Recognition Memory for Valenced and Arousing Materials Under Conditions of Divided Attention ...

20 Pages·2006·0.17 MB·English

RecognitionMemory 1
RunningHead: RECOGNITIONMEMORY
RecognitionMemoryforValencedandArousing
MaterialsUnderConditionsofDividedAttention
ArloClark-Foos
and
RichardL.Marsh
UniversityofGeorgia
Addresscorrespondence:
RichardL.Marsh
DepartmentofPsychology
UniversityofGeorgia
Athens,GA30602-3013
email: [email protected]
706-542-0058
RecognitionMemory 2
Abstract
Twoexperimentsarereportedthatexaminedtheeffectofbothvalenceandarousalon
recognitionmemoryperformance. Eachexperimentusedtwoclassesofnegativeitemsthat
differedinarousal,aswellasaneutalandnonarousingsetofitems. InExperiment1a
difficultdividedattentiontaskwascrossedwiththelearningandtestphasesofthe
experiment. InExperiment2encodingtimewasmanipulatedandremember-know
judgmentswerecollected. Theemotionalenhancementeffectoftenfoundwithverbal
materialssurvivedthedepletionofcognitiveresources,asdidtheextrabenefitacruingfrom
higharousal. Althoughwefoundthatarousalleadtomorerecollection,thegeneral
conclusionthatwedrawisthattheeffectofemotiononrecognitionmemorycanbe
attributedtorelativelyautomaticsourcessuchasthedegreeoffamiliarityengenderedbya
classofmaterials.
RecognitionMemory 3
RecognitionMemoryforValencedandArousing
MaterialsUnderConditionsofDividedAttention
Everyoneknowsthatlifebringswithitavarietyofexperiences,someofwhichare
pleasantandothersareonesthatwewouldratheravoid. Intermsoftheirmemorability,
valencedexperiencestendtobebetterrememberedthanotherwisecomparableneutralones
(forreviewsseeBuchanan&Adolphs,2002;Dolan,2002;Hamann,2001). Thisemotional
enhancementeffectisarathergeneralpropertyofourmemorysystembecauseitoccurswith
anymannerofstimulustypes(e.g.,words,pictures,stories,etc.). Italsogenerallyoccurs
whenmemoryistestedusingawiderangeofassessmenttechniques(e.g.,recognition,free
recall,cuedrecall,etc.). Theexactmechanismsunderlyingthememorialbenefittoemotional
materialshavebeendebatedovertheyears. Forexample,somearguethatemotionalitems
receivemorerehearsalormoreelaborateprocessingatthetimethattheyareencountered
(e.g.,Christianson&Engelberg,1999). Theseaccountsusuallypositfurtherthatsuch
elaborationcanresultinidiosyncraticpersonalrelevanceofthematerialwhichfurther
increasesmeasuresofmemory(inparticular,recollection;Kensinger&Corkin,2003). Others
arguethatthecognitivesystemiswiredinafashiontopreattentivelydetectvalenced
materialsagainstthefabricofeverydayexperiences,andthismaybeespeciallytruefor
negativeoraversivematerial(e.g.,Anderson,2005;Christianson,1992;Williams,Matthews,
&MacLeod,1996). Ofcourse,therearemanybiologicalandpharmacologicaltheoriesforthe
emotionalenhancementeffect(Anderson&Phelps,2001;Cain,Kapp,&Puryear,2002).
Thesetheoriesalignthemselveswitheitherthemorecontrolledprocessingexplanationsor
theonespositingmoreautomaticbenefitstomemory.
Inrecentyears,investigatorshavebecomeincreasinglyawareofthefactthatemotional
informationdoesnotvaryalongoneunderlyingdimension(Bradley,Greenwald,Petry,&
Lang,1992). Rather,emotionalmaterialhastwounderlyingdimensions: valenceandarousal.
Valencereferstothedimensionofhowastimulusevokespositiveversusnegativeaffect. By
RecognitionMemory 4
contrast,arousalisthedegreetowhichastimulusevokesanexcitingversusacalming
reaction. Thepsychophysiologicalevidencesuggeststhatvalenceexertsitsinfluenceonmore
controlledprocessessuchaselaborationandrehearsal. Consequently,whenvalenceditems
areexperiencedthatarenotarousingthenprefrontalcorticalareasaremoreactivatedas
comparedwithwithneutralmaterialsthatlackavalencedcomponent(e.g.,Kensinger&
Corkin,2004). But,whenitemsarepresentedthatarebothvalencedandarousingthen
amygdalarandhippocampalregionsbecomeactivatedtherebyimplicatingtheeffectof
arousalasamoreautomaticinfluenceonmemory(Cahill&McGaugh,1990;Kensinger&
Corkin,2004;McGaugh,Introini-Collison,Cahill,Kim,&Liang,1992). Thus,thereappearsto
betworoutesbywhichtheemotionalenhancementeffectcanoccur: onethroughcontrolled
processingdistinguishingbetweenneutralversusvalenceditemsandonethroughmore
automaticprocessingdistinguishingbetweenarousingvalencedmaterialsandnonarousing
valencedmaterials.
Supportingthisviewofthedualityinherentintheemotionalenhancementeffect,
KensingerandCorkin(2004)conductedabehavioralstudyinwhichtheypresentedneutral
andtwoclassesofnegativeitemsthatdifferedintheirlevelofarousal(arousingand
nonarousing). Underconditionsoffullattentionatencoding,bothclassesofnegativeitems
wererecognizedbetterthanneutralitems. However,underdividedattentionduring
learning,thenegativeandarousingitemscontinuedtoberecognizedmorefrequently,but
thenegativeandnonarousingitemsnolongerheldanyadvantageoverneutralwordsin
theirrateofsubsequentrecognition. Therefore,theeffectofdividedattentionduringlearning
eliminatedtheemotionalenhancementeffectduetovalencebecauseitpresumablyinterfered
withmorecontrolledprocesses. However,thearousingmaterialscontinuedtodisplaytheir
advantageimplyingthattheeffectofarousalonmemoryisarelativelyautomaticprocess
thatsurvivesdivisionofattention.
Thepurposeofthepresentstudywastoexploretheseeffectsfurther. Morespecifically,
ourgoalwastocomparetheeffectsofdividingattentionatbothencodingandretrieval.
RecognitionMemory 5
Obviously,withdivisionofattentionatencodingwewouldexpecttofindthatnegativeand
arousingitemsarebetterrecognizedtherebyreplicatingKensingerandCorkin(2004). Hicks
andMarsh(2000)haveclaimedthatdivisionofattentionduringarecognitiontestreduces
memoryforwell-learned,recollectiveinformationbutleavesintactinformationthatwould
havebeenrecognizedbasedonvaguerfeelingsoffamiliarity(cf. Jacoby,1999;Jennings&
Jacoby,1993,1997). Therefore,ifthedifferencebetweenarousingandnonarousingitems
persistsunderdividedattentionattest,thenthedifferenceislikelyowingtoaverage
differencesinvaguerfeelingsoffamiliaritybetweenthetwoclassesofnegativeinformation.
Ifthedifferencedoesnotpersist,thenthatoutcomewouldsuggestthatarousaland
amygdalarprojectionsconfertheirmemorialadvantagethroughmoredisruption-prone
recollectivedetails. Inaddition,thedivisionofattentionatbothencodingandretrievalforces
participantstorelysolelyonfamiliarityfortheirrecognitionjudgmentsandhasbeenknown
tohavetheironiceffectofresultinginbettermemory,thansay,dividingattentiononly
duringencoding(Jacoby,1991;Hicks&Marsh,2000). Toourknowledge,whethervalence
andarousalstillconfermemorialadvantageshasnotbeentestedunderdividedattentionat
bothstudyandtest. Theoretically,findingeitheravalenceadvantageand/oranadditional
arousaladvantagewouldhelptospecifythetypeofinformationconferringthatadvantage
(i.e.,recollectionorfamiliarity).
Experiment1
ThegoalofExperiment1wastoorthogonallycrossdivisionofattentionwiththephase
(encodingvs. test)inwhichitwasapplied. Theresultwasfourconditions: onewithfull
attentionatbothencodingandretrieval,anotherwithdividedattentionduringbothphases,
andtwoadditionalconditionswithdividedattentiononlyduringlearningortestbutnot
both.
RecognitionMemory 6
Method
Participants. UndergraduatestudentsfromtheUniversityofGeorgiavolunteeredin
exchangeforcredittowardaresearchappreciationrequirement. Eachparticipantwastested
individuallyinsessionsthatlastedapproximately30min. Wetested25volunteersineachof
thefourbetween-subjectsconditions. Twopeoplewithat-chanceperformancewerereplaced
undertheassumptionthattheywerenotcognitivelyengagedinthetasksthatweaskedthem
toperform.
MaterialsandProcedure. ThematerialswerewordsselectedfromtheAffectiveNorms
forEnglishWords(ANEW;Bradley&Lang,1999). Eachofthethreeclassesofitemswas
comprisedof48wordsthatwereequatedonbothANEWwordfrequencyandKucˇeraand
Francis(1967)measures. Obviously,theneutralandbothnegativeclassesitemsdiffered
significantlyinvalence(5.78vs. 2.43,respectively,inANEWvalues),buttheneutraland
negativenonarousingitemswereofthesamelowlevelofarousal(4.38inANEWvalues).
Onlythetwonegativeclassesofitemsdifferedinarousal(4.38vs. 6.84inANEWvalues). For
agivenparticipant,thesoftwarecontrollingtheexperimentrandomlychoseanew24items
fromeachofthethreeclassestobestudiedandreservedtheremaining24itemsineachclass
toserveasdistractorsontherecognitiontest. Inthisway,theencodingphasewas72trials
longandthetestphasewas144itemslong. Eachitemwasstudiedfor2sinthecenterofthe
computermonitorduringencoding;andthetestphasewasselfpaced. Allinstructionsto
participantswerefirstreadfromthecomputermonitorandthentheywerereiteratedinthe
experimenter’sownwords. Noparticipantwasallowedtocontinuewithanytaskunlessthe
experimenterwasconfidentthattheparticipanthadcompleteunderstandingofwhatwas
beingrequested. Thepresentationofallstimuliwereprecededbya250mswarningtoneand
fixationpointatbothstudyandtest. Theintertrialintervalduringtestingwas700ms.
Participantswhowereaskedtoperformrandomnumbergeneration(RNG)asthe
dividedattentiontaskweregivendetailedinstructionsonhowtoberandom(seeHicks&
RecognitionMemory 7
Marsh,2000). Theywereaskedtocalloutanumberbetween1and10(inclusive)forevery
beepofanelectronicmetronomeprogrammedtoissueabeepat1sintervals. Thispacingis
quitefastandthetaskisquitedifficult. Participantsweregivenapproximately1.5minto
practicethetaskunencumberedbyeitherlearningortestingduringwhichtheexperimenter
recordedthedigits,missedbeats,etc. toserveasabaselinemeasureofrandomnessto
comparewithperformancewhenthetaskwasperformedconcurrently. Afterpractice,either
thelearningphaseortestphasewasadministered. Inallcaseswherethebaselinedidnot
needtobetaken(oralreadyhadbeentakenearlierinthecaseofdividingattentionatboth
studyandtest)allotherparticipantsweregivenamathematicaldistractortasktoequatethe
timingandretentionintervalsacrossallfourbetween-subjectsconditions.
ResultsandDiscussion
p
Inthisandthefollowingexperiment,unlessa valueisreportedwithastatisticaltest,
theprobabilityofaTypeIerrordoesnotexceedtheconventional5%. Webeginbyreporting
theresultsoftheRNGtask. Ameasureofrandomnesswascomputedusingthefirst100
digitsatbothbaselineandwhenthetaskwasperformedconcurrently. Numericallylower
valuesofRNGindicatemorerandomsequencesandhighervaluesindicatelessrandom
performance. Fortheconditionswherethetaskwasperformedwhilestudyingwords,
baselineperformancewas0.29anditwas0.33whenperformedconcurrentlyduring
t
encoding, (59)=5.65. Fortheconditionswherethetaskwasperformedduringtesting,
baselineperformancewas0.30anditwas0.34whenperformedconcurrentlyduringtesting,
t
(59)=4.57. Consequently,therewerenodualtasktradeoffsinwhichparticipantssacrificed
performanceononetasktoperformwellontheotherbecause,aswewillshowshortly,
memoryperformancealsosufferedwhenperformedconcurrentlyaswell. Inshort,
performancedeficitswereshownonbothtasks(cf.,Marsh&Hicks,1998).
ThehitratesandfalsealarmratesarereportedinTable1foreachofthethreeclassesof
itemsacrossthefourbetween-subjectconditions. Thesemetricshavealsobeencombinedby
RecognitionMemory 8
subtractingthefalsealarmratefromthehitratewithinagivenclassofitemstoarriveat
measuresofcorrectedrecognition. OnlythelastthreecolumnsofTable1wereanalyzed
×
statistically. Weconducteda2(fullvs. dividedattentionatencoding) 2(fullvs. divided
×
attentionattest) 3(itemtype)AnalysisofVariance(ANOVA).Asthereadercansee,
F
negativeitemswererecognizedmoreoftenthantheirneutralcounterparts, (2,192)=27.81,
η2
p =.23. Thus,theemotionalenhancementeffectwasobtained. Insimpleeffectsteststhat
contrastedthenegativearousingitemsagainstthenegativenonarousingitems,therewere
significantdifferenceswhenattentionwasdividedatstudyaloneandtestalone,smallerof
t
thetwo (24)’s=2.15. However,therewasonlyanominaleffectfavoringthearousing
negativeitemsoverthenonarousingintheremainingtwoconditions. Mostcritically,the
evidenceappearstoconvergeontheideathattheemotionalenhancementeffectfornegative
itemsoverneutralitemsisnotnecessarilyeliminatedbydivisionofattentionateitherstudy
ortest(cf. Kensinger&Corkin,2004). Inaddition,thebenefitofarousingovernonarousing
itemswasnumericallypresentintwoofthefourconditions,andstatisticallypresentinthe
othertwoconditionssoittooappearstogenerallysurvivethedepletionofcognitive
resources. ThisclaimcanbefurtherbolsteredbyrunningareducedANOVAmodelwithout
thefullattentionconditionandwithouttheneutralitemsthatshowsthedifferencebetween
F η2
thetwoclassesofnegativeitemsisstatisticallysignificant, (1,72)=8.26, p =.10.
Notsurprisingly,performancewasmuchlowerwhenattentionwasdividedduring
F η2
studyascomparedwithfullattention, (1,96)=25.03, p =.21. Thatoutcomereplicatesthe
extensiveworkthatNaveh-Benjaminandhiscolleagueshaveperformedtoshowthatalmost
inevitablydepletionofresourcesduringstudyhasadeleteriouseffectonmemory(e.g.,
Naveh-Benjamin,Kilb,&Fisher,2006;Naveh-Benjamin,Guez,&Marom,2003). Inthe
omnibustest,themaineffectofdivided(versusfull)attentionattestdidnotreach
significanceandnoneoftheinteractionsweresignificant. Theabsenceofthistesteffectin
contrasttoHicksandMarsh’s(2000)significanteffectislikelyowingtothefactthat
two-thirdsoftheentiuresetofmaterialswereprotectedbytheemotionalenhancementeffect.
RecognitionMemory 9
Inaddition,participantsassignedtotheconditionwithbothdividedattentionatstudyand
testperformednumericallybetterthantheconditionwithonlydividedattentionduring
study. Participantsintheformerconditionareforcedtorelyalmostexclusivelyonfamiliarity
andindoingsoadjusttheirdecisioncriteriatomaximallycapturestudieditems.
Insum,althoughthedepletionofresourcesatstudyandtestdidnegativelyimpact
memory,itgenerallyleftboththeemotionalenhancementeffectandtheadvantageto
arousingovernonarousingitemsintact. OnecannotclaimthattheRNGtaskwastooeasy
becauseHicksandMarsh(2000)usedtheverysametaskataslowerpaceandfounda
significantreductioninrecognitionmemoryforneutralmaterials. Therefore,theseresults
suggestthattherearetasksandconditionswherethebenefitstoemotionalmaterialsurvive
evenaseveredepletionofresources.
Experiment2
Ourgoalinthisnextexperimentwastoascertainjusthowearlyintheprocessing
sequencetheemotionaladvantagetoarousingitemsoccurs. Althoughdividingattention
duringstudyhurtperformanceinExperiment1,participantsstillhadafull2satencodingto
processtheitems. Becauseshorteningthestudytimeactslikedividedattention,weexpected
worseperformancewhenitemswerestudiedfor250msascomparedwith2000msof
encodingtime. Thequestionwaswhethertheemotionalenhancementeffectwouldbe
observedwithsuchshortprocessingtime,andoverandabovethat,whetherthearousing
itemswerestillbetterrecognized. IfourconclusionsfromExperiment1areaccuratethat
theseeffectsarelargelyduetoautomaticprocesses,thentheeffectmayindeedsurvivevery
fastpresentationrates. Toprovidealargerwindowintomemoryperformance,wealsotook
remember-knowjudgmentsinthisexperiment. Valencedmaterialswilloftenberecognized
togreaterdegreewithrememberresponsesthanmoreneutralmaterial(e.g.,Kensinger&
Corkin,2003;Ochsner,2000).
RecognitionMemory 10
Method
Participants. UndergraduatesfromtheUniversityofGeorgiavolunteeredinexchange
forpartialcredittowardaresearchappreciationrequirement. Eachofthe30participantswas
testedindividuallyinsessionsthatlastedapproximately30min.
MaterialsandProcedure. ThematerialsusedinExperiment1wereusedagain,aswasthe
coreoftheprocedures. Themaindifferencewasthathalfofeachclassofitemswerestudied
for250mswhereastheotherhalfwerestudiedfor2000ms. Studydurationinthestudy
sequenceappearedrandomtotheparticipant,buttheywereinformedthatdifferentstudy
timeswerebeingmanipulated. Attest,detailedinstructionsonthedistinctionbetween
rememberingandknowingwerereadinitiallyfromthecomputermonitor. Thesewere
followedbyadetailedrestatementfromtheexperimenterinhisorherownwords. Finally,
theparticipanthadtorepeatbacktotheexperimentertheirunderstandingofthisdistinction.
Becausethiswasafairlyinvolvedprocessrequiringapproximately6min,nodistractortask
wasadministered. Duringthetestitself,participantsdecidedforeachitemwhetherthey
recollectedit,knewthatithadbeenstudied,oritwasbrandnew(i.e.,threeresponseoptions).
ResultsandDiscussion
Weanalyzedtherememberresponsesseparatelyfromtheknowresponses;andthese
×
proportionscanfoundinTable2. Intheomnibus2(encodingtime) 3(itemtype)ANOVA,
F η2
therewasamaineffectofencodingtimeonrememberresponses, (1,29)=38.31, p =.57.
Greaterencodingtimeresultedinmorerecollection. Therewasalsoamaineffectofitem
F η2
type, (2,58)=7.08, p =.20,butnointeraction. Asthereadercansee,arousingitems
receivedmorerememberresponsesthannegativenonarousingorneutralitemsdid. The
specificcontrastbetweenthetwonegativeclassesofitemswasstatisticallysignificantatboth
t t p
short, (29)=2.09,andlong, (29)=1.98, =.05,encodingdurations. Thus,inrecollectionwe
didnotfindageneralemotionalenhancementeffect,butratherfoundonlyaneffectof
arousalthatwaspresentevenattheveryshortencodingduration.