PSY 368 Human Memory

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PSY 368 Human Memory

• Memory
• Implicit memory

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Outline

• Implicit versus explicit memory
• Definitions
• Dissociations
• Process-dissociation procedure
• Theories accounting for Implicit vs. Explicit
  memory

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Demo

• PDP exercise
• Pass out sheets and read instructions

• Collecting the data count up number of study
  words that were written down for each task, write
  this on your sheet

Pleasantness Vowels
Inclusion
Exclusion
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Questions to Think About

• Does the type of memory test matter?
• Weve seen that the answer is yes. So far have
  covered intentional vs. incidental, and recall
  vs. recognition. These have largely been what are
  considered direct tests of memory (know that it
  is a memory test related to something earlier).
• There are also indirect tests of memory (dont
  know that the test is related to memory/to
  something done earlier)

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Memory Tasks
Test Instructions
indirect direct
incidental implicit memory expts. Levels of Processing expts.
intentional ? explicit memory expts.
Study Instructions
Implicit Memory Often defined as "memory without
awareness

• Also Non-declarative procedural (Squire,
  Knowlton, Mesen, 1993)

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Implicit Memory Tasks
Often defined as "memory without awareness

• Perceptual Tasks
• Word identification
• Word stem completion
• Word fragment completion
• Degraded word naming
• Anagram solution
• Lexical decision

Non-Verbal Tasks Picture fragment naming Object
decision task Possible/impossible object decision
Conceptual Tasks Word association Category
instance generation Answering general knowledge
questions
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Implicit Memory Tasks
Often defined as "memory without awareness

• Perceptual Tasks
• Word identification
• Word stem completion
• Word fragment completion
• Degraded word naming
• Anagram solution
• Lexical decision

Non-Verbal Tasks Picture fragment naming Object
decision task Possible/impossible object decision
Conceptual Tasks Word association Category
instance generation Answering general knowledge
questions
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Implicit Memory Tasks

• Examples
• Study bird, house, balloon, horse, rocket,
  dolphin
• (maybe levels of processing, or divided attention
  manipulation)
• Tests
• Lexical decision bronk no - - horse yes --
  
• Stem Completion - hor- horde vs horse
• Fragment Completion - h_r_s_ hares vs horse
• Category exemplar production - Animal-? pig vs
  horse
• Word Association - saddle - ? leather bags
  horse

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Implicit Memory Tasks

• Examples
• Study bird, house, balloon, horse, rocket,
  dolphin
• (maybe levels of processing, or divided attention
  manipulation)
• Tests
• Picture fragment naming

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Do amnesics have memory?

• Warrington and Weiskrantz (1968, 1970, 1974)
  showed differences in memory performance for
  amnesic patients

• Amnesic patients
• Cant complete typical explicit memory tasks
• Typically dont even remember seeing a list
• Performance on implicit tasks is similar to
  control participants

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Explicit vs. Implicit Memory

• The Search for Dissociations
• Suggests that these tasks rely on different forms
  of memory
• Dissociation different effects of an IV on the
  two test types (similar to the recognition vs.
  recall dissociations)

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Explicit vs. Implicit Memory
Jacoby (1983) Generation Effect

• Study tasks
• Read aloud w/o context
• COLD
• Read w/ context
• hot COLD
• Generate from context
• hot - ???
• Test tasks
• Recognition
• Perceptual Identification

Opposite pattern of results with implicit task
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Explicit vs. Implicit Memory

• Roediger Weldon, (1987)

• Study tasks
• Lists of pictures and words
• Test tasks
• Free recall of pictures and words
• Word fragment completion
• Priming effect compared studied vs. unstudied
  completions

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Explicit vs. Implicit Memory
Rajarm, Srinivas, Travers (2001) Attention
Effect

• Study
• Full attention
• read word as quickly as possible
• Divided attention
• Name the color the word is presented in

• Test
• Word stem completion
• 2 instructions
• Use words from earlier list
• First word you think of

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Explicit vs. Implicit Memory

• Tulving, Schacter, Stark (1982) Forgetting
  Effects

• Study
• List of words

• Test
• Word fragment completion
• After 1 hr. 7 days later

• Memory score priming effect
• Compare fragment completions of old vs. new items

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Mixing Measures

• Tasks are not process pure (Jacoby, 1991)
• Indirect measures of memory may be contaminated
  by intentional uses of memory
• E.g., in stem completion task, subjects might
  remember items from previous list and use them to
  complete the stems
• Direct measures may be influenced by unconscious
  or automatic influences (Jacoby, Toth,
  Yonelinas, 1993)
• Process-Dissociation Procedure was developed to
  separate automatic (unconscious) and conscious
  processes

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Process Dissociation Procedure

• Jacoby (1991)
• Read a list of words List 1
• Hear a list of words List 2
• Two recognition tests
• Both tests include List 1, List 2 and novel
  words.
• Inclusion complete task with studied or any
  item
• Respond old if word was on either list.
• Exclusion complete task with item NOT studied
  (exclude studied items)
• Respond old only if word was on List 2.

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Process Dissociation Procedure
Jacoby (1991)

• Can calculate C and A for each condition in the
  experiment
• C (Proportion of studied items in inclusion) -
  (Proportion of studied items in exclusion)
• A (Proportion of studied items in exclusion) /
  (1-C)
• The C and A values are estimated as proportions -
  values between 0 and 1.0
• Data
• Proportion of studied items in inclusion C
  (1-C)(A)
• Proportion of studied items in exclusion
  (1-C)(A)

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Process Dissociation Procedure
Jacoby (1991)

• Exclusion Respond old only if word was on List
  2.
• Use equations to calculate conscious (C) and
  automatic (A) memory from target performance on
  the tasks
• P(old) A(1-C)
• Subject will only respond old to List 1 words
  if two things happen
• A The automatic process responds old due to a
  feeling of familiarity
• (1-C) The intentional process fails to recognise
  the word (if it had, it would recall it was from
  List 1)

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Process Dissociation Procedure
Jacoby (1991)

• Inclusion Respond old if word was on either
  list.
• Use equations to calculate conscious (C) and
  automatic (A) memory from target performance on
  the tasks
• P(old) C A (1-C)
• If either process concludes old, the subject
  will respond old
• A Automatic process will also have a certain
  probability of concluding old for List 1 words
• C Conscious (intentional) process will have a
  certain probability of concluding old for List
  1 words

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Process Dissociation Procedure

• Jacoby (1991)
• Read a list of words List 1
• Hear a list of words List 2
• Inclusion Respond old if word was on either
  list.
• Exclusion Respond old only if word was on
  List 2.

• Inclusion test P(old) 0.48
• Exclusion test P(old) 0.37
• C Inclusion Exclusion 0.11
• A Exclusion / (1-C) 0.37 / 0.89 0.42
• in exclusion condition, OLD are errors

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Process Dissociation Procedure

• Jacoby, Toth, Yolelinas (1993) Attentional
  effects

• Study read words
• full attention
• divided attention read aloud while listening
  for odd numbers
• Task stem completion
• inclusion complete with list word or guess
• green stem ? inclusion (may use as a cue from
  list)
• exclusion complete with new words only
• red stem ? exclusion (complete with word not from
  list)

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Process Dissociation Procedure

• Jacoby, Toth, Yolelinas (1993) (Exp 1b)

• Divided attention
• Inclusion task ? P(old)
• Exclusion task ? P(old)

• Results
• Inclusion div (46) lt full (61)
• Exclusion div (46) gt full (36)
• Interpretation
• div attention knocked out recollection
• recollection ? accuracy in both conditions

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Process Dissociation Procedure
Jacoby, Toth, Yolelinas (1993) (Exp 1b)

• Conclusions
• Conscious recollection greatly reduced under
  divided attention condition

Conscious Automatic
Full .25 .47
Divided .00 .46
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Process Dissociation Procedure

• Toth, Reingold, and Jacoby (1994) Levels of
  Processing

• Study
• Pleasantness rating
• Shared vowels
• Test
• Stem completion task

Conscious Automatic
Deep .27 .42
Shallow .03 .45

• Study
• Read word
• Say aloud missing word in sentence
• Test
• Stem completion task

Conscious Automatic
Read .21 .48
Generate .34 .28
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Accounting for Implicit and Explicit Effects

• Four major approaches have been proposed
• The Activation view
• Multiple Memory systems view
• Transfer appropriate processing view
• Bias View

• STOP HERE FOR TODAY

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Activation view

• Insert slide here

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Memory Systems

• Many believe there are different systems of
  memory
• What is a system?
• Could involve different brain areas (amnesia)
• Could involve different rates of forgetting

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Memory Systems
Squire (1987)
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Memory Systems
Squire (1987)
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Memory Systems

• Brain areas
• Brain imaging studies found that different areas
  of the brain are used when completing implicit
  and explicit tasks
• But there isnt just one structure involved in
  each type of memory
• And different kinds of implicit tasks seem to
  involve different areas
• Conclusion brain area involvement may be a
  function of type of processing and type of memory

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Memory Systems

• Forgetting
• Tulving et al. (1989) showed a difference in
  forgetting rate for recognition and fragment
  completion
• Confirmed with other tasks (stem completion)

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Memory Systems

• Forgetting
• But these studies looked at long-term forgetting
  (days, months)
• Didnt follow RIC or use PDP

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Memory Systems

• Forgetting
• More recent studies showed no difference in
  forgetting rates for implicit/explicit stem
  completion
• Used RIC and PDP

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Memory Systems
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Memory Systems
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Mixing Implicit and Explicit Effects

• Jacoby (1990) proposed that implicit vs. explicit
  memory is confounded with two different kinds of
  memory processes (associated with two kinds of
  information)

Memory system Memory system
Mode of Processing Declarative (Episodic) Procedural (Priming)
Mode of Processing Perceptual (Data-driven) Perceptual identification Word Fragment Completion
Mode of Processing Meaning based (conceptually-driven) Free Recall Recognition
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Processing View

• Based on TAP view
• Tasks used for implicit memory usually have
  perceptual cues
• app-
• a_p_l_
• Explicit tasks often are more conceptual

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Processing View

• Differences found between implicit/explicit tasks
  could reflect perceptual/conceptual differences
• Tested by Blaxton (1989)

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Processing View
Explicit Implicit
Perceptual Task ???? Stem and fragment completion
Conceptual Task Free recall ????
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Processing View
Explicit Implicit
Perceptual Task Graphemic cued recall Stem and fragment completion
Conceptual Task Free recall Gen. Knowledge
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Processing View

• Read/Generate study
• Compared tasks across both dimensions

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Processing View

• Shows that match between study and test
  processing is more important
• Weldon Roediger (1987) found different picture
  superiority effect for two implicit tasks

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Summary of Implicit/Explicit

• TAP may be more important than memory process
• Implicit and explicit tasks are not process
  pure
• PDP offers a measurement method for processes
• Implicit/Explicit memory show dissociations on
  several variables

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Explicit vs. Implicit memory

• Generation effect (Java, 1993) - found for
  explicit but reversed for implicit
• Subjects studied words - read or generated
• Completed implicit and explicit stem completion

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Explicit vs. Implicit memory

• Level of Processing (Roediger et al., 1992) -
  found for explicit but not implicit
• Subjects studied words - pleasantness vs. letter
  tasks
• Completed implicit and explicit stem and
  fragment completion

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Explicit vs. Implicit memory

• Attention (Mulligan, 1998) - dividing attention
  at study reduces explicit not implicit
• Study - just study words vs. study words and do
  extra task
• Test - implicit/explicit fragment completion

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Explicit vs. Implicit memory

• Forgetting (Tulving, Schacter, Stark, 1982) -
  difference in forgetting rates for
  explicit/implicit task performance
• Looked at performance for recognition and
  implicit fragment completion at 1 hr and 2 days
• Recognition performance declined, but implicit
  task performance did not

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Processing View

• Studied pictures and words
• Tested with picture fragment naming and word
  fragment completion
• Picture fragment naming name degraded picture
  with first thing it looks like

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• Processing View

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Processing View

• Supports the perceptual/conceptual distinction
• But distinction not always shown
• Weldon and Coyote (1996) compared picture/word
  memory with category production tasks
• Found picture superiority for explicit category
  production, but no difference for implicit task

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Stochastic Independence

• Hayman and Tulving (1989)
• Measure correlation between explicit and implicit
  task performance
• If not correlated (independent), then tasks
  measure different processes

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Dual-process theories
Dissociating Recollection and Familiarity

• Process Dissociation Procedure (Jacoby, 1991)
• Task
• Participants study two sets of items in different
  contexts
• Two different recognition tests follow
• Inclusion Condition
• Say yes if they recognize an item from either
  context
• Correct recognition Recollection Familiarity
• Exclusion Condition
• Say yes only if they recognize an item from one
  of the two contexts
• Familiarity False alarms in exclusion condition
• Recollection Inclusions correct recognition
  minus Familiarity