Chronopsychological learning effects of rapidly-rotating shift work on day-shift attention

135 Pages·1999·3.1 MB·English

by  McAdaragh, Raymon M.

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