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Psychology

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Storage. Reconstructive memory. Loftus, Miller & Burns, 1978 ... Photo ID supplemented with voice ID. Judging if eyewitnesses are mistaken. Confidence Accuracy ... – PowerPoint PPT presentation

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Title: Psychology


1
Psychology the Law
  • Eyewitness Testimony
  • Why are they wrong?
  • Judging if they are mistaken
  • Judging if they are lying
  • Improving testimony
  • My research ?

2
Most experts agree that the primary cause of
false convictions is inaccurate eyewitness
identification
  • Why are they wrong?
  • Acquisition
  • Storage
  • Retrieval

3
Acquisition
  • Duration of crime
  • Viewing conditions
  • Victim vs. bystander
  • Expectations
  • Own-race bias

4
Storage
  • Reconstructive memory

Correct Picture ID Accurate Questions
75 Misleading Questions 41
Loftus, Miller Burns, 1978
  • Source Monitoring

5
Retrieval
  • Relative Decision Model
  • Witnesses compare all the people presented in
    the lineup to each other and then select the
    person that is most similar to the culprit
  • Strong form
  • Weak form

6
Target Present Target Absent
Target Present
Target Absent
7
External Validity
  • True rate of TP vs. TA lineups in the real world
    is currently unknown
  • Lab studies 50 TP, 50 TA
  • If all lineups were TP in the real world, an
    innocent suspect would never be chosen

8
Reduce False Positive IDs
  • 1. Expert testimony regarding factors known to
    decrease eyewitness accuracy
  • 2. Improving the validity of methods used to
    collect eyewitness ID evidence
  • Match to description vs. Match to photo
  • Witness Admonishment
  • Include some TA lineups
  • Blind lineup administrators
  • Obtain witness confidence before giving feedback
  • Sequential vs. simultaneous lineups
  • Photo ID supplemented with voice ID

9
Judging if eyewitnesses are mistaken
  • Confidence ? Accuracy
  • Signs of inaccuracy
  • Increase decision time
  • Comparing faces vs. seeing one pop out
  • Process of elimination
  • Verbalization problem
  • Accuracy in ID from lineup after verbalization
    (38) versus no-verbalization (64)

10
Judging if eyewitnesses are lying
  • Experience ? better at detecting deception
  • Polygraph
  • Control question test
  • Guilty knowledge test
  • 10-15 inaccuracy

11
My research first year project
  • Eyewitness accuracy in the real world DNA
    evidence as ground truth for eyewitness
    accuracy rates

12
External Validity
  • True rate of TP vs. TA lineups in the real world
    is currently unknown
  • Lab studies 50 TP, 50 TA
  • If all lineups were TP in the real world, an
    innocent suspect would never be chosen

13
Innocence Project
  • Purpose exonerate wrongfully convicted
  • 61 of first 70 exonerations contained mistaken
    identification

Innocence Project, 2001
14
Predictions
From Laboratory Study Meta-Analysis
Steblay et al., 2001
15
Method
  • Background screening at SDPD and DA
  • 352 cases coded at SDPD crime lab
  • ? 160 linked to cases at DA office
  • ? 70 coded to date
  • Case selection
  • March 2000, known victim, known suspect, at least
    1 source of evidence

16
Case Characteristics
  • Avg. of 2.3 witnesses/case
  • 58 victims of the crimes
  • ID Procedures Used

17
ID Accuracy
18
ID Accuracy in Lineups
19
DNA evidence lineup type

?2(10) 20.7, p lt .05
20
Surprising?
  • Results inconsistent with lab studies
  • Case selection
  • Attention in real world
  • Nature of crimes
  • Data are preliminary
  • Questions generalizations from laboratory
    studies
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