Comparison of Identification Thresholds in Simultaneous and Sequential Lineups Heather D. Flowe, Ann

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Comparison of Identification Thresholds in
Simultaneous and Sequential LineupsHeather D.
Flowe, Anneka Besemer, Ebbe B.
EbbesenUniversity of California, San Diego
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Study Overview

• Compared decision process in simultaneous and
  sequential lineups
• Examined conditions under which lineup responses
  are conservative
• Lineup is sequentially administered
• Strength of memory is low
• Decision evidence available in lineup is low

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Effects of Lineup Procedure on ID Accuracy

• Accuracy affected by lineup procedure
  (Steblay et al., 2001)
• Hits higher in simultaneous
• False alarms lower in sequential

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Effects of Lineup Procedure on ID Accuracy

• Relative-Absolute Judgment Model
  (Wells and Lindsay, 1980)
• Differential Discrimination of Distinctive
  Suspects (Gronlund, 2004)
• Differential Criterion Placement Account (Ebbesen
  Flowe, 2002 Meissner et al., 2005)

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Effects of Lineup Similarity on ID Accuracy

• In the verbal learning experiments, similarity of
  distractors affects criterion placement
  (Benjamin, 2005 Benjamin Bawa, 2004)
• In lineup experiments, similarity structure of
  lineup also has an effect (Clark Davey, 2005
  Ebbesen Flowe, 2006)

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Experiment 1Overview

• Used multiple lineup procedure (similar to method
  of ascending limits) to present lineup pictures.
• Examined where in the series of lineups the
  identification occurred.

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Multiple Lineup Procedure
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Decision Processes in Lineups

• If sequential lineups leads to better target
  discrimination
• Positive identifications should be greater in
  sequential compared to simultaneous lineups when
  fewer features are available.

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Decision Processes in Lineups

• More conservative responding when
• Strength of memory is low
• Few features are available to make the
  identification
• The lineup is administered sequentially rather
  than simultaneously

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Experiment 4Design and Procedure
Study Session 6 faces presented for 10 or 20 sec
each
Test Session
Feature Level (0, 1, 3, 4, or 5) Order of
Feature (eyes, mouth, and face shape)
Introduction Counterbalanced ID Procedure
(simultaneous or sequential)
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Memory Strength Results
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Memory Strength Results
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Memory Strength Results
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Lineup Procedure Results
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Lineup Procedure Results
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Lineup Procedure Results
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Results
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Experiment 2Overview

• Is accuracy higher in sequential compared to
  simultaneous lineups when the identification made
  is based on few features?

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Experiment 2Overview

• When forced to make a choice, does recognition
  accuracy vary between simultaneous and sequential
  lineups?

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Experiment 2Design and Procedure
Study Session 4 faces presented for 10 sec each
Test Session
Feature Level (2, 3, 4, or 5) Choice Level (no
choice option or forced) ID Procedure
(simultaneous or sequential)
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Results
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Results
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Conclusions

• Witnesses will tend to use a conservative
  decision criterion when
• The lineup is administered sequentially rather
  than simultaneously
• Strength of memory is low
• Few features are available to make the
  identification