long-term memory: explicit & implicit...
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Long-term Memory:
Explicit & Implicit memory
Explicit vs. Implicit memory
Explicit memory
Effortful, conscious recollection
Memory tasks: Recall; Cued-recall; Recognition
Implicit memory
Remembering without awareness
Memory tasks: Word-stem or word-fragment;
Perceptual identification; Repetition priming
Procedural memory
Implicit memory for skills and motor movements
Implicit learning
Learn w/o awareness
Implicit measures
Word-stem or fragment completion
See list of words (e.g. rose)
Fill-in with first thing that comes to mind (e.g. r__e)
Perceptual identification
See list of words or pictures
Stimulus flashed (38ms), asked to identify it
Repetition priming
See list of words (e.g. fruit)
Judge if correct (e.g. fruit – apple or fruit – dog)
Faster when previously exposed to word
Study: read pairs
BALANCE – CHAIR
MOLD – BREAD
KIND – STICK
RIPE – APPLE
DELICATE – FRAGILE
COVERING – BLANKET
KNEE – BEND
JAIL – STRANGE
BED – SHEET
DRYER – BLOCK
TABLE – WOOD
CUP – MOVIE
DOOR - BOOK
Test completion
Explicit vs. Implicit INSTRUCTIONS Retrieval process (not storage)
Test item with same related context MOLD – BR; RIPE – AP; BED – SH; CUP – MO
Test item with same unrelated context KIND – STI; JAIL – STR
Test item with different context TOWN – BL; DETAIL – FRA; BELIEF – CHA
Test item with no context BLA; WO; BOO
Distractors ABS; FLA; DU; THI
Tulving (1962)
Study: Ss presented with 96 words
Test: Implicit word-completion test
Fill-in fragment to create a word w. first word that comes to mind
Explicit recognition test IV: tests given 1hr and 7days after study session
Results: Implicit test:
Previously seen fragments: 47% completed New fragments: 30% completed No change in scores over time
Explicit test: 1hr recognition 60%; 7 days 22% acc
Conclusion: Implicit memory for words for up to 7days
Parkin & Streete (1988)
Warrington & Weiskrantz (1968)
Can implicit memory performance improve for amnesic patients?
Method
Ss: Korsakoff’s patients
Picture identification
Same task for 3 days
Results
Conclusions Implicit memory intact
Amnesic patient vs. control
Warrington & Weiskrantz (1970) Explicit
Free recall
Recognition
Implicit
Perceptual identification
Fragment-completion
Graf, Squire, & Mandler (1984) Explicit
Free recall
Cued-recall
Implicit
Word-completion
Warrington & Weiskrantz (1970)
5
10
15
20
Free recall Recog PID Frag-Compl
Control
Amnesia
Explicit Implicit
Graf, Squire, & Mandler (1984)
Free recall
Word-completion
Jacoby & Witherspoon (1982)
Anterograde amnesia patients
Study homophones
“book-read” OR “saxophone-reed”
Test
Recognition test
Generate test: listen and write down homophone
Word fragment test: fill-in “R_ _ D”
Results:
No explicit memory
Previous experience influenced spelling performance
Evidence of intact implicit memory
Jacoby (1983)
Study:
No context: “woman”
Context: “man-woman”
Generate: “man –”, say
woman
Test:
Explicit: recollection
Implicit: perceptual
identification
Famous or non-famous? Don Imus
Lucca Richards
Minnie Pearl
Sebastian Weisdorf
Valerie Marsh
Bonnie Blair
Tim Robbins
Daniel Tucker
Harold Evans
Roger Clemons
Charlie McFadden
Linda Whalen
Pierce Brosnan
Adrian Marr
Chris Rock
Jon Secada
F
NF
F
NF
NF
F
F
NF
NF
F
NF
NF
F
NF
F
F
Jacoby, et al. (1989)
Probability judge as
famous:
New famous: 63%
New nonfamous: 32%
Old nonfamous: 38%
Ironic effects of implicit memory
False fame effect
Effect of familiarity on recollection
Explicit and implicit memory can work together for
better memory
Or can work against each other to create errors
Propaganda effect
More likely to accept information as true if
previously exposed to it
Mere exposure effect
Like stimulus more if previously exposed to it
Process dissociation procedure (PDP) Jacoby (1991); Jacoby, et al. (1993)
Study list of words
Full attention vs divided attention
Word-completion (old and new stems)
Inclusion: recall or guess words from list
Exclusion: do not use prior study words
PDP: (calculated on old word answer probability)
Inclusion: Recollection (R) or familiarity
R + F - RF
Exclusion: familiarity
F (1 – R) = F – RF
R = Inclusion – Exclusion; F = Exclusion / (1 – R)
Conclusions
Full vs divided: R = .25 vs .00; F = .47 vs. .46
Case studies: Amnesia http://www.liveleak.com/view?i=fd0_1261475829
• H.M. (1926 – 2008) • “Every day is alone.”
• Background • Brain surgery (1953) due to
epileptic seizures
• Temporal lobotomy (removal of both hippocampal areas)
• Anterograde amnesia
• Cognitive findings • STM intact; LTM deficit
• Implicit memory intact; explicit memory deficit
• Intact repetition priming
• Procedural memory intact
• Intact problem solving
Clive Wearing
• Dense retrograde and anterograde amnesia patient
• Born in 1938, contracted viral encephalitis in 1985
• Prior to illness a very successful musician
• Husband to 2nd wife; has children from 1st marriage
• What is he (in terms of cognition) able and not able to do?
• BBC 2005 – “Man with the 7s memory”
• 20 yrs post injury – 67 yrs old
• http://www.youtube.com/watch?v=wDNDRDJy-vo&feature=related
• 1998 documentary
• 13 yrs post injury – 60 years old
• http://www.youtube.com/watch?v=Lu9UY8Zqg-Q&feature=related
• http://www.youtube.com/watch?v=xCyvzI2aVUo&fea
• http://www.youtube.com/watch?v=9BrCBq2FY_U&feature=related
Underside of brain
Main structures of medial temporal lobe (MTL)
Brain areas associated with memory
Explicit memory
Medial temporal lobe
Hippocampus
Perirhinal cortex
Implicit memory
Striatum for procedural skills
Neocortex for priming tasks
Semantic memory
Left inferior prefrontal cortex
Neocortex - widely distributed
Episodic memory
Right anterior and dorsolateral prefrontal cortex
Medial temporal lobes
Case studies & brain areas
H.M.: anterograde amnesia (retrograde 2yr) STM intact; LTM deficit; intact implicit memory
Bilateral medial temporal lobes
Posterior region of hippocampus intact
R.B.: anterograde (retrograde 1yr) Memory deficits less severe than H.M.
Lesion to CA1 pyramidal cells (bilateral) of hippocampus
K.C.: retrograde and anterograde amnesia STM and semantic intact; no episodic memory
Medial temporal lobe, frontal parietal, occipital
Greater damage on left side
M.S.: Intact explicit; impaired implicit Right occipital lobe – areas 18 and 19
Korsakoff’s syndrome Dorsomedial nucleus of thalamus & mamillary bodies
Medial temporal lobe
• Medial temporal lobe NOT responsible for… • Implicit memory or procedural memory
• Not where LTM are stored
• STM or WM
• Medial temporal lobe IS responsible for… • Conscious LTM formation
• Consolidation: Strengthening association
• Transfer of info from STM to LTM
• Problems and other theories • Based on case studies
• MTL for encoding or retrieval?
• Subtraction technique with imaging
Longitudinal study of implicit and explicit
memory in older adults Fleishman et al. (2004)
Cross-sectional vs longitudinal studies
Participants: “Religious Orders longitudinal study” – older nuns, priests, brothers
N = 161 w/o dementia; 4 annual evaluations
Materials: Explicit tasks: 4 tests of story retention, 3 word list
Implicit tasks: word-stem completion; category-exemplar production, word identification; picture naming
Results: Explicit: ~0.05 unit decline per year for 75yr old; ~0.1 unit decline per year for 85yr old (decline related to age)
Implicit: no decline per year or by age
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