The Effect of Administrator Knowledge on Eyewitness Decision-Making and Confidence Assessment in a Simultaneous Line-up Procedure

Abstract

Eyewitness misidentification has been determined to be a major contributor to wrongful convictions. Thus, factors that may deleteriously affect eyewitness decision-making have been the focus of extensive research. Moreover, another point of concern is the amplification effects of eyewitness confidence on the perceived credibility of an identification. However, result inconsistencies and inadequate methodologies within literature fail to meaningfully determine the nature of these effects. Therefore, the aim of this study is to examine the effects of administrator knowledge and perpetrator presence on eyewitness decision-making and confidence assessment, in line-up procedures. This study employed a 2 x 2 design, following a double-blind line-up administration paradigm. A mock police simultaneous line-up investigation was replicated from a study by Zimmerman, Chorn, Rhead, Evelo, and Kovera (2017); whereby, two concurrent participants act as either a line-up administrator or an eyewitness. Data analysis was conducted within a Bayesian framework. A correlational analysis determined that pressuring behaviours expressed by a non-blinded administrator decreased the eyewitness’s confidence. Further evaluation of the data through a binomial test determined that witness’s choosing from the line-up in the non-blinded and blinded conditions, was at a chance rate. Additionally, no difference in confidence between the single- and double-blinded administrator conditions was found for witnesses who possessed weak memory-accuracy for the perpetrator. The pattern of results suggests that administrator pressuring witnesses has the potential to occur regardless of what the administrator knows; highlighting the importance of recording the administration of lineups and witness confidence so that this can be evaluated in court.