Transcript Nancy arrived at the cocktail party. She looked

Memory Errors and
Forgetting
Distortions and Intrusions
 Although having several retrieval cues can
help us recall more information, they can
also serve to confuse us.
 Consider the following example from
Owens, Bower and Black (1979)…
Nancy arrived at the cocktail party. She looked around the room to see who was there.
She went to talk with her professor. She felt she had to talk to him but was a little
nervous about just what to say. A group of people started to play charades. Nancy
went over and had some refreshments. The hors d’oevres were good but she was
interested in talking to the rest of the people at the party. After a while, she decided
she’d had enough and left the party.
Some subjects also heard that passage, but w/ this prologue:
Nancy woke up feeling sick and she wondered if she really were pregnant. How could
she tell the professor she had been seeing? And the money was another problem.
The prologue offered some background information and some retrieval
cues, which increased recall (not unlike the “laundry” we discussed
earlier).
However, the background info. also lead to more INTRUSIONS
(memory for information not present), such as “The professor got
Nancy pregnant.”
Distortions and Intrusions cont.
 Bartlett (1932) was the first to demonstrate
distortions for prose.
– Read stories about Native Americans.
– Subjects were good at recalling gist
information.
– Omission of detail was systematic.
• Tended to omit information that did not make sense
to his subjects.
Intrusions and Distortions cont.
 Brewer and Treyens (1981)
– Subjects sat in an office for a few minutes.
– Later asked what objects were in the office.
– Results showed that subjects remembered
“typical” items.
• 1/3 remembered books that were NOT there.
• 1/3 remembered a bulletin board.
So what?
 Are subjects actually remembering information
that was never presented?
 YES! If we ask Ss to rate their memories on
confidence, or if we time their responses, we find
that “real” memories do not differ from “inferred”
memories.
 If Ss have equal confidence in accurate and
inaccurate memories, what does that tell us about
confidence in memory? Should we give more
weight to testimony that in which a witness is very
confident in their memory?
Intrusions and Distortions
Applied
 Elizabeth Loftus has done several studies
demonstrating how memory fallibility has
real-world consequences.
 Leading questions:
– “Hit” vs. “Smashed” study.
– Stop sign vs. Yield sign study.
Sources of Memory Errors
 Obviously, our memory system is pretty
efficient, but the cost of that efficiency is in
accuracy. What are some factors that lead
to inaccurate memories?
 Schemas: prototypical memories for events
and situations.
– When recalling info, we may recall from our
schema, not from what actually happened.
Sources cont.
 Reconstruction: when you recall information, you
are actively reconstructing the information… you
may fill in “gaps” with the most probable
information (perhaps from schemas).
 Intention: if we want to remember details, we can
get ourselves to do so. However, the “default”
setting for memory seems to be memory for gist.
Sources cont.
 Time: the simple passage of time affects memory
adversely… why?
– Decay: with the passage of time, memory trace fade or
erode.
– Interference: you cannot access one memory because
others are getting in the way.
• Retroactive: new events interfere w/ old.
• Proactive: old events interfere w/ new.
Jenkins and Dallenbach (1924)
Two groups of subjects learned CVC trigrams, and tested under a
variety of retention intervals. The groups differed in that one group
spent the retention interval awake and the other group spent that time
sleeping.
Do these data
support decay or
interference theory?
Retention Accuracy
Here are the data:
asleep
awake
2
4
8
12
Retention Interval (Hours)
Paired Associates Test
To test retroactive interference:
1st List
A-B
A-B
2nd List
A-C
C-D
Test List
A-B (experimental)
A-B (control)
If RI is at work, what should we see in the data?
To test proactive interference:
1st List
A-B
B-D
2nd List
A-C
A-C
Test List
A-C (experimental)
A-C (control)
If PI is at work, what should we see in the data?
Hypnosis
 Will memory be enhanced if the person is placed
under hypnosis?
 NO!!!!
– Ss will recall more, but they have more intrusions.
– They are compliant, and as such are very susceptible to
leading questions.
– State-dependent memory problems.
False Memories / Memory
Illusions
 Roediger & McDermott (1995)
– Present Ss w/ list of associated words, missing one
“target” word (e.g., tired, bed, night, dream, etc., but
not SLEEP).
– With immediate recall, Ss tend to recall the nonpresented target item.
– More importantly, when asked whether they
“remember” or “know” the word was on the list, they
report an actual memory for the item.
False Memory cont.
 Garry, Manning, Loftus & Sherman (1996)
– Ss complete Life Events Inventory (LEI).
– Ss lead through imagination exercises.
– Ss fill out LEI again.
The results show that when Ss imagine events that
they previously said did not happen to them, they
are more likely to say they DID happen to them.
Emotion and Memory
 There is a strong relationship (.90) between the
emotionality of an event, and it’s vividness in
memory. This does NOT mean that the memory is
accurate however.
 Emotional events seem to be less resistant to
forgetting over time…
– Perhaps they are perceived better.
– Perhaps Ss think about them more.
 How can these findings be reckoned w/ a notion of
Freudian repression?
Flashbulb Memory
 Memories that have extraordinary clarity, highly
emotional, and are retained despite the passage of
many years. The JFK assassination is an example
for one generation… most of “us” may have the
Shuttle Explosion as a Flashbulb Memory
 Neisser and Harsch (1992)
– Tested immediate memory for Shuttle Explosion, and
then tested it again 3 years later.
– There was little agreement w/ the two “memories”
despite the alleged clarity and confidence of the Ss.
Long, Long-term Remembering
 We do not remember much from the first 3 or 4
years of our life, a phenomenon called childhood
amnesia.
 Why does this occur?
Freud: repression.
Cognitive: schemas are not yet developed.
Physiological: the brain changes a lot in the first few years… the
memories may have been stored in a “format” that the adult brain
cannot interpret.