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Memory (1) . Atkinson & Shiffrin (1968) Model of Memory. Visual Sensory Store. It appears that our visual system is able to hold a great deal of information but that if we do not attend to this information it will be rapidly lost. Sperling (1960)

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Memory (1)

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Memory (1)


Atkinson & Shiffrin (1968) Model of Memory


Visual Sensory Store

  • It appears that our visual system is able to hold a great deal of information but that if we do not attend to this information it will be rapidly lost.

  • Sperling (1960)

    • Presented array consisting of three rows of four letters

    • Subjects were cued to report part of display

Demo at:http://www.dualtask.org/

XMRJ

CNKP

VFLB


Visual Sensory Memory

  • Vary the delay of cue in partial report

  • After one second, performance reached asymptote

Mean number of words reported

Delay of cue (in seconds)


Iconic Memory

  • Sperling’s experiments indicate the existence of a brief visual sensory memory – known as iconic memory or iconic store

  • Information decays rapidly unless attention is transfers items to short-term memory

  • Analogous auditory store: echoic store


Atkinson & Shiffrin (1968) Model of Memory

Short-term memory (STM) is a limited capacity store for information -- place to rehearse new information from sensory buffers

Items need to be rehearsed in short-term memory before entering long-term memory (LTM)

Probability of encoding in LTM directly related to time in STM


a memory test...

TABLE

CANDLE

MAPLE

SUBWAY

PENCIL

COFFEE

TOWEL

SOFTBALL

CURTAIN

PLAYER

KITTEN

DOORKNOB

FOLDER

CONCRETE

RAILROAD

DOCTOR

SUNSHINE

LETTER

TURKEY

HAMMER


In free recall, more items are recalled from start of list (primacy effect) and end of the list (recency effect)

Distractor task (e.g. counting) after last item removes recency effect

Serial Position Effects

nodistractor task

distractor task


Explanation from Atkinson and Shiffrin (1968) model:

Early items can be rehearsed more often

 more likely to be transferred to long-term memory

Last items of list are still in short-term memory (with no distractor task)

 they can be read out easily from short-term memory

Serial Position Effects


Forgetting over time in short-term memory.

Peterson and Peterson (1959)


Baddeley’s working memory system.

  • Baddeley proposed replacing unitary short-term store with working memory model with multiple components:

    • Phonological loop

    • Visuo-spatial sketchpad

    • Central executive (ignore the episodic buffer)

  • Baddeley and Hitch (1974)

  • Baddeley (1986)


Phonological Loop(a.k.a. articulatory loop)

  • Stores a limited number of sounds – number of words is limited by pronunciation time, not number of items

  • Experiment:

  • Word length effect – mean number of words recalled in order (list 1  4.2 words; list 2  2.8 words)

  • Phonological loop stores 1.5 - 2 seconds worth of words

LIST 1:

Burma

Greece

Tibet

Iceland

Malta

Laos

LIST 2:

Switzerland Nicaragua Afghanistan Venezuela Philippines

Madagascar


Two routes to phonological loop

Articulatory control process

  • Articulatory control process converts visually presented words into a speech code

  • Articulatory suppression (e.g. saying “the” all the time) disrupts phonological loop

  • Prediction:

    • Word length effect depends on phonological loop

    • With articulatory suppression, visuallypresented items should not display word length effect

Visualpresentation

Speech code

Phonological

loop

Auditorypresentation


Immediate word recall as a function of modality of presentation (visual vs. auditory), presence vs. absence of articulatory suppression, and word length.

Baddeley et al. (1975).


Different languages have different #syllables per digit

Therefore, recall for numbers should be different across languages

E.g. memory for English number sequences is better than Spanish or Arabic sequences

Working memory and Language Differences

(Naveh-Benjamin & Ayres, 1986)


Evaluation of the Evidence for the Phonological Loop

  • Accounts for phonological similarity and the word-length effect

  • Support from neuroimaging studies

  • Baddeley, Gathercole, and Papagno (1998)

    • Its function may be to learn new words


Encoding & Retrieval Effects


Levels of Processing(Craik & Lockhart, 1972)

Levels of processing effect:

Deeper levels of processing (e.g., emphasizing meaning)

leads to better recall.


Encoding Specificity Principle

  • Recollection performance depends upon the interaction between the properties of the encoded event and the properties of the retrieval information


Context Change

  • Information learned in a particular context is better recalled if recall takes place in the same context

  • Similarly, information learned in a particular context may be difficult to recall in a dramatically different context


Godden & Baddeley (1975, 1980)

Memory experiment with deep-sea divers

  • Deep-sea divers learned words either on land or underwater

  • They then performed a recall or recognition test on land or underwater


Mood-dependent Memory

  • Easier to remember happy memories in a happy state and sad memories in a sad state.

  • Subjects study positive or negative words in normal state. Test in positive or negative induced states.

     mood primes certain memory contents

Kenealy (1997).


State-dependent recall

  • Does physical state matter?

  • Eich et al. (1975): study while smoking normal or marijuana cigarette. Test words under same or different physical condition


Forgetting


Forgetting Functions

  • Ebbinghaus (1885/1913): Forgetting over time as indexed by reduced savings.

  • Most forgetting functions show:

  • Negative acceleration

    • Rate of change gets smaller and smaller with delay

  • Power law of forgetting


Forgetting

Why do we forget?

Some possibilities:

  • Memory has disappeared

     decay theory

  • Memory is still there but we can’t retrieve it

     repression

     inhibition theory

     interference theory


What is Repression?

  • “Something happens that is so shocking that the mind grabs hold of the memory and pushes it underground, into some inaccessible corner of the unconscious.”- Loftus (1993)

  • Some self-help book (“Courage to Heal”) relate repressed memories to sexual abuse


Recovered memory vs. False Memory

  • How do we know whether repressed memories are accurate?

  • In some cases, traumatic information is misremembered or simply “made up”

    • Loftus has been involved in many cases

    • Points out problems of

      • hypnosis

      • suggestive questioning

      • dream interpretations

Elizabeth Loftus


False Memory in the Lab

  • Deese, Roediger, McDermott paradigm

  • Study the following words

  • Recall test ....

  • Recognition memory testUse ratings 1) sure new 2) probably new 3) probably old 4) sure old

  • TEST:

SNOOZE

BED

REST

AWAKE

TIRED

DREAM

DOZE

WAKE

SLUMBER

SNORE

NAP

PEACE

YAWN

DROWSY

BLANKET

REST

COFFEE

SNORE

SLEEP


Results

  • Critical lure (“sleep”) are words not presented but similar to studied words. These words are often falsely recalled (sleep: 61% of Ss.)

  • Recognition memory results

    proportion of items classified with confidence levels:

    confidence rating4321

    studied items.75.11.09.05

    not studied

    unrelated.00.02.18.80

    critical lure.58.26.08.08

(e.g. “REST”)

(e.g. “COFFEE”)

(e.g. “SLEEP”)


Subjects reporting recovered memories are more vulnerable to false memories

False recognition of words not presented in four groups of women with lists containing eight associates.

Clancy et al. (2000)


Proactive and retroactive interference


Cued recall as a function of the number of times the cues had been presented before for recall (respond condition) or for suppression (suppress condition).

Inhibitory mechanisms in Forgetting

Anderson and Green (2001)


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