The effect of lineup size on eyewitness identification accuracy

Eyewitness identification via lineup procedures is an important and widely used source of evidence in criminal cases. However, the current scientific literature provides inconsistent guidance on a very basic question of lineup procedure: lineup size. Some of the ambiguity in the field may be due to different ways in which performance in a lineup memory task is assessed, many of which conflate choosing rate (response bias) with actual memory (discriminability). In two experiments, we examined whether the number of fillers presented with a suspect affects diagnostic accuracy in a lineup, as assessed with Receiver Operating Characteristic (ROC) analysis. Experiment 1 used a between-subject design (N=4401) with one video and lineup per subject. Experiment 2 used a within-subjects (N=105) design with 60 still photographs. For both experiments, showups—a lineup without any fillers—led to lower discriminability than standard lineups with six members. However, in neither experiment did the number of fillers affect discriminability.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Psychology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2019

Author dc:creator

• Akan, Melisa

Contributors dc:contributor

• Benjamin, Aaron S.

• Eyewitness memory, lineup size, ROC analysis

Statement dc:rights

• Copyright 2018 Melisa Akan

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/102803

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/102803