记忆容量选择的控制和价值取向在正常儿童与多动症儿童间的差异毕业论文外文翻译Word文档下载推荐.docx

记忆容量选择的控制和价值取向在正常儿童与多动症儿童间的差异毕业论文外文翻译Word文档下载推荐.docx

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UniversityofCalifornia,LosAngeles

AmyN.Moore

PennsylvaniaStateUniversity

Objective:

Theabilitytoselectwhatisimportanttoremember,toattendtothisinformation,andtorecallhigh-valueitemsleadstotheefficientuseofmemory.Thepresentstudyexaminedhowchildrenwithandwithoutattention-deficit/hyperactivitydisorder（ADHD）performedonanincentive-basedselectivitytaskinwhichto-be-remembereditemswereworthdifferentpointvalues.Method:

Participantswere6-9yearoldchildrenwithADHD（n=57）andwithoutADHD（n=59）.Usingaselectivitytask,participantsstudiedwordspairedwithpointvaluesandwereaskedtomaximizetheirscore,whichwastheoverallvalueoftheitemstheyrecalled.Thistaskallowsformeasuresofmemorycapacityandtheabilitytoselectivelyrememberhigh-valueitems.Results:

Althoughtherewerenosignificantbetween-groupsdifferencesinthenumberofwordsrecalled（memorycapacity）,childrenwithADHDwerelessselectivethanchildreninthecontrolgroupintermsofthevalueoftheitemstheyrecalled（controlofmemory）.Allchildrenrecalledmorehigh-valueitemsthanlow-valueitemsandshowedsomelearningwithtaskexperience,butchildrenwithADHDCombinedtypedidnotefficientlymaximizememoryperformance（asmeasuredbyaselectivityindex）relativetochildrenwithADHDInattentivetypeandhealthycontrols,whodidnotdiffersignificantlyfromoneanother.Conclusions:

ChildrenwithADHDCombinedtypeexhibitimpairmentsinthestrategicandefficientencodingandrecallofhigh-valueitems.ThefindingshaveimplicationsfortheoriesofmemorydysfunctioninchildhoodADHDandthekeyroleofmetacognition,cognitivecontrol,andvalue-directedrememberingwhenconsideringthestrategicuseofmemory.

Keywords:

ADHD,memory,cognitivecontrol,metamemory,encodingstrategies

Attention-deficit/hyperactivitydisorder（ADHD）ischaracterizedbyanearlyonsetofdevelopmentallyaberrantandimpairinglevelsofinattentionand/orhyperactivity-impulsivity（AmericanPsychiatricAssociation[APA],2000）.Inadditiontoitsconcurrentandprospectiveassociationwithdisruptedsocial/familyrelationships,substandardacademicachievement,andelevatedcomorbidity（Barkley,Fischer,Edelbrock,&

Smallish,1990;

Barkley,Fischer,Smallish,&

Fletcher,2002;

Lee,Lahey,Owens,&

Hinshaw,2008;

Owens,Hinshaw,Lee,&

Lahey,2009）,ADHDisalsoassociatedwithneuropsychologicaldeficitsacrossdomainssuchascognitiveflexibility,problemsolving,andworkingmemory（Willcutt,Doyle,Nigg,Faraone,&

Pennington,2005）.Workingmemory（WM）involvestheactivemaintenanceandmanipulationofinformation,andisgovernedbyexecutivecontrolprocesses（Baddeley,1992,2007）.Arecentmeta-analysisshowedthatchildrenwithADHDhavespecific,robustdeficitsinWM,whicharemorepronouncedinspatialWMtasksthaninverbalWMtasks（Martinussen,Hayden,Hogg-Johnson,&

Tannock,2005）.Furthermore,thereisevidencethatneuropsychologicaldeficits,includingproblemswithWM,partiallymediatethepersistenceofADHDovertime,aswellasthedegreeoffunctionalimpairmentassociatedwithADHD（Halperin,Trampush,Miller,Mark,&

Newcorn,2008）.&

NewcornForexample,ADHDisassociatedwithineffectiveuseofmemorystrategiesand/orafailuretosustaineffortfulprocessingovertime（O’Neill&

Douglas,1996）.Thismayalsoberelatedtoimpairmentsingoalmaintenance（Kane&

Engle,2003）.Agreatdealofresearchshowsthatinhibitorycontrolchangesdramaticallyacrossthelifespan（Bedard,Nichols,Barbosa,Schachar,Logan,&

Tannock,2002;

Zelazo,Craik,&

Booth,2004）,andthatchildrenwithADHDhavespecificdeficitsininhibitorycontrol（Barkley,1997）.However,mostresearchonWM,inhibition,andexecutivecontrolhasusedtasksthatdonotprovidestrongincentivestoselectivelyfocusonandrememberimportantorhigh–valueinformation,atthecostoflower-valueinformation.TypicallyWMtasksdonotdiscriminateitemsbytheirrelativeimportanceandWMperformanceisoperationalizedbyhowmanyitemsareretained.ThepresentstudyexpandsontheliteratureonWMbyexamininghowchildrenwithandwithoutADHDstrategicallyfocusonandretainhigh-valueinformationinWMandhowthisabilitychangeswithtaskexperience.

The“selectivitytask,”arelativelynovelmethodforexamininghowpeoplecanselectivelyencodeandmaintainhigh-valueinformation,differsfromtraditionalmeasuresofWMinthatitinvestigateshowoneselectivelyencodesinformationusingstrategiccontrol,andhasnowbeenusedinseveralstudieswithvariouspopulations（seeCastel,Benjamin,Craik,&

Watkins,2002;

Castel,Farb,&

Craik,2007;

Hanten,Li,Chapman,Swank,Gamino,Roberson,&

Levin,2007;

Watkins&

Bloom,1999）.Inthepresentstudy,weusedamodifiedformofthisparadigm,inwhichwordswithdifferentvalues（e.g.,points）weretoberememberedbytheparticipant.Thisprocedureallowsonetoexaminetheextenttowhichpeopleusevalue-basedinformationtoguidetheefficientuseofmemory（e.g.,byintentionallyrecallinghighervalueditems）.Thepointvalueassignedtoeachitemduringencodingindicateshowimportanteachitemistoremember.ThistaskdiffersfromtraditionalmeasuresofepisodicmemoryorcommontestsofWMspanasitexaminesthestrategiccontrolofencodinghigh-valueinformation.Whereasthisvalue-directedrememberingapproachmaysharesomeresourceswithWMfunction,theselectivitytaskspecificallyallowsforanexaminationofthestrategicdeploymentofmemorycapacity,andtheawarenessoflimitedmemorycapacity（whichcanbeconceptualizedasaformofmetamemory）.

Intheselectivityparadigm,participantsarepresentedwithlistsofwords,witheachwordinthelisthavingadistinctvaluerangingfrom1to12points.Participantsareinstructedtorememberasmanywordsaspossible,withthegoalofmaximizingtheirscore,whichisthesumofthepointvaluesofeachrecalledword.Afterrecall,participantsaretoldtheirscore,andthenaregivenanewlist,withinstructionstomaximizetheirscore.Usingaselectivityindex（SI）developedbyWatkinsandBloom（1999;

seealsoHantenetal.,2007）,weexaminedhowselectivitychangedwithtaskexperience.ThisSIisbasedontheparticipant’sscore（thesumofthepointsthatwerepairedwiththerecalleditems,orthe“value”oftherecalleditems）,relativetochanceandidealperformance.Theequationaccountsfortheparticipant’sscorerelativetoanidealscorethatrepresentsrecallofonlythemosthighlyvaluedwordsatthatlevelofrecall.Forexample,ifagivenparticipantrememberedfourwords,andthepointsassociatedwiththewordswere12,10,9,and8,thatparticipants’SIwouldbeconsideredquitehigh.Theidealscoreforfourwordsis12+11+10+9=42,whereasthescoreoftheparticipantinquestionis39.Achancescoreisbasedoncalculatingtheaveragevalueofthepoints（usinga12-wordlist,withnumbersrangingfrom1to12,theaveragewouldbe6.5）andmultiplyingthatvaluebythenumberofwordsrecalled（inthiscase,4）.Thus,theSIinthiscaseis（39–26）/（42–26）=.81.Itisimportanttonotethattheindexcanrangefrom1to_1.PerfectselectivitywouldresultinanSIof1.0,whereasselectionofwordswiththelowestvalues（e.g.,recallingthe1-,2-,and3-pointwords）wouldresultinanSIof_1.0.Asetofwordsrecalledwithnoregardtotheirpointvalues（i.e.,showingnoselectivity）wouldresultinaselectivityindexcloseto0.Thus,theSIprovidesaselectivity,orefficiency,indexbasedonone’sactualscore,relativetoanidealscore,takingintoaccountthenumberofwordsrecalled.

Previousworkusingtheselectivitytaskhasshownthatalthoughhealthyolderadultsrecalledfewerwordsthanyoungeradults,olderadultsenhancedtheirselectivityscore（tolevelssimilartoyoungeradults）byrecallinghigh-valueitems（Casteletal.,2002）.Inaddition,Castelandcolleagues（2009）haveshownthat,despiterecallingfeweritemsrelativetoyoungeradults,healthyolderadultsbegintodevelopastrategy（afterseverallists）offocusingonthehighervalueitemstomaximizetheirscore.ThisabilitytobeselectivewasfoundtobesomewhatimpairedinolderadultswithearlysignsofAlzheimer’sdisease（Castel,Balota,&

McCabe,2009）.Inaddition,Hantenandcolleaguesfounddeficitsamongchildrenwithbraininjuryandautism（Hantenetal.,2002,2004）.Ofsignificancetothecurrentstudy,Hantenandcolleagues（2007）observedthatthenumberofwordsrecalledandselectivitywereindependentinadiversesampleofchildren,suggestingthatperhapsdifferentneuralsystemsmaycontributetomemorycapacityandtheselectivecontrolofattentiontohigh-valueitems.Thus,theSIprovidesausefulmeasureofmemoryefficiencythatgoesbeyondsimplymeasuringtheoverallquantityofrecalleditems（cf.Koriat&

Goldsmith,1996）.Thesefindingssuggestanimportantdistinctionbetweenmemoryquantityandefficiencyacrossthelifespan.

Theselectivitytaskcanalsoprovideameasureofhowpeoplelearnwhichitemstoattendtoacrosslists（i.e.,withtaskexperience）.Inthistask,participantsarepresentedwithseverallistsortrials,andaftereachlistaregivenfeedbackabouttheirscore,whichisthesumofthepointvaluesofthewordsthattheyrecalled.Toachieveanoptimalscore（viaefficientuseofmemory）,participantsneedtofocusonorattendtothehigh-valueitemsandrecallthemontheimm