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The effects of allowing a second sequential lineup lap on choosing and probative value.

Ruth Horry Orcid Logo, Neil Brewer, Nathan Weber, Matthew A. Palmer

Psychology, Public Policy, and Law, Volume: 21, Issue: 2, Pages: 121 - 133

Swansea University Author: Ruth Horry Orcid Logo

DOI (Published version): 10.1037/law0000041

Abstract

When presented with a sequential lineup, witnesses see each member of the lineup individually, essentially making a yes/no decision for each person shown. An important policy question is whether witnesses should be allowed to see an additional lap of a sequential lineup. We investigated the impact o...

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Published in: Psychology, Public Policy, and Law
Published: 2015
URI: https://cronfa.swan.ac.uk/Record/cronfa20294
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Abstract: When presented with a sequential lineup, witnesses see each member of the lineup individually, essentially making a yes/no decision for each person shown. An important policy question is whether witnesses should be allowed to see an additional lap of a sequential lineup. We investigated the impact of a second lap on eyewitness decision-making and on the probative value of suspect identifications. We recruited a large community sample of participants (N = 393), each of whom viewed a target person before seeing a sequential lineup that did or did not include the target. A second lap was either required or optional. The group of participants who accepted the second lap were less able to discriminate between the target and the fillers and responded more conservatively in lap 1 than the group of witnesses who declined the second lap. Responding became more lenient from lap 1 to lap 2. Of the participants who saw a second lap, roughly 40% changed their response, most frequently from a non-identification to an identification. Both culprit identifications and filler identifications increased from lap 1 to lap 2. The probative value of suspect identifications was not significantly different whether witnesses were allowed two laps or one. However, the observed effects may be moderated by a number of system and estimator variables. Further, even small changes in probative value can have very different consequences depending upon the target-absent base rate.
Keywords: Eyewitness identifiction; sequential lineup; response bias
College: Faculty of Medicine, Health and Life Sciences
Issue: 2
Start Page: 121
End Page: 133