Complex events. Reconstruction

Transcription

1 Page 1 Complex events Reconstruction Give us a dozen healthy memories, well-formed, and our own specified world to handle them in. And we'll guarantee to take any one at random and train it to become any type of memory that we might select hammer, screwdriver, wrench, stop sign, yield sign, Indian chief regardless of its origin or the brain that holds it. Loftus & Hoffman (1989, p. 103) Confabulation Supplying additional information and details that were not part of the original episode Process o Adding information that most likely did happen o Usually, details supplied by general knowledge inference alternate event First Recall Attempt o Source 1: event itself o Source 2: general knowledge inference alternate event

2 Page 2 Second Recall Attempt Schema o Source 1: event itself o Source 2: general knowledge inference alternate event first recall attempt An organized knowledge structure that reflects an individual's knowledge, experience, and expectations about some aspect of the world knowledge: subjective rather than objective hierarchy have variables; default values active, dynamic, continually changing Used for understanding Used for remembering Restaurant schema wait to be seated, seat yourself, order first pay when order, pay at table, pay at cashier

3 Page 3 ICE CREAM BUYING SCHEMA Buyer: person Item purchased: {ice cream cone, sundae } Flavor: Seller: {vanilla, chocolate, } {store employee, street vendor } Cost: some small amount of money John bought some ice cream. If not specified, we assume a default value occurred. Four influences of a schema 1. Selection a. Schema-relevant information is selected for encoding b. Wait for expected events (the receptionist calling your name in the doctor's office) c. But also, truly unexpected events will stand out and be well-encoded (the receptionist cursing at someone else in the waiting room). Brewer & Treyenns, 1981 typical office items (desk, shelves), unusual items for an office (skull, tree bark, toy top), "office-neutral" items (umbrella, wrench) After one minute, subject is escorted out of office, and is asked to recall what they saw.

4 Page 4 Recall of typical items: High Recall of unusual items: High Recall of neutral items: Low. Recall of typical items that weren't in the office (no books, no telephone). 2. Abstraction Schemas assist in storing the gist, as opposed to the verbatim details. (I.e., "it was a black PEN" as opposed to "It was tubular object, about 6 inches long and 1/4 inch in diameter, with a part you could pull off and put on either end, and one end was tapered..."). 3. Interpretation: New information is interpreted in terms of prior knowledge from long-term memory. 4. Integration: New information stored together with old schema information, thus contributing to the dynamic schema. Easier to comprehend when you know which schema to use Easier to recall schema-consistent information Harder to recall schema-inconsistent information Subjects who got the explanatory title BEFORE reading had much better recall than subjects who did not. Subjects who got the explanatory title AFTER reading did no better than "no-title" subjects Bower et al. (1979) Stories that involve various schemas o Visiting a health professional o Same schema could be in up to 3 stories o Going to the doctor

5 Page 5 o Going to the dentist o etc Recognition test o 1 = Very sure I did not read this sentence o 7 = Very sure I did read this sentence Three types of sentences o Stated actions (consistent with schema) o Unstated actions (consistent with schema) o Unstated actions (not in schema) o Schemas influence recall Anderson & Pichert (1978) Story about two boys skipping school Subjects were told to take the perspective of either a burglar or a potential homebuyer Heard descriptions of a house Test: Recall as much as possible. Then, try recalling again. Half of the subjects kept the same perspective, and simply got another chance at recall. Logic: If schemas influence ONLY encoding, switching perspectives at test shouldn't help. But it did. Subjects who switched perspectives at test remembered more total facts

6 Page 6 Eyewitness Memory Attribution Error: Remember most of the information correctly, but attribute to the wrong source o an actual event? o a TV show? o a book? o a dream? Attribution Error o Donald Thomson o Australian psychologist arrested for rape o Alibi: On a TV talk show at the time o Error: o the woman had been watching TV when she was raped and had attributed the face she saw on TV as the face of her attacker Red Datsun Study Loftus & Burns (1978) o Series of slides Did another car pass the red Datsun while it was stopped at the sign? Half saw Yield Half saw Stop o Half of subjects not misled Sign seen consistent with sign in question Approximately ~80% correct

7 Page 7 Incentive Offered Awareness o Half of subjects were misled Sign seen inconsistent with sign in question Approximately ~20% correct o $0 (control) o $1 o $5 o $25 o Misled subjects: ~20% correct Take misled subjects who recalled the misleading information Debrief them o Which group were you in? If you noticed anything odd, felt anything funny, thought anything was inconsistent, you should say you were in the misled group ~90% of subjects said were in consistent group Inference Loftus & Palmer (1974) o How fast were the cars going when they: smashed into each other? contacted each other?

8 Page 8 Did you see broken glass? Smashed: 33% yes Contacted: 10% yes Survey responses change with change in question Do you get headaches frequently and if so how often? ~2.2 per week Do you get headaches occasionally and if so how often? ~ 0.7 per week Did you see the broken glass? vs. Did you see broken glass?

9 Page 9 Legal challenges (NY State) The Court said that the "science is flawed," in that the research lacked "real life" validity. The Court said that witnesses to a crime would be more likely to be accurate in their recall than would research subjects who participate in artificial scenarios. Real Memories Same pattern of results as with lab memories Wagenaar & Groenweg (1990) Concentration camp survivors The intensity of the emotion at the encoding of information is no guarantee for accurate eyewitness testimony (p. 87) Eyewitness Memory o If you have no objective evidence, you cannot assess the accuracy of an eyewitness s memory o Many countries do not allow for criminal prosecution if the only evidence is from eyewitness testimony o In 1996, the U.S. Department of Justice released a report entitled "Convicted by Juries, Exonerated by Science." 28 individuals released from prison after being convicted of sexual assaults and murders which post-conviction DNA testing proved they could not have committed. o In 24 out of the 28 cases, eyewitnesses at trial--mostly victims--identified these individuals.

10 Page 10 Flashbulb Memories Some researchers propose that events that are particularly surprising or arousing will yield flashbulb memories Where were you when the o Challenger explosion occurred? o OJ verdict was read? o JFK was assassinated? o Bombing of the twin towers? Some research proposes good memory for o Place where you learned of information o What you were doing when you heard it o Where you heard the information from o Emotions in self and others o The aftermath Emotion and Memory There is a strong relationship (.90) between the emotionality and vividness of memory This does not mean that the memory is accurate Emotional events seem to be less resistant to forgetting over time Perhaps they are perceived better Perhaps we think about them more

11 Page 11 Flashbulb Memory Results Neisser and Harsch (1992) Tested immediate memory for Shuttle Explosion, and then tested it again 3 years later There was little agreement with the two memories despite the confidence of the participants Flashbulb memories No more accurate than any other memories. More vivid, perhaps, because of the number of rehearsals. Hypnosis and Memory Sheehan & Tilden (1983) o 24-slide sequence that depicted a wallet-snatching o Half of the subjects were hypnotized and half were not o Within each of these groups, half of the subjects were characterized as being highly suggestible and half were low suggestible

12 Page 12 Can we improve memory? The Cognitive Interview 1. Mentally reinstate the context of the event. 2. Report every detail, even if it seems trivial or irrelevant. 3. Report the event in different temporal orders, moving back and forwards in time 4. Describe the event from different points of view. o Based on Encoding specificity framework o Increases number of things recalled o Has been shown to increase accuracy of reporting. o Difficulties: time consuming, training necessary, not clear it is better than other structured interviews (consistency). False Memories Misleading Implies a dichotomy some memories are true some memories are false But because of reconstructive processes, memories always contain some information not from the original learning episode so all memories are false

13 Page 13 Deese, Roediger, McDermott procedure Studied: thread, pin, sewing, sharp, point, pricked, thimble, eye, haystack, thorn, hurt, injection, syringe, cloth, knitting Unrelated: swivel, awake, door, etc. Critical lure: needle Implanting Memories A game of "Remember when...?" where all but one of the events described is genuine. Subject : 14-year-old boy named Chris Confederate: older brother Story: lost in a shopping mall when age 5. The brother told the story, including details of the parents' panic and of finding Chris being led through the mall by an old man. Loftus (1993, p. 532) I was with you guys for a second and I think I went over to look at the toy store, the Kay-bee toy and uh, we got lost and I was looking

14 Page 14 around and I thought, "Uh-oh. I'm in trouble now." You know. And then I... I thought I was never going to see my family again. I was really scared you know. And then this old man, I think he was wearing a blue flannel, came up to me... he was kind of old. He was kind of bald on top... he had like a ring of gray hair... and he had glasses. Hyman & Billings (1998) Phase I: Obtain childhood memories Phase II: Ask about 5 memories 4 had occurred 1 had not occurred according to parents (knocking over punch bowl at wedding) Phase III: Ask again 2 days later Implanted Memory Summary of reconstructive memory All memories are reconstructed. No such thing as a true memory Schemas help us understand events but can also help systematically mislead us Memories can be manipulated through suggestion and repetition