PSY 368 Human Memory

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PSY 368 Human Memory. Memory Forgetting cont. & Recognition. How do we forget?. Theories of forgetting: Failure of Consolidation Failure of retrieval Decay Context /cue mismatch Interference. How do we forget?. Interference ( McGeoch , 1932) - PowerPoint PPT Presentation


  • PSY 368 Human MemoryMemory Forgetting cont. &Recognition

  • Theories of forgetting:Failure of ConsolidationFailure of retrievalDecayContext/cue mismatch InterferenceHow do we forget?

  • Interference (McGeoch, 1932)Info encoded before or after can interfereStoring similar memories impedes retrieval.Over time, many similar experiences occur, especially since people are creatures of habit.

    Two types:Retroactive = info that comes AFTER interferesProactive = info that comes BEFORE interferesHow do we forget?

  • Retroactive Interference (RI)How do we forget?Forgetting caused by encoding new traces into memory in between the initial encoding of the target and when it is tested.Introducing a related second list of items impairs recall of the first list compared to a control condition.

  • How do we forget?Dog BookTree - CloudShoe - CarPen - SodaClip - HornLeaf - CupTruck - AntFish - GoatLake - Peach

    Recall from first listDog ?Tree - ?Shoe - ?Pen - ?Clip - ?Leaf - ?Truck - ?Fish - ?Lake - ?

    Dog BedTree - CakeShoe - CouchPen - StoolClip - HouseLeaf - ChairTruck - AppleFish - GasLake - Penny

  • How do we forget?Dog BookTree - CloudShoe - CarPen - SodaClip - HornLeaf - CupTruck - AntFish - GoatLake - Peach

    Recall from first listDog ?Tree - ?Shoe - ?Pen - ?Clip - ?Leaf - ?Truck - ?Fish - ?Lake - ?

    Dog BedTree - CakeShoe - CouchPen - StoolClip - HouseLeaf - ChairTruck - AppleFish - GasLake - Penny

  • Proactive Interference (PI)How do we forget?The tendency for older memories to interfere with the retrieval of more recent experiences and knowledge.The number of previous learning experiences (e.g. lists) largely determines the rate of forgetting at long delays.

  • DemoStudy the list of words on the front page (see the highlighted 1), one at a time, for 1 min.On a separate sheet of paper: Write down all the words from the 2nd list- on back side - you rememberTurn the paper over and study the list of words on the back page, one at a time, for 1 min.

  • How do we forget?List 1TulipDaisyHydrangeaOrchidVioletMagnoliaCarnationRoseLilac

    List 2aDandelion PansyIrisGardeniaDaffodilLilyPeonyGeraniumMarigold

    List 2bCheetahHorseSkunkLlamaMouseRaccoonLemurRabbitMonkey

  • Rosetulips.Rose....horseSame total number or items learnedHow do we forget?Release from PI (2nd list doesnt interfere as much)Change in item type can release interference Learn 2 lists of flowers vs. 1 of flowers and 1 of animals

  • Tend to remember faces, languages, some skills for very long time permastoreForgetting due to decay and/or interference (retroactive, proactive) and/or lack of consolidation

    Forgetting Summary

  • Questions to Think AboutDoes the type of memory test matter?Which test is easier a recognition test or a recall test? (What makes one test easier than another?)Why is it easier to recognize faces of ones own age-group?

  • Questions to Think AboutDoes the type of memory test matter?Yes, but the language used to describe the different tasks is messyHere is how Ill try to use the vocabularyIncidental subject doesnt know about future memory testIntentional subject does know about future memory testImplicit memory: memory without awareness, involves unintentional influence of memoryExplicit memory: memory with awareness, involves intentional retrieval

  • Memory Task TypesExplicit tests Implicit tests Intentional retrieval Free recallRecognition Unintentional retrieval use memory w/o knowing it Lexical DecisionStem Completion

  • Recall vs RecognitionList the names of the seven dwarves

  • Recall vs RecognitionY/N this is one of the seven dwarves


  • DefinitionsHollingworth (1913)In a recall test, the experimenter provides the context and the subject has to retrieve the target; in a recognition test, the experimenter provides the target and the subject has to retrieve the context.

    Recall must generate the responseRecognitionAlternative Forced Choice (2AFC, 4AFC)Given multiple choices, choose the one already seenYes-NoGiven one choice, indicate whether the item is old or new

    Recall vs Recognition

  • Recall vs RecognitionShepard (1967)Subjects presented with lists of stimuliWords, sentences, photographsRecognition TestAt test, presented with two stimuli, one from original list, one new (similar to the old one)Words: 88%Sentences: 89%Pictures: almost 100%1 week later, still at 87% for pictures

  • Recall vs RecognitionMntyl (1986)Subjects presented with lists of words, for which they had to generate three properties for eachRecall experiment At test, experimenter presented the propertiesSubjects recalled approximately 91% of the words at an immediate testPerformance dropped off over time1 day 78%, 2 days 71%, 7 days 60%So with the appropriate cues, recall can be very good too(best the more self-generated properties they made)

  • Two classes of theoriesSingle process theories - retrieval is one process regardless of taskDual process theories - two processes needed for retrieval - can be task dependentHow does Recognition work?

  • Single Process ModelsEarly theories of recognitionTagging Model (Yntema & Trask, 1963) When an item occurs, it is tagged with the relative time of occurrence, during retrieval look for items with tagsExplains why you can say which item came firstStrength Theory (Wickelgren & Norman, 1966)Items vary in strength- Studied items increase strength (as a function of recency)

  • Single Process ModelsEarly theories of recognitionLimitationsThese models contain only a single processPredict same results for recognition and recallMeaning that the same manipulation (word frequency, intentionality, etc) should have the same effect on both recall and recognition)

  • Eagle & Leiter (1964)Learning types (Intentional vs. Incidental)Single Process ModelsTask: Intentional (INT)Hear words, will recall laterIncidental (INC)Hear words, is it a Noun or Verb?Recall and RecognitionResults Recall: INT > INCRecognition: INT < INC

  • Kinsbourne & George (1974)Word frequency effectsSingle Process ModelsTask: study high or low frequency words (e.g., tree - high freq. vs. arboretum - low freq.)Tests: Recall and RecognitionResults: Recall: high > low Recognition: low > high

  • Generate-recognize model (G-R)E.g., Anderson & Bower (1972), Kintsch (1970)Remember/Know processes model (R/K)

    Dual-process theories

  • Generate-recognize model (G-R)Recall is made up of two processesFirst, generate a set of plausible candidates for recall (Generation stage)Second, confirm whether each word is worthy of being recalled (Recognition stage not the same as the recognition test)Recognition is made up of only one processBecause the experimenter provides a candidate, recognition does not need the generation stageDual-process theories

  • Generate-recognize model (G-R)Dual-process theoriesStudy listDandelion PansyIrisGardeniaDaffodilLilyPeonyGeraniumMarigold

    Recall the list(1) Generate set of candidatesPansyLilyCarnationDaffodilDandelion TulipRoseDaisy

    (2) Recognition Check if worthy

    Recall needs steps 1 & 2Recognition only needs step 2 (since 1 it is done for you)

  • Dual-process theoriesGenerate-recognize model (G-R)Example: Human Associative Memory (HAM) Anderson and Bower (1973)Assumes words are stored in associative networkAt encodingAs words are presented, they are tagged with a contextual markerPathways to associated words are also taggedAt recall:Contextual markers are followed to generate a set of plausible candidates (Generation stage)After examining number of associations between target word and context, old or new is chosen depending on sufficient contextual evidence (Recognition stage)

  • Generate-recognize model (G-R)Solves limitations of single process modelThe same manipulation does not have to have the same effect on both recall and recognitionThis model does a better job of explaining learning type and word frequency effectsIncidental learning means fewer inter-item associations (no reason to form associations if dont know about upcoming test)Hurts generation & helps recognition High frequency items are easier to generate, but they are also more likely to have appeared in other contexts, so recognition is harderHelps generation & hurts recognitionDual-process theories

  • Recall failure is quite common and explainable, but recognition failure is contrary to the prediction of generate-recognize modelsRecalled words should also be recognized Because the second stage is common to both recall and recognition, a successful outcome in one test should mean a successful outcome for the otherWatkins and Tulving (1975) tested this predictionProblem with G-R theory

  • Recognition FailureWatkins & Tulving (1975)Demonstrated that a word could be recalled, even though it could not be recognizedTraditional paired associate learningStrong associate of probe in List 3Forced choice recognition49% of recalled items (step 6) not recognized (step 5)

    StepProcedureExample1a1bList 1 presentedCued recall of List 1badge-buttonbadge- ? (button)2a2bList 2 presentedCued recall of List 2preach-rantpreach- ? (rant)3List 3 presentedglue-chair4a4bFree association stimuli presentedFree association responses madetabletable-chair, cloth, desk, dinner5a5bRecognition test sheets presentedRecognized items circleddesk top chairdesk top chair6Cued recall of List 3glue- ? (chair)

  • Generate-Recognize ModelsAdding a search process during recognition stage could allow a generate-recognize model to account for recognition failureFamiliarity instantly computed to make response (automatic and fast process, based on ease of processing)If familiarity value is not decisive enough, a search is performed (a slower process)In the previous experiment, the target word (chair) is not found in the search because the retrieval phase (step 5) contained inappropriate cuesThe recall test (step 6) provided appropriate cues, so the search process is successful

  • Dual-process theories(Tulving , 1985; Gardiner, 1988)Relatively recent change in recognition methodologyDoes someone Specifically rememberConscious recollection of the informations occurrence at study Just somehow knowKnowing that it was on the list, but not having the conscious recollection, just a feeling of knowingRemember versus Know Process Model

  • Dual-process theoriesTulving (1985)Present subjects with category-member pairs (PET cat)Recall tests:Free recall testCued recall test (category) PETCued recall test (category + first letter of target) PET - cThe proportion of remember judgments decreased over the three kinds of testsRemember versus Know Process Model

  • Remember Versus KnowGardiner (1990, 1993) gives an explanation:Remember judgments are influenced by conceptual and attentional factorsKnow judgments are based on a procedural memory systemLike explicit and implicit memory (more on this next week)Data from remember/know experiments support the idea that recognition is a combination of two processesRecollection (remember judgments) andFamiliarity (know judgments)

  • Remember/Know processes Make R/K judgment for Old itemsRemember = consciously recollect details of the items presentationKnow = sure an item was presented, but cant recall any of the details of presentation

    Dual-process theoriesR/K differ by:Picture superiority effectR: P > WK: W > PGeneration effectR: G > RK: R = GWord frequency effectR: L > HK: H = L

  • Special recognition abilityFace Recognition

  • Evidence for special ability:ProsopagnosiaThe inability to recognize previously seen faces, with relative sparing of other perceptual, cognitive and memory functions.Intact ability to identify people using nonfacial features (voice)Due to brain injury (typically to the right temporal lobe)Broad Subtypes: 1. Apperceptive - failure to generate a sufficiently accurate percept to allow a successful match to stores of previously seen faces.2. Associative - accurate percept, but failure to match because of loss of facial memory stores or disconnection from them.Face Recognition

  • Evidence for special ability:(2) Newborn preferencesStudies done by Fantz (1961, 1963) - had kids look at three kinds of figures

    Johnson and Morton (1991) report that new-born babies will preferentially view facesFace Recognition

  • Yin (1969) found that whilst people are generally better at recognising upright faces than they are other objects. They are worse for inverted faces than they are for other inverted objects.Evidence for special ability:(3) Face inversion effectThis suggests that the processing underlying normal face recognition is different from those underlying object recognition.

    Face Recognition

  • Evidence for special ability:(4) Pop-out effect for faces (Herschler & Hochstein, 2005)

    Face RecognitionFind the human face in the display as fast as you can. Ready?

  • Face RecognitionFind the human face in the display as fast as you can. Ready?

  • Evidence for special ability:(4) Pop-out effect for faces (Herschler & Hochstein, 2005)

    Face RecognitionNow find the animal face. Ready?

  • Face Recognition

  • Recognition is an explicit memory test. Single- and dual-process theories of recognition Single-process cant account for differences across recall and recognition G-R theory cant account for recalled, but not recognized items Face recognition seems to be a special abilitySummary

  • Recognition is an explicit memory test. Single- and dual-process theories of recognition Single-process cant account for differences across recall and recognition G-R theory cant account for recalled, but not recognized items Face recognition seems to be a special abilitySummary

  • The Mirror EffectObserved when The type of stimulus that is accurately recognized as old when old is also accurately recognized as new when new. The type that is poorly recognized as old when old is also poorly recognized as new when new. (Glanzer & Adams, 1985, p.8)Pervasive in recognition testsHigh/low word frequency and hit/false alarm rates, presentation rate, age of subject, ...

  • The Mirror Effect - Example

    The Mirror Effect and the Word Frequency EffectWord FrequencyHighLowHits27.8431.00False Alarms10.207.63Source: Human Memory, p. 214

  • The Mirror EffectSignificance: It eliminates all theories of recognition based on a unidimensional conception of strength or familiarity (single process models)May be able to be explained by dual process modelsExplanations for the mirror effect are still being formed

  • Ethnicity effect (OToole et al., 1994)Face recognition better for same ethnicity

  • Yes-No Recognition Test

    Possible Outcomes in a Yes-No Recognition TestSubjects ResponseYesNoTest ItemOldHitMissNewFalse AlarmCorrect Rejection

  • *The Thatcher Illusion(Thomson, 1980)

  • *The Thatcher Illusion(Thomson, 1980)

  • *Why does the Thatcher illusion occur?Bartlett and Searcy (1993) conducted experiments to measure face grotesqueness.Their results supported the configural processing hypothesisi.e. We have a difficulty in understanding the configuration of features when faces are inverted.We arent aware of the odd configuration of elements within the...