Eyewitness Identification

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Eyewitness Identification

• Steven E. Clark
• University of California, Riverside

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Lineup 1
3
2
1
4
5
6
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Lineup 2
2
3
1
4
5
6
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Target Present(Suspect is Guilty)
3
2
1
4
5
6
6
Target Absent(Suspect is Innocent)
2
3
1
4
5
6
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TARGET TARGET PRESENT ABSENT
Suspect .45 .30 Foil .35 .55 No
ID .20 .15
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TARGET PRESENT (suspect is guilty)
STAGED CRIME
TARGET ABSENT (suspect is innocent)
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Why not study real crimes?
RONALD COTTON
BOBBY POOLE
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Of the 235 DNA Exonerations on the
InnocenceProject website 75 percent were
convicted based on Mistaken Identification
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Why do witnesses make mistakes?

• Memory isnt perfect.
• Lineup composition.
• Expectations and instructions.
• Police influence.
• The way witnesses make decisions

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Why do witnesses make mistakes?

• Clark and Godfrey (2009)
• Meta-analysis of dozens of eyewitness
  identification experiments, involving hundreds
  (probably thousands) of experimental witnesses.
• Problems and solutions

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Lineup Composition

• Problem. Foils that dont match the witnesss
  description of the perpetrator

CORRECT .72
FALSE .49

• Solution. Foils that do
• match the witnesss description of the
  perpetrator

CORRECT .61
FALSE .21
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Expectations Instructions

• Problem. Witness expects perpetrator to be in
  lineup (or is told this by police)

CORRECT .55
FALSE .10
CORRECT .50
FALSE .06

• Solution. Witness is informed that the
  perpetrator may or may not be in the lineup

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Police Influence

• Problem. Police officer influences witness while
  looking at lineup.

CORRECT .78
FALSE .36
CORRECT .36
FALSE .14

• Solution. Police officer does not influence
  witness while looking at lineup.

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Decision-Making
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Decision Making
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3
1
4
5
6
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Sequential Lineup

• Rod Lindsay and Gary Wells (1985)

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Decision-Making

• Problem. Witness makes decision based on relative
  judgment. (Simultaneous)

CORRECT .54
FALSE .17
CORRECT .43
FALSE .10

• Solution. Witness does not make decision based on
  relative judgment (Sequential)

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Summary

• Research has revealed a lot about why witnesses
  make false identifications.
• Research has led to recommendations about how to
  conduct identification procedures so as to reduce
  false identifications.

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Summary

• The recommended procedures work.
• They do reduce the risk of false identifications.
• However, they also reduce the rate of correct
  identifications.
• This has been underappreciated in the research
  literature.
• Herein lies the controversy.
• Protecting the innocent is not free.

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From Sam Gross et al. Exonerations in the U.S
1989 - 2003