Transcript False Memory

Pranking Memory
How is information stored in LTM?
• Information is stored based on meaning.
• Information to be remembered collects
together because it is related, so meaning of
one concept is derived from its relationship to
other concepts
Example Semantic Network
Schema Theory
• Schemas provide a skeleton structure, which is
filled in with details from an experience
• Schema knowledge also organized around
scripts
– Knowledge about what occurs during routine
activities
Reconstructive Memory
• Memories are reconstructed, and as such,
subject to the influence of expectations
– Sir Frederic Bartlett (1932)
– “The War of the Ghosts”
Schemas and Memory Errors
• Schematic processing is among the most
pervasive sources of predictable errors in
memory.
• Why?
• The graduate
student office
study
Grad Student Office
• Most everyone recalled that the office had a
chair, desk and walls.
• Some participants recalled schema consistent
items, like books that were not present.
What is false memory?
• False memory refers to the circumstances in
which we are possessed of positive, definitive
memories of events – although the
definitiveness may vary – that did not actually
happen to us.
Some Factors Reducing the
Accuracy of Eyewitness Memory
Wait…why eyewitnesses?
• Eyewitnesses generally
are taken off guard by the
crime
– They are often preoccupied
with their own thoughts and
plans
• The criminal’s actions are
often brief and swift
• Criminals take steps to
avoid recognition
– e.g., they wear disguises
• Eyewitnesses are subject
to:
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Inattentional blindness
Change blindness
Prior expectations
Post-event information
Weapon focus
Inattentional Blindness
• A failure to see fully visible objects or events
because attention is focused elsewhere.
Change Blindness
• The phenomenon in which some prominent feature of the visual
environment is dramatically changed without the perceiver
apparently noticing
• It seems our LTM for complex scenes is much less detailed than we
often believe
Prior Expectations
• Hastorf and Cantril (1954)
– Design:
• Dartmouth and Princeton students watched an
American football game between the two schools
• They were asked to detect violations of rules
– Results:
• Princeton students detected twice as many
violations by Dartmouth than did Dartmouth
students
• Remember Schemas?
Post-event Factors
• Information provided after an event, both
visual or verbal, can dramatically affect
eyewitness memory.
Post-event Factors: The
Misinformation Paradigm
• The contents of our memories are subject to
interference from any number of sources.
– Based on the underlying idea that memory is
reconstructive
Post-event Factors: Leading Question
Effect
• Loftus and Palmer (1974)
• Can cause witnesses to remember episodes
differently
– estimate the speeds of the cars when they
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smashed
bumped
collided
hit
contacted
Implanting False Memories
• As previously discussed, memory for events
can be altered to include false information.
– E.g., Misinformation
• Can an entirely false memory be implanted?
The “Lost-in-the-Mall” Paradigm
• Participants are presented with scenarios of
past events.
• Some of the events are true (corroborated by
relatives and friend)
• One or more of the events is false.
• Memory for all events is tested at multiple
time points.
The “Lost-in-the-Mall” Paradigm
• Interesting findings.
– 25% of participants falsely recalled being lost in a
shopping mall. (Loftus & Pickrell, 1995)
– 37% of participants recalled false events such as
being rescued by a lifeguard (Heaps & Nash, 2001)
– 25.5% recalled spilling a bowl of punch on the
parents of the bride at a wedding. (Hyman,
Husband, & Billings, 1995)
Sample Interview from (Hyman, Husband, & Billings, 1995)
I: Next one looks like an eventful wedding reception. Looks
like you were 5 years old. You’re at a wedding of a family
friend, playing with some other kids, while you’re running
around uh you bump into a table and spill punch on the parents
of the bride.
S: [laughs] I don’t remember that either. That’s pretty funny
though [laughs]
I: [laughs] Yeah, that seems like it would be kind of eventful.
S: Yeah, God, maybe my mom never talks about these. She
never talked about, she’s never told me about that, jeez, that’s
funny. A wedding. I wonder whose wedding it could be…
man, I want to talk to her and find out where she’s getting these,
cause…a wedding reception. I can totally see myself like
running around and bumping into the table. I would do that.
Final Interview
I: The next one I have is an eventful wedding at age 5.
S: Yeah I thought about this one too. I definitely think it’s a
friend of my mothers for some reason and the people I spill
punch on, I picture them to be a heavy set man, not fat but
like tall and big, and I picture him having a dark suit on, like
greyish dark hair and balding on top, and uh I picture him with
a square face and I picture him being kind of irritated or mad,
then the woman, I see her in a light coloured dress that has like
flowers on it, I think I see flowers on it and stuff, and I see like
a big red punch thing down the front of them, can see that.
Her hair hadn’t turned grey yet, it was still dark, it was brown.
Implanting False Memories
• What about implausible or impossible events?
– Participants who viewed an advertisement for Disney
World that included an image of Bug Bunny were
significantly more likely to recall meeting Bugs during a trip
to the theme park (Braun, Ellis, & Loftus, 2002).
• Many of the participants who falsely remembered the event
recalled specific details including shaking hands or hugging Bugs.
– Participants presented with articles and testimony about
demonic possession where more confident that they had
witnessed such an event as a child (Mazzoni, Loftus, &
Kirch, 2001).
Implanting False Memories
• Frenda, Knowles, Saletan, and Loftus (2012)
– What did they do?
– What did they find?