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 fromprior Saturday (control) .89 .11

“FLASHBULB” MEMORIES(Christiansen, 1989)

Swedish students interviewed within 24 hours of the assassination of Olaf Palme

Then questioned again after . . .

MEMORY OVER TIME:THE FORGETTING FUNCTION

Ebbinghaus (1885): forgetting of list of nonsense syllables

0

0.2

0.4

0.6

0.8

Pe

rce

nt

Sa

vin

gs

20 min 8 hr 2 days31 days

Retention Interval

Bahrick & Phelphs (1987): forgetting of Spanish learned in college

0

20

40

60

80

100

Pe

rce

nt

of

last

sco

re

1 2 5 9 14 25 34 49

Years since class

English-Spanish

Spanish-English

RECOVERY FROM “CONCUSSION AMNESIA”

time of accident

hours lateryrs mo day

days . .

weeks . .

RetrogradeAmnesia

- can be severe- worse for recent events- almost complete recovery

AnterogradeAmnesia

- mild to moderate- worse for events just after trauma- “blank periods” may remain

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? ?? ? ?? ?

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• Electroshock Therapy (EST)– used to treat depression– can help, with minimal side-effects– transient amnesia often seen

• Memory following EST (Squire, 1975)– tests memory for “non-syndicated” TV

shows 1964 through 1972– dramatic “reverse recency” amnesia

dissipates as time goes by:

• Ribot’s Law and the process of consolidation

RECOVERY FROM “ELECTRO-SHOCK” AMNESIA

30

40

50

60

70

80

Re

co

gn

itio

n (

%)

'72 '70 '68 '66 '64

Year of TV Show

no EST

one hr after EST

one mnth after EST

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 officelab lab 27%

office lablab 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, chair, flat– WHITE: black, snow, 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)

C

BA

learning AC interferes with AB

AB learned first: Retroactive (RI)AC learned first: Proactive (PI)

RETROACTIVE INTERFERENCE IN PAIRED-ASSOCIATE MEMORY(Barnes & Underwood, 1959)

task: study and remember lists of paired-associates

10 Trials of AB pairsthen

1 to 20 trials of AC pairs

0

20

40

60

80

100

Cu

ed

Re

ca

ll (

%)

0 5 10 15 20

# Trials on AC Lists

"C" recall

"B" recall

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 & -- birdCATEGORIES -- 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 wonderedif she was pregnant”

Theme No ThemeMean 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 facesfalsely 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 factselicited by trained & untrained detectives

Before Aftertrained 26.8 39.6untrained 23.8 24.2

(Fisher, Geiselman & Amador, 1989)

• 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

AUTOBIOGRAPHICAL MEMORY

Crovitz & Schiffman, 1974cue-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

Renee ZellwegerAs Nurse Betty

Richard Gere and EdNorton in Primal Fear

• 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 vanWinkle 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”