Memory II Reconstructive Memory Forgetting

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Memory IIReconstructive Memory Forgetting
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Observe this crime scene
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What does a penny look like?
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Memory Biases

• Memory is better for meaningful significant
  features than for details of language or
  perception
• ? gist is remembered better than detail

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Label distorts memory of objects
Carmichael, Hogan, Walter (1932)
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Reconstructive nature of memory

• Memory is often side-effect of comprehension
• details can be filled in or reconstructed
• Constructive approach to memory
• Memory actual events knowledge, experiences,
  expectations

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Effect of Expectation on Memory

• A simple demonstration experiment
• I am going to show you a picture of a graduate
  students office. Just take a look at it for a
  while

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(No Transcript)
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Now write down all the things you can remember
Potential responses Chairs Desk Table Boxes Bott
le of wine Picnic basket Books Skull
Brewer Treyens (1981) 30 of subjects
(falsely) recalled that books were present
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Misinformation Effect

• Memory for event can be influenced by information
  given after the event

Elizabeth Loftus
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Misinformation Effect

• Subjects view a movie of a car accident
• Different expressions used to describe car
  contact
• Subjects estimate speed of a car at time of
  contact

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Misinformation Effect
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Explaining Misinformation Effect

• Three hypotheses
• Overwriting
• misleading information alters the memory trace
• Source confusion
• Sometimes we misremember the source of a memory
• Perhaps the memory of the question is confused
  with the memory of the visual scene
• Misinformation acceptance
• Ss. believe the information in the postevent is
  true

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Overwriting Hypothesis seems unlikely

• McCloskey and Zaragoza (1985)
• See event yield sign
• Receive misinformation, as the car passed
  the...
• misleading ...stop sign? nonmisleading
  ...yield sign?
• Test yield sign OR stop sign ? 35 drop in
  accuracy for misleading information
• yield sign OR no U-turn ? no difference in
  accuracy for misleading information
• (both groups much higher than
  chance)

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Relevance to Criminal Justice System

• most obvious case
• crime ? study
• picture of suspect (mugshot) ? misinformation
• Lineup ? test
• Eyewitness may recognize suspect from mugshot,
  not from crime scene.
• Conclusions
• Do not let potential witnesses see suspects.
• Interrogate without asking leading questions

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Traditional Lineup
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Sequential Lineup
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Recovery of Lost Memories?

• Several lawsuits have relied on eyewitness
  testimony of repressed memories. These memories
  were recovered by family member or therapist
• Claim repression follows stress, but repressed
  material can be returned to consciousness with
  the removal of stress (e.g., Zeller, 1950, 1951
  Merrill, 1954)
• Problem
• Are these repressed memories or false memories
  (based on misinformation)?

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Recovered memory vs. False Memory

• How do we know whether repressed memories are
  accurate? Hard to falsify
• 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

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Can false memories be implanted?
Loftus and Pickrell (1995)
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Imagination Inflation
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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

BED
REST
AWAKE
TIRED
DREAM
WAKE
SNOOZE
BLANKET
DOZE
SLUMBER
SNORE
NAP
PEACE
YAWN
DROWSY
SNORE
REST
COFFEE
SLEEP
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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 rating 4 3 2 1
• 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)
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Accuracy and Confidence

• Eyewitness testimony requires accuracy and
  confidence
• eyewitness testimony is likely to be believed by
  jurors, especially when it is offered with a high
  level of confidence (Loftus, 1979)
• Should we rely on the confidence level given by a
  witness (I am sure I saw this)?
• False memory experiment shows sometimes
  confidence is high while accuracy is low

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Forgetting
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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
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Why do we forget?

• Some possibilities
• Memory has disappeared
• ? decay theory
• Memory is still there but we cant retrieve it
• ? interference theory
• e.g. blocking
• ? inhibitory mechanisms
• e.g. retrieval induced forgetting
• supression

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Example

• You call a friend, but realize you need an older
  phone number that you have not used for a while.
  With effort, you recall the correct old phone
  number

FRIEND
Explanation 1 the old number is blocked by the
new association
OLD PHONE NUMBER
NEW PHONENUMBER
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Example

• You call a friend, but realize you need an older
  phone number that you have not used for a while.
  With effort, you recall the correct old phone
  number

FRIEND
Explanation 2the old memory has been
suppressed ? Retrieval induced forgetting
OLD PHONE NUMBER
NEW PHONENUMBER
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Evidence for Retrieval Induced Forgetting

• Blocking would predict that using a new cue would
  remove blocking effect. Suppression would predict
  the memory cannot be accessed with a new cue
  either
• ? some evidence for suppression

FRIEND
OTHER MEMORY CUES
OLD PHONE NUMBER
NEW PHONENUMBER
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Inhibitory processes in memory?

• Suppression is an example of an inhibitory
  process
• Two paradigms based on idea of inhibition
• Retrieval induced forgetting
• Think-no-Think paradigm
• Can we voluntarily repress certain thoughts or
  memories from our awareness?

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Think-no-Think Paradigm

• Subjects studied pairs of weakly related words
• Recall and say aloud the response word
• Or avoid thinking of the response word
  (no-think condition)
• Recall of no-think words was impaired compared
  to respond pairs

no-think
Anderson and Green (2001)