduringtracking).Thelearningcurves'slopesand residualswerecomparedusingatwo-waygenerallinearmodel, repeated-measuresanalysis,whichincludedthreestatisticaltests (groupmaineffect,timemaineffect,andgroup-timeinteraction). Thet-testsdeterminedthattherapidly-rotatingshiftworkers haveasignificantlybetterattentionallocationabilitythanthe day/eveningshiftworkersonbothvariablesmeasured. Thelearning curvecomparisonsindicatedthattherapidly-rotatingshiftworkers improvedtheirattentionallocationabilityduringthespatial visualizationtask,whiletheday/eveningshiftworkersdidnot,and thatthetwogroupsstabilizedaroundtheirmeansatdifferentrates onthelearningcurveforattentionallocationduringthetracking vi task.Nodifferenceswerefoundbetweenthegroups'learningcurves forthethreeothervariables. Itissuggestedthatdayandevening shiftworkersmaypracticeirregularsleep-wakeschedulesand/or accumulateagreatersleepdebtduringtheworkweekthando rapidly-rotatingshiftworkers. vii CHAPTER1 INTRODUCTION Theoccupationofairtrafficcontrollercarrieswithitagreat responsibilityintermsofbothlifeandproperty,inthatthe controller'sjobrequireshim/hertomaintainthesafeand expeditiousflowofairtrafficinhis/herareaofresponsibility. McAdaragh(1995)hasdemonstratedthatmanycontrollerswork rotatingworkschedulesthathavebeenshowntoinducecircadian dysrhythmia,amisalignmentordesynchronizationofanindividual's biologicaland/orpsychologicaldailyrhythmiccycles(Hawkins, 1987).Chronopsychologicalresearch(thestudyofbehavioraland psychologicalrhythms)indicatesthatthesetypeofworkschedules produceahighdegreeofsubjectivefatigueintheseindividuals duringmidnightanddayshifts,withthelowestdegreebeing reportedontheeveningshifts(Melton,1985;Monketal.,1988; Saldivaretal.,1977;Smithetal.,1971).Theterm"shift-work insomnia"hasbeenusedtodescribetheconditioncausedby circadiandysrhythmiawhichreducesthetotalamountofsleep achievedbyaffectedindividualswhoworkshiftwork(Akerstedt& Kecklund,1991). 7 Babkoffetal.(1991)determinedthatsubjectivesleepiness ratingsofindividualsduringperiodsofsleepdeprivationare dependentuponthephaseofeachindividual'scircadiancycle. Manberetal.(1996)demonstratedthat,evenwhenanormalfull- night'ssleepisachievedbybothgroups,individualswhosleepat irregularschedulesreportalesseramountofalertnessandagreater amountofsleepinessduringthedaythandoindividualswhosleepat regularsleep-wakeschedules. Billiardetal.(1987),inastudy involvingFrenchmilitarydraftees,foundthatsleepdifficultiesand irregularsleep-wakeschedulesweremajorfactorscontributingto excessivedaytimesomnolenceinyoungmenbetweentheagesof1 and22yearsofage. Circadiandysrhythmiahasalsobeenshowntocause performancedecrementsinaffectedindividuals(Higgins,etal.,1975; Monketal.,1988),anddysrhythmiaandsleepdeprivationhave beenshowntoproducealearningeffect(Rankinetal.,1989). Luna etal.(1997),inastudyofairtrafficcontrollersworkingarapidly rotatingschedule,foundthatcontrollersonthemidnightshiftofa forwardrapidly-rotatingscheduleappearedtobefallingasleepand reportedincreasedconfusionandfatigue. Inatelephone conversationconcerningthisstudyonMarch31,1997,Dr.French advisedtheauthorthat,althoughtheperformancedatacollectedwas notreportedduetoalackofsufficientdata,thedatathatwere collectedindicatedasignificantnegativeinitiallearningeffectforthe controllerswhiletheywereonthemidnightshiftrelativetowhen theywereonthedayoreveningshifts. PilcherandHuffcut(1996) found,throughameta-analysisofsleep-deprivationstudies,that sleepdeprivationhasitsgreatesteffectonmoodwithalessereffect oncognitiveperformanceandmotorperformanceindescending order.Theyalsodeterminedthatpartialsleepdeprivation(sleep losswhichoccurswheneverthereisareductionintheusualamounts ofsleepobtainedina24-hourperiod),ratherthanlong-termor short-termsleepdeprivation,hasagreaternegativeeffectonmood andcognitiveperformance.Thisisimportanttoshiftworkers, becausepartialsleepdeprivationresultsfromtheconditionknown as"shift-workinsomnia"which,inturn,resultsfromworking irregularorrotatingschedules. PilcherandHuffcutalsoindicatethatonecleargoaloffuture researchwillbetodeterminewhypartialsleepdeprivationhassuch apronouncedeffectonmoodandcognitiveperformance. Forexample,partialsleepdeprivationmayaltercertain circadianrhythmeffectsonperformanceandmood.Whiletotal sleepdeprivationhasbeenfoundtointeractwithcircadian rhythms(Monketal.,1985;Naitohetal.,1985),fewstudies haveinvestigatedtheeffectsofpartialsleepdeprivationon circadianrhythms. Inaddition,partialsleepdeprivationmaybe similartofragmentedsleepinthatsubjectsinbothcasesobtain
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