1. Memory Implicit memory
PSY 368 Human Memory
Memory
Implicit memory

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

3. 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

4. Questions to Think About
Does the type of memory test matter?
We’ve 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 (don’t know that the test is related to memory/to something done earlier)

5. Memory Tasks Test Instructions Study Instructions
indirect
direct
incidental
implicit memory
expts.
Levels of Processing
intentional ?
explicit memory
Study Instructions
Implicit Memory: Often defined as "memory without awareness”
Also “Non-declarative” & “procedural” (Squire, Knowlton, & Mesen, 1993)

6. 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

7. 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

8. 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”

9. Implicit Memory Tasks Examples
Study: bird, house, balloon, horse, rocket, dolphin
(maybe levels of processing, or divided attention manipulation)
Tests:
Picture fragment naming

10. Do amnesics have memory?
Warrington and Weiskrantz (1968, 1970, 1974) showed differences in memory performance for amnesic patients
Amnesic patients
Can’t complete typical explicit memory tasks
Typically don’t even remember seeing a list
Performance on implicit tasks is similar to control participants
Typically, don’t even remember seeing a list at all, let alone what words were on the list.

11. 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)
Work since then has focused on looking for dissociations

12. 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
Typically, don’t even remember seeing a list at all, let alone what words were on the list.
Opposite pattern of results with implicit task

13. 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
Typically, don’t even remember seeing a list at all, let alone what words were on the list.

14. 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
Typically, don’t even remember seeing a list at all, let alone what words were on the list.

15. Explicit vs. Implicit Memory
Tulving, Schacter, & Stark (1982): Forgetting Effects
Study
List of words
Test
Word fragment completion
After 1 hr. & 7 days later
Typically, don’t even remember seeing a list at all, let alone what words were on the list.
Memory score = priming effect
Compare fragment completions of old vs. new items

16. 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
Conscious vs. automatic memory?

17. 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.
Currently, most popular measurement method

18. 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)

19. 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)

20. 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

21. 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
Currently, most popular measurement method

22. 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)
Currently, most popular measurement method

23. Process Dissociation Procedure
Jacoby, Toth, & Yolelinas (1993) (Exp 1b)
Divided attention:
Inclusion task:  P(old)
Exclusion task:  P(old)
Results:
Inclusion: div (46%) < full (61%)
Exclusion: div (46%) > full (36%)
Interpretation:
div attention knocked out recollection
recollection  accuracy in both conditions
Currently, most popular measurement method

24. 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
Currently, most popular measurement method

25. 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
Typically, don’t even remember seeing a list at all, let alone what words were on the list.
Conscious
Automatic
Read
.21
.48
Generate
.34
.28

26. 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
Explicit contamination
STOP HERE FOR TODAY

27. Activation view Insert slide here
These are the systems criteria that people generally agree upon.

28. 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
These are the systems criteria that people generally agree upon.

29. Memory Systems
Squire (1987)

30. Memory Systems
Squire (1987)

31. Memory Systems Brain areas
Brain imaging studies found that different areas of the brain are used when completing implicit and explicit tasks
But there isn’t 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
Perceptual vs. conceptual tasks use different brain areas

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

33. Memory Systems Forgetting
But these studies looked at long-term forgetting (days, months)
Didn’t follow RIC or use PDP

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

35. Memory Systems
Typically, don’t even remember seeing a list at all, let alone what words were on the list.

36. Memory Systems
Typically, don’t even remember seeing a list at all, let alone what words were on the list.

37. 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
Mode of Processing
Declarative
(Episodic)
Procedural
(Priming)
Perceptual
(Data-driven)
Perceptual identification
Word Fragment Completion
Meaning based
(conceptually-driven)
Free Recall
Recognition
Explicit contamination

38. 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
(generation of items in free recall occurs through semantic relations between items)

39. Processing View
Differences found between implicit/explicit tasks could reflect perceptual/conceptual differences
Tested by Blaxton (1989)

40. Processing View Explicit Implicit Perceptual Task ????
Stem and fragment completion
Conceptual
Free recall
Typically, don’t even remember seeing a list at all, let alone what words were on the list.

41. Processing View Explicit Implicit Perceptual Task
Graphemic cued recall
Stem and fragment completion
Conceptual
Free recall
Gen. Knowledge
Typically, don’t even remember seeing a list at all, let alone what words were on the list.

42. Processing View Read/Generate study
Compared tasks across both dimensions

43. Typically, don’t even remember seeing a list at all, let alone what words were on the list.

44. 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

45. 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

46. 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
Read - horse
Generate - A jockey rides a ____ in a race.
Hor- complete with studied word vs. complete with first word you think of

47. 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

48. 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

49. 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

50. 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

51. Processing View
Typically, don’t even remember seeing a list at all, let alone what words were on the list.

52. 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

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

54. 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 = Inclusion’s correct recognition minus Familiarity
Used to further investigate two possible processes involved in recognition
Recognition - Old/New response + Remember/Know judgment for “Old” items
Remember = consciously recollect details of the item’s presentation
Know = sure an item was presented, but can’t recall any of the details of
Presentation
R/K responses for correct “Old” items have been shown to differ for the
following effects:
Typically studied pics are better remembered than words (picture superiority
effect) R: Pics > words and K: words > pics
Generate similar or related word
Hot - ?
Cat - ?
vs. reading hot-cold and cat-dog