Download reliability and memory ppt

Reliability in Memory

In 1984 Jennifer Thompson, a 22-year-old
college student was raped at knifepoint. She
testified that during the crime she made a
conscious effort to memorize every detail of the
rapist’s face so that she could identify him
later. A few days after the attack, she picked
the face of Ron Cotton out of a series of police
photos.
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Jennifer claimed she was completely
confident in her identification of Cotton.
Cotton was later convicted on the
strength of her eyewitness testimony and
received two life sentences.
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3 years later at Cotton’s appeals hearing
Jennifer was presented with another inmate,
Bobby Poole who had bragged in jail that he
was the one who had raped her.
Upon seeing Poole in court, Jennifer testified, “I
have never seen him in my life. I have no idea
who he is.”
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In the U.S. eyewitness testimony is the #1
cause for wrongful conviction.
The U.S. Justice Department claims that
as much as 10% of the current prison
population is innocent.
In England, of cases where the only
evidence was eyewitness testimony, 74%
resulted in conviction.
CLO #9 With reference to relevant
research studies, evaluate the
extent to which one cognitive
process is reliable.
Can a witness be lead into the
correct answer through
suggestive questioning?
AIM: To investigate the role of
leading questions in recall.
 To see if changing one word in
certain critical questions would
influence speed estimates.

45 students were shown a video of a traffic
accident.
 The first group was asked the following
question: About how fast were the cars going
when they hit each other?
 The next group was asked, “About how fast
were the cars going when they smashed into
each other?”
 In later groups, “hit” was replaced by
“collided”, “bumped”, and “contacted”.
Verb Used
Mean Speed Estimate
Smashed
40.8
Collided
39.3
Bumped
38.1
Hit
34.0
Contacted
31.8
1.
2.
Different verbs activate different
schemas. For example,
“smashed” activated a schema of
a serious accident, thus distorting
the original memory or
Participants were led into answers
by wording of question by
interviewer.
Elizabeth Loftus, a Cognitive Psychologist,
was interested in whether a person’s
memory was changed by information
presented after the original event.

AIM: To determine if memory was,
in fact, influenced by presenting
new information after the original
memory was stored


150 student participants saw the video of a car
accident.
They were then divided into three groups and
asked questions about the accident.



The first group was also asked the same question
about estimation of speed with the word “hit”.
The second group was also asked the question about
the estimation of speed with the word “smashed”.
The last group was not asked about the speed.
This time all the groups were
asked whether or not they saw
broken glass in the accident film.
Note: There was no broken glass
in the film.
 Which group do you think was
most likely to see glass?

Response
Smashed
Hit
Yes
16
7
Control
Group
6
No
34
43
44
The word “smashed” activates a
schema of a serious accident.
 Therefore, it is possible to create
a false memory using post-event
information.
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Other researchers argue that the
original trace is actually saved and
the secondary record results from a
problem of retrieval. The idea
behind this is that the primary
record is not altered, so given a
correct retrieval cue it can be
recalled.
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All participants were US students so
there may have been a bias.
The experiment was controlled and
participants were told they would be
watching a video so question of
ecological validity.

Yuille & Cutshall (1986) used
Loftus’s technique in interviewing
people who had witnessed a real
robbery. They found that wording
of the question had no effect on
recall and those who were most
distressed had the most accurate
memories.

Researchers have conducted laboratory
studies that involved showing
participants violent events like attacks or
robberies on film. Participants were
more likely to remember violent events
than neutral events. (Baddeley, 1993)
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Bartlett concluded that memory was
reconstructive, not reproductive. In other
words, we used our imaginations to fill in the
semantic gaps. Does this mean the less we
know about something (if we don’t already
have a schema) the more likely we are to create
an idea about it to make sense of it?
What does this mean for our memory of
different races for which we don’t have as
many schemas ?
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Richard Russell, a law professor, says there
is plenty of evidence that people make
mistakes when they have to identify faces
across ethnic lines.
Loftus explains that this is because we are
more able to distinguish the features of
those we are most familiar with. She thinks
it has to do with how we scan faces.
Other research suggests that facial
recognition is highly fallible regardless of
ethnicity.

Sigmund Freud believed we repress or “forget”
certain memories to protect our conscious
minds from being aware of things we are not
yet ready to deal with. Memories that are
likely to be repressed are intensely emotional
or anxiety-provoking ones that are repressed
into our unconscious, but might show up
through symbolism in dreams or therapy.
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In 1995 Cotton provided a DNA sample so that
it could be run against a sample after the rape.
The DNA did not match Cotton, but was later
matched to Bobby Poole, who then confessed
to the crime.
Cotton spent 11 years in prison for a crime he
did not commit.

As of 2009, DNA had been used to
overturn 235 convictions. Of those,
75% relied on eyewitness testimony
for the original conviction.