Transcript PSY 368 Human Memory - the Department of Psychology at Illinois

PSY 368 Human
Memory
Reconstructive Memory cont.
Announcements
• Experiment 3 Report due April 16
• If you missed the details of the Experiment, I included
them in the lectures last week
Experiment 3
• Interaction of Episodic and Semantic Memory
(Exp 3) (Download detailed instructions form Blackboard)
• Modification of Anderson, Bjork, & Bjork (1994)
• (see Blackboard Media Library Optional Readings to
download a pdf of this paper if you want to read more)
• Question: Can the retrieval of some items impact the
retrieval of others?
• e.g., Suppose that you are studying for a test. You decide to
study half the material. Does studying half the material have
an impact on the half of the material that you didn’t study?
Experiment 3 Results
• Interaction of Episodic and Semantic Memory
(Exp 3)
• Scoring:
Class Avg.
Data
Sample data
Banana
Orange
Lemon
Tomato
Club
Sword
Bomb
Guppy
Trout
Ale
Rum
Vodka
Beercount
Don’t
“beer”, not
on list
Practiced # recalled
% (divide # by 6)
Non-practiced # recalled
4.6
77.2%
2.9
% (divide # by 6)
47.7%
Control # recalled
6.4
% (divide # by 12)
53.5%
“drinks – v”, “weapons – s”, “drinks – r”, “weapons – r”, “drinks – g”, “weapons – t”
Experiment 3 Results
• Interaction of Episodic and Semantic Memory
(Exp 3)
• Scoring:
*
ANOVA results
F(2,118) = 59.49
comparisons:
Practice vs control
t(59) = 8.9, p < .05
Non-practice vs control
t(59) = -2.0, p < .05
*
General conclusions: Evidence for “retrieval induced forgetting.” Items within
the same category as those studied, that weren’t studied were worse than controls.
May be due to inhibition of items following spreading of activation.
Experiment 3 Results
• Interaction of Episodic and Semantic Memory
(Exp 3)
bourbon
vodka
rum
gin
whiskey
beer
ale
General conclusions: Evidence for “retrieval induced forgetting.” Items within
the same category as those studied, that weren’t studied were worse than controls.
May be due to inhibition of items following spreading of activation.
False Memories
• Memory is reconstructive
• Sometimes we may “remember” things that never actually
happened
• And for these “false memories” we may be as confident in them as
we are with actual memories
• We are surprisingly unaware of how unreliable our memory can be
and overly confident in the accuracy of our memories
• Overconfidence comes from two factors:
• Source Memory: Memory of the exact source of the information (original
event, later information, or general knowledge of the situation)
• Processing Fluency: The ease with which something is processed or comes
to mind (remember “sleep” too easily for you to have imagined it)
False Memories
• Why do we study them?
• Real World Implications
• Perceptual illusions, can give better understanding of
“normal” processes
• DRM procedure
• Eyewitness testimony credibility
• Recovered memories issue
False Memories
Roediger & McDermott (1995) study
• DRM paradigm (Deese, 1959; Roediger & McDermott,
1995)
• Creates false memories in the lab
• DEMO (like the task that we saw Schacter give Alan Alda)
False Memories
• A week ago I gave you a long list of words to remember
(1) haystack
(2) sandals
(3) fright
(4) weather
(5) sharp
(6) hot
(7) creek
(8) king
(9) thread
(10) shoe
(11) winter
(12) tide
(13) airplane
(14) flow
(15) pretty
(16) ankle
(17) awake
(18) doctor
(19) frame
(20) jelly
(21) top
(22) jazz
(23) sugar
(24) needle
(25) rye
(26) melody
(27) spider
(28) music
(29) girl
(30) bread
(31) sweet
(32) stream
(33) soft
(34) river
(35) jail
(36) glacier
(37) thief
(38) hill
(39) power
(40) butter
(41) foot
(42) father
(43) jagged
(44) door
(45) throne
(46) money
(47) mountain
(48) steal
False Memories
• A week ago I gave you a long list of words to remember
Studied list words - Accurate memories
(1) haystack
(2) sandals
(3) fright
(4) weather
(5) sharp
(6) hot
(7) creek
(8) king
(9) thread
(10) shoe
(11) winter
(12) tide
(13) airplane
(14) flow
(15) pretty
(16) ankle
(17) awake
(18) doctor
(19) frame
(20) jelly
(21) top
(22) jazz
(23) sugar
(24) needle
(25) rye
(26) melody
(27) spider
(28) music
(29) girl
(30) bread
(31) sweet
(32) stream
(33) soft
(34) river
(35) jail
(36) glacier
(37) thief
(38) hill
(39) power
(40) butter
(41) foot
(42) father
(43) jagged
(44) door
(45) throne
(46) money
(47) mountain
(48) steal
False Memories
• A week ago I gave you a long list of words to remember
Studied list words - Accurate memories
Critical theme words - False memories
(1) haystack
(13) airplane
(25) rye
(2) sandals
(14) flow
(26) melody
(3) fright
(15) pretty
(27) spider
(4) weather
(16) ankle
(28) music
(5) sharp
(17) awake
(29) girl
(6) hot
(18) doctor
(30) bread
(7) creek
(19) frame
(31) sweet
(8) king
(20) jelly
(32) stream
(9) thread
(21) top
(33) soft
(10) shoe
(22) jazz
(34) river
(11) winter
(23) sugar
(35) jail
(12) tide
(24) needle
(36) glacier
(37) thief
(38) hill
(39) power
(40) butter
(41) foot
(42) father
(43) jagged
(44) door
(45) throne
(46) money
(47) mountain
(48) steal
False Memories
Roediger & McDermott (1995)
• Recall: ~ 40% recalled
“sleep”
• Recognition: Remembering
the lure (sleep) during recall
strengthened participants
memories of the lure during
recognition
• Participants claimed to
“remember” the lure rather
than merely “know” it had
been on the list
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Studied
Critical
Lure
DRM Paradigm
• How strong is this effect?
• Recent studies indicate it is very robust
• Replicated may times
• Explicit warnings fail to eliminate the effect
• May see a reduction in the effect
• As the number of list items increases, rate of false recollection
increases (Robinson & Roediger, 1997)
• Young children are less susceptible to DRM paradigm
• Have not yet developed associations
• But they are easily influenced by suggestive questioning
• Older adults are more susceptible to the illusion
• Rely more on gist than verbatim traces
False Memories
• So what is going on in the DRM task?
• The lists rely on properties of semantic association
• Words that are similar in meaning or co-occur in language are
associates
• Look at the original list (different order now)
Thief
Bread
Mountain
Steal
Shoe
Butter
Queen
Foot
King
Needle
Robber
Hand
Food
Crown
Crook
Toe
Eat
Castle
Burglar
Kick
Sandwich England
Money
Sandals
Rye
Throne
Cop
Soccer
Jam
Ruler
Bad
Yard
Milk
Prince
Rob
Walk
Flour
Royalty
Jail
Ankle
Jelly
Power
Hill
Valley
Climb
Summit
Top
Molehill
Peak
Plain
Glacier
Thread
Pin
Eye
Sewing
Sharp
Point
Prick
Thimble
Haystack
False Memories
• So what is going on in the DRM task?
• Two main theoretical accounts
• Activation/Monitoring Theory
• Fuzzy Trace Theory
• Status of the debate: mixed results, with each theory having some
support
False Memories
• Activation-Source Monitoring Theory: Two components
• Part I. Activation
• Lure is consciously or unconsciously activated
• Activation is automatic
• High activation results in false recollection
• Part II. Source Monitoring
• Memories for imagined
power
events are attributed to
other source
ruler
• Participants think they studied
items they thought about
• Increased familiarity
royalty
queen
prince
crown
jewel
king
throne
England
castle
False Memories
• Fuzzy-Trace Theory
• Information is encoded in two formats in parallel
• Gist – meaning based representation
• Longer lasting representations
• Verbatim – details
• Are not as well preserved
• More sensitive to interference effects
• List memory = verbatim + gist
• Lure memory = gist only
• The verbatim memories for all items may not be there so
rely on gist, which may include the lure (since it is
consistent with the general gist)
Eyewitness Testimony
• Eyewitness Testimony
• Reconstructive memory
• Schema driven errors
• Effect of leading questions
Eyewitness Testimony
• Persuasiveness
• Most persuasive form of evidence
• Eyewitnesses believed ~80% of the time (Loftus, 1983)
Type of Evidence
% guilty votes
Eyewitness testimony
78
Fingerprints
70
Polygraph
53
Handwriting
34
• Juries cannot tell the difference between an accurate
and an inaccurate witness
• Accurate witness believed 68% of time
• Inaccurate witness believed 70% of time
Eyewitness Testimony
• Persuasiveness
• Juries cannot tell the difference between an accurate
and an inaccurate witness
• Wells et al. (1998)
• Studied 40 people who were convicted but later cleared by DNA
• In 90% (36) of the cases, there was false eyewitness identification
• Rattner (1988)
• Studied 205 wrongfully convicted defendants
• 52% were due to inaccurate eyewitness testimony
• Brandon and Davies (1973)
• Described 70 cases of people wrongfully convicted due to inaccurate
eyewitness testimony
Eyewitness Testimony
• Persuasiveness
• Experimental studies
• Buckhout (1975)
• Simulated crime on a TV newscast
• 2,145 callers
• 14.7% were accurate
• Buckhout (1974)
• Staged assault on professor in front of 141 students
• 7 weeks later, students shown line-up of six photographs
• 40% identified attacker
• 36% identified bystander
• 23% identified person not there
Eyewitness Testimony
• What do witnesses report?
Attribute
% Reporting
% Accurate
Gender
99.6
100
Height
91.2
44
Clothing (upper body)
90.8
58
Clothing (head)
89.6
56
Build
84.4
57
Weapon
76.4
71
Clothing (pants)
73.6
53
Age
62.4
38
Type of speech
46.8
84
Fashsing, Ask, & Granhag (2004)
Eyewitness Testimony
• Schema Driven Errors
• Witnesses to crimes filter information during acquisition &
recall
• Their schematic understanding may influence how info is both
stored & retrieved
• Distortions may occur without the witness realizing, based on
things like:
• Past experiences
• Assumptions about what usually happens
• Stereotypes & beliefs about crime & criminals
Eyewitness Testimony
• Experimental Evidence: Interference paradigms
• Information presented after an event can lead to distortions
• Post-event information can be incorporated into the original
memory
• Misinformation effects
• Repeated questioning about an event can enhance recall of certain
details and induce forgetting of others (also increases confidence
in memory of the event)
• Repeated exposure to misinformation strengthens memory about
the misinformation
• Are even found when participants are warned that misleading
information might be presented
Eyewitness Testimony
• Effect of leading questions on recall
• Leading questions introduce new information
• Leading info may activate wrong schemas in witness‘ mind
• Consequently, witness may recall events incorrectly
• Most affected by leading Qs when:
•
•
•
•
Witness believes questioner knows more than them
Witness does not realize they may be misled
Leading information is peripheral, not central
Leading information is not blatantly incorrect
Eyewitness Testimony
• Effect of leading questions on recall
Loftus & Palmer (1974)
• Showed film of car accident
• Estimated speed
• How fast were the cars going when they ____ into each other?
(smashed, hit, collided, etc)
• ‘Smashed’ led to higher speed estimates Smashed 40.8 mph
Collided
Bumped
Hit
Contacted
39.3 mph
38.1 mph
34.0 mph
31.8 mph
• Did you see a/the broken headlight?
• ‘The’ produced more affirmative (incorrect) responses
Eyewitness Testimony
• Effect of misleading information on recall
• Loftus, Miller, & Burns (1978)
• Saw slides of car turning to hit a
pedestrian
• Either saw stop or yield sign
• Asked questions including:
• “Did another car pass the red
Datsun while it was at the
____ sign?” (consistent vs.
inconsistent)
Eyewitness Testimony
• Effect of misleading information on recall
• Loftus, Miller, & Burns (1978)
Consistent “… while it was at the
stop sign?”
Inconsistent) “… while it was at
the yield sign?”
Consistent “… while it was at the
yield sign?”
Inconsistent) “… while it was at
the stop sign?”
• Recognition test for correct
photo of car with sign
Accuracy
Immediate
Consistent
75%
Inconsistent
40%
2 week delay
Inconsistent
20%
Misattribution & Misinformation
• Genuine alteration for the original memory
may be only one part of the memory distortion
explanation
• Three important effects:
• Overconfidence in the accuracy of the memory
• Source misattribution
• Misinformation acceptance
Misattribution & Misinformation
• Source Misattribution
• The inability to distinguish whether the original event or
some later event was the source of the information
(misremember what we have experienced)
• Did I remember the word “sleep” because it was actually in the
list ?
OR
• Because I thought about the word when I heard the list?
Misattribution & Misinformation
• Misinformation Acceptance:
• Accepting additional information as having been part
of an earlier experience without actually remembering
that information (form memories on the basis of suggestion
from some other source)
• Do I remember the car speeding because it was?
OR
• Because the policeman said it was?
• Tendency grows stronger as more time elapses
Recovered Memories
• A person remembers a traumatic event from many
years ago
• The memory was “repressed”, but is now recovered
in therapy
• Intentional forgetting of painful or traumatic
experiences
• Little empirical evidence for this type of forgetting
(could have the opposite effect)
Recovered Memories
• In 1986, Nadean Cool, a nurse’s aid in Wisconsin,
sought therapy from a psychiatrist to help her cope
with her reaction to a traumatic event experienced
by her daughter
• Psychiatrist used hypnosis and other suggestive
techniques to uncover buried memories of abuse that
Cool herself had experienced
Recovered Memories
• Cool became convinced that she had repressed
memories of
•
•
•
•
•
having been in a satanic cult
eating babies
being raped
having sex with animals
being forced to watch murder of her 8-year-old friend
• Cool came to believe that she had more than 120 alter
personalities: children, adults, angels, duck
Recovered Memories
• Cool eventually came to believe that false memories
had been implanted
• Cool sued psychiatrist for malpractice
• in March, 1997, after 5 weeks of trial, her case was
settled for $2.4 million
Recovered Memories
• Increasing numbers of people believe that they were
sexually abused as children, but repressed the memory
until it was later recovered, often with help of therapist
• 1990’s: A big spike in cases of people in therapy recovering
memories of childhood sexual abuse
• “Courage to Heal”: General premise that we were all abused as
children, we need help to remember
• Even if there is no evidence and we have no recollection of being abused
• Therapies included…
• Hypnosis (uses imagery, suggestive questioning, & repetition)
• Guided Imagery (for now, just imagine that you were abused by your
father)
• Drug Therapies (sodium amytal, mostly)
Recovered memories
• Could some of the recovered memories be false?
• If it is possible to create false memories, then some
recovered memories might be false
• Stakes are high
• must find justice and safety for victims of abuse; must
prevent perpetrators from harming others
• must protect individuals from false charges that can
destroy their lives
Recovered memories
• Recovered Memory
• all memories recovered in therapy should be
taken seriously
• False memories are rare
• If raise doubts, betray children and support
pedophiles
• Pseudomemory
• Memories recovered in therapy should be
viewed with skepticism
• False memories can be manufactured by
naïve/unscrupulous therapists
• Many false accusations
Recovered memories
• Loftus’s “shopping mall” studies
• asked subjects to try to remember childhood events that
had been told to researchers by their parents, older
siblings, or other close family members
• 3 events were real; 1 event (getting lost in a shopping
mall at age 5) was false
• 29% “remembered” false event
Recovered memories
• Hyman and colleagues (reported in Loftus,
1997)
• asked college students to recall childhood
experiences told to the researchers by their parents
• each subject given one false event (either an
overnight hospitalization for a high fever and ear
infection or a birthday party with pizza and a
clown)
• during first interview, no one “remembered” false
event
• during second interview, 20% “remembered” false
event
Recovered memories
• McNally (2003) – review of several studies
• Identified 4 groups
•
•
•
•
Repressed memory
Recovered memory
Continuous memory
Control
Recovered memories
• McNally (cont.)
• No differences in terms of personality traits between
continuous & control
• Repressed scored higher than all other groups in terms of
negative affectivity
• Repressed also reported more dissociative & PTSD symptoms
• Repressed & recovered scored higher in terms of fantasy
proneness
Recovered memories
• Recovered are more likely than control to develop
FM in laboratory paradigms
• Clancy et al. (2002)
• Ss reported being abducted by aliens
• Exhibited robust FM effects
Recovered memories
• Brief Summary
• Both extreme positions of “children always lie” and
“children never lie” are wrong
• Most children do recollect accurately most of what they have
seen or observed
• Some children will say something happened when it did not
• Like adults, children can be influenced to report an event in a
certain way, depending on the frequency of suggestions and
the insistence of the person making them