Transcript Memory

Memory
Eyewitness Testimony
Learning objectives
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Understand what is meant by eyewitness
testimony (EWT)
Be aware of some of the factors that affect the
accuracy of EWT.
Understand the impact of misleading
information on EWT.
Describe the cognitive interview technique and
understand its rationale.
Describe and evaluate evidence that
underpins our understanding of EWT.
From The Times
May 23, 2007
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201 wrongful convictions are tip of the iceberg, says DNA charity
Tim Reid in Washington
A man who spent 19 years in jail for the murder of two children
will be exonerated formally in July, putting the number of inmates
in America cleared by DNA evidence at more than 200.
Byron Halsey, who narrowly avoided the death penalty when he
was convicted in 1988 of the sexual assault and murder of a girl,
7, and a boy, 8, had his conviction thrown out by a judge last
week after DNA evidence pointed to another man as the killer.
Mr Halsey’s exoneration means that since the first American
inmate was cleared by DNA evidence in 1989 another 200 have
now been proven to be convicted wrongfully, according to the
Innocence Project, a New York legal charity that pioneered the
use of DNA analysis.
Affects of misleading information
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Distortion after the event
Due to post-event
information
Loftus (1992) called this
‘misinformation
acceptance’
More so as time goes on
after the event
Important implications
for questioning
suspects.
Elizabeth Loftus
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Used lab
experiments
 Using videos of road
traffic incidents
Barbara Loftus
Followed by post-event information
 Including leading questions
 Test for memory of original event
 Finding – false info after the event can
change the original memory
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Classic study by Loftus (1975)
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Participants were
shown a film
 Then divided into 2
groups
 Group 1 was asked
questions consistent
with what they had
seen
Procedure
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How fast was the
white sports car
going when it passed
the Stop sign.
 How fast was the
white sports car
going when it passed
the barn while
travelling along the
country road?
Findings
There had been a stop sign in the film
but no barn.
 17% in the experimental group (the
group asked the leading questions)
reported seeing a barn.
 Only 3% in the control group (not asked
leading questions) made this error.
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Conclusion
Participants who are given misleading
post-event information believed they had
really seen the barn.
 This information had been absorbed into
their original memory.
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Criticisms
Is it possible that participants are
responding to demand characteristics?
 This would mean participants hadn’t
really had their memory changed.
 To test this…
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Loftus offered a money reward
 For correct recollection of details from a
film of an accident.
 One group saw a film involving a
pedestrian being knocked over after a
car stopped at a Stop sign.
 The other group saw the same incident
except the car stopped at a Yield sign
(American equivalent of Give Way).
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Two days later
Participants were given a set of questions
about the incident.
One question was misleading.
Participants who saw the Stop sign were
asked about a Yield sign.
Participants who saw the Yield sign were
asked about a Stop sign.
Loftus showed pairs of slides, one with a Yield
and one with a Stop.
Participants were divided as follows:
 1 offered no monetary reward
 Offered $1 for each correct answer
 Offered $5 for each correct answer
 $25 offered for person in the group who
scored the most correct answers
 NEED FOR CORRECT ANSWERS
WAS EMPHASISED BY LOFTUS
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Findings
In spite of financial incentives
 Over 70% made an error on the crucial
question in line with the misleading info
they received.
 This suggests
 That the original memory had been
altered as a result of the misleading
post-event information.
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Divide class into 2 groups:
 A and B
 Group B should close their eyes when
Group A are doing the task and vice
versa
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Group B – write your answers down
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Did you see a broken headlight in the clip you saw
earlier?
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How fast do you think the bike was going when it
made contact with the car?
Group A – write your answers down
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Did you see the broken headlight in the
clip you saw earlier?
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How fast do you think the bike was going
when it smashed into the car?
findings
Are our findings the same as Loftus and
Zanni (1975)?
 They found
 17% of those with the leading question
reported seeing it
 7% of those asked about ‘a’ broken
headlight reported seeing it.
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findings
The verbs, ‘smashed’, ‘bumped’,
‘collided’, or ‘contacted’
 Had a significant effect on the estimates
of speed.
 A week later, those who had been given
the word ‘smashed’ were more likely to
report seeing broken glass even though
there had been none.
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Other factors affecting EWT
Information may not be registered in the
first place.
 In real life situations, accidents happen
suddenly and people aren’t expecting
something to happen.
 Memories are reconstructed with
preconceptions.
 We fill in gaps with our own knowledge
and experience of the world (schemas).
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Schema for a bank robbery
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Write a list of things that immediately comes to
mind when thinking of a bank robbery.
Male
Disguise
Dark clothes
Getaway car outside
Driver in the car waiting
According to Tuckey and Brewer (2003)
Interference with memory
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Palace
or
museum
Lindsay et al. (2004)
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Participants told
about a
 Burglary at a palace
 Or a school trip to a
palace
Interference when things are similar
When shown a video of a burglary at a
museum who would make more errors
on recall of details?
 Those who had heard about palace
burglary previously rather than a school
trip.
 Why?
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Other factors that affect EWT
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Anxiety
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http://www.onlineclassroom.tv/psycholog
y/catalogue/psychology_critical_issues/e
yewitness_testimony