Memory - Griffith University · encoded, or cast into a representational form or ‘code’ that...

MemoryL E A R N I N G O B J E C T I V E S

After studying this chapter you should be able to:

1 describe memory and outline the model of information processing

2 describe working memory

3 outline the major types of long-term memory

4 describe how information is encoded and organised in long-term memory

5 explain why remembering, misremembering and forgetting occur.

7

Burton, Lorelle, et al. Psychology, Wiley, 2014. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/griffith/detail.action?docID=3059089.Created from griffith on 2018-02-26 16:59:57.

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7 CONCEPT MAP

Memory

Central questions: what is memory?◆ The concept of memory is expanding and we are beginning to see an integration among the

differing psychological perspectives.

Long-term memory

Central executiveShort-term memory

Visuospatial sketchpad

Verbal phonological store

Sensory memory

Procedural

Semantic (general memory)

(Memory for particular events)

• driving• reading• typing

• covers memory for colours, smells, taste, images, sounds and feeling

• flashbulb memories• autobiographical

Information processing

• sensory• verbal• motoric

Short-term memory(20–30 seconds)

response

maintenancerehearsal Retrieval

Rehearsal

Long-term memory(enduring storage)

Sensory memory

Working memory

Central executive



articulatory or phonological loop

Long-term memorySensory memory

A memory is a mental representation for something to be remembered.

A visual overview of memory

Central quest ions: what is memory? ◆ The concept of memory is expanding and we are beginning to see an integration among the differing psychological perspectives.

Memory and information processing

• Forinformationtocomebacktomindafteritisnolongerpresent,ithastoberepresented.Sensory representationsstoreinformationinasensorymode;verbal representationsstoreinformationinwords.

• Thestandardmodelofmemoryispredicatedonthemetaphorofthemindasacomputer;itdistinguishesthree memorystores:sensory memory,short-term memory (STM)andlong-term memory (LTM).

Varieties of long-term memory

• Declarative memoryreferstomemoryforfactsandevents;itcanbesemanticorepisodic.Procedural memoryrefersto‘howto’knowledgeofproceduresor skills.

• Explicit memoryreferstoconsciousrecollection.Implicit memoryreferstomemorythatisexpressedin behaviour.

• Everyday memoryreferstomemoryasitoccursindaily life.

Encoding and organisation of long-term memory

• Toberetrievedfrommemory,informationmustbeencoded,orcastintoarepresentationalformor‘code’thatcanbereadilyaccessed.

• Mnemonic devicesaresystematicstrategiesforrememberinginformation.

• Knowledgestoredinmemoryformsnetworks of association—clustersofinterconnectedinformation.

• LTMisorganisedintermsofschemas,organisedknowledgestructuresorpatternsofthought.

Remembering, misremembering

and forgetting• Psychologistsoftendistinguishbetweentheavailability

of informationinmemoryanditsaccessibility.• Peoplemakememoryerrorsforavarietyofreasons.• Psychologistshaveproposedseveralexplanationsforwhy

peopleforget,includingdecay,interferenceandmotivatedforgetting.

• Memoriesrecoveredintherapycannotbeassumedtobeaccurate,buttheyalsocannotberoutinelydismissedasfalse.

• Specifickindsofdistortioncanalsooccurwithinthememoriesofpeoplewhosebrainshavebeenaffectedbyillnessorinjury.Anterograde amnesiainvolvestheinabilitytoretainnewmemories.Bycontrast,retrograde amnesiainvolveslosingmemoriesfromaperiodbeforethetimethataperson’sbrainwasdamaged.

Working memory• Working memoryreferstothetemporarystorageand

processingofinformationthatcanbeusedtosolveproblems,respondtoenvironmentaldemandsorachievegoals.

• BaddeleyandHitch’s(1974)modelproposedrehearsal,reasoningandmakingdecisionsabouthowtobalancetwotasksaretheworkofalimited-capacitycentralexecutivesystem.

• Mostcontemporarymodelsdistinguishbetweenavisualstore(thevisuospatialsketchpad)andaverbalstore.

• WorkingmemoryandLTMaredistinctfromoneanotherinboththeirfunctionsandneuroanatomy,butinteractto helpenhancememorycapacities.

246 Psychology | 4th Australian and New Zealand EditionBurton, Lorelle, et al. Psychology, Wiley, 2014. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/griffith/detail.action?docID=3059089.Created from griffith on 2018-02-26 16:59:57.

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CONCEPT MAP

Memory

Central questions: what is memory?◆ The concept of memory is expanding and we are beginning to see an integration among the

differing psychological perspectives.

Long-term memory

Central executiveShort-term memory



Sensory memory

Procedural

Semantic (general memory)

(Memory for particular events)

• driving• reading• typing

• covers memory for colours, smells, taste, images, sounds and feeling

• flashbulb memories• autobiographical

Information processing

• sensory• verbal• motoric

Short-term memory(20–30 seconds)

response

maintenancerehearsal Retrieval

Rehearsal

Long-term memory(enduring storage)

Sensory memory

Working memory

Central executive



articulatory or phonological loop

Long-term memorySensory memory

A memory is a mental representation for something to be remembered.

A visual overview of memory

Central quest ions: what is memory? ◆ The concept of memory is expanding and we are beginning to see an integration among the differing psychological perspectives.

Memory and information processing

• Forinformationtocomebacktomindafteritisnolongerpresent,ithastoberepresented.Sensory representationsstoreinformationinasensorymode;verbal representationsstoreinformationinwords.

• Thestandardmodelofmemoryispredicatedonthemetaphorofthemindasacomputer;itdistinguishesthree memorystores:sensory memory,short-term memory (STM)andlong-term memory (LTM).

Varieties of long-term memory

• Declarative memoryreferstomemoryforfactsandevents;itcanbesemanticorepisodic.Procedural memoryrefersto‘howto’knowledgeofproceduresor skills.

• Explicit memoryreferstoconsciousrecollection.Implicit memoryreferstomemorythatisexpressedin behaviour.

• Everyday memoryreferstomemoryasitoccursindaily life.

Encoding and organisation of long-term memory

• Toberetrievedfrommemory,informationmustbeencoded,orcastintoarepresentationalformor‘code’thatcanbereadilyaccessed.

• Mnemonic devicesaresystematicstrategiesforrememberinginformation.

• Knowledgestoredinmemoryformsnetworks of association—clustersofinterconnectedinformation.

• LTMisorganisedintermsofschemas,organisedknowledgestructuresorpatternsofthought.

Remembering, misremembering

and forgetting• Psychologistsoftendistinguishbetweentheavailability

of informationinmemoryanditsaccessibility.• Peoplemakememoryerrorsforavarietyofreasons.• Psychologistshaveproposedseveralexplanationsforwhy

peopleforget,includingdecay,interferenceandmotivatedforgetting.

• Memoriesrecoveredintherapycannotbeassumedtobeaccurate,buttheyalsocannotberoutinelydismissedasfalse.

• Specifickindsofdistortioncanalsooccurwithinthememoriesofpeoplewhosebrainshavebeenaffectedbyillnessorinjury.Anterograde amnesiainvolvestheinabilitytoretainnewmemories.Bycontrast,retrograde amnesiainvolveslosingmemoriesfromaperiodbeforethetimethataperson’sbrainwasdamaged.

Working memory• Working memoryreferstothetemporarystorageand

processingofinformationthatcanbeusedtosolveproblems,respondtoenvironmentaldemandsorachievegoals.

• BaddeleyandHitch’s(1974)modelproposedrehearsal,reasoningandmakingdecisionsabouthowtobalancetwotasksaretheworkofalimited-capacitycentralexecutivesystem.

• Mostcontemporarymodelsdistinguishbetweenavisualstore(thevisuospatialsketchpad)andaverbalstore.

• WorkingmemoryandLTMaredistinctfromoneanotherinboththeirfunctionsandneuroanatomy,butinteractto helpenhancememorycapacities.

CHAPTER 7 | Memory 247Burton, Lorelle, et al. Psychology, Wiley, 2014. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/griffith/detail.action?docID=3059089.Created from griffith on 2018-02-26 16:59:57.

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Imagine walking into a room to find 300 people you have never met before, seated aroundtables. You briefly walk around the room, finding out the name of each person. Then, halfan hour later, you must go around the room and identify all 300 people by name. That’simpossible, you might think. No-one could memorise that many people’s names in such a

short spaceoftime.Well,don’ttellthattoKerryDomann,anAustralianentertainerwhoregularlyamazesdinnerfunc-

tionswithhisabilitytorecallthenamesofupto300audiencemembersjustminutesaftermeetingthemforthefirsttime.Performingunderthestagename‘TheAmazingNigel’,Kerryisindemandaroundthecountryasanafter-dinnerspeakerwhoenter-tainswithamixofcomedyandmagic.Theextremelyfunnyactregularlyhasthecrowd institches.But theclimaxof thestageshowoccurswhen‘Nigel’walks theroomnamingeachof theguests individually, to theamazementofthecrowd.Hisastoundingmemoryisnofluke—andhenowalsotrainspeopleinhistechniquesforimprovingmemory.So,howisitthatTheAmazingNigelcanperformfeatsofmemorythattomostpeoplewouldappearimpossible?Istheresomethinguniqueabouthimandhismemory?

Butwhat if yourmemory disappears altogether?One ofAustralia’smostlovedandmostenduringentertainmentfigureshashadanumberofepisodesofamnesia(memoryloss),whichthankfullyhaveturnedouttobetemporary.PattiNewton, thewife of television legendBertNewton, attended the 2012LogieAwardsinMelbourne.Afterwards,Pattiwenttosleepinherhotelroombutthenawokeinthemiddleofthenightandcouldnotrememberwhereshewas orwhat shewas doing.This followed similar episodes in recent years.AftersheattendedtheSydneypremiereofthemusicalWicked(featuringhus-band Bert) she flew back to Melbourne, but lost her memory on the drivehomefromtheairport.Shestoodoutsideherhousestaringatit,withnoideawhereshehadbeen,whatshehaddoneorwhereshewas.Similarly,onedayinMarch2006,Pattitookherclothesoffinherdriveway,thoughtitwas1950andcouldnotrecogniseBert.WhilePatti’sfullmemoryreturnedshortlyafter

thoseepisodesandsheisotherwisehealthy,sheisunderstandablyshakenbytheexperienceoflosingheridentityforthoseshortperiods.

Sojusthowdoesmemorywork?HowcanTheAmazingNigelrememberthenamesof300peoplehehasjustmet,whilePattiNewtonsometimescannotevenrememberherownname?Casestudiesofneurologically impairedpatientsandexperimental studiesofnormal subjectshavedemonstratedthatmemoryisnotasinglefunctionthatapersoncanhaveorlose.Rather,memoryiscomposedofseveralsystems.Justhowmanysystems,andhowindependentlytheyfunction,arequestionsattheheartofcontemporaryresearch.

Thepreviouschapterwasdominatedbythebehaviouristperspective; thisoneandthenextfocusprimarilyonthecognitiveperspective.Webeginbyconsideringsomeofthebasicfeaturesofmemoryandanevolvingmodelofinformationprocessingthathasguidedresearchonmemoryforoverthreedecades.Wethenexplorethememorysystemsthatallowpeopletostoreinformationtemporarilyandpermanently,andexaminewhypeoplesometimesforgetandmisremember.Alongtheway,wecon-sidertheimplicationsofmemoryresearchforissuessuchastheaccuracyofeyewitnesstestimonyincourtandtheexistenceofrepressedmemoriesinvictimsofchildhoodsexualabuse.

Twoquestionsformthebackdropofthischapter.Thefirstisdeceptivelysimple:Whatdoesitmeantoremember?Ismemorysimplytherecollectionof‘facts’?Ordoesmemoryextendtotheactivation(or reactivation)ofgoals, emotionsandbehaviours—aswhenweeffortlessly ‘remember’how todrive, evenwhile deeply engrossed in conversation? Second,what is the relationship between thekindoflearningdescribedinthelastchapter,whichemphasisedbehavioursandemotionalresponses,andmemory?

Central quest ions ◆ What does it mean to remember?

◆ What is the relationship between learning and memory?


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■ Memory and information processingMemoryissobasictohumanfunctioningthatwetakeitforgranted.Considerwhatwasinvolvedthelasttimeyouperformedtheseeminglysimpletaskofrememberingafriend’sphonenumber.Didyoubringtomindavisualimage(apictureofthenumber),anauditory‘image’(pronouncingaseriesofnumbersout loud inyourmind)orsimplyapatternofmotormovementsasyoupunchedthenumbersonthephone?Howdidyoubringtomindthisparticularnumber,giventhatyouprob-ablyhaveadozenothernumbersstoredinmemory?Onceanumberwasinyourmind,howdidyouknowitwas therightone?Andwereyouawareasyoureachedforthephonethatyouwererememberingatthatverymomenthowtouseaphone,whatphonesdo,howtoliftanobjectsmoothlytoyourface,howtopushbuttonsandwhoyourfriendis?

This example suggests how complex the simplest act of memoryis.Memory involves taking somethingwe have observed, such as awritten phone number, and converting it into a form we can store,retrieveanduse.Webeginbybrieflyconsideringthevariouswaysthebrain canpreserve thepast— the ‘rawmaterial’ ofmemory—andanevolvingmodelofinformationprocessingthathasguidedpsychol-ogists’effortstounderstandmemoryforthelastquarterofacentury.

Mental representationsForasound,imageorthoughttoreturntomindwhenitisnolongerpresent,ithastoberepresentedinthemind—literally,re-presented,orpresentedagain—thistimewithouttheoriginalstimulus.Aswesawinchapter4,amentalrepresentationisapsychologicalversionormentalmodelofastimulusorcategoryofstimuli.Inneuropsychologicalterms,itisthepatternedfiringofanetworkofneuronsthatformstheneural‘code’foranobjectorconcept,suchas‘dog’or‘sister’.

Representationalmodesarelikelanguagesthatpermitconversationwithinthemind(seeJackendoff,1996).Thecontentofourthoughtsandmemories—abird,anangryfriend,abeautifulsunset—canbedescribedortranslatedintomany‘languages’—images,sounds,wordsandsoforth —butsomelanguagescannotcapturecertainexperiencesthewayotherscan.Fortunately,weareall‘multilingual’andfrequentlyprocessinformationsimultaneouslyusingmultiplerepresentationalcodes(chapter3).

Somekindsof representationaredifficult toconceptualiseandhave received lessattention fromresearchers.Forexample,people storememoriesofactions, suchashow topress thebuttonsonaphoneorhowtosqueezethelastdropsoftomatosauceoutofthebottle,whichsuggeststheexistenceofmotoric representations,orstoredmemoriesofmusclemovements.Themostcommonlystudiedrepresentationsaresensoryandverbal.

Sensory representationsSensory representations store information inasensorymode,suchasthesoundofadogbarkingortheimageofacityskyline.Thecognitivemaps discovered in rats running mazes (chapter 6) probably includevisual representations. People rely on visual representations to recallwhere they left their keys last night or to catch a ball that is sailingtowards them through the air.Visual representations are like picturesthatcanbementallyscrutinisedormanipulated(Burton,2003;Burton&Fogarty,2003;Kosslyn,1983).

The auditory mode is also important for encoding information(Thompson&Paivio, 1994). Some forms of auditory information aredifficulttorepresentinanyothermode.Forinstance,mostreaderswouldbeabletoretrieveatunebytheFooFightersorGuySebastianwithlittledifficulty,butwouldhavemuchmoretroubledescribingthemelodythan‘hearing’itintheirminds.

Other types of sensory information have their own mental codes as well. People can identifymany objects by smell, a finding that suggests that they are comparing current sensory experi-encewith olfactory knowledge (Degel,Piper,&Koster,2001;Schab&Crowder,1995).Olfactory

MAKING CONNECTIONS

Although olfactory memory is less ‘accurate’ than visual memory, it is far more emotionally charged. The smell of freshly cut grass can evoke powerful emotional memories from childhood. The scent of a favourite perfume may elicit recognition from grandmother, even in the last stages of Alzheimer’s. Thus, smell (chapter 4) and emotion (chapter 11) are strongly linked by memory.

Fans of pop star Guy Sebastian would likely find it easier to ‘hear’ one of his songs than to describe it.


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representations in humans are, however, far less reliable than visual representations in identifyingeven common objects (deWijk, Schab,&Cain, 1995). For example, if exposed to the smell of alemon,peopleoftenmisidentifyitasanorange,whereaspeoplewithanintactvisualsystemrarelyconfusethetwofruitsvisually.Morerecentresearchindicatesthattwoodoursneedtobepresentedinitiallyasamixture, rather thanas twoseparateodours, to increaseparticipants’similarityratingsof the twoodours ineachpair.This perceptual learningeffect is rapidandresistant to interference(Stevenson,Case,&Boakes,2005).

Interestingly,memoriesofourpast canbeevokedby smell.MilesandBerntsen (2011) recentlydemonstratedthatodourcaninduceparticipantstorememberandrelivepastevents,especiallythosethatoccurredinthefirst10yearsoftheirlives.

Verbal representationsAlthoughmany representations are stored in sensorymodes,much of the time people think usingverbal representations,orinformationstoredinwords.Trytoimaginewhat‘liberty’or‘mentalrep-resentation’meanswithoutthinkinginwords.Otherexperiences,incontrast,arevirtuallyimpossibletodescribeorrememberverbally,suchasthesmellofbacon.Infact,usingwordstodescribethingsaboutwhichonehaslittleverbalknowledgecanactuallydisruptsensory-basedmemory.

Neuroimaging studies confirm that verbal representations are in fact distinct from sensory rep-resentations.ConsiderwhathappenswhenresearcherspresentparticipantswithastringofX’sversusaword(Menard,Kosslyn,Thompson,Alpert,&Rauch,1996).Bothstimulileadtoactivationofthevisualcortex,sincebothareprocessedvisually.Presentationoftheword,however,leadstoadditionalactivationofaregionatthejunctureoftheleftoccipital,parietalandtemporallobesthatappearstobeinvolvedintransformingthevisualrepresentationintoaverbalorsemanticone.

I N T E R I M S U M M A R YForinformationtocomebacktomindafteritisnolongerpresent,ithastoberepresented.Sensory representationsstoreinformationinasensorymode;verbal representationsstoreinformationinwords.Peoplealsostoreknowledgeaboutactionsasmotoricrepresentations.

Information processing: an evolving modelPsychologistsbeganstudyingmemoryinthelatenineteenthcentury,althoughinterestinmemorywanedunder the influenceofbehaviourismuntil the ‘cognitive revolution’of the1960s. In1890,WilliamJamesproposedadistinctionbetweentwokindsofmemory,whichhecalledprimaryandsecondarymemory.Primarymemoryisimmediatememoryforinformationmomentarilyheldinconsciousness,suchasa telephonenumber.Secondarymemoryis thevaststoreof information that isunconsciousexceptwhencalledback intoprimarymemory,suchas the10or20phonenumbersapersoncouldbringtomindifhewantedtocallvariousfriends,familymembers,shopsandsoforth.James’distinc-tionisembodiedinwhatwewillcallthestandardmodelofmemory.Thismodelhasguidedresearchonmemoryandcognitionsincethe1960s(Atkinson&Shiffrin,1968;Healy&McNamara,1996).

Thestandardmodelispredicatedonthemetaphorofthemindasacomputer,whichplacesinfor-mationintodifferentmemorystores(thesystem’s‘hardware’)andretrievesandtransformsitusingvariousprograms(‘software’).Accordingtothismodel(figure7.1),memoryconsistsofthreestores:sensory registers, short-term memory (James’ primary memory) and long-term memory (James’secondarymemory).Storingandretrievingmemoriesinvolvepassinginformationfromonestoretothenextandthenretrievingtheinformationfromlong-termmemory.

Re

hearsal

Sensoryregisters

Short-termmemory (STM)

Long-termmemory (LTM)Stimulus

Information lost Information lost Information lost

Retrieval

FIGURE 7.1Standard model of memory. Stimulus information enters the sensory registers. Some information enters STM and is then passed on for storage in LTM. Information can be lost from any of the sensory stores, usually if it is not very important or if a traumatic event has occurred that interferes with memory consolidation or retrieval.


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Sensory registersSuppose you grab a handful of coins (say, six or seven) from your pocket at the laundromat and,whilelookingaway,stretchoutyourhandsothatallofthecoinsarevisible.Ifyouthenglancefora secondatyourhandbut lookawaybeforecounting thechange,youare still likely tobeable toreportaccurately thenumberofcoins inyourhandbecause the image isheldmomentarily inyourvisual sensory register.Sensory registershold informationaboutaperceivedstimulus forapproxi-matelyhalfasecondafterthestimulusdisappears,allowingamentalrepresentationofittoremaininmemorybrieflyforfurtherprocessing(figure7.2)(Sperling,1960).

Display

M Q T Z

R F G A

N S L C

High

Medium

Low

If low tonewas sounded

“N, S, L, C”

Tone Response FIGURE 7.2Visual sensory register. In a classic experiment, participants briefly viewed a grid of 12 letters and then heard a tone after a short delay. They had been instructed to report the top, middle or bottom row, depending on whether a high, medium or low tone sounded. If the tone sounded within half a second, they were 75 percent accurate, by reading off the image in their mind (iconic storage). If the tone sounded beyond that time, their accuracy dropped substantially because the visual image had faded from the sensory register.Source: Sperling (1960).

Most research has focused on visual and auditory sensory registration.The term iconic storagedescribesmomentarymemory for visual information. For a brief period after an image disappearsfromvision, people retain amental image (or ‘icon’) ofwhat they have seen.This visual trace isremarkably accurate and contains considerablymore information than people can report before itfades(Baddeley&Patterson,1971).Thedurationoficonsvariesfromapproximatelyhalfasecondtotwoseconds,dependingontheindividual, thecontentoftheimageandthecircumstances(Neisser,1976).Recentresearchindicatesthatemotionalinformation,particularlyvisualstimulievokingfear,is subject to slow decay in iconic storage (Kuhbandner, Spitzer, & Pekrun, 2011). The auditorycounterpartoficonicstorageiscalledechoic storage,momentarymemoryforauditoryinformation(Battacchi,Pelamatti,Umilta,&Michelotti,1981;Neisser,1967).

Short-term memoryAccording to the standardmodel, then, thefirst stage ofmemory is a brief sensory representationof a stimulus.Many stimuli that people perceive register for such a short time that they drop outof the memory system without further processing, as indicated in figure 7.1 (‘information lost’).Otherstimulimakeagreaterimpression.Informationaboutthemispassedontoshort-term memory (STM),amemorystorethatholdsasmallamountofinformationinconsciousness—suchasaphonenumber—for roughly20 to30seconds,unless thepersonmakesadeliberateeffort tomaintain itlongerby repeating itoverandover (Waugh&Norman,1965).SeeNairne (2002) fora reviewofrecentresearchthatidentifiestheconceptualandempiricalproblemsofthestandardmodelofSTM.Nairneargues thatSTMiscuedriven,much like long-termmemory,and thatneither rehearsalnordecayislikelytoexplainshort-termforgetting.

Limited capacityShort-termmemory has limited capacity— that is, it does not holdmuch information. To assessSTM,psychologistsoftenmeasureparticipants’digitspan;thatis,howmanynumberstheycanholdinmindatonce.Onaverage,peoplecanrememberaboutsevenpiecesofinformationatatime,withanormalrangeoffromfivetonineitems(Miller,1956).Thatphonenumbersinmostcountriesarefivetosevendigitslongisnocoincidence.

HermannEbbinghaus(1885/1964)wasthefirsttonotetheseven-itemlimittoSTM.Ebbinghauspioneered thestudyofmemoryusing themostconvenientandagreeablesubjecthecouldfind—himself—withamethod that involved inventing some2300nonsense syllables (suchaspir andvup).Ebbinghausrandomlyplacedthesesyllablesinlistsofvaryinglengthsandthenattemptedtomemorisethelists;heusednonsensesyllablesratherthanrealwordstotrytocontrolthepossibleinfluenceof prior knowledgeonmemory.Ebbinghaus found that he couldmemoriseup to seven

APPLY ✚ DISCUSS• In what ways is the mind like

a computer?

• In what ways does the computer metaphor fail to capture important aspects of human psychological functioning?


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syllables,butnomore,inasingletrial.ThelimitsofSTMseemtobeneurologicallybased,astheyaresimilarinothercultures,includingthosewithverydifferentlanguages(Yuetal.,1985).

BecauseofSTM’slimitedcapacity,psychologistsoftenlikenittoalunchcounter(Bower,1975).Ifonlysevenstoolsareavailableatthecounter,somecustomerswillhavetogetupbeforenewcus-tomerscanbeseated.Similarly,newinformation‘bumps’previousinformationfromconsciousness.Figure7.3illustratesthisbumpingeffect.

RehearsalShort-termmemoryisnot,however,acompletelypassiveprocessofgettingbumpedoffastool.Peoplecan control the information stored in STM. For example, after looking up a phone number, mostpeoplewillrepeat theinformationoverandoverintheirminds—aprocedurecalledrehearsal—topreventitfromfadinguntiltheyhavedialledthenumber.Thiskindofmentalrepetitioninorderto maintaininformationinSTMiscalledmaintenance rehearsal.

Rehearsalisalsoimportantintransferringinformationtolong-termmemory,afindingthatwillnotsurpriseanyonewhohasevermemorisedapoemoramathsformulabyrepeatingitoverandover.Aswewill see, however,maintenance rehearsal is not as useful for storing information inlong-term memory as actively thinking about the information while rehearsing, a procedureknown aselaborative rehearsal.Rememberingthewords toapoem,forexample, ismucheasieriftheperson reallyunderstandswhatitisabout,ratherthanjustcommittingeachwordtomemorybyrote.

I N T E R I M S U M M A R YThe standard model of memory is predicated on the metaphor of the mind as a computer. Itdistinguishes three memory stores: sensory memory (or sensory registers), short-term memoryand long-term memory. Sensory registers hold information about a perceived stimulus forapproximatelyhalfasecondafterthestimulusdisappears.Fromthesensoryregisters,informationispassedontoalimited-capacityshort-term memory (STM),whichholdsuptosevenpiecesofinformation inconsciousnessfor roughly20 to30secondsunless thepersonmakesa deliberateefforttomaintainitbyrepeatingitoverandover(maintenance rehearsal).Elaborative rehearsal,whichinvolvesactuallythinkingaboutthematerialwhilecommittingittomemory,ismoreusefulforlong-termthanforshort-termstorage.

Long-term memoryJustas relativelyunimportant informationdropsoutofmemoryafterbrief sensory registration, thesame is trueafter storage inSTM.An infrequentlycalledphonenumber isnotworthclutteringupthememorybanks.Moreimportantinformation,however,goesontolong-term memory (LTM),inwhich representationsof facts, images, thoughts, feelings, skills andexperiencesmay reside for aslongasalifetime.Accordingtothestandardmodel,thelongerinformationremainsinSTM,themorelikely it is tomakeapermanent impression inLTM.Recovering informationfromLTM,knownasretrieval,involvesbringingitbackintoSTM(whichisoftenusedininformation-processingmodelsasasynonymforconsciousness).

Why did researchers distinguish short-term from long-term memory? One reason was simple:short-termmemoryisbrief,limitedincapacityandquicklyaccessed,whereasLTMisenduring,vir-tuallylimitless,butmoredifficulttoaccess(asanyoneknowswhohastriedtorecallaperson’snameoratermonanexamwithoutsuccess).

Another reason emerged as psychologists testedmemory using free-recall tasks. In free-recalltasks, the experimenter presents participants with a list of words, one at a time, and then asksthem to recall as many as possible.When the delay between presentation of the list and recallis short, participants demonstrate a phenomenon known as the serial position effect: a ten-dency to remember information towards thebeginningandendofa list rather than in themiddle(figure 7.4).

FIGURE 7.3Short-term memory. In an experimental task, the participant is presented with a string of seven digits (a). Without rehearsal, 20 seconds later, the representations of the digits have begun to fade but are still likely to be retrievable (b). At 25 seconds, however, the experimenter introduces three more digits, which ‘bump’ the earliest of the still-fading digits (c).

(a) 7 6 3 8 8 2 6(b) 7 6 3 8 8 2 6 (20 seconds later)(c) 9 1 8 8 3 2 6 (25 seconds later)


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Prob

abili

ty o

f rec

all

1

.5

0

Primacy

Recency

Middle Late

Order of items

Early

FIGURE 7.4Serial position effect. Items earlier in a list and those at the end show a heightened probability of recall in comparison to those in the middle.Source: Atkinson and Shiffrin (1968).

Evolution of the modelAlthough the standard model provides a basic foundation for thinking about memory, in the lastdecadeithasevolvedinfourmajorrespects.First,thestandardmodelisaserialprocessingmodel:it proposes a series of stages ofmemory storage and retrieval thatoccuroneata time(serially) inaparticularorder,with informationpassingfromthesensoryregisterstoSTMtoLTM.ForinformationtogetintoLTM,itmustfirstberepresentedineachofthepriortwomemorystores,andthelongeritstaysinSTM,themorelikelyitistoreceivepermanentstorageinLTM.

Subsequentresearchsuggeststhataserialprocessingmodelcannotprovideafullaccountofmemory.Mostsensoryinformationisneverprocessedconsciously(i.e.,placedinSTM),butitcanneverthelessbestoredandretrieved—anexplanationforthefamiliarexperienceoffindingoneselfhummingatunethatwasplayinginthebackgroundatastorewithouteverhavingnoticedconsciouslythatitwasplaying.

Further, the process of selecting which sensory information tostore in STM is actually influenced byLTM; that is, LTM is oftenactivated before STM rather than after it. The function of STM isto hold important information in consciousness long enough touse it to solveproblems andmakedecisions.Buthowdoweknowwhatinformationisimportant?Theonlywaytodecidewhichinfor-mationtobringintoSTMistocompareincomingdatawithinformationstoredinLTMthatindicatesitspotentialsignificance(Logie,1996).Thus,LTMmustactuallybeengagedbeforeSTMtofigureouthowtoallocateconsciousattention(chapter5).

Asecondmajorshiftisthatresearchershavecometoviewmemoryasinvolvingasetofmodules —discrete but interdependent processing units responsible for different kinds of remembering.Thesemodulesoperate simultaneously (i.e., inparallel), rather thanserially (oneata time) (Fodor,1983;Rumelhart,McClelland,&thePDPResearchGroup,1986).Thisviewfitswithneuropsychologicaltheoriessuggesting that thecentralnervoussystemconsistsofcoordinatedbutautonomously func-tioningsystemsofneurons.

Forinstance,whenpeoplesimultaneouslyhearthunderandseelightning,theyidentifythesoundusing auditory modules in the temporal cortex and identify the image as lightning using visualmodules in theoccipitalandlower(inferior) temporal lobes(the‘what’pathway),andpinpoint thelocation of the lightning using a visual–spatial processingmodule (the ‘where’ pathway) that runsfromtheoccipital lobesthroughtheupper(superior)temporalandparietal lobes(chapter4).Whentheyremembertheepisode,however,allthreemodulesareactivatedatthesametime,sotheyhavenoawarenessthatthesememorysystemshavebeenoperatinginparallel.

Similarly,researchershavecometoquestionwhetherSTMisreallyasinglememorystore.Aswewillseeshortly,experimentalevidencesuggeststhatSTMispartofaworkingmemorysystemthatcanbrieflykeepatleastthreedifferentkindsofinformationinmindsimultaneouslysothattheinfor-mationisavailableforconsciousproblemsolving(Baddeley,1992,1995).

Third, researchers once focused exclusively on conscious recollection of word lists, nonsensesyllables and similar types of information. Cognitive psychologists now recognise other forms ofremembering thatdonot involveretrieval intoconsciousness.Anamnesic likeJimmie(whosecaseopenedthischapter)wholearnsanewskill,orachildwholearnstotieashoe,isstoringnewinfor-mation inLTM.When this information is remembered, however, it is expresseddirectly in skilled

APPLY ✚ DISCUSS

At times, we all have trouble remembering certain things, such as a friend’s birthday. But, what about remembering to remember? If I put a shirt in the dryer to dry for only 20 minutes, I need to remember in a short time to take the shirt out of the dryer.

• What part of the memory system do you think is related to remembering to remember?

• During the 20-minute interval that the shirt is drying, do most people constantly rehearse in their minds that they need to take the shirt out? Do they use external memory aids, such as a timer?

• How successful are you at remembering to remember?


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behaviour rather than retrieved into consciousness or STM. Further, researchers are now payingcloser attentionto thekindsofrememberingthatoccur ineverydaylife,aswhenpeoplerememberemotionallysignificanteventsortrytoremembertopickupseveralitemsatthesupermarketonthewayhomefromwork.

Thefourthchangeisashiftinthemetaphorunderlyingthemodel.Researchersinthe1960swerestruck by the extraordinary developments in computer science that were just beginning to revol-utionise technology, and they saw in the computer a powerful metaphor for the most impressivecomputingmachineeverdesigned:thehumanmind.Today,afteradecadeormoreofsimilarlyextra-ordinaryprogressinunravellingthemysteriesofthebrain,cognitivescientistshaveturnedtoadif-ferentmetaphor:mindasbrain.

Intheremainderofthischapterwewillexplorethemajorcomponentsofthisevolvingmodel.Webeginwithworkingmemory(thecurrentversionofSTM)andthenexaminethevarietyofmemoryprocessesandsystemsthatconstituteLTM.

I N T E R I M S U M M A R YIn long-term memory (LTM), representations of facts, images, thoughts, feelings, skills andexperiencesmayresideforaslongasalifetime.RecoveringinformationfromLTM,orretrieval,involvesbringingitbackintoSTM.Theserial position effect isa tendencytorememberinfor-mationtowardsthebeginningandendofalistratherthanfromthemiddle.Althoughthestandardmodel still provides a foundation for thinking aboutmemory, in the last decade it has evolvedin fourmajorways. First, the assumption that a serial processingmodel can account for all ofmemory no longer seems likely. Second and related, researchers have come to view memoryas involving a set of modules— discrete but interdependent processing units responsible fordifferentkindsofremembering thatoperatesimultaneously(inparallel) rather than sequentially(oneatatime).Third,thestandardmodeloveremphasisesconsciousmemoryforrelativelyneutralfacts and underemphasises other forms of remembering, such as skill learning and everydayremembering. Fourth, the underlying metaphor has changed, from mind as computer to mindas brain.

■ Working memoryBecausepeopleuseSTMasa‘workspace’toprocessnewinformationandtocalluprelevantinfor-mation from LTM, many psychologists now think of STM as a component of working memory.Working memory refers to the temporary storage and processing of information that can be usedto solveproblems, respond toenvironmentaldemandsorachievegoals (seeBaddeley,1992,1995;Richardson,1996a,1996b).

Workingmemoryisactivememory:informationremainsinworkingmemoryonlyaslongastheperson is consciously processing, examining or manipulating it. Like the older concept of STM,workingmemory includes both a temporarymemory store and a set of strategies, or control pro-cesses, for mentally manipulating the information momentarily held in that store. These controlprocessescanbeassimpleasrepeatingaphonenumberoverandoveruntilwehavefinisheddiallingit—orascomplexastryingtosolveanequationinourheads.

Researchersinitiallybelievedthatthesetwocomponentsofworkingmemory—temporarystorageandmentalcontrol—competedfor the limitedspaceat the lunchcounter. In thisview,rehearsinginformationisanactiveprocessthatitselfusesupsomeofthelimitedcapacityofSTM.Researchersalso tended toviewSTMas a single system that couldhold amaximumof about sevenpiecesofinformationofanykind,whethernumbers,wordsorimages.

Morerecentresearchsuggests,instead,thatworkingmemoryconsistsofmultiplesystemsandthatitsstorageandprocessingfunctionsdonotcompetefor limitedspace.According tooneprominentmodel,workingmemoryconsistsofthreememorysystems:avisualmemorystore,averbalmemorystore and a ‘central executive’ that controls andmanipulates the information these two short-termstoreshold inmind(Baddeley,1992,1995).Webeginbydiscussing thecentralexecutiveand thenexaminethememorystoresatitsdisposal.


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Processing information in working memory: the central executiveIn 1974,Alan Baddeley andGrahamHitch challenged the view of a single all-purposeworkingmemorybypresentingparticipantswith twotaskssimultaneously,one involvingrecallofaseriesof digits and the other involving some kind of thinking, such as reasoning or comprehendingthe meaning of sentences. They reasoned that if working memory is a single system, trying toremembersevenoreightdigitswouldfillthememorystoreandeliminateanyfurthercapacityforthinking.

TheinvestigatorsdidfindthatperformingSTMandreasoningtaskssimultaneouslyslowedpar-ticipants’ ability to think. In one study, holding amemory load of four to eight digits increasedthetimeparticipantstooktosolveareasoningtask(figure7.5).However,amemoryloadofthreeitems had no effect at all on reasoning speed, despite the fact that it should have consumed atleast threeof the‘slots’ inSTM.Further,performingthetwotaskssimultaneouslyhadnoimpacton the numberoferrorsparticipantsmadeon the thinking task, suggesting that carryingoutpro-cesses suchas reasoningand rehearsal doesnot competewith storingdigits for ‘workspace’ in ashort-term store.

TheseandotherdataledBaddeleyandhiscolleaguestoproposethatstoragecapacityandpro-cessing capacity are two separate aspects ofworkingmemory. Processes such as rehearsal, rea-soning and making decisions about how to balance two tasks simultaneously are the work ofa central executive system that has its own limited capacity, independent of the information itis storing or holdingmomentarily inmind. Other researchers have found that workingmemoryas a whole does seem to have a limited capacity— people cannot do and remember toomanythingsat the same time —butworkingmemorycapacityvariesacross individualsand is relatedtotheirgeneralintellectualability(chapter9)(Baddeley,2001;Daneman&Merikle,1996;Just &Carpenter, 1992; Logie, 1996). Indeed, children also demonstrate working memory limitations.For example, Halford and his colleagues at theUniversity ofQueensland’s Cognition and Human Reasoning Laboratoryhave investigated the role of learning and information pro-cessinglimitationsinshapingchildren’scognitions.Theyhavefoundevidenceforacapacity limitation inyoung infants,andtheirresearchindicatesthatthecomplexityofinformationpro-cessed by children increases with age (Halford, Maybery, &Bain, 1986; Halford,Wilson, & Phillips, 1998). Similarly, astudy of 144 Year 1 children fromQueensland state primaryschoolsshowedastrongrelationshipbetweenworkingmemoryand children’s cognitive functioning (O’Connor, Spencer, &Patton,2003).

Recent research indicates that children with attention-deficithyperactivitydisorderarelikelytohavedeficitsinworkingmemorywhencomparedtotheirpeers(Kasper,Alderson,&Hudec,2012).Forboys,theseworkingmemorydeficitsmostlikelyoccurintheareaofthecentralexecutive(Rapportetal.,2008).

Visual and verbal storageMostcontemporarymodelsofworkingmemorydistinguishbetweenatleasttwokindsoftemporarymemory: a visual store and a verbal store (Baddeley, 1995; Baddeley, Gathercole, & Papagno,1998). Evidence that these are indeed distinct components comes from several lines of research(figure7.6,overleaf).

Thevisualstore(alsocalledthevisuospatialsketchpad)islikeatemporaryimagethepersoncanholdinmindfor20or30seconds.Itmomentarilystoresvisualinformationsuchasthelocationandnatureofobjectsintheenvironment,sothat,forexample,apersonturningaroundtograbamugatthesinkwillrememberwheresheplacedateabagamomentbefore.Imagesinthevisualstorecanbementallyrotated,movedaroundorusedtolocateobjectsinspacethathavemomentarilydroppedoutofsight.

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FIGURE 7.5Speed and accuracy of reasoning as a function of number of digits to remember. Having to remember up to eight digits slowed the response time of participants as they tried to solve a reasoning task, but it did not lead to more errors. Keeping one to three digits in mind had minimal impact on reasoning time or speed.Source: Adapted from Baddeley, A. ‘Working Memory’, (1986), Fig 4.5 p. 67, by permission of Oxford University Press.

Research suggests there is a strong relationship between working memory and children’s cognitive functioning.


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FIGURE 7.6Independence of verbal and visual working memory storage. In one task, participants had to memorise briefly a sequence of letters (‘verbal span’), whereas in another they had to remember the location of an extra grey block on a grid (‘visual span’). At the same time, they either had to perform a verbal task (adding) or a visual one (imaging). As can be seen, the visual task interfered primarily with visual span, whereas the verbal task interfered primarily with verbal span.Source: Adapted from Logie, R., ‘The seven ages of working memory’, from ‘Working memory and Human Cognition’ by John T. E. Richardson et al., 1996, Fig 2.4, p. 47, by permission of Oxford University Press.

Theverbal(orphonological)storeisthefamiliarshort-termstorestudiedusingtaskssuchasdigitspan.Verbalworkingmemory is relatively shallow:words are stored in order, based primarily ontheirsound(phonology),not theirmeaning.TehanandHumphreys(1995)demonstratedtheimpor-tance of phonemic codes inworkingmemory bymanipulating the strength of phonemic codes intargetwords.They suggested that phonemic informationhelps tomake itemsmoredistinctive andthuseasilydiscriminablefromothertargetitems.

Researchers learnedabout the‘shallowness’ofverbalworkingmemorybystudyingthekindsofwords that interferewitheachother (Baddeley,1986; seealsoLange&Oberauer,2005).A list ofsimilar-soundingwords(suchasman,mat,capandmap)ismoredifficulttorecallthanalistof wordsthatdonotsoundalike.Similarityofmeaning(e.g., large,big,huge, tall)doesnotsimilarly inter-ferewithverbalworkingmemory,butitdoesinterferewithLTM.ThesefindingssuggestthatverbalworkingmemoryandLTMhavesomewhatdifferentwaysofstoringinformation.

I N T E R I M S U M M A R YMany psychologists now refer to STM asworking memory— the temporary storage and pro-cessing of information that can be used to solve problems, respond to environmental demandsor achieve goals.Workingmemory includes both a storage capacity and a processing capacity.According to themodel proposed byBaddeley and his colleagues, processes such as rehearsal,reasoningandmakingdecisionsabouthowtobalancetwotaskssimultaneouslyaretheworkofalimited-capacitycentralexecutivesystem.Mostcontemporarymodelsdistinguishbetweenatleasttwokindsoftemporarymemory—avisualstore(thevisuospatialsketchpad)andaverbalstore.

The neuropsychology of working memoryRecently researchers have begun tracking down the neuropsychology of working memory. Theemergingconsensus is thatworkingmemoryis‘orchestrated’,ordirected,by theprefrontalcortex,aregionofthebrainlongknowntobeinvolvedinthemosthigh-levelcognitivefunctions(Kane&Engle,2002).Wheninformationistemporarilystoredandmanipulated,theprefrontalcortexisacti-vatedalongwithwhicheverposterior regions (i.e., regions towards thebackof thebrain)normallyprocess thekindof informationbeingheldinmemory,suchaswordsor images(D’Espositoetal.,1997;Faw,2003;Goldman-Rakic,1996;Smith,2000).

Activationoftheprefrontalcortexseemstoprovideaccesstoconsciousnesstorepresentationsnor-mallyprocessedinotherpartsofthecortex,sothatthepersoncantemporarilyholdtheinformationinmindandmanipulateit.Evidenceforthepivotalroleoftheprefrontalcortexbegantoaccumulatewhenresearchersdesignedworkingmemorytasksformonkeysandobservedtheactivityofneuronsinthisregion(Fuster,1989,1997;Goldman-Rakic,1995).

Similar studieshavenowbeenconductedwithhumans. Inonestudy, the researchersused fMRI(functionalmagnetic resonance imaging) to study the activation of different cortical regionswhileparticipants tried to remember facesor scrambled faces (ameaninglessvisual stimulus) (Courtney,Ungerleider,Keil,&Haxby, 1997).The resultswere striking.Relativelymeaningless visual infor-mation activated posterior regions of the occipital lobes involved in the early stages of processingvisualstimuli.Facialstimuliactivatedareasof thevisualcortexintheoccipitalandtemporal lobesinvolved in processing and identifyingmeaningful visual stimuli (and perhaps faces in particular).


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Anteriorregionsofthefrontallobes,thatis,theprefrontalcortex,weremostactiveduringthedelayperiodinwhichthefacesandscrambledfaceswereremovedandhadtobeheldinworkingmemory.

Researchalsodemonstratestheindependenceofdifferentcomponentsof working memory. For example, neuroimaging studies confirm thatverbal and visual working memory activate different cortical regions(Smith, Jonides,&Koeppe,1996).A recentneuroimagingstudy foundthatgammabandactivityreadingsindicatewhetheramemoryisverbalor visual in nature (Hamamé et al., 2012). Studies even document theexistenceoftwodistinctkindsofvisualworkingmemory,processedindifferentareasoftheprefrontalcortex:memoryforlocationandmemoryforobjects(Courtney,Petit,Ungerleider,Maisog,&Haxby,1998;Rao,Rainier,&Miller,1997).Thisfindingmakessenseinthelightofresearchdescribed in chapter 4 that distinguishes between two visual pathwaysinvolvedinperception,the‘what’pathway(involvedinidentifyingwhatobjectsare)andthe‘where’pathway(involvedinidentifyingwheretheyareinspace).Researchershaveevenbeguntrackingdowntheanatomicallocationofthecentralexecutive.

Using fMRI, one team of researchers identified a region of the pre-frontal cortex that may be involved in functions such as managingthe demands of two simultaneous tasks (D’Esposito et al., 1997).Theresearchers presented participants with two tasks that do not involveshort-term storage, one verbal (making simple decisions about somewords)andtheothervisual(mentallyrotatingimages).

As expected, the verbal task activated the left temporal cortex,whereas the visual task activated the occipital and parietal cortex. Neither task alone acti-vated the prefrontal cortex. However, when participants had to complete both tasks at the sametime, regions of the prefrontal cortex became active — a suggestion that prefrontal workingmemory circuits are indeed activated when people have tomake ‘executive decisions’ about howto manage the limited workspace in working memory (see also Adcock, Constable, Gore, &Goldman-Rakic,2000;Bunge,Klingberg,Jacobsen,&Gabrieli,2000).

The relationship between working memory and long-term memoryWhatcanweconcludefromthesevariousstudiesaboutworkingmemory?First,consistentwiththeoriginalconceptofSTM,workingmemoryappearstobeasystemfortemporarilystoringandpro-cessing information,awayofholding information inmindlongenoughtouse it.Second,workingmemory includes anumberof limited-capacity componentprocesses, includinga central executivesystem,averbalstoragesystem,andatleastoneandprobablytwoorthreevisualstoragesystems(onefor location,one for identificationofobjects andperhaps another that storesboth simultaneously).Third,workingmemoryisbetterconceivedasaconsciousworkspaceforaccomplishinggoalsthanasawaystationorgatewaytostorageinLTM,becauseinformationcanbestoredinLTMwithoutbeingrepresentedinconsciousness,andinformationinLTMisoftenaccessedpriortoitsrepresentationinworkingmemory(Logie,1996).

How distinct are working memory and long-term memory?AreworkingmemoryandLTMreallydistinct?Insomeways,yes.Aswehaveseen,workingmemoryisrapidlyaccessedandseverelylimitedincapacity.ImagineifourLTMallowedustorememberonlysevenpiecesofverbalinformation,sevenobjectsorfacesandsevenlocations!

Some of the strongest evidence for a distinction betweenworkingmemory and LTM is neuro-logical. Patients like Jimmie with severe amnesia can often store and manipulate information formomentary usewith little trouble.Theymaybe able, for example, to recall sevendigits andkeeptheminmindbyrehearsingthem.Themomenttheystoprehearsing,however, theymayforgetthattheywereeventryingtorecalldigits,anindicationofasevereimpairmentinLTM.Researchershavealsoobservedpatientswiththeoppositeproblem:severeworkingmemorydeficits(suchasamemoryspanofonlytwodigits)butintactLTM(Caplan&Waters,1990;Shallice&Warrington,1970).

APPLY ✚ DISCUSS

Originally, researchers used the term short-term memory (which eventually became working memory) and consciousness as synonyms.

• Are there aspects of consciousness that are not represented in working memory?

• Is everything of which we are consciously aware held in working memory?

• Are there aspects of working memory that are not conscious?


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Interactions of working memory and long-term memoryWorkingmemoryandLTMmaybedistinct,butmuchof thetimetheyaresointertwinedthat theycanbedifficulttodistinguish(Baddeley,2002;Burgess&Hitch,2005;Tehan,Hendry,&Kocinski,2001).Forexample,whenpeopleareasked to recall a sequenceofwordsafter abriefdelay, theirperformance isbetter if thewordsaresemantically related (suchaschicken andduck),presumablybecause they recognise the linkbetween themandcanuse thememoryofone to cue thememoryof theother fromLTM(Wetherick,1975).Similarly,wordsaremoreeasily remembered thannon-sensesyllables(Hulme,Maughan,&Brown,1991;Roodenrys,Hulme,&Brown,1993).Thesefind-ingssuggestthatworkingmemoryinvolvestheconsciousactivationofknowledgefromLTM,sincewithoutaccessingLTM,thepersoncouldnottellthedifferencebetweenwordsandnon-words.Morerecently, Unsworth, Brewer, and Spillers (2011) demonstrated that participants with highworkingmemory capacityweremore efficient in searching their long-termmemory thanwere participantswith lowworkingmemorycapacity.Thisfinding further supports thenotion thatworkingmemoryandlong-termmemoryarenotmutuallyexclusive.

Indeed, from a neuroanatomical standpoint,workingmemory appears to become engagedwhenneural networks in the frontal lobes become activated alongwith (and linked to) networks in theoccipital,temporalandparietallobesthatrepresentvariouswordsorimages.Thesementalrepresen-tationsofwordsorimagesthemselvesreflectaninteractionbetweencurrentsensorydataandstoredknowledgefromLTM,suchasmatchingavisualpatternwithastoredimageofaparticularperson’sface.Inthissense,workingmemoryinpartinvolvesaspecialkindofactivationofinformationstoredinLTM(seeCowan,1994;Ericsson&Kintsch,1995).

ChunkingPerhaps the best example of the interaction betweenworkingmemory and LTM in daily life is astrategypeopleusetoexpandthecapacityoftheirworkingmemoryinparticularsituations(Ericsson &Kintsch, 1995).We have noted that the brain holds a certain number of units of information inconsciousnessatatime.Butwhatconstitutesaunit?Aletter?Aword?Perhapsanentiresentenceoridea?

Considertheworkingmemorycapacityofaskilledwaiterinarestaurant.Howcanapersontaketheorderof eightpeoplewithout the aidof anotepad, armedonlywith amental sketchpadandalimited-capacityverbalstore?Onewayistousechunking,amemorytechniquethatusesknowledgestoredinLTMtogroupinformationinlargerunitsthansinglewordsordigits.Chunkingisessentialineverydaylife,particularlyinculturesthatrelyuponliteracy,becausepeopleareconstantlycalledupontoremembertelephonenumbers,writtenwordsandlists.

Nowconsiderthefollowingsequenceofletters:ASXBHPASICSMH.Thisstringwouldbeimposs-ibleformostpeopletoholdinworkingmemory,unlesstheyareinterestedinbusinessandrecognisesomemeaningfulchunks:ASXforAustralianSecuritiesExchange;BHPforBrokenHillProprietary;ASICforAustralianSecuritiesandInvestmentsCommission;SMHforSydney Morning Herald. Inthisexample,chunkingeffectivelyreducesthenumberofpiecesofinformationinworkingmemoryfrom13 to4, byputting threeor four customerson each stool.People tend touse chunkingmosteffectivelyintheirareasofexpertise,suchaswaiterswhoknowamenu‘likethebackoftheirhands’.Similarly,knowledgeofareacodesallowspeopletostore10or11digitsatatime,since61(thetele-phonecountrycodeforAustralia)or64(thetelephonecountrycodeforNewZealand)canbecomea singlechunkratherthantwo‘slots’inverbalworkingmemory.

I N T E R I M S U M M A R YWorkingmemoryandLTMaredistinctfromoneanotherinboththeirfunctionsandneuroanatomybecausepatientswithbraindamage can show severedeficits ononebut not theother.Workingmemoryappearstooccurasfrontallobeneuralnetworksbecomeactivatedalongwithandlinkedtonetworks in theoccipital, temporalandparietal lobes that representvariouswordsor images.WorkingmemoryclearlyinteractswithLTMsystems,asoccursinchunking—usingknowledgestoredinLTMtogroupinformationinlargerunitsthansinglewordsordigitsandhencetoexpandworkingmemorycapacityinspecificdomains.

APPLY ✚ DISCUSSOn your university course website for this subject, you should be able to access a website that contains many interactive presentations of phenomena in memory and cognition, including verbal rehearsal, elaboration and short-term memory decay, as well as many others.

• How does working memory help us to remember?

• How does rehearsal and/or chunking help us to remember?

• What strategies best help you to remember things?

MAKING CONNECTIONSPsychologists once viewed memory as a warehouse for stored ideas. Today, however, many cognitive neuroscientists believe that memory involves the activation of a previously activated network to create a similar experience. Because the activated network is never identical to the original one, however, multiple opportunities for error exist (chapter 2).


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■ Varieties of long-term memoryMostreadershavehadtheexperienceofgoingintotherefrigeratorlookingforacondimentsuchasmustard.Ourfirstpassat‘remembering’wherethemustardisseemsmorelikehabitthanmemory —we automatically look in a particular place, such as the side door, wherewe have found itmanytimes.Ifthebottleisnotthere,wetypicallyemployoneoftwostrategies.Thefirstistothinkaboutwhereweusuallyputit,drawingonourgeneralknowledgeaboutwhatwehavedoneinthepast —dowe usually put it in the door or on the top shelf?The second is to try to remember a specificepisode,namelythelasttimeweusedthemustard.

This simple example reveals something not so simple: thatLTMcomes inmultiple forms, suchasautomatic‘habits’,generalknowledgeandmemoryforspecificepisodes.ResearchersdonotyetagreeonpreciselyhowmanysystemsconstituteLTM,butdevelopments inneuroimagingover thelastdecadehavemadeclearthatthethreedifferentwaysoffindingthemustardrepresentthreeverydifferentkindsofmemory,eachwithitsownneuroanatomy.Inthissection,weexploresomeofthemajortypesofLTM.

Declarative and procedural memoryIngeneral,peoplestore twokindsof information:declarativeandprocedural.Declarative memoryrefers tomemory for facts and events,much ofwhich can be stated or ‘declared’ (Squire, 1986).Procedural memoryrefersto‘howto’knowledgeofproceduresorskills.

Whenwethinkofmemory,weusuallymeandeclarativememory:knowledgeoffactsandevents.RememberingthatEdmundBartonwasthefirstPrimeMinisterofAustraliaandHenrySewellwasthefirstPremier ofNewZealand, or callingup ahappymemory from thepast, requires access todeclarativememory.

Declarative memory can be semantic or episodic (Tulving, 1972, 1987), and the hippocampusandmedialtemporallobeareinvolvedinitsfunctioning(seeTownsend,Richmond,Vogel-Farley,&Thomas,2010).Semantic memory refers togeneralworldknowledgeor facts, suchas theknowl-edge thatwintersarecold inDunedinor thatNaCl is thechemical formula for tablesalt (Tulving,1972).Thetermissomewhatmisleadingbecausesemanticimpliesthatgeneralknowledgeisstoredinwords,whereaspeopleknowmanythingsaboutobjects,suchastheircolourorsmell,thatareencodedas sensory representations. For this reason,many psychologists now refer to semanticmemory asgeneric memory.

Episodic memoryconsistsofmemoriesofparticularevents,ratherthangeneralknowledge(Tulving,2002).Episodicmemoryallowspeople to travelmentally through time, to remember thoughts andfeelings(orinmemoryexperiments,wordlists)fromtherecentordistantpast,ortoimaginethefuture(Wheeler,Stuss,&Tulving,1997).

Ineverydaylife,episodicmemoryisoftenautobiographical,aswhenpeoplerememberwhattheydidontheireighteenthbirthdayorwhattheyateyesterday(seeHowe,2000).Itisalsocloselylinkedto semantic memory (Menon, Boyett-Anderson, Schatzberg, & Reiss, 2002), since when peopleexperiencesimilarepisodesovertime(suchas180daysayearinschoolorhundredsofthousandsofinteractionswiththeirfather),theygraduallydevelopgenericmemoriesofwhatthosesituationswerelike(e.g.,‘Iusedtoloveweekendswithmyfather’).

Declarativememoryisthemostobviouskindofmemory,butanotherkindofmemoryisequallyimportantindailylife:proceduralmemory,alsoreferredtoasskillorhabitmemory.Peopleareoftenastonishedtofindthateventhoughtheyhavenotskatedfor20years,theskillsarereactivatedeasily,almostasiftheirusehadneverbeeninterrupted.Whenpeopleputabackspinonatennisball,speakgrammaticallyordriveacar,theyaredrawingonproceduralmemory.Indeed,Lum,Conti-Ramsden,Page, andUllman (2012) posited that abnormalities of the brain structures involved in proceduralmemorymaybe responsible for specific language impairments in children.Otherprocedural skillsarelessobvious,suchasreading,whichinvolvesasetofcomplexproceduresfordecodingstringsoflettersandwords.

Althoughproceduralmemoriesoftenformwithoutconsciouseffort(asinconditioningprocedureswithrats,whopresumablydonotcarefullythinkouttheirnextmoveinamaze),atothertimespro-ceduralmemories are ‘residues’ of prior conscious knowledge and strategies,which have becomeautomaticandhighlyefficient.Forexample,whenwefirstlearntotype,westudythelayoutofthe


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keyboard, trying to form declarativememories.Aswe are typing our firstwords,we also hold inworkingmemorythesequenceofkeystohitandknowledgeaboutwhichfingerstouseforeachkey.Overtime,however,ourspeedandaccuracyimprove,whileconsciouseffortdiminishes.Thisprocessreflects theformationofproceduralmemoryfor typing. In theend,we thinkonlyof thewordswewanttotypeandwouldhavedifficultydescribingthelayoutofthekeyboard(declarativememory),eventhoughourfingers‘remember’.Aswewillsee, thisshiftfromconscious,effortfulmemorytoautomaticproceduralmemoryoccursasregionsofthecortex‘passthetorch’ofmemorytosubcor-ticalregionsinthebasalganglia.

Explicit and implicit memoryFormuchof the last century, psychologists studiedmemoryby asking subjects tomemorisewordlists,nonsensesyllablesorconnectionsbetweenpairsofwordsandthenaskingthemtorecallthem.These tasks all tap explicit memory, or conscious recollection. Recently, however, psychologistshaverecognisedanotherkindofmemory:implicitmemory(Graf&Schacter,1987;Roediger,1990;Schacter&Buckner, 1998). Implicit memory refers tomemory that is expressed inbehaviourbutdoesnotrequireconsciousrecollection,suchastyingashoelace.

Somepsychologistsuseexplicitandimplicitmemoryassynonymsfordeclarativeandproceduralmemory.Although there isclearlysomeoverlap, thedeclarative–proceduraldichotomyrefersmoretothetypeofknowledgethatisstored(factsversusskills),whereastheexplicit–implicitdistinctionrefersmoretothewaythisknowledgeisretrievedandexpressed(withorwithoutconsciousaware-ness).Aswewillsee,people’sknowledgeoffacts(declarativeknowledge)isoftenexpressedwithoutawareness(implicitly).Figure7.7providesamodelofthedifferentdimensionsofLTM.

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Generic/semantic(general knowledge)

Way knowledge is expressed

Explicit memoryExplicitmemoryinvolvestheconsciousretrievalofinformation.Researchersdistinguishbetweentwokindsofexplicitretrieval:recallandrecognition.RecallisthespontaneousconsciousrecollectionofinformationfromLTM,aswhenapersonbringstomindmemoriesofherweddingdayorthenameofthecapitalofEgypt.Neuroimagingstudiesshowthatrecallactivatespartsofthebrainthatarealsoactivated duringworkingmemory tasks involving the central executive (Nolde, Johnson, &Raye,1998).Thismakessensegiventhatrecallrequiresconsciouseffort.

Although recall occurs spontaneously, it generally requires effortful use of strategies for callingthe desired information to mind. When efforts at recall fail, people sometimes experience thetip-of-the-tongue phenomenon, inwhich thepersonknows the information is ‘in there’but isnotquite able to retrieve it (Brown&McNeill, 1966).Recent research suggests that this phenomenonstemsfromproblemslinkingthesoundsofwords(whicharearbitrary—atablecouldjustaseasilyhavebeencalledablah)withtheirmeanings(Merriman,Marazita,Jarvis,Evey-Burkey,&Biggins,1996).Thus,usingtheword‘prognosticate’inaconversationwithsomeonewhohastheword‘pon-tificate’onthetipofhistonguecanleadtosuddenrecall(andafeelingofrelief!).

FIGURE 7.7Key distinctions in long-term memory


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Recognition refers to the explicit sense or recollection that some-thing currently perceived has been previously encountered or learned.Researchers often test recognition memory by asking participantswhether a word was on a list they saw the previous day. Recognitioniseasier thanrecall (asanystudentknowswhohasansweredmultiple-choice items that simply require recognition of names or concepts),becausethepersondoesnothavetogeneratetheinformation,justmakeajudgementaboutit.

Implicit memoryImplicitmemoryisevidentinskills,conditionedlearningandassociativememory (i.e., associations between one representation and another). Itcanbe seen in skills suchas turning thewheel in the correctdirectionwhen the car starts to skid on a gravel road (which skilled drivers incountryregionsdobeforetheyhaveevenformedthethought‘I’mskid-ding’)aswellasinresponseslearnedthroughclassicalandoperantcon-ditioning,suchasavoidingafoodthatwasonceassociatedwithnausea,whetherornotthepersonhasanyexplicitrecollectionoftheevent.

Implicit associative memory emerges in experiments on priming effects, in which prior exposure to a stimulus (the prime) facilitatesor inhibits the processing of new information. Participants inmemoryexperiments show priming effects even when they do not consciouslyrememberbeingexposedtotheprime(Bowers&Schacter,1990;Tulving,Schacter,&Stark,1982).For example, theymight be exposed to a list ofwords that are relatively rarely used in everydayconversation,suchasassassin.Aweeklater,theymayhavenoideawhetherassassinwasonthelist(a testofexplicitrecognitionmemory),butifaskedtofillinthemissinglettersofawordfragmentsuchasA--A--IN,theyaremorelikelytocompleteitwiththewordassassinthancontrolparticipantswho studied a different list theweek earlier. Priming effects appear to rely on activation of infor-mationstoredinLTM,eventhoughthepersonisunawareofwhathasbeenactivated.

I N T E R I M S U M M A R YTypesofLTMcanbedistinguishedbykindofknowledgestored(factsversusskills)andthewaythis knowledge is retrieved and expressed (with or without conscious awareness). People storetwokindsofinformation,declarativeandprocedural.Declarative memory referstomemoryforfacts and events; it can be semantic (generalworld knowledge or facts) orepisodic (memoriesofparticular events).Procedural memory refers to ‘how to’knowledgeofproceduresor skills.Knowledge canbe retrieved explicitlyor implicitly.Explicit memory refers to conscious recol-lection,whereas implicit memory refers tomemory that is expressed inbehaviour.Researchersdistinguish between twokinds of explicit retrieval: recall (the spontaneous retrieval ofmaterialfromLTM) and recognition (memory forwhether something currently perceived has been pre-viously encountered or learned). Implicitmemory is evident in skills, conditioned learning andassociativememory(associationsbetweenonerepresentationandanother).

If asked to name the majority of the members of the Melbourne Storm’s 2012 NRL premiership winning team (a recall task), even ardent rugby league fans may have some difficulty, beyond star players such as Cameron Smith, Billy Slater and Cooper Cronk. If, however, they were shown this team photo (a recognition task), many fans would readily and correctly come up with additional names such as Ryan Hoffman, Bryan Norrie, Gareth Widdop and Will Chambers.

Long-term memory and neuropsychologyHowdistinctarethesevarietiesoflong-termmemories?Areresearcherssimplysplittinghairs,oraretheyreally‘carvingnatureatitsjoints’,makingdistinctionswheredistinctionstrulyexist?

Someofthemostdefinitivedatasupportingdistinctionsamongdifferenttypesofmemoryareneuro-anatomicalstudies,includingcasestudiesofpatientswithneurologicaldamage,brainimagingwithnormalandbrain-damagedpatientsandexperimentalstudieswithanimals(Gabrieli,1998;Gluck &Myers, 1997; Squire, 1992, 1995). Researchers discovered the distinction between implicit and

FROM BRA IN

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explicitmemoryinpartbyobservingamnesicpatientswhohavetroublestoringandretrievingnewdeclarative information (such as their age or the name or face of their doctor) but showminimalimpairment on implicit tasks (Schacter, 1995a).Consider the case ofH.M.,who hadmost of hismedialtemporallobes(theregioninthemiddleofthetemporallobes,includingthehippocampusandamygdala) removedbecauseofuncontrollableseizures (figure7.8).Following theoperation,H.M.hadoneofthedeepest,purestcasesofamnesiaeverrecorded,leadingtotheconclusionthatmedialtemporalstructuresplayacentralroleintheconsolidation(i.e.,encodingand‘solidification’)ofnewexplicitmemories.Despite his inability to store newmemories, however,H.M.was able to learnnewproceduralskills,suchaswritingwordsupsidedown.EachnewtimeH.M.wasaskedtoper-formthistask,hisspeedimproved,buthehadnorecollectionthathehadeverperformeditbefore.Sadly,H.M.diedon2December2008,aged82.Hissurvivalofill-conceivedbrainsurgeryenabledresearchers to identifyhowandwherememories are formed in thebrain.His formof anterogradeamnesiapreventedhimfromcollectinganynewmemoriesandhelivedinapre-1953world.H.M.istoberememberedandsalutedforallthathehascontributedtothescientificcommunity.

Hippocampus

Temporalcortex

Occipitalcortex

Parietalcortex

Prefrontalcortex

Amygdala

FIGURE 7.8Anatomy of memory. The medial temporal region (inside the middle of the temporal lobes), particularly the hippocampus, plays a key role in consolidation of explicit, declarative information. The frontal lobes play a more important role in working memory, procedural memory and aspects of episodic memory, such as dating memories for the time at which they occurred. Posterior regions of the cortex (occipital, parietal and temporal cortex) are involved in memory just as they are in perception, by creating mental representations.

Lesion research with monkeys and imaging research with humans have demonstrated that thehippocampusandadjacentregionsofthecortexarecentraltotheconsolidationofexplicitmemories(Eichenbaum,1997;McGaugh,2000;Squire&Zola-Morgan,1991).Incontrast,thefactthatamne-sicslikeH.M.oftenshownormalskilllearningandprimingeffectssuggeststhatthehippocampusisnotcentraltoimplicitmemory.

Indaily life,ofcourse, implicit andexplicitmemoryareoften intertwined.Forexample,peoplelearn through conditioning to fear and avoid stimuli that are painful, but they are also frequentlyawareoftheconnectionbetweenvariousstimuliorbehavioursandtheireffects.Thus,achildmightlearnbytouchingastovethatdoingsoispunishing(conditioning)butalsomightbeableexplicitlytorecalltheconnectionbetweenthetwoevents:‘IfItouchthestove,Igetanouchie!’

Neurologically speaking, however, implicit and explicit memory rely on separate mechanisms(Becharaetal.,1995).Forexample,fearconditioningandavoidancelearningrequireanintactamyg-dala.Inaclassicalconditioningprocedureinwhichaparticularsound(theconditionedstimulusorCS) is pairedwith an electric shock (the unconditioned stimulus orUCS), patientswith an intacthippocampusbut a damaged amygdala can explicitly state the connectionbetween theCSand theUCS—thatis,theyconsciouslyknowthatthetoneisassociatedwithshock.However,theirnervoussystemshowsnosignsofautonomicarousal(e.g.,increasedheartrate)orbehaviouralexpressionsoffearwhenexposedtotheCS.Theyknowtheconnectionbutcannotfeelit.Incontrast,patientswithanintactamygdalabutadamagedhippocampusmayhavenoconsciousideathattheCSisassociatedwithelectricshock—infact,theymayhavenorecollectionofeverhavingencounteredthestimulus


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I N T E R I M S U M M A R YImplicit and explicit memory are neuroanatomically distinct. The hippocampus and adjacentregionsofthecortexarecentrallyinvolvedinconsolidatingexplicitmemories.Amnesicswithhip-pocampaldamageoftenshownormalskilllearning,conditioningandprimingeffects,suggestingthatthehippocampusisnotcentraltoimplicitmemory.Differentkindsofexplicitmemory,notablyepisodicandsemantic,alsoappeartoconstitutedistinctmemorysystems.Thesameistrueoftwotypesofimplicitmemory,proceduralandassociative.

Everyday memoryIndesigningstudies,researchershavetostrikeabalancebetweentheoftenconflictinggoalsofmaxi-mising internalvalidity—creatingastudywhosemethodsaresoundandrigorousandcan lead toclearcausalinferences—andexternalvalidity—makingsuretheresultsgeneralisetothereal world(chapter 2). SinceEbbinghaus’ studies in the late nineteenth century,memory research has tendedto emphasise internal validity, bymeasuringparticipants’ responses as theymemorisewords, non-sensesyllablesandpairsofwords,totrytolearnaboutbasicmemoryprocesses.Increasingly,how-ever,researchershavebeguntoarguefortheimportanceofstudyingeveryday memoryaswell;thatis,memory as it occurs in daily life (Ceci&Bronfenbrenner, 1991;Herrmann,McEvoy,Hertzod,Hertel,&Johnson,1996;Koriat,Goldsmith,&Pansky,2000;Rogoff&Lave,1984).

Inthelaboratory,theexperimenterusuallysuppliestheinformationtoberemembered,thereasontorememberit(theexperimenterasksthepersonto)andtheoccasiontorememberit(immediately,a weeklateretc.).Oftentheinformationtoberememberedhaslittleintrinsicmeaning,suchasisolatedwordsonalist.Incontrast,indailylife,peoplestoreandretrieveinformationbecausetheyneedtoforonereasonoranother,theinformationisusuallymeaningfulandemotionallysignificant,andthecontext for retrieval issometimesa futurepoint in time that itselfmustberemembered,aswhena

before—butnonetheless theyshowaconditionedfearresponse to it, includingautonomicarousal(seechapters3and6).

Subsystems of implicit and explicit memoryImplicit and explicit memory are themselves broad categories that include neurologically distinctphenomena.Thetwokindsofexplicitmemory,semanticandepisodic,relyondifferentneuralmech-anisms.Patientswithdamage to the frontal lobeshave little trouble retrievingsemanticknowledgebut often show deficits in episodicmemory (Shimamura, 1995;Wheeler, Stuss,&Tulving, 1995,1997).Theymay, forexample,have trouble remembering theorderofevents in their lives (Swain,Polkey,Bullock,&Morris,1998),ortheymayvividlyrecalleventsthatneveroccurredbecausetheyhavedifficultydistinguishingtruefromfalsememoriesofevents(Schacter,1997).Positronemissiontomography(PET)studiesshowgreateractivationofprefrontalregionswhenrecallingepisodicratherthansemanticinformation(Nyberg,1998).However,otherstudieshavesincefailedtoreplicatethisfinding(seeMenonetal.,2002).

Implicitmemory also likely comprises at least two systems. Patientswith damage to the cortexcausedbyAlzheimer’s diseasemayhavenormalproceduralmemorybut impairedperformanceonpriming tasks. In contrast, patients with Huntington’s disease, a fatal, degenerative condition thataffectsthebasalganglia,shownormalprimingbutimpairedprocedurallearning(Butters,Heindel,&Salmon,1990).

Brain imagingdataonnormalparticipantshaveprovided insight into thewayknowledge thatatfirstrequiresconsiderableeffortbecomesprocedural,asthebrainessentiallytransferstheprocessingof the task from one network to another (see Poldrack,Desmond,Glover,&Gabrieli, 1998). Forexample, after practice at readingwordsbackwards in amirror, people showdecreased activity invisualpathwaysbutincreasedactivityinverbalpathwaysinthelefttemporallobe.Thisswitchsug-geststhattheyaremorerapidlymovingfromthevisualtaskofmentallyturningthewordaroundtothelinguistictaskofunderstandingitsmeaning.


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person tries to remember to call a friend later in the day.Thus, researchers are choosing to studyeveryday memory in its naturalistic setting — such as people’s memory for appointments(Andrzejewski,Moore,Corvette,&Hermann,1991)—aswellastodevisewaystobringitintothe

laboratory.Forexample,Unsworth,Brewer,andSpillers(2012)showedthatlaboratorytestsofattentionandmemoryaccuratelypredicteverydaymemoryfailures.

Everyday memory is functional memoryIn their daily lives, people typically remember for a purpose, to achievesomegoal (Anderson,1996;Gruneberg,Morris,&Sykes,1988).Memory,like all psychological processes, is functional. Of all the things we couldcommittomemoryoverthecourseofaday,wetendtorememberthosethataffectourneedsandinterests.

The functional nature of memory was demonstrated in a set of studiesthatexaminedwhethermenandwomenwouldhavebetterrecallforstereo-typically masculine and feminine memory tasks (Herrmann, Crawford, &Holdsworthy, 1992). In one study, the investigators asked participants to

rememberashoppinglistandalistoftraveldirections.Aspredicted,women’smemorywasbetterfortheshoppinglist,whereasmenhadbettermemoryforthedirections.

Doesthismeanthatwomenareborntoshopandmentonavigate?Asecondstudysuggestedother-wise.This time, someparticipants received a ‘shopping list’ to rememberwhereas others receiveda ‘hardware list’.Additionally, some received directions on ‘how tomake a shirt’ whereas othersreceiveddirectionson ‘how tomakeaworkbench’. In reality, thegroceryandhardware listswereidentical,aswerethetwolistsof‘directions’.Forexample,theshoppinglistincludeditemssuchasbrush,oil,chips,nutsandgum thatcouldjustaseasilybeinterpretedasgoodsatasupermarketashardwareitems.The‘directions’weresogeneralthattheycouldrefertoalmostanything(e.g.,‘First,yourearrangethepiecesintodifferentgroups.Ofcourse,onepilemaybesufficient...’).

Aspredicted,womenweremorelikelytorememberdetailsaboutshirtmakingandgrocerylists.The biases in recall for directions for menwere particularly strong (figure 7.9).Apparently, ‘realmen’donotmake shirts.Thesefindingsdemonstrate the importanceofnon-cognitive factors suchasmotivationand interest ineverydaymemory:whatmendefineasnot relevant,not interestingorthreatening to theirmasculinitydoesnotmakea lasting impressionon theirmemory (Colley,Ball,Kirby,Harvey,&Vingelen,2002).

Other research links some forms of everyday memory to the hippocampus. Researchers testedLondon taxi drivers’ knowledge of the streets of their city.Drivers showedmore activation in thehippocampusforanavigationtaskthatrequiredtheirexpertisethanforseveralothermemorytasks(Maguire,Frackowiak,&Frith,1997).Infact, thesizeoftheactivatedregionsofthehippocampuswasstronglycorrelatedwiththenumberofyearstheyhadbeendriving,asuggestionthatthebraindevotesmore‘room’inthehippocampusforfrequentlyusedinformation,justasitdoesinthecortex(Maguire,Mummery,&Buechel, 2000).More recently, researchhasusedvirtual reality to furtherexaminetheroleofthehippocampusinspatialnavigationandepisodicmemory(seeBurgess,2002).

Prospective memoryMoststudiesofmemoryhaveexaminedretrospective memory, thatis,memoryforthingsfromthepast, suchasa listofwordsencountered20minutesearlier. Ineveryday life,anequally importantkind ofmemory isprospective memory, ormemory for things that need to be done in the future,suchaspickingupsomeitemsat thecornershopafterwork(Brandimonte,Einstein,&McDaniel,1996; Einstein&McDaniel, 1990;McDaniel, Robinson-Riegler, & Einstein, 1998; Smith, 2003).Prospectivememory has at least two components: remembering to remember (‘be sure to stop atthecornershopafterwork’)andrememberingwhattoremember(e.g.,aloafofbreadandmilk).Inotherwords,prospectivememoryrequiresmemoryofintentaswellascontent(Kvavilashvili,1987;Marsh,Hiscks,&Bink,1998).ExperimentalstudiessuggestthatintendingtocarryoutcertainactsinthefutureleadstotheirheightenedactivationinLTM(Goschke&Kuhl,1993,1996).

Thestudyofprospectivememoryisagrowingareaofresearch(Dismukes,2012).Failuresinpros-pectivememoryhavebeen linked to illicit polydruguse (Hadjiefthyvoulou,Fisk,Montgomery, &

MAKING CONNECTIONS

Research from the Australian National University has challenged the myth that pregnant women and mothers become forgetful. This short-term memory loss is often described as ‘baby brain’ or ‘placenta brain’ and has been contested by Professor Christensen and her team in a 20-year population study on health and ageing. Christensen, Leach, and Mackinnon (2010) analysed the memory and cognitive speed of a group of women before and during pregnancy and in the early stages of motherhood, and found no support for the notion that pregnancy and motherhood are related to persistent cognitive deterioration. Their research indicates that memory lapses can happen to any one of us, pregnant or not, and that cognitive decline varies across individuals (see chapter 12).


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Bridges, 2011), binge-drinking (Heffernan, Clark, Bartholemew,Ling,&Stephens,2010),andautismspectrumdisorders(Jones et al.,2011).

Although prospectivememory is probably not itself amemory‘system’ with its own properties, it does have elements that dis-tinguishitfromotherkindsofmemory(seeMcDaniel,1995).Oneisitsheavyemphasisontime.Partofrememberinganintentionisrememberingwhentorememberit,suchasataspecifictime(e.g.,rightafterwork)oran intervalof time (tonight, tomorrow, some-timeoverthenextfewdays).

Another unique feature of remembered intentions is that thepersonhastorememberwhethertheyhavebeenperformedsotheycanbe‘shutoff’.Thisfacetofprospectivememoryismoreimpor-tantwithsometasksthanwithothers.InadvertentlyhiringaDVDthatyoualreadywatchedamonthagoisclearlylessharmfulthantakingmedicationyoudidnotremembertakinganhourearlier.

I N T E R I M S U M M A R YEveryday memory refers tomemory as it occurs in daily life. Everydaymemory is functional,focused on remembering information that is meaningful. One kind of everyday memory isprospective memory,memoryforthingsthatneedtobedoneinthefuture.

■ Encoding and organisation of long-term memory

Wehavenowcompletedourtourofthevarietiesofmemory.ButhowdoesinformationfinditswayintoLTMinthefirstplace?Andhowisinformationorganisedinthemindsothatitcanbereadilyretrieved? In this section,we explore these two questions.The focus is on the storage and organ-isationofdeclarativeknowledge,sinceithasreceivedthemostempiricalattention.

EncodingFor information tobe retrievable frommemory, itmustbeencoded,orcast intoa representationalform,or‘code,’thatcanbereadilyaccessed.Themannerofencoding—how,howmuchandwhenthepersontriestolearnnewinformation—hasasubstantialinfluenceonitsaccessibility(easeandabilityofretrieval—i.e.,howreadilyitcanbeaccessed).

Levels of processingAnyonewhohasevercrammedforatestknowsthatrehearsalisimportantforstoringinformationinLTM.Asnotedearlier,however,thesimple,repetitiverehearsalthatmaintainsinformationmomen-tarilyinworkingmemoryisnotoptimalforLTM.Usually,amoreeffectivestrategyistoattendtothemeaningofthestimulusandformmentalconnectionsbetweenitandpreviouslystoredinformation.

Some encoding is deliberate, such as studying for an exam, learning lines for a play or theatreproductionor trying to remember a joke.However,muchof the timeencoding simplyoccurs as aby-productofthoughtandperception—areasonwhypeoplecanrememberincidentsthathappenedtothem10yearsagoeventhoughtheywerenottryingtocommitthemtomemory.

Deep and shallow processingThedegree towhich information is elaborated, reflected upon andprocessed in ameaningfulwayduringmemorystorage is referred toas thedepthor level of processing (Craik&Lockhart,1972;Lockhart&Craik,1990). Informationmaybeprocessedat a shallow, structural level (focusingonphysicalcharacteristicsofthestimulus);atasomewhatdeeper,phonemiclevel(focusingonsimplecharacteristicsofthelanguageusedtodescribeit);oratthedeepest,semanticlevel(focusingonthemeaningofthestimulus).

Forexample,atashallow,structurallevel,apersonmaywalkbyarestaurantandnoticethetypeface andcoloursof its sign.At aphonemic level, shemay read the sign toherself andnotice that

Condition(remembering directions)

Mea

n nu

mbe

r of i

tem

s re

calle

d

6

7

8

9

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Shirt

MalesFemales

Workbench

FIGURE 7.9Gender and everyday memory. The figure shows men’s and women’s memory, following a distracter task, for a list of directions that they thought were for making either a workbench or a shirt. Women recalled slightly more items when they thought they were remembering sewing instructions. Men’s performance was dramatically different in the two conditions: men were much more likely to remember the ‘manly’ instructions for the workbench.Source: From Herrmann et al. (1992).

MAKING CONNECTIONSAs the philosopher of science Thomas Kuhn argued, a paradigm (or perspective in psychology) includes a set of propositions that constitute a model, an underlying metaphor, and a set of agreed-upon methods (chapter 1). In the last few years, all these have changed in cognitive psychology. We have moved from three sequential memory stores to multiple-memory systems operating in parallel; from a computer metaphor to a brain metaphor; and from a set of methods (such as memorising word pairs) that tended to study memory divorced from meaning to more diverse methods, including those that can examine memory in its natural habitat — everyday life.


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it sounds Italian.Processingmaterial deeply, in contrast,meanspaying attention to itsmeaningorsignificance, noticing, for instance, that this is the restaurant a friend has been recommending formonths.

Processinginformationatadeep,semanticlevel isalsopositivelyrelatedtoacademicsuccessinfirst-year studies, with a shallow learning approach predicting poor achievement (Burton, Taylor,Dowling,&Lawrence,2009).InarelatedAustralianstudy,resultsfrom134pre-serviceteacheredu-cation students at a rural university in New SouthWales indicated that modifications to teachingmethods,taskrequirements,andassessmentprocessescanhelpminimiseashallowlearningapproachandencourageinstudentsadeeplearningapproach(Gordon&Debus,2002).

Differentlevelsofprocessingactivatedifferentneuralcircuits.Asonemightguess,encodingthatoccursaspeoplemakejudgementsaboutthemeaningofwords(suchaswhethertheyareconcreteor abstract) leads to greater activation of the left temporal cortex,which is involved in language

comprehension, than if they attend to qualities of the printed words,suchaswhethertheyareinupper-orlowercaseletters(Gabrielietal.,1996).Deliberateuseofstrategies to remember (suchas rememberingtobuybreadandbottledwaterbythinkingofaprisonerwhoisfedonlybread andwater) activates regionsof theprefrontal cortex involved inotherexecutivefunctionssuchasmanipulatinginformationinworkingmemory (Kapur, Tulving, Cabeza, & McIntosh, 1996). Subsequentresearch has even shown that the amount of activity in the prefrontaland temporal cortices predicts the extent to which participants arelikely to remember studied material successfully (Brewer, Zhao,Des-mond,Glover,&Gabrieli,1998;Wagneretal.,1998).Otten,Henson,and Rugg (2001) further extended this finding, showing that episodicencodingforwords inasemantic task involvesasubsetof theregionsactivatedbydeepprocessing.

Encoding specificityAdvocatesof depth-of-processing theoryoriginally thought that deeperprocessing is alwaysbetter.Although this is generally true, subsequentresearch shows that the best encoding strategy depends on what thepersonlaterneedstoretrieve(seeAnderson,1995).Ifapersonisasked

to recall shallow information (such aswhether awordwas originally presented in capital letters),shallowencodingtendstobemoreuseful.

The fact that ease of retrieval depends on the match between the way information is encodedandlaterretrievedisknownastheencoding specificity principle(Tulving&Thomson,1973).Forexample, a student who studies for a multiple-choice test by memorising definitions and detailswithout trying to understand the underlying conceptsmaybe inmuchmore trouble if the lecturerdecidestoincludeanessayquestion,becausethestudenthasencodedtheinformationattooshallowalevel.

Whydoes thematchbetweenencoding and retrieval influence the easewithwhichpeople canaccess information from memory? According to several theorists, memory is not really a pro-cess distinct from perception and thought; rather, it is a by-product of the normal processes ofperceiving and thinking, which automatically lay down traces of an experience as it is occur-ring.Whenpeople remember, theysimply reactivate the sameneuralnetworks thatprocessed theinformation in the first place (Crowder, 1993; Lockhart & Craik, 1990). If the circumstances atencodingandretrievalaresimilar,thememoryismoreeasilyretrievedbecausemoreoftheneuralnetworkthatrepresentsit isactivated.Toputitanotherway,anewthought,feelingorperceptionis like a bushwalkerwho has to create a new trail through the bush. Each time another travellertakesthatpath,thatis,eachtimeasimilareventoccurs,thetrailbecomesmoredefinedandeasiertolocate.

Context and retrievalAccording to the encoding specificity principle, the contexts inwhich people encode and retrieveinformationcanalsoaffecttheeaseofretrieval.Onestudypresentedscubadiverswithdifferentlistsof words, somewhile the diverswere underwater and otherswhile theywere above (Godden&Baddeley,1975).Thedivershadbetterrecallforliststheyhadencodedunderwaterwhentheywere

Australian actress Cate Blanchett’s prefrontal cortex was activated when she used deliberate techniques to learn her lines for her role as Galadriel in The Hobbit film series.


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underwateratretrieval;conversely, listsencodedabovewaterwerebetterrecalledabovewater.AnAustralian study (Pearse, Powell,&Thomson, 2003) also found context is important in recall foryoung children. The study participants took part in the same staged event four times, with somedetailsvariedeachtime(e.g.,thecolourofacoat).Threedayslater,thechildrenwereaskedtorecallthosedetails.During the interviewprocess, contextual cuesweregiven to someof the children—such as a different person undertaking one of the tests, or a newwatch that the interviewerwore.Thosechildrenwhoweregivenacontextualcueperformedbetter inrecallingdetailsof theevents.However, opponents of the encoding specificity principle suggest that the diagnostic value of theretrievalcueisabetterpredictorofmemoryperformancethanthecontext(seeGoh&Lu,2012,forafullreview).

Thesamephenomenonappearstooccurwithpeople’semotionalstateatencodingandretrieval,aphenomenoncalledstate-dependentmemory:beinginasimilarmoodatencodingandretrieval(e.g.,angrywhilelearningawordlistandangrywhiletryingtorememberit)canfacilitatememory,aslongastheemotionalstateisnotsointensethatitinhibitsmemoryingeneral(seeBower,1981;Keenly,1997).Having thesamecontextduringencodingand retrieval facilitates recallbecause thecontextprovidesretrieval cues,stimuliorthoughtsthatcanbeusedtofacilitaterecollection.

SpacingAnother encoding variable that influences memory is of particular importance in educational set-tings:theintervalbetweenstudysessions.Studentsintuitivelyknowthatiftheycramthenightbeforea test, the information is likely to be available to themwhen they need it the next day.They alsotendtobelievethatmassedrehearsal(i.e.,studyinginonelongsessionorseveraltimesoverashortinterval,suchasaday) ismoreeffectivethanspaced,ordistributed,rehearsalover longer intervals(Zechmeister&Shaughnessy,1980).Butisthisstrategyreallyoptimalforlong-termretentionoftheinformation?

Infact,itisnot(Bruce&Bahrick,1992;Dempster,1996;Ebbinghaus,1885/1964).Massedrehearsalseemssuperiorbecauseitmakesinitialacquisitionofmemoryslightlyeasier,sincethematerialisataheightenedstateofactivation inamassedpractice session. In the long run,however, researchonthespacing effect— the superiorityofmemory for information rehearsedover longer intervals—demonstratesthatspacingstudysessionsoverlongerintervalstendstodoublelong-termretentionofinformation.

Inone study, theBahrick family tested the long-termeffectsof spaced rehearsalon the studyof300 foreign language vocabularywords (Bahrick,Bahrick,Bahrick,&Bahrick, 1993).Themajorfindingwasthat,overafive-yearperiod,13trainingsessionsat intervalsof56daysapart increasedmemory retention rates compared to 26 sessions spaced at 14-day intervals (figure 7.10). Theseresultsarerobustacrossavarietyofmemorytasks,evenincludingimplicitmemory(Perruchet,1989;Toppino &Schneider,1999).Morerecently,CallanandSchweighofer(2010)foundthattheleftfrontaloperculum—known to facilitate the transferof information intoLTM—shows increasedactivityduringspacedrehearsals.

Theseandrelatedfindingshaveimportantimplicationsforstudentsandteachers(Bruce&Bahrick,1992;Herbert&Burt,2004;Rea&Modigliani,1988).Studentswhowanttorememberinformationformorethanadayortwoafteranexamshouldspacetheirstudyingovertimeandavoidcramming.Medicalstudents,lawstudentsandotherswhointendtopractiseaprofessionbasedontheircourseworkshouldbeparticularlywaryofall-nighters.

Moreover,muchasstudentsmightprotest,cumulativeexamsover thecourseofasemesteraresuperior to exams that test only thematerial that immediately preceded them.Cumulative examsrequire students to relearnmaterial at long intervals, and the tests themselves constitute learningsessionsinwhichmemoryisretrievedandreinforced.Infact,researchonspacingispartofwhatledtheauthorsofthistexttoincludebothinterimsummariesandageneralsummaryattheendofeach chapter, since learning occurs best with a combination of immediate review and spacedrehearsal.

Representational modes and encodingTheabilitytoretrieveinformationfromLTMalsodependsonthemodesusedtoencodeit.Ingeneral,themorewaysamemorycanbeencoded,thegreaterthelikelihoodthatitwillbeaccessibleforlater

APPLY ✚ DISCUSSResearch in New Zealand (Harper, 2000; Parkes & White, 2000; White & Ruske, 2002) into the effect of drugs that decrease acetylcholine activity in the brain suggests that memory loss is related to a problem at the initial encoding of the stimulus rather than to a problem with later recall.

• Is information processed at a deep level easier to retrieve than information processed at a shallow level?

• When might shallow information be more useful than deep processing?

• Why is a memory more easily retrieved when the circumstances at encoding emulate those at retrieval?

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FIGURE 7.10Impact of spacing on memory retention over five years. Longer intervals between rehearsal sessions for English–foreign language word pairs predicted higher long-term retention of the information one, two, three and five years after the last training session.Source: Bahrick et al. (1993).


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retrieval.Storingamemoryinmultiplerepresentationalmodes—suchaswords,imagesandsounds—providesmoreretrievalcuestobringitbacktomind(seePaivio,1991).

Forinstance,manypeoplerememberphonenumbersnotonlybymemorisingthedigitsbutalsobyformingamentalmapofthebuttonstheyneedtopushandamotoric(procedural)representationofthepatternofbuttonstopushthatbecomesautomaticandisexpressedimplicitly.Whenpushingthebuttons,theymayevenbealertedthattheyhavedialledthewrongnumberbyhearingasoundpatternthatdoesnotmatchtheexpectedpattern,suggestingauditorystorageaswell.

I N T E R I M S U M M A R YForinformationtoberetrievablefrommemory,itmustbeencoded,orcastintoarepresentationalformthatcanbereadilyaccessedfrommemory.Thedegree towhich information iselaborated,reflected upon and processed in ameaningfulway duringmemory storage is referred to as thedepthorlevel of processing.Althoughdeeperprocessingtendstobemoreusefulforstoringinfor-mation for the long term, ease of retrieval depends on thematch between theway informationis encoded and the way it is later retrieved, a phenomenon known as the encoding specificity principle. Similar contexts during encoding and retrieval provide retrieval cues — stimuli orthoughtsthatcanbeusedtofacilitaterecollection.Asidefromlevelofprocessing,twoothervari-ables influence accessibility ofmemory, the spacing of study sessions and the use ofmultiplerepresentationalmodes.

Mnemonic devicesTheprinciplesofencodingwehavejustbeendescribinghelpexplaintheutilityofmanymnemonic devices—systematicstrategiesforrememberinginformation(namedaftertheGreekwordmneme,which means ‘memory’). People can use external aids (such as note taking or asking someoneelse) to enhance their memory, or they can rely on internal aids, such as rehearsal and variousmnemonicstrategies(Harris,1980a).Mostmnemonicdevicesdrawontheprinciplethatthemoreretrievalcues thatcanbecreatedandthemorevividthesecuesare,thebettermemoryislikelytobe. Generally, mnemonic devices aremost useful when the to-be-remembered information lacksclearorganisation.

Method of lociOnemnemonicstrategyisthemethod of loci,whichusesvisualimageryasamemoryaid.TheancientRomanwriterCiceroattributedthistechniquetotheGreekpoetSimonides,whowasattendingaban-quetwhen hewas reportedly summoned by the gods from the banquet hall to receive amessage.Inhis absence, the roofcollapsed,killingeveryone.Thebodiesweremangledbeyond recognition,butSimonideswasabletoidentifytheguestsbytheirphysicalplacementaroundthebanquettable.He thus realised that images could be remembered byfitting them into an orderly arrangement oflocations(Bower,1970).

To use the method of loci, you must first decide on a series of ‘snapshot’ mental images offamiliar locations. For instance, locations in your bedroom might be your pillow, your ward-robe, the topofyourdresserandunder thebed.Now,suppose thatyouneed todo thefollowingerrands: pick up vitamin C, buymilk, return a book to the library andmake planswith one ofyour friends for theweekend.You can remember these itemsbyvisualising each in oneof yourloci,makingtheimageasvividaspossibletomaximisethelikelihoodofretrievingit.Thus,youmightpicture thevitaminCpillsasspilledalloveryourpillow,abottleofmilkpouredover thebestoutfit inyourwardrobe, thebook lyingon topofyourdresserandyour friendhidingunderyour bed until Friday night. Often, themore ridiculous the image, the easier it is to remember.Whileyouareoutdoingyourerrands,youcanmentallyflip throughyour imaginedloci tobringbackthementalimages.

SQ4R methodAstrategy specificallydeveloped tohelp students remember information in textbooks is called theSQ4R method, for the six steps involved in themethod: survey, question, read, recite, review and

APPLY ✚ DISCUSS• What are the best ways

to study material so that it ‘sinks in’?

• What forms of rehearsal and spacing are likely to lead to long-term retention of information?

• Are the same methods useful in procedural learning? What methods would be most useful in remembering a new tennis serve, or learning to type?


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write(Martin, 1985;Robinson,1961).TheSQ4Rmethodfostersactiverather than passive learning while reading. In brief, the steps of thismethodareasfollows.• Survey. Skim through the chapter, looking at headings and the sum-

mary.Thiswillhelpyouorganisethematerialmoreefficientlyasyouencode.

• Question.Whenyoubeginasection,turntheheadingintoaquestion;this alerts you to the content and makes reading more interesting.Forexample, for the subheading, ‘Long-termmemory systems’,youmightaskyourself,‘Whatevidencecoulddemonstratetheexistenceofseparatememorysystems?CouldpatientswithdifferentbrainlesionshaveonekindofLTMintactandanotherdisrupted?’

• Read.Asyouread,trytoanswerthequestionsyouposed.• Recite.Mentally (or orally) answer your questions and rehearse rel-

evantinformationbeforegoingontothenextsection.• Review.Whenyoufinishthechapter,recallyourquestionsandrelatewhatyouhavelearnedto your

experiencesandinterests.• wRite.Asyoureadorlistentolectures,activelywriteanswerstoquestionsandtakenotes.

I N T E R I M S U M M A R YMnemonic devices are systematic strategies for remembering information. Themethod of lociassociates new information with a visual image of a familiar place. The SQ4R method helpsstudentsstudytextbookmaterialefficientlybyencouragingthemtosurvey,question,read,recite,reviewandwrite.

Networks of associationOne of the reasons mnemonics can be effective is that they connect new information with infor-mation already organised inmemory. Thismakes the new information easier to access because a‘trail’blazedintheneuralwoodsbypriorknowledgecanbemoreeasilyspottedthananew,barelywornpath.AsWilliamJamesproposedoveracenturyago(1890,p.662,italicsdeleted):

Themoreother facts a fact is associatedwith in themind, thebetter possessionof it ourmemoryretains.Eachofitsassociatesbecomesahooktowhichithangs,ameanstofishitupbywhensunkbeneath the surface. Together, they form a network of attachments by which it is woven into theentiretissueofourthought.The‘secretofagoodmemory’isthusthesecretofformingdiverseandmultipleassociationswitheveryfactwecaretoretain.

James’ comments bring us back once again to the concept of association,which, aswe saw inchapter 6, is central tomany aspects of learning.Associations are crucial to rememberingbecausethepiecesofinformationstoredinmemoryformnetworks of association,clustersofinterconnectedinformation.Forexample,formostpeopletheworddogisassociativelylinkedtocharacteristicssuchas barking and fetching (figure 7.11, overleaf). It is also associated, though less strongly,withcatbecausecatsanddogsarebothhouseholdpets.Thewordor imageofadog isalso linked tomoreidiosyncraticpersonalassociations,suchasanepisodicmemoryofbeingbittenbyadoginchildhood.

Each piece of information along a network is called a node. Nodes may be thoughts, images,concepts, propositions, smells, tastes,memories, emotions or any other piece of information.Thatone nodemay have connections tomany other nodes leads to tremendously complex networks ofassociation.Onewayto thinkofanode isasasetofneuronsdistributed throughout thebrain thatfiretogether(seechapter3).Theirjointfiringproducesarepresentationofanobjectorcategorysuchas dog, which integrates visual, tactile, auditory, verbal and other information stored in memory.To search through memory means you go from node to node until you locate the right infor-mation.Inthissense,nodesarelikecities,whichareconnectedtoeachother(associated)byroads(Reisberg, 1997).

Recital is a key component of the SQ4R method.


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CatDog

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FIGURE 7.11Networks of association. Long-term knowledge is stored in networks of association, ideas that are mentally connected with one another by repeatedly occurring together.

Not all associations are equally strong;dog ismore strongly connected tobarks than to cat oranimal.Toreturntothecitiesanalogy,somecitiesareconnectedbysuperhighways,whichfacilitaterapidtravelbetweenthem,whereasothersareconnectedonlybyslow,windingcountryroads.Othercitieshavenodirectlinksatall,whichmeansthattravelbetweenthemrequiresanintermediatelink.Thesameistrueofassociativenetworks:infigure7.11catisnotdirectlyassociatedtocold weather,butit isthroughtheintermediatelinkofmy cat Mittens,whichissemanticallyrelatedtowear mit-tens,whichisinturnlinkedtothecold weathernode.

From a neuropsychological perspective, if two nodeswithout a direct link become increasinglyassociated through experience, a ‘road’ between them is built; and if the association continues togrow,thatroadwillbe‘widened’toensurerapidneuraltransitbetweenoneandtheother.If,ontheotherhand,aneuralhighwaybetweentwonodesfallsintodisusebecausetwoobjectsoreventsstopoccurring together (suchas the linkbetween thewordgirlfriend andaparticulargirlfriendmonthsafter the relationship has ended), the highwaywill fall into disrepair and be less easily travelled.The old road will not likely disappear completely: occasionally a traveller may wander off themain roaddowntheoldhighway,aswhenapersonaccidentallycallshisnewgirlfriendbyhisoldgirlfriend’sname.

Spreading activationOne theory that attempts to explain the workings of networks of association involves spreadingactivation (Collins&Loftus, 1975;Collins&Quillian, 1969).According to spreading activation theory,activatingonenodeinanetworktriggersactivationincloselyrelatednodes.Inotherwords,presenting a stimulus that leads to firing in the neural circuits that represent that stimulus spreadsactivation,orenergy,torelatedinformationstoredinmemory.

Spreadingactivationdoesnotalwaysstartwithastimulussuchasaspokenword.Activationmayalsobeginwithathought,fantasyorwish,whichinturnactivatesothernodes.Forexample,apsychotherapypatienttryingtodecidewhethertodivorcehiswifefoundthesongWe can work it outcomingtomindondayswhenheleanedtowardsreconciliation.Ondayswhenhewascontemplatingdivorce,however,hefoundhimselfinadvertentlysingingadifferenttune,Fifty ways to leave your lover.

Considerableresearchsupportsthetheoryofspreadingactivation.Inonestudy,theexperimenterspresentedparticipantswithwordpairstolearn,includingthepairocean–moon(seeNisbett&Wilson,1977).Later,whenaskedtonamealaundrydetergent,participantsinthisconditionweremorelikelyto respond with Tide than control participants, who had been exposed to a different list of wordpairs.YouwouldexpectsimilarfindingsifyoureplacedTidewithSurf inacomparativesampleofAustralianparticipants—SurfisapopularlaundrydetergentinAustralia—althoughtheconnectionwouldprobablynotbeasstrong.

MAKING CONNECTIONSThe neural processes underlying memory involve synaptic activity. No pun intended, but memories are formed by neurons making connections, or by breaking connections. Those synapses that are used repeatedly retain and strengthen their dendritic spines (site of synaptic connections), whereas others develop but are lost if not used frequently (chapter 3).


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The researchers offered an intriguing explanation (figure 7.12): the network of associations thatincludesoceanandmoonalsoincludestide.Primingwithocean–moonthusactivatedothernodesonthenetwork,spreadingactivationtotide,whichwasassociatedwithanothernetworkofassociations,laundrydetergents.

Laundrydetergents FabTideMoon

CheerWaves

AllOceanFIGURE 7.12Spreading activation. Tide stands at the intersection of two activated networks of association and is thus doubly activated. In contrast, other brands only receive activation from one network. (This experiment, of course, only works in places where Tide has a substantial market share.)

According tomanycontemporarymodels, each timea thoughtor image isperceived,primedorretrievedfrommemory,thelevelofactivationoftheneuralnetworksthatrepresentitincreases.Thus,twokindsofinformationarelikelytobeatahighstateofactivationatanygivenmoment:recentlyactivatedinformation(suchasanewsstoryseenamomentagoontelevision)andfrequentlyactivatedinformation(suchasadoctor’sknowledgeaboutdisease).Forexample,apersonwhohasjustseenadocumentaryoncancerislikelytoidentifythewordleukaemiafasterthansomeonewhotunedintoadifferentchannel;adoctorissimilarlylikelytoidentifythewordquicklybecauseleukaemiaisatachronicallyhigherstateofactivation.

Hierarchical organisation of informationAlthoughactivatingadognodecantriggersomeidiosyncraticthoughtsandmemories,networksofassociationarefarfromhaphazardjumblesofinformation.Efficientretrievalrequiressomedegreeoforganisationofinformationsothatthemindcanfinditswaythroughdensenetworksofneuraltrails.Research suggests that people with the thought disorder schizophrenia experience an abnormalincrease in the spread of activation in semantic memory (Kreher, Holcomb, Goff, & Kuperberg,2008),makingitdifficultforthemtolinkideastogether.

Some researchers have compared LTM to a filing cabinet, in which important information iskept towards the front of the files and less important information is relegated to the back ofourmental archives or to a box in the attic.Thefiling cabinetmetaphor also suggests thatsomeinformationisfiledhierarchically;thatis,broadcategoriesarecomposedofnarrowersubcategories,whichinturnconsistofevenmorespecificcategories.

For example, a person could store information about animals under the sub-categories pets, farm animals andwild animals. Under farm animals are cows,horsesandchickens.Ateachlevelofthehierarchy,eachnodewillhavefeaturesassociatedwithit(suchasknowledgethatchickenssquawkandlayeggs)aswellasotherassociationstoit(suchasroastedchicken,whichisassociatedwithaverydifferentsmellthanisthegeneric‘chickens’).

Hierarchical storage is generallyquite efficient, but it canoccasionally lead toerrors. For instance,when asked, ‘Which is farther north, Perth orSydney?’manypeoplesaySydney.Infact,Perthisfarthernorth.PeoplemistakenlyassumethatSydneyis north ofPerth because theygo to their general level of knowledge aboutWesternAustralia andNewSouthWales.They remember thatPerth is right at thebottomof thewest coast ofAustralia,whileSydneyisasignificantdistanceuptheeastcoast.Inreality,theeastcoastofAustraliaextendsmuchfurthersouththanthewestcoast.

I N T E R I M S U M M A R YKnowledgestoredinmemoryformsnetworks of association—clustersofinterconnectedinfor-mation. Each piece of information along a network is called a node.According to spreading activation theory, activating one node in a network triggers activation in closely related nodes.Somepartsofnetworksareorganisedhierarchically,withbroadcategoriescomposedofnarrowersubcategories,whichinturnconsistofevenmorespecificcategories.

Sydney

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SchemasThe models of associative networks and spreading activation we have been discussing go a longway towards describing the organisation of memory, but they have limits. For example, psychol-ogistshavenotyetagreedonhowtorepresentpropositionslike‘Thedogchasedthecat’usingnet-

workmodels,sinceifdogandcatarenodeshowisthelinkbetweenthem (chased) represented?Further, activationofonenodecanactu-allyeither increaseor inhibitactivationofassociatednodes,aswhenapersonidentifiesanapproachinganimalasadogandnotawolfandhence‘shutsoff’thewolfnode.

Psychologists have argued for over a century about the adequacyof principles of association in explaining memory (Bahrick, 1985).Somehavearguedthatwedonotassociateisolatedbitsofinformationwitheachotherbutinsteadstoreandrememberthe‘gist’offactsandevents.Theynotethatwhenpeoplerememberpassagesofproseratherthansinglewordsorwordpairs, theytypicallyrememberthegeneralmeaningofthepassageratherthanaverbatimaccount.

Accordingtothisview,whenconfrontedwithanoveleventpeoplematch it against schemas stored inmemory.Schemas arepatternsofthought, or organised knowledge structures, that render the environ-

ment relatively predictable.When students walk into a classroom on the first day of class and apersonresemblingaprofessorbeginstolecture,theylistenandtakenotesinaroutinefashion.Theyarenotsurprisedthatonepersonhasassumedcontrolofthesituationandbeguntalkingbecausetheyhaveaschemaforeventsthatnormallytranspireinaclassroom.Proponentsofschematheoriesarguethatmemoryisanactiveprocessofreconstructionofthepast.Rememberingmeanscombiningbitsandpiecesofwhatweonceperceivedwithgeneralknowledgethathelpsusfill in thegaps.Inthisview,memoryisnotliketakingsnapshotsofanevent;itismoreliketakingnotes.

Schemas affect the way people remember in two ways: by influencing the information theyencodeandbyshapingthewaytheyreconstructdatathattheyhavealreadystored(Davidson,1996;Rumelhart,1984).

Schemas and encodingSchemasinfluencethewaypeopleinitiallyunderstandthemeaningofaneventandthusthemannerinwhichtheyencodeitinLTM.HarryTriandis(1994)relatesanaccountoftwoEnglishmenengagedinafriendlygameoftennisinnineteenth-centuryChina.ThetwoweresweatingandpantingunderthehotAugustsun.As theyfinished theirfinalset,aChinesefriendsympatheticallyasked, ‘Couldyounotgettwoservantstodothisforyou?’Operatingfromadifferentsetofschemas,theirChinesefriendencodedthiseventratherdifferentlythanwouldanaudienceatWimbledon.

Schemas and retrievalSchemasnotonlyprovidehooksonwhichtohanginformationduringencoding,buttheyalsoprovidehooksforfishinginformationoutofLTM.Manyschemashave‘slots’forparticularkindsof infor-mation(Minsky,1975).ApersonshoppingforaDVDplayerwhoistryingtorecallthemodelsshesawthatdayislikelytorememberthenamesSonyandPioneerbutnotPaulCollins(thesalesmanatoneofthestores).UnlikeSony,PaulCollinsdoesnotfitintotheslot‘brandnamesofDVDplayers’.RecentfMRIstudiessuggestthatnewinformationthatfitsanestablishedschemaislikelytobemorequicklyassimilatedinneocorticalnetworks,andthatthemedialprefrontalcortexmayfacilitatethisprocess(VanKersteren,Rijpkema,Ruiter,&Fernández,2010).

Theslots inschemasoftenhavedefaultvalues, standardanswers thatfill inmissing informationthepersondidnotinitiallynoticeorbothertostore.Whenaskedifthecoverofthisbookgivestheauthors’names,youare likely to report that it does (default value= yes) even if younever reallynoticed,becausetheauthors’namesnormallyappearonabookcover.Infact,peoplearegenerallyunabletotellwhichpiecesofinformationinamemoryaretrulyrememberedandwhichreflecttheoperationofdefaultvalues.

Oneclassicstudydemonstratedthereconstructiveroleofschemasusingavisualtask(Brewer&Treyens, 1981).The experimenter instructed university student participants towait (one at a time)

APPLY ✚ DISCUSS

• If people’s memories for events are, in part, driven by schemas, what implications would this have for people recalling details of crime scenes (Tuckey & Brewer, 2003)?

• Might their memory for those details be influenced by a ‘crime schema’?

• What role would such schemas play in eyewitness testimony?


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ina‘graduatestudent’soffice’similartotheonedepictedinfigure7.13whileheexcusedhimselftocheckonsomething.Theexperimenterreturnedin35secondsand led the student to a different room.There, he asked the participant either towritedownadescriptionofthegraduatestudent’sofficeortodrawapictureofit,includingasmanyobjectsascouldberecalled.

Theroomcontainedanumberofobjects(e.g.,bookshelves,coffeepot,desk)thatwouldfitmostparticipants’schemaofagraduatestudent’soffice.Severalobjects,however,wereconspicuous—or rather, inconspicuous—by theirabsence,suchas afiling cabinet, a coffee cup, books on the shelves, awindow, pens and pen-cils,andcurtains.Manyparticipantsassumedthepresenceof thesedefault items,however, and ‘remembered’ seeing themeven though theyhadnot actually beenpresent.

Without schemas, life would seem like one random event after another, andefficientmemorywould be impossible.Yet as the research just described shows,schemascanleadpeopletomisclassifyinformation,tobelievetheyhaveseenwhattheyreallyhavenotseenandtofailtonoticethingsthatmightbeimportant.

I N T E R I M S U M M A R YOnewaypsychologistsdescribetheorganisationofLTMisintermsofschemas,organisedknowl-edgeaboutaparticulardomain.Proponentsofschematheoriesarguethatmemoryinvolvesrecon-structionofthepast,bycombiningknowledgeofwhatweonceperceivedwithgeneralknowledgethathelpsfillinthegaps.Schemasinfluenceboththewayinformationisencodedandthewayitisretrieved.

Cultural models and memoryThroughoutthischapter,wehavedescribedmemoryasifitoccursinisolatedinformationprocessors(seeCole, 1975).However, cultural models, or shared cultural concepts, organise knowledge andshapethewaypeoplethinkandremember(chapter19;D’Andrade,1992;Moore&Mathews,2001;Strauss&Quinn, 1997). Imagine, for example, howmuchmore difficult the task of rememberinghowaneuronworksmightbeforsomeonewhoseculturelackedtheconceptofcells.

Yearsago,FredericBartlett(1932)demonstratedtheimpactofculturalmodelsonretrieval.BritishparticipantsreadaNorthAmericanIndianfolktale,waited15minutesandthenattemptedtorepro-duceitverbatim.Theirerrorsweresystematic:participantsomittedorreworkedunfamiliardetailstomakethestoryconsistentwiththeirownculturallyshapedschemas.

I N T E R I M S U M M A R YAcrossandwithincultures,people tend toremember information thatmatters to them,and theyorganise information in memory to match the demands of their environment. Shared culturalconcepts,orcultural models,alsoshapethewaypeoplethinkandremember.

■ Remembering, misremembering and forgetting

Wecouldnotdowithoutourmemories,butsometimeswewishwecould.AccordingtoDanielSchacter(1999),whohas spenthis life studyingmemory,humanmemory systemsevolved throughnaturalselection,butthesamemechanismsthatgenerallyfosteradaptationcanregularlycausememoryfailures.Hedescribes‘sevensinsofmemory’thatplagueusall:• transience(thefactthatmemoriesfade)• absent-mindedness(thefailuretoremembersomethingwhenattentioniselsewhere)• misattribution (misremembering the sourceof amemory—somethingadvertisers relyonwhen

they tell half-truths about competing brands and people remember the half-truth but forget itssource)

FIGURE 7.13Influence of schemas on memory. Participants asked to recall this graduate student’s office frequently remembered many items that actually were not in it but were in their office schemas.Source: Brewer and Treyens (1981).

Now is the time for all good men to to come to the aid of their countrymen.

The extra ‘to’ at the beginning of the second line is easily overlooked because of the schema-based expectation that it is not there. Students often fail to notice typographical errors in their papers for the same reason.


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• suggestibility(thinkingwerememberaneventthatsomeoneactuallyimplantedinourminds)• bias (distortions in thewaywe recall events that often tell the story in awaywewould rather

rememberit)• persistence(memorieswewishwecouldgetridofbutwhichkeepcomingback)• forgetting(theinabilitytoremember).Although at first glance these ‘sins’ all seemmaladaptive,many stem fromadaptivememory pro-cessesthatcangoawry.Forexample,ifmemorywerenottransientortemporary,ourmindswouldoverflowwithirrelevantinformation.

Perhaps the cardinal sin ofmemory is forgetting.Over a century ago, Ebbinghaus (1885/1964)documented a typical pattern of forgetting that occurswithmany kinds of declarative knowledge:rapid initial loss of information after learning and only gradual decline thereafter (figure 7.14).Researchers have since refined Ebbinghaus’ forgetting curve slightly to make it more precise—finding, in fact, that the relationbetweenmemorydeclineand lengthof timebetween learningandretrieval is logarithmic and hence predictable by a very precisemathematical function (Wixted&Ebbesen, 1991). This logarithmic relationship is very similar to Stevens’ power law for sensorystimuli(chapter4).

This forgettingcurveseems toapplywhether theperiodof time ishoursoryears.Forexample,thesamecurveemergedwhenresearchersstudiedpeople’sabilitytorememberthenamesofoldtele-visionshows: theyrapidlyforgot thenamesofshowscancelledwithin the lastsevenyears,but therateofforgettingtrailedoffafterthat(Squire,1989).

How long is long-term memory?Whenpeople forget, is the informationno longer storedor is it simplyno longereasy to retrieve?Andissomeinformationpermanent,ordoesthebraineventuallythrowawayoldboxesintheatticifithasnotusedthemforanumberofyears?

The first question is more difficult to answer than the second. Psychologists often distinguishbetweentheavailabilityofinformationinmemory—whetheritisstill‘inthere’—anditsaccessi-bility—theeasewithwhichitcanberetrieved.Thetip-of-the-tonguephenomenon,liketheprimingeffectsshownbyamnesics,isagoodexampleofinformationthatisavailablebutinaccessible.

Inlargepart,accessibilityreflectslevelofactivation,whichdiminishesovertimebutremainsformuchlongerthanmostpeoplewouldintuitivelysuppose.Memoryforapictureflashedbrieflyonascreenayear earlier continues toproduce someactivationof thevisual cortex,which is expressedimplicitlyevenifthepersonhasnoconsciousrecollectionofit(Cave,1997).Andmostpeoplehavevividrecollectionsfromtheirchildhoodofcertainincidentsthatoccurredonce,suchasthemomenttheyheardthenewsthatabelovedpetdied.Butwhatabouttheotherhundredsofmillionsofinci-dentsthattheycannotretrieve?Towhatdegreethesememoriesarenowunavailable,ratherthanjustinaccessible,isunknown.

Studiesof very long-termmemory suggest, however, that if information is consolidated throughspacingoverlonglearningintervals,itwilllastalifetime,evenifthepersondoesnotrehearseitforhalfacentury(Bahrick&Hall,1991).Eightyearsafterhavingtaughtstudentsforasinglesemester,university lecturerswill forget thenamesand facesofmostof their students (sorry!),but35 yearsafter graduation people still recognise 90 percent of the names and faces from their high schoolyearbook.

The difference is in the spacing: the lecturer teaches a student for only a fewmonths,whereashighschoolstudentstypicallyknoweachotherforatleastthreeorfouryears.Similarly,peoplewhotake university mathematics courses that require them to use the knowledge they learned in highschoolalgebrashownearlycompletememoryforalgebra50yearslatereveniftheyworkasartistsandneverbalancetheirchequebook.Peoplewhostopathighschoolalgebraremembernothingofitdecadeslater.

How accurate is long-term memory?Aside from the question of how long people remember is the question of how accurately theyremember.Theshortansweristhatmemoryisbothfunctionalandreconstructive,sothatmostofthetimeitservesuswell,butitissubjecttoavarietyoferrorsandbiases.

Time

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FIGURE 7.14Rate of forgetting. Forgetting follows a standard pattern, with rapid initial loss of information followed by more gradual later decline. Increasing initial study time (the dotted line) increases retention, but forgetting occurs at the same rate. In other words, increased study shifts the curve upward but does not change the rate of forgetting or eliminate it.


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Forexample,thenormalassociativeprocessesthathelppeopleremembercanalsoleadtomemoryerrors (seeRobinson&Roediger,1997;Schacter,Verfaellie,Anes,&Racine,1998). Inone setofstudiestheresearcherspresentedparticipantswithaseriesofwords(suchasslumber,napandbed)thatwereallrelatedtoasinglewordthathadnotbeenpresented(sleep).Thisessentiallyprimedtheword ‘sleep’ repeatedly (Roediger&McDermott,1995).Notonlydidmostparticipants rememberhavingheardthemultiplyprimedword,butthemajorityevenrememberedwhichoftwopeoplehadread theword to them.Someparticipants refused to believe that theword had not been presentedevenafterhearinganaudiotapeofthesession!

Emotionalfactorscanalsobiasrecall.Theinvestigatorsinonestudyaskeduniversitystudentpar-ticipantstorecalltheirmaths,science,history,Englishandforeignlanguagegradesfromhighschoolandthencomparedtheirrecollectionstotheirhighschooltranscripts(Bahrick,Hall,&Berger,1996).Studentsrecalled71percentoftheirgradescorrectly,whichiscertainlyimpressive.

Moreinteresting,however,wasthepatternof theirerrors(figure7.15).Participantsrarelymisre-memberedtheirAs,buttheyrarelycorrectlyrememberedtheirDs.Infact,aDwastwiceaslikelytoberememberedasaBorCthanasaD.Approximately80percentofparticipantstendedtoinflatetheir remembered grades, whereas only 6 percent reported grades lower than they had actuallyachieved.(Theremaining14percenttendedtoremembercorrectly.)

Flashbulb memoriesIf remembering ismore like consulting an artist’s sketch than a photograph,what dowemake offlashbulb memories, that is, vividmemories of exciting or highly consequential events (Brown&Kulik,1977;Conway,1995;Winograd&Neisser,1993)?Manypeoplecan recall precisely where and when they first heard the news of theSeptember11attacksontheUnitedStatesin2001,almostasifacamerahad recorded thatmoment in time.People report similarly vividmem-ories of the announcement that Sydney had been awarded the 2000OlympicGames,aswellaspersonaleventssuchasthedeathofalovedoneoraromanticencounter(Rubin&Kozin,1984).

Flashbulbmemoriesaresoclearandvividthatwetendtothinkofthemastotallyaccurate;however,considerableevidencesuggeststhattheyareoftennotofsnapshotclarityoraccuracyandcanevenbeentirelyincor-rect(Neisser,1991).Forexample,onthedayfollowingtheChallengerspaceshuttledisasterintheUnitedStatesin1986,peoplereportedwherethey were when they heard the space shuttle had disintegrated. Threeyears laterwhen theywere again askedwhere theywere, not a singlepersonrecalledwithcompleteaccuracywheretheyhadbeen,andathirdoftherespondentswerecompletelyincorrectintheirrecall(McCloskey,Wible,&Cohen,1988;Neisser&Harsch,1992).

Emotional arousal and memoryIn trying tounderstand‘flashbulb’memories,Cahill,Prins,Weber,andMcGaugh, (1994)designedanelegantexperimentthatmanipulatedboththeemotionalcontentofthematerialtoberememberedand adrenalin (the fight-or-flight hormone, chapter 3) (see figure 7.16). First, they developed twoseriesof12slidesdepictinga littleboy leaving for school,havinganunusualexperienceand thenreturninghome.Inthemiddlesectionofslides,theunusualexperiencedifferedforthetwoseries.Inthecontrolorneutralcondition,thelittleboygoesonafieldtriptothehospitalandseesadisasterdrill.Intheexperimentalorarousalcondition,thelittleboyisinatragicaccidentinwhichhisfeetareseveredfromhislegsandaconcussionleadstobleedinginthebrain.Miraculously,thedoctorsareabletoreattachtheboy’sfeetandcontrolthebrainbleeding.

Half the participantswere shown the neutral slide series; the other halfwere shown the arousalslide series.The secondmanipulation, that of adrenalin activity,was createdbygiving adrug thatantagonises the actions of adrenalin (propranolol) to half the participants in each group.The pro-pranololblockedanyeffectofadrenalinthatthearousalslidesproduced.Inthistwo-by-twodesign,twofactorswerestudied:(1)neutralorarousalslideversions,and(2)placebodrugortheadrenalinantagonistpropranolol.Thus,therewerefourgroups(seefigure7.16)—NPl:neutral,placebodrug;NPr:neutral,propranolol;APl:arousal,placebodrug;andAPr:arousal,propranolol.

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FIGURE 7.15Distortion in memory for high school grades. The lower the grade, the less memorable it seems to be, demonstrating the impact of motivation and emotion on memory.Source: Adapted from Bahrick et al. (1996).

Do you remember where you were when you heard that Crocodile Hunter Steve Irwin had died?

Placebodrug (Pl)

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FIGURE 7.16In an investigation of the relationship between emotional arousal and memory, researchers found that memory was higher for participants in the arousal condition who had not received propranolol, relative to the other three conditions.


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Theresearchershypothesisedthatthememoryforallgroups,whentestedoneweeklater,wouldbethesame,exceptfortheAPlgroup,forwhichmemoryofthemiddlesetofslides(whentheboywasintheaccident)wouldbebetterthantheothergroups.Thatis,theyhypothesisedthattheemotionallyarousingslides,which triggeredadrenalinrelease,would lead toenhancedmemoryof thoseslides.Neither of the neutral groups would have any adrenalin release (thus, the propranolol would nothaveanyadrenalintoantagonise)andthearousalgroupwhoseadrenalinactivitywasantagonisedbypropranololwouldnothaveenhancedmemory,eventhoughtheysawthearousingslides.Theresultssupportedtheirhypothesis.

These results support the notion that our ‘flashbulb’ memories for emotionally arousing eventsare dependent on the fight-or-flight hormone, adrenalin. It is important to note that memory wasenhancedonlyforthearousalslides,notfortheneutralbeginningandendingslides.Thus,emotionalarousal,viaadrenalinactivityinthebrain,canleadtoenhancedmemory.However,recentresearchdemonstratesthatifpeopleareinastateofalarmatthetimetheyreceiveinformationtobeencodedandstoredinmemory, thetruthfulnessof thismemorymaybeaffectedbyreconstructiveprocesses(Lanciano,Curci,&Semin,2010).

Eyewitness testimonyResearchon the accuracyofmemoryhas an important real-life application in the courtroom: howaccurateiseyewitnesstestimony(seeMelinder,Scullin,Gunnerod,&Nyborg,2005;Schacter,1995b;Sporer,Malpass,&Koehnken,1996;Wellsetal.,2000;Wells&Olson,2003)?Numerousstudieshaveexploredthisquestionexperimentally,usuallybyshowingparticipantsashortfilmorslidesofaneventsuchasacaraccident(Wells&Loftus,1984;Zaragosta&Mitchell,1996).Theexperimenter thenasksparticipantsspecificquestionsaboutthescene,sometimesintroducinginformationthatwasnotpresentintheactualscene,askingleadingquestionsorcontradictingwhatparticipantssaw.

These studies show that seeminglyminor variations in thewordingof a question candeterminewhat participants remember froma scene.One study simply substituted the definite article the for

the indefinitearticlea in thequestion‘Didyousee the/abrokenheadlight?’Usingthe insteadofa increasedboth the likelihood thatparticipantswould recall seeinga broken headlight and their certainty that they had, even if they never actuallyobservedone(Loftus&Palmer,1974;Loftus&Zanni,1975).

OneAustralian study (Dietze&Thomson,1993)explored theaccuracyofchildwitness testimony by showing participants a film and then asking them questionsabout it under three conditions— first, where the film was being viewed at thetime; second, using a seriesof specificquestions; and third, using free recall.Thecorrectnessofrecallwasbetterwhenthefilmwasbeingviewedincontextorwhenspecificquestionswereasked,ascomparedtofreerecall.Thusretrievalofmemorieswasaffectedby theway inwhich theparticipantswereasked torecalldetailsofapastevent.

A more recentAustralian study by Tuckey and Brewer (2003) examined howschemas,orexpectations,foracrimeinfluencedthetypesofinformationeyewitnessesrememberedandforgotovertime.Theirresultsshowedthatwhenawitnessreportsdetailsthatarecommontothattypeofcrime(i.e.,whichareexpectedofthatcrime),the schema-consistent details are likely to be accurate and recalled at subsequentinterviews.

These findings have clear implications both in the courtroom and in the waypolice interrogate witnesses. However, individuals vary in their susceptibility tomisleading information (Loftus, Levidow, & Diensing, 1992; see also Melinder,Goodman, Eilertsen, & Magnussen, 2004). Further, some aspects of a memory

maybemorereliablethanothers.Theemotionalstressofwitnessingatraumaticeventcanleadtoheightenedprocessingof(andhencebettermemoryfor)coredetailsoftheeventbutlessextensiveprocessingofperipheraldetails (Christianson,1992).Asharpbarristercould thusattack thecred-ibilityofawitness’sentiretestimonybyestablishingthathermemoryofperipheraldetailsisfaulty,even though she clearly remembers the central aspects of the event. Consequently, an emergingfield is the study ofmethods for evoking and assessing traumaticmemories.The aim is to betterdeterminetheprocessesandcontentsofmemoryretrievalintraumatisedindividuals(seeHopper&van der Kolk, 2001).

ETHICAL DILEMMAA seven-year-old boy witnesses a brutal assault on his mother by a home invader in the early hours of the morning. The house is dark and the attacker leaves unaware of the child’s presence. The boy is the only witness to the assault and has to come to the aid of his mother after the assault. The police later arrest a suspect and need evidence to secure a conviction when the case goes to trial. Eyewitness testimony identifying the culprit would certainly help.

• Should the young boy be allowed to testify at trial? Why or why not?

• How accurate is the child’s testimony likely to be?

• Discuss the ethical issues most relevant to this case.


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I N T E R I M S U M M A R YTheflipsideofmemoryisforgetting.Manykindsofdeclarativeknowledgeshowasimilarforget-tingcurve,whichisinitiallysteepandthenlevelsoff.Psychologistsoftendistinguishbetweentheavailabilityofinformationinmemory—whetheritisstill‘inthere’—anditsaccessibility —theeasewithwhichitcanberetrieved.Peopletendtomakememoryerrorsforavarietyofreasons,somecognitiveandsomeemotional.Flashbulb memories—vividmemoriesofexcitingorhighlyconsequential events— are sometimes extremely accurate but sometimes completelymistaken.Eyewitnesstestimonyisalsosubjecttomanybiasesanderrors.

Should we be worried when a senior complains about their memory?By Professor Craig Speelman, Edith Cowan University

Humanmemory is a fallible storage device. Evenwhen ourmemory of an experience feels clear,comparisonwithobjectiveinformationwillrevealthatourmemoryispronetogaps,distortionsandillusions.There are countless timeswhenwe notice thatwe have forgotten something and yetwedo not assume that ourmemory is faulty. Forgetting is a normal feature ofmemory.Nonetheless,memoryperformancedoestendtodeclineasweage,particularlymemoryforepisodicinformation.

Memorydeclinewithageisanormaloccurrence,althoughsomechangesinmemoryperformancearemoreseverethanothersandcouldbeasignofdementia.Atwhatpointshouldwebeconcernedaboutachangeinmemoryperformanceorcomplaintsfromseniorsthattheirmemoryisfailing?Aroundtwo-thirdsofseniors(thoseover70yearsold)livinginthecommunityreportmemorydifficulties(Slavinetal.,2010);however,thereisonlyaweakassociationbetweenself-reportedmemorydifficultiesandobservablememoryperformance(Reid&MacLullich,2006).ResearchindicatesthatthisrelationshipisstrongerwhenageandIQaretakenintoaccount(Merema,Speelman,Kaczmarek,&Foster,2012).

Importantly,thelikelihoodofsomeonereportingmemorycomplaintsisrelatedtowhetherornottheysufferfromdepression(Meremaetal.,2012).Thisrelationshiphasbeenreportedmanytimesbefore.However,newresearchhasfoundthatdepressionexhibitslittlerelationshipwithmemorycomplaints,beyondwhat can already be explained by personality characteristics (predominantly neuroticism)(Merema,Speelman,Foster,&Kaczmarek,2013).What thissuggests is thatdepressionmaynotbedirectlyrelatedtomemorycomplaintsbut,rather,therelationshipismediatedthroughcharacteristicsofpersonality.Forexample,highlevelsofneuroticismaretypicallyassociatedwithmorefrequentorseverememorycomplaintsaswellasanincreasedriskofdepressivesymptoms,whichwouldgenerateanindirectassociationbetweenthem.Thissuggeststwoimportantclinicalimplications.1. Older adults complaining of memory problems likely exhibit an

ongoing risk for depression. Such complaints are associated withhigherlevelsofneuroticism,aknownriskfactorfordepression.

2. Memory complaints are often associated with an increased risk ofsubsequentdementia,despitegenerallybeingapoorpredictorofcon-currentmemoryperformance.Thehigherratesofdementiainolderadults complaining of memory problemsmay be partially attribut-able to this increased vulnerability to depression (Byers,Covinsky,Barnes,&Yaffe,2011),aswellastherelationshipbetweenneuroti-cismanddementiarisk(Low,Harrison,&Lackersteen,2013).So, should we be concerned when seniors complain about their

memory?Yes— not necessarily because theirmemory is failing, butbecauseofotherissuesthecomplaintsmaysuggest,suchasdepression.Theresultsdiscussedhereunderlinethegreatextenttowhichourmentalfaculties—memoryandpersonality—areinterrelated.

ONE S TEP

FURTHER


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Why do people forget?Thereconstructivenatureofremembering—thefactthatwehavetoweavetogetheramemoryfrompatchesof specificandgeneralknowledge— leavesmemoryopen toanumberofpotential errorsandbiases.Butwhydopeoplesometimesforgetthingsentirely?Psychologistshaveproposedseveralexplanations,includingdecay,interferenceandmotivatedforgetting.

Decay theoryDecay theoryexplainsforgettingasaresultofafadingmemorytrace.Havingathoughtorpercep-tionproduceschangesinsynapticconnections,whichinturncreatethepotentialforrememberingiftheneuralcircuitsthatwereinitiallyactivatedarelaterreactivated.Accordingtodecaytheory,these

neurophysiological changes fadewith disuse,much as a path in theforestgrowsoverunlessrepeatedlytrodden.Thedecaytheoryisdiffi-culttocorroborateordisproveempirically.However,itfitswithmanyobservedmemoryphenomena.Further,somestudiesdoshowapatternofrapidandthenmoregradualdeactivationofneuralpathwaysinthehippocampus(whichisinvolvedinmemoryconsolidation),whichsug-gestsapossiblephysiologicalbasisfordecay(seeAnderson,1995).

Interference theoryA prime culprit in memory failure is interference, the intrusion ofsimilarmemoriesoneachother,aswhenstudentsconfusetwotheoriestheylearnedaroundthesametimeortwosimilar-soundingwordsinaforeignlanguage.Findingtherightpathintheneuralwildernessisdiffi-cultiftwopathsareclosetogetherandlookalike.Ortousethefiling

cabinetmetaphor,storingtoomanydocumentsunderthesameheadingmakesfindingtherightonedif-ficult.Cognitivepsychologistsdistinguishtwokindsofinterference.Proactive interferencereferstotheinterferenceofpreviouslystoredmemorieswiththeretrievalofnewinformation,aswhenapersoncallsanewromanticpartnerbythenameofanoldone(acommonbutdangerousmemorylapse).Inretroactive interference,newinformationinterfereswithretrievalofoldinformation,aswhenpeoplehavedifficulty recalling theirhomephonenumbers frompast residences.One reasonchildren takeyearstomemorisemultiplicationtables,eventhoughtheycanlearnthenamesofcartooncharactersorclassmateswithastonishingspeed, is the tremendous interference that is involved,becauseeverynumberispairedwithsomanyothers(Anderson,1995).

Motivated forgettingAnothercauseofforgettingismotivated forgetting,orforgettingforareason.Peopleoftenexplicitlyinstructthemselvesorotherstoforget,aswhenapersonstopsinthemiddleofasentenceandsays,‘Oops—forgetthat.That’sthewrongaddress.Therightoneis...’(Bjork&Bjork,1996).Atothertimes, the intention to forget is implicit, aswhen a personwho parks in a different parking spaceeverydayimplicitlyrememberstoforgetwheresheparkedthedaybeforesoitdoesnotinterferewithmemoryforwheresheparkedtoday(Bjork,Bjork,&Anderson,1998).

Experimentalevidencesuggests thatgoal-directedforgettingrequiresactive inhibitionof thefor-gotten information, which remains available but inaccessible. Researchers have demonstrated thisby using directed forgetting procedures: participants learn a list of words but are toldmidway toforgetthewordstheyjustlearnedandrememberonlythelastpartofthelist.Thisprocedurereducesrecallforthewordsinthefirstpartofthelistanddecreasesproactiveinterferencefromthem,sothatparticipantscanmoreeasilyrememberwordsinthelasthalfofthelist.Thisoutcomesuggeststhatthe procedure is in fact inhibiting retrieval of the to-be-forgottenwords.This procedure does not,however,decreaserecognitionof,orimplicitmemoryfor,theto-be-forgottenwords,andtheyremainavailable,justlessaccessible.

Otherstudiesshowthatinstructingapersonnottothinkaboutsomethingcaneffectivelykeeptheinformationfromconsciousness,butthatdeliberatelysuppressinginformationinthiswaycreatesanautomatic,unconsciousprocess that ‘watchesout’ for the informationandhencekeeps it available

APPLY ✚ DISCUSS

Most people cannot explicitly remember events before about age four, a phenomenon known as childhood amnesia.

• What is your earliest memory?

• Why might we be unable to retrieve memories from before age three or four? What aspects of the way we represent, store and retrieve information might affect our capacity to recall early memories?

• What neurological factors might limit access to early episodic memories?


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(Wegner,1992).Forexample,whenpeopleareinstructedtosuppressanexcitingthoughtaboutsex,theyremainphysiologicallyarousedevenwhilethethoughtisoutsideawareness.Infact,theyremainjustasarousedasparticipantsinstructedtothinkaboutthesexualthought(Wegner,Shortt,Blake,&Page,1990).Inasense,goal-directedforgettingislikeaformofprospectivememory,inwhichtheintentionistoforgetsomethinginthefutureratherthantorememberit.Inthissituation,forgettingis actually a form of remembering! In real life, people often try to inhibit unpleasant or anxiety-provokingthoughtsorfeelings(chapter11).Theyoftenforgetthingstheydonotwanttoremember,suchas‘overlooking’adentistappointment.

False memories and repressed memoriesTheconceptofrepressionhasalwaysbeencontroversialinpsychology(Holmes,1990),butitisnowthecentrepieceofcontroversy(Sivers,Schooler,&Freyd,2002).Itisattheheartofclaimsofchild-hoodsexualabuseandcounterclaimsof falsememories raisedbyallegedperpetrators.Theallegedperpetratorsclaimthatthechargesofsexualabuseagainstthemhavebeeninventedbyincompetentclinicianswhohaveconvincedtheirpatientsoftheexistenceofeventsthatneveroccurred(Del Monte,2001;Howe,2000;Pezdek&Banks,1996).

Thequestionof implanting falsememories is exceedinglydifficult toaddress scientifically foranumber of reasons. First, distinguishing true from false allegations is difficult in all legal circum-stances, but it is evenmore difficultwhen the eventsmay have occurred 15 years ago. Second, acardinalfeatureofsexualabuseis that theperpetratordoeseverythingpossible tomaintainsecrecy(including threatening the victim) and to discredit the victim if she or he ever tells the story—a situation not unlikewhat often occurswith rape, political torture and genocide (Herman, 1992).Third, some number of innocent people are unfairly accused: divorcing parents sometimes accuseformerspousesasatacticincustodydisputes,andsomepoorlytrainedtherapistslookfor(and‘find’)abusewheneveranadultfemalepatientstepsintotheirofficecomplainingofanxietyordepression(Loftus, 1993).

Evidence of false memoriesDatafromnumerouslaboratorystudiessuggestthatpeoplecansometimesbeledtocreatecompel-lingmemoriesof things that didnot happen (Loftus, 1997a;Payne,Nevschate,Lampien,&Lynn,1997).Aswe have seen, presenting peoplewith a series ofwords semantically related to a targetwordthatwasnotpresentedcanproducehighratesoffalserecognitionofthetarget,andpeoplecanbequitefirm in theirbeliefsabout these falsememories.Womenreportinga recoveredmemoryofchildhood sexual abuse aremore likely than otherwomen to recognise a targetword (sweet)mis-takenly as having been present in an earlier list of related words (sugar, candy, honey) (Clancy,Schacter,McNally,&Pitman,2000).Womenwhoreport rememberingabuseallalong(asopposedto recoveringit)donotshowthisbias.

In another experimental design that bears on false memories, researchers obtain detailed infor-mation fromparents of university students about events that actually occurredwhen their childrenwereyounger and thenpresent the studentswith several realmemories andone falseone, suchasgettinglost inashoppingcentreatagefiveandbeingfoundbyanelderlywoman(Loftus,1997b).Theinvestigatorstheninterviewparticipantsabouteachevent,askthemiftheyrememberit,andaskthemtorecallwhattheyremember.Inthesestudies,roughly15to25percentofparticipantscanbeinduced to recall a falsememoryover the courseof twoor three interviews.More recent researchfromNewZealandindicatesthatdrawingthingsrelatedtofalseinformationwhilebeingquestionedmay promote false memories in children (see Strange, Garry, & Sutherland, 2003). Furthermore,Sharman,Manning,andGarry(2005)foundthataskingadultstoexplainearliereventsinflatedtheirconfidenceandmemoryforthoseevents.Otherresearchhasdemonstratedtheroleofsociolinguisticcuesonmemory.For example,Vornik,Sharman, andGarry (2003) found that people are likely tobemisledbyaninaccuratenarrationifthenarratorishigh(ratherthanlow)onsocialattractiveness.

Formostpeople,however,thevulnerabilitytorecallfalsememoriesisnotwithoutlimit.Whenoneresearcher tried to inducememoriesmore like thoseof sexualabusevictims (in thiscase,memoryof a rectal enema in childhood), noneof theparticipants created a falsememory (Pezdek, cited inLoftus,1997b).Thereisobviouslyaneedforcautioninextendingthefindingsoftheseexperimentalstudiestothecreationoffalsememoriesofsexualabuse,ahighlytraumaticandevocativeevent.


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Evidence of repressed memoriesOtherstudiescall intoquestion thecharge thatmostpsychotherapypatientswhobelieve theyhavebeen sexually abused invent thesememories.Themajority of victims of repeated or severe sexualabuseinchildhoodhaveatleastsomememoriesoftheabusepriortopsychotherapy,althoughtheirmemoriesareoftenfragmented(Herman,1992).Theirrecollectionofchildhoodeventstendstohavegapsofmonthsoryears,andthememoriesoftraumaticexperiencestheydorecallfrequentlycometotheminflashbacks,inphysicalforms(suchasthesensationofgaggingthatinitiallyattendedtheexperience of being forced to perform oral sex), or in nightmares. Such intrusions and flashbacksexperiencedbytraumasurvivorsandthosewhohaveexperiencedpost-traumaticstressdisorderarelinkedtoaninabilitytoselectivelycontrolepisodicmemory(Zwissleretal.,2012).

Several studies document that periods of amnesia for sexual abuse are common (see Briere &Conte,1993;Loftus,Polonsky,&Fullilove,1994),justasinothertraumaticeventssuchascombatorrape(Arrigo&Pezdek,1997).Perhapstheclearestempiricalevidenceforrepressedmemoriescomesfrom a study that tracked downwomenwho had been treated at a hospital for sexualmolestationwhentheywerechildren(Williams,1994).Seventeenyearsaftertheirdocumentedabuse,38percentwereamnesic for the incident.Whenasked ifanyfamilymembershadevergotten into trouble fortheirsexualbehaviour,oneparticipant,whodeniedsexualabuse,reportedthatbeforeshewasbornanunclehadapparentlymolestedalittlegirlandwasstabbedtodeathbythegirl’smother.Examinationofnewspaperreports17yearsearlier foundthat theparticipantherselfhadbeenoneof theuncle’stwovictimsandthatthemotheroftheothervictimhadindeedstabbedtheperpetrator.

Perhapsthemoralofthestoryisthatpsychologistsshouldalwaysattendbothtothephenomenontheyarestudying—inthiscase,repressedmemories—andtotheirownneeds,fearsandcognitivebiases.Forexample,researchdemonstratesthatpeoplewithabusehistoriesaremorelikelytoseeorhearthemesofabuseinambiguoussituations(Nigg,Lohr,Westen,Gold,&Silk,1992).Thus,clini-cianswithpainfulmemoriesoftheirownchildhoodshouldbeparticularlycarefultoavoidjumpingtoconclusionsorsubtlyinfluencingpatientswithleadingquestions.

Ontheotherhand,researcherswhomayhavehadlittleornoexposuretorealsexualabusevictimsshould be circumspect about overstepping the limits of their vantage point.Researchers and clini-ciansalikeneedtolookcarefullyattheirowncognitiveandmotivationalbiasesbeforeattemptingtorewrite—orwriteoff—thelifehistoriesofothers.

MemoryBy Professor Rick Richardson, The University of New South Wales

The idea ofmemory erasure has attracted considerable interest, both scientifically and in popularculture (e.g., the movie Eternal Sunshine of the Spotless Mind). One reason for this interest hasto dowith the possibility of erasing trauma-relatedmemories that often underlie anxiety disorders(e.g., post-traumatic stress disorder is due to persistent, vivid, traumatic memories that adverselyimpactonanindividual’sabilitytofunctionnormally).Whiletreatmentslikecognitive–behaviouraltherapyareundoubtedlyeffectiveintreatingmanyanxietydisorders,theyarenotperfect,withsomepatientsnotimprovingandothersrelapsingaftersuccessfulcompletionoftreatment(McNally,2007).Whatwouldhappeniftheunderlyingmemorycouldbeerased?

The idea of memory erasure has been raised in several areas of research. For example, someresearchers have lesioned just thoseneurons thatwere active at the timeofmemory encoding andfounda selective lossofmemory (e.g.,Hanet al., 2009).Althoughvery exciting, this approach isnotcurrentlypossibleinhumans.However,otherresearchershaveexaminedtheconceptofmemoryerasureinsettingsthatcanbeappliedtohumans.

It has been suggested that extinction of fear can involve the unlearning, or erasure, of the orig-inalmemoryunderlying the fear, at least incertaincircumstances (Quirketal.,2010). Ina typicalextinction experiment, animals (either humans or non-humans) first learn to fear a stimulus, oftenthrough Pavlovian conditioning (see chapter 6). Extinction training then involves repeated presen-tationsof thefear-elicitingconditionedstimulus(CS)byitself,whichleadstoagraduallossoffear.Extinction usuallyresultsintheformationofacompetingmemorythatinhibitstheoriginalmemory

COMMENTARY


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I N T E R I M S U M M A R YThedecay theoryexplainsforgettingasaresultofafadingmemorytrace;disuseofinformationleads to a gradual decrease in the strength of neural connections. Interference of similar infor-mation isanothercauseof forgetting.Proactive interference refers to the interferenceofprevi-ously storedmemories with the retrieval of new information, whereas retroactive interferencerefers to the interferenceofnewinformationwith retrievalofold information.Anothercauseofforgetting ismotivated forgetting, or forgetting for a reason. The final word has not yet beenwrittenaboutrepressedmemoriesofchildhoodsexualabuse,althoughthedatasuggestcautiononbothsides:memoriesrecoveredintherapycannotbeassumedtobeaccurate,buttheyalsocannotberoutinelydismissedasfalse.

Disordered memoriesWehave seen thatdistortioncanoccurwithin thememoriesofpeoplewithnormalbrain function.Specifickindsofdistortion can alsooccurwithin thememoriesofpeoplewhosebrainshavebeenaffectedbyillnessorinjury.Thesearecalleddisorderedmemories.Therearetwomaintypesofdis-orderedmemories—anterogradeandretrograde.

Anterograde amnesiaAnterograde amnesiainvolvestheinabilitytoretainnewmemories.Thisamnesiaistypicallycausedbydamageinthetemporallobe,particularlyinthehippocampusandsubcorticalregion(Mishkin&Appenzeller, 1987). People with this condition often have no problem retrievingmemories storedbefore theirbrainsweredamaged,butcannot learnanythingnew(Gleitman,Fridlund,&Reisberg,1999). The brain simply does not retain or retrieve fresh information.Anterograde amnesia is asymptomthatistypicallyassociatedwithAlzheimer’sdisease(chapter12).

Retrograde amnesiaBycontrast,retrograde amnesiainvolveslosingmemoriesfromaperiodbeforethetimethataperson’sbrainwasdamaged.Braintumoursandstrokesoftencausethisformofamnesia.Severelydepressedormanicpatientsmayalsoexperienceabriefperiodofretrogradeamnesiafollowingelectroconvulsive

(Todd,Vurbic, &Bouton,inpress),whichallowsforthepossibilityoftheoriginalmemoryreturning(i.e.,relapse).

There is evidence that adding particular pharmacological treatments to extinction reduces theoccurrenceofrelapse(seeGraham,Langton,&Richardson,2011),andthatitmightevenleadtotheerasureof theoriginal fearmemory (Graham&Richardson,2011).Althoughmuchmore researchis needed in this area, the pharmacological modification of extinction is particularly exciting asextinctionistheempiricalbasisforexposure-basedtherapy,whichisthemosteffectivetreatmentforanxietydisorders.

There is also evidence that reactivating amemory (i.e., such that theperson/animal is currentlythinkingaboutit)maymakeitsusceptibletobeingerased.Insomestudies,participantsgivenextinc-tiontrainingshortlyafterafearmemoryhadbeenreactivatedexhibitedmuchlessrelapsecomparedtoparticipantsmerelygivenextinctiontraining(Monfils,Cowansage,Klann,&LeDoux,2009;Schilleretal.,2010;seeXueetal.,2012,foranexampleofthisfindingwithdrug-relatedcues).Thetypicalinterpretationof thisfinding is that thereconsolidationof theoriginalmemorywasdisrupted in thereactivation–extinctioncondition, leading tomemoryerasure.While this is averyexcitingfinding,somehave failed to replicate it (e.g.,Chan,Leung,Westbrook,&McNally,2010;Kindt&Soeter,2013),whileothershavereplicatedthebasiceffectbuthaveraisedquestionsabouthowitshouldbeinterpreted(Baker,McNally,&Richardson,2012).Moreresearchinthisareaisclearlyneeded.

Whatevertheoutcomeofthisfutureresearch,thetypesofresearchdescribedinthissectionholdgreat promise for not only enhancing our understanding of memory, but also for improving theefficacyoftreatmentsforavarietyofpsychologicaldisorders.


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therapy(Andreason&Black,1996)—theyhavenomemoryofthetreatmentoroftheeventsdirectlyprecedingit(chapter16).Commonlytheamnesiacoversonlyashortperiod(althoughthiscanbeuptoseveralyears)beforetheinjuryorillnessdamagedthebrain—oldermemoriesandnewmemoriesarenotaffected.Thereasonswhythisoccursarestillbeingdebated(seeSquire,1987).

I N T E R I M S U M M A R YSpecifickindsofdistortioncanalsooccurwithinthememoriesofpeoplewhosebrainshavebeenaffectedbyillnessorinjury.Anterograde amnesiainvolvestheinabilitytoretainnewmemories.Bycontrast,retrograde amnesia involves losingmemories fromaperiodbefore the time thataperson’sbrainwasdamaged.

Central quest ions rev is ited ◆ What is memory?

Webeganthischapterwithacentralquestion:whatisthenatureofmemory?Ismemorytherecol-lectionoffacts?Orarethefeelingsthatreturnwiththeepisodicmemoryofourfirstkiss(orthepro-ceduralmemoryofhowtokissafteralongdryspell!)rightlyconsideredmemoryphenomena?Andwhatistherelationshipbetweenlearningandmemory?

Toanswerthesequestionsrequiresaconsiderationoftheperspectivesthathaveguidedourinquiryintomemory.Wehavefocusedinthischapterprimarilyonthecognitiveperspective,justasthepre-vious chapter on learning focused on the behaviourist perspective. But as the concept ofmemoryhasexpandedtoincludephenomenasuchasimplicitmemory,wearebeginningtoseeanintegrationofperspectives thatwouldhaveseemedunimaginable just10yearsago,ascognitivepsychologistsmoveintoterraintraditionallyviewedasthe‘turf’ofotherperspectives.

Take,forexample,therelationshipbetweenlearningandmemory.Whateverhappenedtoclassicalandoperantconditioninginthestandardmodelofmemory?Surelyananimalmustberememberingsomething when it produces an adaptive response based on prior experience? But behaviouristsemphasised that these forms of learning do not require conscious attention (that is, retrieval intoSTM)andofteninvolveemotionallearning(aswhenaratlearnstoavoidsituationsassociatedwithfear-inducingstimuli).Apreliminaryanswerhasbeguntoemerge:conditioningisaformofassoci-ativememorythatisexpressedimplicitlyratherthanretrievedasexplicit,declarativememory.

Our expanding understanding ofmemory has also begun to narrow the gulf between cognitive,psychodynamic and evolutionary approaches. The standard model assumed that information hadto be processed consciously (inSTM)before being stored inLTMand that remembering requiredconscious retrieval.Psychoanalysis, incontrast,proposed thatmostmentalprocessesoccuroutsideawareness,areprocessedinparallelandcanbeexpressedinbehaviourwithouteverbecomingcon-scious. Freud, likemost contemporary cognitive theorists, was schooled in classical associationistthought,andheproposedanetworktheoryofthemindandamechanismsimilartospreadingacti-vationacenturyago (seeErdelyi,1985;Freud,1895/1966;Pribram&Gill,1976).Heargued thatnetworksofassociationoperateunconsciously,leadingpeopletothink,feelandbehaveinwaystheymaynotunderstand.Freudandlaterpsychodynamictheoriststhusdevelopedanapproachtotreatingpsychologicalproblemsthat involves trying tomapthesenetworks,so that thepersoncanbegin torecognisetheimplicittriggersforideas,feelingsandbehaviourpatternsthatleadtoproblemssuchasrepeatedstruggleswithbossesorotherauthorityfigures.

Finally,thestandardmodelviewedthecapacityformemoryandthoughtasessentiallyindependentof content; that is, as applying to any kind of information. Themind was a general information-processingmachinethatcouldtakealmostanyinput,manipulateitandrememberitwithappropriateencodingand rehearsal.But an increasinglymodular conceptionof thebrain andmemory systemshasmade contemporary cognitivemodelsmore compatible with a view of cognition emerging inevolutionarycircles.Thisviewmaintainsthatthebrainhasevolvedcontent-specificmechanismsthatfacilitatetherememberingandprocessingofveryparticularkindsofinformation(Tooby&Cosmides,1992).Itisnoaccidentthatwehavethecapacitytoperceiveandrecognisefacesthatdifferinwhatareobjectivelysomeincrediblytrivialways.(Toapossum,wealllookalike.)Knowingwhoweare


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dealingwithisincrediblyimportantfromanadaptiveperspective,soitisperhapsnotsurprisingthatwearebornwithspecialisedneuralcircuitsthathelpusrecognisefaces.

Insum,ascognitiveneurosciencehasexpandedthedomainofmemory,ithasledtoanunforeseenpotentialforintegrationamongcognitive,behavioural,psychodynamicandevolutionaryperspectives.Perhapssomedaywewillnotrememberthedifferencesamongthemsoclearly.

S U M M A R Y1 Memory and information processing

• Case studies of neurologically impaired patients and experimentalstudies of normal participants have demonstrated that memory iscomposedofseveralsystems.

• Forinformationtoreturntomindafteritisnolongerpresent,ithasto be put into amental code, or representation. Themajor formsof representations studied by psychologists are sensory represen-tations andverbal representations.People also storememory foractionsasmotoricrepresentations.

• The standard model of memory views the mind as a computer,which stores, transforms and retrieves information processing. Itincludes threesequentialmemorystoresorstagesofmemory.Thefirst is the sensory register, the split-secondmental representationofaperceivedstimulusthatremainsverybrieflyafterthatstimulusdisappears. Iconic storage describes visual sensory registration;echoic storagedescribesauditorysensoryregistration.

• Short-term memory (STM) stores information for roughly 20 to30seconds,unlesstheinformationismaintainedthroughrehearsal(repeatingtheinformationagainandagain).Thisformofrehearsal,whichmerelymaintainsinformationinSTM,iscalledmaintenance rehearsal.Elaborative rehearsal—thinkingaboutandelaboratingon the information’s meaning— tends to be superior for storinginformationinlong-termmemory.

• Important information is passed along to long-term memory (LTM),whererepresentationsmaylastaslongasalifetime.Recov-eringinformationfromLTM,orretrieval,bringsitbackintoSTM,orconsciousness.

• Inrecentyears,thismodelhasbeenchangingsubstantially.Insteadofviewingmemoryexclusivelyintermsofserialprocessing(whichassumes that informationpasses through a series of stages, one ata timeandinorder),researchersnowviewmemoryasinvolvingasetofmodulesthatoperatesimultaneously(inparallel)ratherthansequentially(oneatatime).Researchersnowrecognisethatnotallrememberingisexpressedbyretrievinginformationintoconscious-ness,orSTM,andtheyrelylessonthemetaphorofmindascom-puterthanmindasbrain.

2 Working memory

• PsychologistsnowrefertoSTMasworking memory,thetemporarystorageandprocessingofinformationthatcanbeusedtosolveprob-lems,respondtoenvironmentaldemandsorachievegoals.Accordingto one prominent model, control processes such as rehearsal, rea-soningandmakingdecisionsabouthowtobalancetwotaskssimul-taneouslyaretheworkofalimitedcapacitycentralexecutivesystem;whereas storage involves at least two limited-capacity systems, avisualstore(alsocalledthevisuospatialsketchpad)andaverbalstore.

• The existence of neurological patientswho showdeficits in eitherworkingmemoryorLTMbutnotbothsuggeststhatthesememorysystems are neurologically distinct, although in everyday life theywork together, as frontal working memory networks provide aspecial formofactivation tonetworks in theposteriorpartsof the

cortex that represent current perceptions and information storedin LTM.Oneway to expand the capacity of workingmemory inparticulardomains ischunking; that is,grouping information intolargerunitsthansinglewordsordigits.Theroughlysevenpiecesofinformationstored invisualorauditoryworkingmemorycan rep-resentlarger,moremeaningfulpiecesofinformation.

3 Types of long-term memory

• Typesoflong-termmemorycanbedistinguishedbythekindofknowl-edgestoredandthewaythisknowledgeisretrievedandexpressed.People store twokindsof information,declarativeandprocedural.Declarative memory refers tomemory for factsand eventsand issubdividedintosemanticorgeneric memory(generalworldknowl-edgeorfacts)andepisodic memory(memoriesofparticularevents).Procedural memoryrefersto‘howto’knowledgeofproceduresorskills.

• Informationcanberetrievedeitherexplicitlyorimplicitly.Explicit memory refers to conscious recollection, expressed through recall(the spontaneous retrieval of material from LTM) or recognition(memory forwhether somethingcurrentlyperceivedhasbeenpre-viously encountered or learned). Implicit memory is expressed inbehaviourratherthanconsciouslyretrieved.

• Neurologicaldatasuggestthatdifferentkindsofmemoryformdis-cretememory systems. The hippocampus and adjacent regions ofthecortexarecentraltotheconsolidationofexplicitmemoriesbutdonotappeartoplayanimportantroleineitherimplicitmemoryorworkingmemory.

• Everyday memory—memoryasitoccursindailylife—tendstobe functional (focused on remembering information that ismean-ingful)andemotionallysignificant.Prospective memoryismemoryforthingsthatneedtobedoneinthefuture.

4 Encoding and organisation of long-term memory

• Forinformationtoberetrievablefrommemory,itmustbeencoded,or cast into a representational form, or ‘code,’ that can be readilyaccessedfrommemory.

• Among the factors that influence later accessibility of memoryare the degree to which information is elaborated, reflected uponandprocessedinameaningfulwayduringencoding(level of pro-cessing); the presence of retrieval cues (stimuli or thoughts thatcanbeusedtofacilitaterecollection);thespacingofstudysessions(withlongerintervalsbetweenrehearsalsessionstendingtobemoreeffective); and the use of multiple and redundant representationalmodestoencodetheinformation,whichprovidesmorecuesforitsretrieval. Mnemonic devices, or systematic strategies for remem-bering information, can also be useful for remembering, as canexternalmemoryaidssuchasnotes.

• Information stored in memory forms networks of association —clusters of interconnected units of information called nodes.Accordingtospreadingactivationtheory,activatingonenodeinanet-worktriggersactivationincloselyrelatednodes.Someinformationis


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R E V I E W Q U E S T I O N S1. Describethecharacteristicsofworkingmemory,short-termmemoryandlong-termmemory.2. Distinguishbetweenprocedural,declarative,explicitandimplicitmemories,andbetweenthetwo

kindsofexplicitretrieval.3. Explainhowinformationisencodedinlong-termmemoryusingdeepandshallowprocessing.4. Describetechniquesforretrievinginformationfromlong-termmemory.5. Outlinethesevencharacteristicsofhumanmemorysystemsthatcanregularlycausememoryfailures.

D I S C U S S I O N Q U E S T I O N S1. Howareworkingmemoryandlong-termmemoryrelated?2. Istheeyewitnessontrialwhengivingevidenceinlegalcases?3. Howaccuratearerepressedmemories?

A P P L I C AT I O N Q U E S T I O N S1. Testyourunderstandingofthedifferentmemorytypesdiscussedinthischapterbymatchingeachof

thescenarioslistedherewithoneofthefollowing:declarativememory,episodicmemory,explicitmemory,implicitmemory,flashbulbmemory,everydaymemory,proceduralmemory,prospectivememory,retrospectivememoryandsemanticmemory.(a) AlthoughithasbeenquiteafewyearssinceGeorgehadriddenhisbike,heisabletopedaldown

theroadafterabitofawobblystart.(b) Inatutorial,Yincanrecogniseanumberofwordpairsshememorisedfromawordlistthatwas

providedinthelecture.(c) Whilegoingthroughsomeoldhoneymoonphotos,Triciarecallshowbeautifulandbluetheocean

lookedinthefullmoonlight.(d) Antonioshutsdownhiscomputerbeforeleavingworkfortheday.

organisedhierarchically,withbroadcategoriescomposedofnarrowersubcategories,whichinturnconsistofevenmorespecificcategories.

• Schemas are organised knowledge about a particular domain.According to schema theory, memory is an active, reconstruc-tive process that involves reactivation of both the initial represen-tations of an event and general knowledge that helps fill in thegaps.Schemasfacilitatememorybyorganisinginformationatbothencodingandretrieval.

• Many schemas are shaped by culture, from beliefs about foodsthat are appropriate to eat to beliefs about the meaning of life.Acrosscultures,peopletendtorememberwhatmatterstothem.

5 Remembering, misremembering and forgetting

• Ebbinghaus discovered a forgetting curve that applies to manykindsofdeclarativememory, inwhichconsiderable information isinitiallylostbutforgettingthentapersoff.

• Memory is a reconstructive process that mingles representationsof actual experiences with general knowledge.Although memoryis functionaland tends toworkwellmostof the time,misremem-beringiscommon,eveninflashbulb memories(vividmemoriesofexcitingorhighlyconsequentialevents)andeyewitness testimony,whichcanbebiasedbyevenseeminglyminorchanges in thewayquestionsareasked.

• Three theories attempt to account for forgetting: decay theory(which explains forgetting as a result of a fadingmemory trace);interferenceofnewandoldinformationwithretrievaloftheother;andmotivated forgetting (forgetting for a reason, which leads toinhibitionofretrieval).

• Specifickindsofdistortioncanalsooccurwithin thememoriesofpeoplewhosebrainshavebeenaffectedbyillnessorinjury.Antero-grade amnesia involves the inability to retain newmemories.Bycontrast, retrograde amnesia involves losing memories from aperiodbeforethetimethataperson’sbrainwasdamaged.

K E Y T E R M Santerogradeamnesia p. 281chunking p. 258culturalmodels p. 273decaytheory p. 278declarativememory p. 259echoicstorage p. 251elaborativerehearsal p. 252encoded p. 265encodingspecificity

principle p. 266episodicmemory p. 259everydaymemory p. 263explicitmemory p. 260flashbulbmemories p. 275

forgetting p. 274genericmemory p. 259iconicstorage p. 251implicitmemory p. 260interference p. 278levelofprocessing p. 265long-termmemory(LTM)

p. 252maintenancerehearsal p. 252methodofloci p. 268mnemonicdevices p. 268modules p. 253motivatedforgetting p. 278networksofassociation p. 269

node p. 269primingeffects p. 261proactiveinterference p. 278proceduralmemory p. 259prospectivememory p. 264recall p. 260recognition p. 261rehearsal p. 252retrieval p. 252retrievalcues p. 267retroactiveinterference p. 278retrogradeamnesia p. 281retrospectivememory p. 264semanticmemory p. 259

sensoryregisters p. 251sensoryrepresentations

p. 249serialpositioneffect p. 252short-termmemory(STM)

p. 251spacingeffect p. 267spreadingactivationtheory

p. 270SQ4Rmethod p. 268tip-of-the-tonguephenomenon

p. 260verbalrepresentations p. 250workingmemory p. 254


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(e) Carlaintendstostopatthenurseryandbuysometreesandshrubstoplantinthegardenthisweekend.

(f) GoranrecallswithconfidencethatSirEdmundBartonwasthefirstPrimeMinisterofAustralia.(g) RodneyremindshimselftophonehisfriendHimeshtowishhimahappybirthday.(h) Mariais80yearsoldbutclearlyrecallsthefondmemoryofherfirstkiss,asthoughithappened

yesterday.(i) SharonrecallspreciselywhereandwhenshewaswhenshefirstheardthenewsofPrincess

Diana’sdeathin1997.(j) ChriswasintroducedtoRussell,AbdulandMischaataconferencebutcannotremembertheir

nameswhenherunsintothematanotherfunctionthenextday.2. Testyourunderstandingofwhyforgettingoccursbyidentifyingthetheoryofforgettingineachof

thefollowingscenarios.Choosefromdecaytheory,proactiveinterference,retroactiveinterferenceandmotivatedforgetting.(a) Jungdoesnotlikepresentinginfrontofothersandforgetswhensheisscheduledtogiveaclass

presentation.(b) Michellehasjustmovedhouseandisconstantlyconfusingheroldhomephonenumberwithher

newone.(c) Matthewflicksthroughhisbabyalbumonhistwenty-firstbirthdayandisamazedbyhowmuch

hehasforgottenabouthisearlymilestones.Hisearliestremainingmemoryisthathelovedridinghistricyclewhenhewasthreeyearsold.

(d) Six-year-oldSharifgoestoswimminglessonsandlearnsthefreestylekick,shortlyfollowedbythebutterflykick.Atswimminglessonsthenextday,heconfusesthebutterflykickwiththefreestylekick.

Thesolutionstotheapplicationquestionscanbefoundattheendofthebook.

M U LT I M E D I A R E S O U R C E SiStudy featuring Cyberpsychisamultimediaresourcetoaccompanythistextbooktofurtherdevelopyourunderstandingofmanykeypsychologyconcepts.Itcontainsawealthofrichmediacontentandactivities,andforthischapterincludes:• videocasestudiesonunforgettablememoriesandeyewitnesstestimony• interactivemodulesondeclarativeversusproceduralmemory,amnesiaandenhancingmemory.


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Burton, Lorelle, et al. Psychology, Wiley, 2014. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/griffith/detail.action?docID=3059089.Created from griffith on 2018-02-26 16:59:57.

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