Michelle Bertrand

Sequential lineup presentation: Patterns and policy

Sequential lineups were offered as an alternative to the traditional simultaneous lineup. Sequential lineups reduce incorrect lineup selections; however, the accompanying loss of correct identifications has resulted in controversy regarding adoption of the technique. We discuss the procedure and research relevant to (1) the pattern of results found using sequential versus simultaneous lineups; (2) reasons (theory) for differences in witness responses; (3) two methodological issues; and (4) implications for policy decisions regarding the adoption of sequential lineups.

Beyond sequential presentation: Misconceptions and misrepresentations of sequential lineups

Malpass, Tredoux, and McQuiston-Surrett (2009), hereinafter ‘MTM’, provide comments on the sequential lineup, research comparing sequential and simultaneous lineups, and the policy implications of this literature. We will comment on points of agreement and disagreement. First, we agree with the following: (1) Peer review, publication of results, and diversity of methods, procedures, and subject populations significantly contribute to the value of research as a basis both for psychological understanding and for recommended policy. (2) Absence of error, omission, and confounds make interpretation and application easier. These conclusions are not revolutionary but seem to occupy a great deal of MTM’s thinking. We disagree with many things that MTM have to say but have room here only to address a few.

The Impact of Multiple Show-Ups on Eyewitness Decision-Making and Innocence Risk

If an eyewitness rejects a show-up, police may respond by finding a new suspect and conducting a second show-up with the same eyewitness. Police may continue finding suspects and conducting show-ups until the eyewitness makes an identification (Study 1). Relatively low criterion-setting eyewitnesses filter themselves out of the multiple show-ups procedure by choosing the first suspect with whom they are presented (Studies 2 and 3). Accordingly, response bias was more stringent on the second show-up when compared with the first, but became no more stringent with additional show-ups. Despite this stringent shift in response bias, innocence risk increased with additional show-ups, as false alarms cumulate (Studies 2 and 3). Although unbiased show-up instructions decreased innocent suspect identifications, the numbers were still discouraging (Study 4). Given the high number of innocent suspects who would be mistakenly identified through the use of multiple show-up procedures, using such identifications as evidence of guilt is questionable. Although evidence of guilt is limited to identifications from a single show-up, practical constraints might sometimes require police to use additional show-ups. Accordingly, we propose a stronger partition between evidentiary and investigative procedures.

Evaluating lineup fairness: Variations across methods and measures.

Triers of fact sometimes consider lineup fairness when determining the suggestiveness of an identification procedure. Likewise, researchers often consider lineup fairness when comparing results across studies. Despite their importance, lineup fairness measures have received scant empirical attention and researchers inconsistently conduct and report mock-witness tasks and lineup fairness measures. We conducted a large-scale, online experiment (N = 1,010) to examine how lineup fairness measures varied with mock-witness task methodologies as well as to explore the validity and reliability of the measures. In comparison to descriptions compiled from multiple witnesses, when individual descriptions were presented in the mock-witness task, lineup fairness measures indicated a higher number of plausible lineup members but more bias toward the suspect. Target-absent lineups were consistently estimated to be fairer than target-present lineups—which is problematic because it suggests that lineups containing innocent suspects are less likely to be challenged in court than lineups containing guilty suspects. Correlations within lineup size measures and within some lineup bias measures indicated convergent validity and the correlations across the lineup size and lineup bias measures demonstrated discriminant validity. The reliability of lineup fairness measures across different descriptions was low and reliability across different sets of mock witnesses was moderate to high, depending on the measure. Researchers reporting lineup fairness measures should specify the type of description presented, the amount of detail in the description, and whether the mock witnesses viewed target-present and/or -absent lineups.