Memory Errors and Memory Gaps

1
Memory Errors and Memory Gaps
2
List of words

• Put your pencils down. Listen to the following
  list, and try to remember as many words as you
  can.

3
(No Transcript)
4
Example Instructions

• When you score your results, do nothing to your
  correct answers, but carefully mark those answers
  which are wrong.

5
Memory Task (a)

• 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. After a while she decided shed
  had enough and left the party.

6
Memory Task (b)

• Identical but added
• Nancy woke up feeling sick again and wondered if
  she really was pregnant. How would she tell the
  professor she was seeing?
• Propositional memory recalled
• The professor had gotten Nancy pregnant.

7
Example Memory Task
8
Memory Task

• Meaningful context helped understanding, promoted
  recall
• Meaningful context also resulted in 3 times as
  many intrusion errors

9
Memory Tasks

• Where were you
• September 11?
• During OJs low speed chase?
• When they tore down the Berlin Wall?
• Name 5 people in your 1st grade class
• Were they also in your classes from 2-5 and
  beyond?
• What is the first thing you can remember?

10
List of words read earlier

• Were the following on the list?
• 1. pie
• 2. pencil
• 3. sweet
• 4. horn

11
List of words read earlier

• Were the following on the list?
• 1. pie Y
• 2. pencil N
• 3. sweet N
• 4. horn N
• Did you think sweet was on the list? Why?

12
Roediger McDermott

• People commonly remembered
• - sweet on list about foods
• - sleep on list about beds, naps, etc.
• gt These are the roots of the lists

13
Professors office

• List the items that you saw in the professors
  office shown earlier

14
Professors office

• Brewer Treyens
• 29/30 correctly remembered desk and chair
• 8/30 remembered bulletin board
• 9/30 remembered books on shelves -- not there!

15
(No Transcript)
16
Which sentence did I give you?

• 1. When you score your results, do nothing to
  correct your answers, but carefully mark those
  answers which are wrong.
• 2. When you score your results, do nothing to
  correct your answers, but mark carefully those
  answers which are wrong.
• 3. When you score your results, do nothing to
  your correct answers, but carefully mark those
  answers which are wrong.
• 4. When you score your results, do nothing to
  your correct answers, but mark carefully those
  answers which are wrong.

17
Wanner (1968)

• Better at specifics when warned. Memory for
  contents uniformly high
• We extract meaning, not exact wording

18
Memory for Visual Information

• Mandler Richey (1977)
• Detail relating to meaning recalled better than
  unrelated detail (e.g., blackboard vs. dress
  style)
• Gersbacher (1985)
• After 10 minutes subjects couldnt tell the
  difference between original and mirror reversed
  picture
• Detail is forgotten rapidly, semantic information
  remains

19
Propositional Representations

• Abstract away all surface characteristics
• Reduce meaning to primitive unit of meaning
• E.g., the dog chased the cat -gt Chased (dog, cat)

20
Memory Accuracy and Confidence

• Often little relation between confidence of
  memory and accuracy
• Confidence hinges on familiarity (or the
  availability principle)
• Things which are consistent with your
  expectations are more likely to be falsely
  recalled.

21
Summary so far

• Often bring memory in line with our other
  knowledge and beliefs
• Memory errors
• can be large (things that arent there)
• often undetectable

22
Sources of Memory Errors

• General Knowledge
• Sally put the vase on the table and it broke.
  What broke?
• Inferences guide perceptions
• Schematic Knowledge
• Offices have books, tables, chairs
• Results in source confusion, memory
  reconstruction
• Schemas and Attention
• Only remember unusual details (pig in restaurant,
  not menus)

23
Autobiographical Memory
24
Autobiographical Memory

• Includes memories of sense of self
• How does this affect recall?
• Contains emotionally charged memories
• How will emotion affect recall?

25
Self Reference Effect

• you best remember
• things you said
• adjectives that apply to you
• names of places youve visited
• Why?
• attention
• reconstruction using self-schema

26
Biases in Episodic Memory

• Self perception affect
• Am I stable / Have I changed a lot?
• Recall of past events modified to fit self
  perception
• Biased Retrieval
• recall memories consistent with desired traits

27
Emotional Memories

• Clearest, most vivid memories
• Trigger amygdala, consolidation of memory
• Emotion may also focus attention (e.g., weapon
  focus in crime)

28
Flashbulb Memory

• Extraordinary clarity of event
• remember as though it was yesterday
• where they where
• what they were doing
• whom they were with
• Often large scale errors in recall, despite
  confidence of recall. Best if event important to
  them.

29
Traumatic Memory

• War-time atrocities, sexual assault
• How accurate is recall (e.g., during trial)?
• Will painful memories fade?

30
Traumatic Memory

• Some events remembered for many years (even
  enhanced), others fade.
• Emotion impacting consolidation?
• Repressed memory / memory recovery?
• no good evidence of repression
• need considerable assistance of therapist
  (convinced problems linked to childhood abuse)

31
Childhood Amnesia

• Name your Kindergarten, 1st Grade teachers.
• What is the first thing you can remember?
• Earliest memories usually around 3.5 years

32
Child Hood Amnesia
33
Source of Childhood Amnesia?

• Freud repression (anxiety ridden memory
  forgotten)
• Children spend little time consolidating memories
  -- reviewing them, summarizing them

34
Long, Long Term Remembering

• Where were you
• During OJ verdict?
• During Woodstock reunion?
• During last major earthquake in California?

35
Very little forgetting in long term
36
Memory for Cognitive Psychology

• Conway, Cohen Stanhope (1991)
• lt3 years Some forgetting of names, specific
  concepts
• gt3 years very little subsequent forgetting

37
Permastore

• Lasting memories result of
• strong initial learning
• further use of memory (e.g., algebra calculus)
• rehearsal
• (5 sec exposure increases recall 60)

38
Advantages of Forgetting

• Makes memories retrievable (not too much
  interference)
• Reduces memory to useful facts (details on board
  vs. clothing on instructor)
• Reveals general relations between events
  (abstract thoughts)

39
Summary

• Memory for details fade quickly
• General Knowledge, Schemas, and Attention affect
  retention
• General knowledge held for very long time (e.g.,
  50 years), begins around 4 years of age
• Forgetting may help to focus memory on relevant
  details

40
Source Memory

• Hypothesis 1 Loftus claims that LTM is
  malleable. You can have synthetic memories of
  things that never happened.
• Against usual claim LTM is permanent

41
Source Memory

• Study 1
• New information can be added to an old memory.
• - Subjects saw a 3 min. film of an automobile
  accident (3 mins).
• - Then all Ss filled out a questionnaire on
  what they had seen. The questionnaire had about
  30 items. One question was critical.

42
Source Memory

• Control Group How fast was the white car going?
• Experimental How fast was the white car going
  when it passed the barn?
• (There was no barn in the movie.)

43
Source Memory

• 20 mins later they answered more questions
• Was there a barn in the movie?
• Control Group 3 Yes
• (Had heard How fast was the white car going?)
• Experimental Group 17 Yes
• (Had heard How fast was the white car going when
  it passed the barn?)

44
Source Memory

• Study 2
• Does the timing of the misleading information
  matter?
• Experiment (Same with barn)
• event------------------------------------test
• misleading
• info.

45
Source Memory

• 1. Without any misleading info.,
• - performance with 20 min retention interval
  90. - After 1 week, 50.
• 2. Misleading info. - more effective after long
  interval,
• - just before test.

46
Two hypotheses

•  Original information must be weak to be
  overwritten.
•  Old information is not overwritten, but new
  information is more retrievable.

47
Source Memory

• Study 3 Can new information actually change
  information?
• - Subjects were shown a series of 30 slides
  showing a red Datsun coming to an intersection,
  turning right, and hitting a pedestrian.
• - Group 1 a Stop sign at intersection
• - Group 2 a Yield sign at intersection

48
Source Memory

• 20 item questionnaire-
• 17 Did another car pass the red Datsun while
  it was at the Yield/Stop sign?

49
Source Memory

• - 20 min intervening activity
• - 2 alternative SLIDE RECOGNITION test.
• Selected correct slide when the misleading info
  was
• Consistent 71 selected correct
• Inconsistent 41 selected correct.

50
Source Memory

• Study 4. You do not have to actually present
  misleading information.
• 1. Show film of accident.
• 2. Questionnaire contained item
• How fast were the two cars going when
  they______(into) each other?
• smashed (40.8), collided (39.3), bumped (38.1)
  
• hit (34.0), contacted (31.8)

51
Source Memory

• Study 5a. Memories can 'BLEND' together
• Slides of a green car driving past an accident
  and not stopping.
• Questionnaire 10 "Did the blue car that drove
  past the accident have a ski rack?
• Test Pick out the color from a color wheel
  from purple to yellow.

52
Source Memory

• Study 5b. How can you keep people from being
  mislead?
• Same as above but recalled event immediately
  after viewing slides and before misleading info.
• --gt Much less of an effect.
• Why?
• 1. Green memory gets stronger, but still some
  blending
• 2. Commitment to green lets one reject blue info.

53
Source Memory

• Hypothesis 1 Loftus claims that LTM is
  malleable. You can have synthetic memories of
  things that never happened.
• Alternative Hypothesis Both real and misleading
  information is stored. The original memory is
  not changed, but sometimes the misleading
  information is retrieved.