Curt A. Carlson

Robustness of the Sequential Lineup Advantage.

A growing movement in the United States and around the world involves promoting the advantages of conducting an eyewitness lineup in a sequential manner. We conducted a large study (N = 2,529) that included 24 comparisons of sequential versus simultaneous lineups. A liberal statistical criterion revealed only 2 significant sequential lineup advantages and 3 significant simultaneous advantages. Both sequential advantages occurred when the good photograph of the guilty suspect or either innocent suspect was in the fifth position in the sequential lineup; all 3 simultaneous advantages occurred when the poorer quality photograph of the guilty suspect or either innocent suspect was in the second position. Adjusting the statistical criterion to control for the multiple tests (.05/24) revealed no significant sequential advantages. Moreover, despite finding more conservative overall choosing for the sequential lineup, no support was found for the proposal that a sequential advantage was due to that conservative criterion shift. Unless lineups with particular characteristics predominate in the real world, there appears to be no strong preference for conducting lineups in either a sequential or a simultaneous manner. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Registered Replication Report

Trying to remember something now typically improves your ability to remember it later. However, after watching a video of a simulated bank robbery, participants who verbally described the robber were 25% worse at identifying the robber in a lineup than were participants who instead listed U.S. states and capitals—this has been termed the “verbal overshadowing” effect (Schooler & Engstler-Schooler, 1990). More recent studies suggested that this effect might be substantially smaller than first reported. Given uncertainty about the effect size, the influence of this finding in the memory literature, and its practical importance for police procedures, we conducted two collections of preregistered direct replications (RRR1 and RRR2) that differed only in the order of the description task and a filler task. In RRR1, when the description task immediately followed the robbery, participants who provided a description were 4% less likely to select the robber than were those in the control condition. In RRR2, when the description was delayed by 20 min, they were 16% less likely to select the robber. These findings reveal a robust verbal overshadowing effect that is strongly influenced by the relative timing of the tasks. The discussion considers further implications of these replications for our understanding of verbal overshadowing.

Exploring the Sequential Lineup Advantage Using WITNESS

Advocates claim that the sequential lineup is an improvement over simultaneous lineup procedures, but no formal (quantitatively specified) explanation exists for why it is better. The computational model WITNESS (Clark, Appl Cogn Psychol 17:629–654, 2003) was used to develop theoretical explanations for the sequential lineup advantage. In its current form, WITNESS produced a sequential advantage only by pairing conservative sequential choosing with liberal simultaneous choosing. However, this combination failed to approximate four extant experiments that exhibited large sequential advantages. Two of these experiments became the focus of our efforts because the data were uncontaminated by likely suspect position effects. Decision-based and memory-based modifications to WITNESS approximated the data and produced a sequential advantage. The next step is to evaluate the proposed explanations and modify public policy recommendations accordingly.

Searching for the sequential line-up advantage: A distinctiveness explanation

Gronlund (2005) proposed that one factor leading to a sequential line-up advantage could be the greater likelihood of recollecting distinctive information about a perpetrator when using a sequential line-up. Since then questions have been raised about the robustness of the sequential advantage and the possible moderating role of line-up fairness and suspect position. We manipulated these factors as well as suspect/target distinctiveness in two experiments. A sequential advantage occurred only after encoding a distinctive target, both for biased line-ups (Experiment 1) and fair line-ups (Experiment 2). Remember-Know results were consistent with the greater use of a recall-to-reject strategy in target-absent sequential line-ups. This provided support for the first process-based explanation of the sequential line-up advantage. No consistent position effects were found, but this might be due to the line-up recognition paradigm used, in which each participant viewed a line-up for each of several targets. Theory-based explorations of eyewitness identification are necessary to continue to delineate the underpinnings of the sequential line-up advantage.