Download Memory Errors, Memory Gaps

Memory Errors, Memory Gaps
Reasons why we remember so much
and so little at the same time...
Memory and its failures
Why do memory errors happen?
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Semantic activation
Inferences
Schemas
Update of memory
Memory errors & everyday life
- In the court
- In therapy
- In important events of your life
Semantic Activation
• Example:
– You will hear a list of words, once the list ends, recall
as many words as possible
– Bed, Rest, Awake, Snooze, Tired, Dream, Blanket, Doze, Slumber, Snore,
Nap, Yawn, Drowsy
– Missing word: ‘sleep’
Inference in Recognition Memory
with the hammer
• John was trying to fix the bird house. He was pounding
the nail when his father came out to watch him and to help
him do the work.
with the hammer
• John was trying to fix the bird house. He was looking for
the nail when his father came out to watch him and to help
him do the work.
Recognition test: “John was using the hammer to fix
the bird house when his father came out to watch him
and to help him do the work.”
Schema (script):
A high-level representation of knowledge about familiar situations.
Schemata help us to deal with the world efficiently by representing
those aspects of our experience that are usually the same from one
time to another…
Event Schema (script): Going to a restaurant
• Enter
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Walk into restaurant
Look for table
Decide where to sit
Go to table
Sit down
• Order
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Get menu
Choose food
Waiter arrives
Give orders to waiter
Wait, talk
Cook prepares food
• Eat
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Cook gives food to waiter
Waiter delivers food
Eat
Talk
• Leave
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Waiter delivers bill
Examine bill
Calculate tip
Leave tip
Get belongings
Pay bill
Leave restaurant
Memory Update: Misinformation Effect
• See event: film of two-car accident
• Receive misinformation
– When the cars smashed each other,
– When the cars hit each other,
• Memory test: the speed was …
– a) “smashed”
– b) “hit”
(Elizabeth Loftus)
(41 mph)
(34 mph)
Is this a ‘memory’ distortion, or a report bias?
A week later: Did you see broken glass? (correct answer: no)
a) “smashed”: 32% yes
b) ‘hit’:
14% yes
(Loftus & Palmer, 1974)
Relevance to Criminal Justice System
• most obvious case
– crime
--> study
– picture of suspect --> misinformation
– Lineup
--> test
• Eyewitness may recognize suspect from police display, not from crime
scene.
• Conclusions:
– Do not let potential witnesses see suspects.
– Interrogate without asking leading questions (Capturing the Freedmans)
• Further sources of error:
– newspaper stories, etc.
Memory Contamination & Psychotherapy
•Therapist repeatedly asks child about abuse at day care
center. Eventually, child “remembers” abuse.
•Therapist repeatedly asks woman about childhood abuse.
Eventually, woman “recovers repressed memory” of abuse.
Are these repressed memories or false memories?
Big debate! (Loftus vs. Freyd)
Autobiographical flashbulb memory
• A type of episodic memory
• Memory for personal experiences
• Components
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Imagery (e.g., visual imagery)
Lots of detail (flashbulb memory: where were you on 9/11?)
High confidence in its accuracy (even if it is wrong!)
Emotion
It has a narrative (it tells a story), thus
It is constructive
– is biased by goals at the time of retrieval
Memory
• memory illusion - a false but convincing memory (false
memory task, 1st day of class)
• Memory is reconstructive - we extract the gist to make things
easier to remember (but this may contribute to memory errors)
Suggestibility and
Child Testimony
• Young children are especially vulnerable to
suggestions to recall events that did not
occur
– May cling to false memory, even when assured
it did not occur
– Repeated questioning may elicit misinformation
– Especially affected by schemas
Copyright © Allyn & Bacon 2009
False Memories
• Flashbulb memories - very vivid, able to be
recalled in detail
– But subject to change over time, just like other memories
• Study of Challenger explosion
• Source monitoring - ability to identify the origins of
a memory
–
Copyright © Allyn & Bacon 2009
Implanting False
Memories in the Lab
• Implanted memories
– Lost in the mall study
– Easier to implant memory for
• Plausible events
• Events in the distant past
– Existence proofs for implanted memories
• Hot air balloon ride
• Bugs Bunny at Disneyland
– Demand characteristics? Not likely, many subjects
continue to insist on the validity of false memories even
when told they are implanted
Copyright © Allyn & Bacon 2009
Eyewitness Testimony
• Weak correlation between witness confidence
in their testimony and its accuracy
– Less accurate when
• Observing others of different race
• Witness has talked to other witnesses
• The observed situation is stressful (e.g., threatening,
weapon involved)
– Improved accuracy with
sequential (vs. simultaneous)
Copyright © Allyn & Bacon 2009
lineup
Schacter’s Seven Sins of Memory
1.
2.
3.
4.
5.
6.
7.
Suggestibility
Misattribution
Bias
Transience
Persistence
Blocking
Absentmindedness
Copyright © Allyn & Bacon 2009