Transcript No Slide Title

“FLASHBULB” MEMORIES
(Christiansen, 1989)
Swedish students interviewed within 24
hours of the assassination of Olaf Palme
Then questioned again after . . .
6 weeks
one year
how were you informed?
1.00
.72
what time of day was it?
.92
.25
what were you doing?
.92
.50
who were you with?
.94
.83
what was your first thought?
.83
.44
most vivid event from
prior Saturday (control)
.89
.11
P e r c e n t o f la s t s c o r eP e r c e n t S a v in g s
MEMORY OVER TIME:
THE FORGETTING FUNCTION
Ebbinghaus (1885): forgetting of
list of nonsense syllables
0.8
0.6
0.4
0.2
0
20 min
8 hr
2 days
31 days
Retention Interval
Bahrick & Phelphs (1987): forgetting
of Spanish learned in college
100
English-Spanish
80
Spanish-English
60
40
20
0
1
2
5
9
14
25
Years since class
34
49
RECOVERY FROM
“CONCUSSION AMNESIA”
time of accident
yrs mo day
??????? ???
hours later
? ?? ? ??
?
? ??
?
days . .
weeks . .
Retrograde
Amnesia
Anterograde
Amnesia
- can be severe
- worse for recent
events
- almost complete
recovery
- mild to moderate
- worse for events
just after trauma
- “blank periods”
may remain
RECOVERY FROM “ELECTROSHOCK” AMNESIA
• Electroshock Therapy (EST)
– used to treat depression
– can help, with minimal side-effects
– transient amnesia often seen
• Memory following EST (Squire, 1975)
R e c o g n itio n (% )
– tests memory for “non-syndicated” TV
shows 1964 through 1972
– dramatic “reverse recency” amnesia
dissipates as time goes by:
80
70
60
no EST
50
one hr after EST
40
30
one mnth after EST
'72
'70
'68
'66
Year of TV Show
• Ribot’s Law and the process of
consolidation
'64
ENCODING SPECIFICITY
PRINCIPLE
How an event is encoded determines
the effectiveness of various retrieval
cues (Tulving, 1972). Memory will be
best if cues/context at study and test
are the same
task: free recall of word lists
(Smith, Glenberg & Bjork, 1978)
Study in..
Test in..
% recalled
office
lab
office
lab
27%
office
lab
lab
office
20%
ENCODING SPECIFICITY versus
RECOGNITION > RECALL
(Tulving & Thompson, 1973)
• Study words in context of weak
associates:
– glue -- chair
– train -- black etc
• Generate words to strong
associates of target words:
– TABLE: desk,
– WHITE: black,
chair,
snow,
flat
rain
• Circle any target words:
–
–
desk, chair, flat
black, snow, rain
recognition 29% above chance
• Recall target words, cued by weak
associates:
– TRAIN?: black
cued recall: 61% correct
ASSOCIATIVE INTERFERENCE
AND FORGETTING
task: study and remember lists
of paired-associates (A-B)
B
A
C
learning AC interferes with AB
AB learned first: Retroactive (RI)
AC learned first: Proactive (PI)
RETROACTIVE INTERFERENCE IN
PAIRED-ASSOCIATE MEMORY
(Barnes & Underwood, 1959)
C u e d R e c a ll (% )
task: study and remember lists
of paired-associates
10 Trials of AB pairs
then
1 to 20 trials of AC pairs
100
80
60
"C" recall
40
"B" recall
20
0
0
5
10
15
20
# Trials on AC Lists
is AB association erased (“unlearned”)?
NO: recognition-matching still good
The War of the Ghosts
(Original Script - Bartlett 1932)
One night two young men from Egulac went down to the
river to hunt seals and while they were there it became
foggy and calm. Then they heard war-cries, and they
thought: "Maybe this is a war-party". They escaped to
the shore, and hid behind a log. Now canoes came up,
and they heard the noise of paddles, and saw one
canoe coming up to them. There were five men in the
canoe, and they said:
"What do you think? We wish to take you along. We are
going up the river to make war on the people."
One of the young men said,"I have no arrows."
"Arrows are in the canoe," they said.
"I will not go along. I might be killed. My relatives do not
know where I have gone. But you," he said, turning to
the other, "may go with them.“ (continued…..)
Recalling The War of the Ghosts
•'Something black came from his mouth' tended to
become 'he frothed at the mouth', 'he vomited' or
'breath escaped from his mouth'.
•'Hunting seals' tended to become 'fishing'.
•'Canoe' tended to become 'boat' and 'paddles' to
become 'oars'.
•The wounded Indian tended to become the hero,
whose wounds were sometimes even 'bathed' at
the end.
•The reference by the Indian who stayed to the
possibility of getting killed tended to be
downplayed or dropped, whilst the reference to
the probable anxiety of his relatives was usually
given greater emphasis (the reference to having
no arrows was often omitted).
•The role of 'the ghosts' shifted (for some, they
become a clan called the Ghosts; for others they
were simply imagined by the Indian when
wounded).
REPRESENTATION OF
MEANING IN MEMORY
WHY BOTHER?
for both visual and verbal stimuli,
--comprehension and memory
are much better if “meaning” is
available:
cue
target
recall without mediator
44%
recall with mediator (“pig in fog”) 73%
(Bower et al. 1972)
-- memory for an event appears based
more on its meaning than its form:
“do nothing to your / correct answers,
but mark / carefully those that are
wrong”
meaning X : 98%
(Wanner, 1969)
style X
: 52%
SCHEMAS AS KNOWLEDGE
STRUCTURES
• Represent our knowledge about an
type of object or event
• Captures the general, typical
characteristics that define the type
• A concept used by philosophers
and computer scientists
• lets us organize, categorize and
reason about complex ideas and
things
• can facilitate comprehension and
inferences
• can lead to bias and “stereotypes”
TYPE OF SCHEMAS
CONCEPTS &
CATEGORIES
-- bird
-- strike
-- women, fire and
dangerous things
FRAMES
-- office
-- golf course
SCRIPTS
-- stories
-- banquets
EFFECTS OF SCHEMATIC
THEMES ON MEMORY
(Owens, Bower & Black, 1979)
task: listen to short stories
“Nancy and the Doctor”
some are first given an organizing theme
“Nancy wondered
if she was pregnant”
Theme
No Theme
Mean recall of:
presented facts
29
20
nonpresented
inferences
15
4
thematic structure increases both
“exact recall” and reconstructive errors
SOURCE AMNESIA: BECOMING
“FAMOUS OVERNIGHT”
(Jacoby, 1988)
task: study faces of famous and
unknown people
test: recognize studied faces
and judge “fame”
Immediate test: few errors
24 hour delayed test:
studied, unknown faces
falsely classed as not
studied but famous
Why?
• The case of John Demjanjuk
– Ukranian immigrant, auto worker in
Cleveland
– On KGB list of German “war criminals”
– Exported and convicted in Israel of
being “Ivan the Terrible” of Treblinka
– Fall of USSR, KGB docs forgeries 1991
– Acquitted and released 1993
EYEWITNESS MEMORY
(Loftus, 1978)
• LIMITS OF ENCODING
– stress and arousal may be too high
– attention may be misplaced (“weapon
focus”
• POTENTIAL FOR INTERFERENCE
– post-event “misinformation” in
interviews, mug shots, etc
• “how fast when they
bumped/crashed?”
• PROBLEMS WITH LINEUPS
– who are the “distractors”?
• PROBLEMS WITH HYPNOSIS
– hits may rise, but so do false
memories
– increases confidence without
accuracy
– other “cognitive strategies” do as well
or better
Who do you recognize?
IMPROVING EYEWITNESS
TESTIMONY
The Cognitive Interview
(Fisher & Geiselman, ’92)
- Recreate original context
- Retrieve partial information
- Vary the perspective
- Use mental imagery
- Encourage active role in EW
- Keep focus on relevant dimensions
- Develop rapport, reduce anxiety
Number of crime-relevant facts
elicited by trained & untrained detectives
trained
untrained
Before
26.8
23.8
After
39.6
24.2
(Fisher, Geiselman & Amador, 1989)
AUTOBIOGRAPHICAL
MEMORY
• Complex mix of episodic and semantic
memories
• Organization of AM
– Conway & Rubin’s hierarchical model
• Life Periods around Themes
• General Events and “minihistories”
• Event-specific Knowledge and details
Crovitz & Schiffman, 1974
cue-word recall of AM
TRAUMATIC AMNESIAS:
psychogenic forgetting?
• Global retrograde amnesias and fugues
– Sudden loss of autobiographical memory and
identity
– May be triggered by severe psychological stress
– Some evidence for link to earlier physical trauma
or disease
– Pattern of recovery is diverse
• Sudden, quick and complete
• Gradual and incomplete
• Failure of recovery
– Rarer than the media suggest
• < 1% of clinical casework in some estimates
Richard Gere and Ed
Norton in Primal Fear
Renee Zellweger
As Nurse Betty
• Recovery from Fugue states: a
sampler
– Libby Morris: lost from a shopping mall
• Rapid, almost complete recovery
• Amnesia for fugue period
– Ricky Stephenson: AWOL
• Unresolved after two years
• Relearning his past
– Jody Roberts: You’re a
thousand miles away
• Unresolved after 12 years
• New, stable identity established
– James Smith: Rip van
Winkle awakes
• Fugue ends after 25 years
• “gap” before recovery
• Amnesia for fugue period
THE MEMORY WARS:
Recovered or False Memories?
The epidemic of “recovered
memories” of childhood abuse
Stress-induced global amnesias
Cases of “selective amnesia” and
recovery
Lack of credible evidence, strong
evidence for “constructive” errors
Lab studies of “false memories”
Cases of “recanting”