Eyewitness Lineups

1. Introduction.

Police lineups come from English criminal law and procedure. According to Devlin (1976), lineups were instituted through a Middlesex magistrate’s order in the mid 19th century. They were intended as a ‘fair’ replacement for the practices of courtroom identification, and showups, which were widely used in 19th century England, but widely recognized as potentially unfair to the defendant. Their origin indicates that the notion of ‘fairness’ is their raisond’etre. They are intended to secure an identification that can potentially incriminate someone, but also is fair to those who are subjected to it, particularly those who are innocent of the crime. Study of the case law in many countries, as well as recent DNA-based exonerations in the U.S., indicates that lineups are not invariably fair – many innocent people are convicted after identification from a lineup by an eyewitness. The problem is significant because eyewitness evidence is cited as the most significant source of wrongful...

The Department of Justice’s Guide for lineups recommends warning eyewitnesses that the culprit’s appearance might have changed since the time of the crime. This appearance-change instruction (ACI) has never been empirically tested. A video crime with four culprits was viewed by 289 participants who then attempted to identify the culprits from four 6-person arrays that either included or did not include the cul-prit. Participants either received the ACI or not and all were warned that the culprit might or might not be in the arrays. The culprits varied in how much their appearance changed from the video to their lineup arrays, but the ACI did not improve identi- fication decisions for any of the lineups. Collapsed over the four culprits, the ACI increased false alarms and filler identifications but did not increase culprit identifi- cations. The ACI reduced confidence and increased response latency. Two processes that could account for these results are discussed, namely a decision criterion shift and a general increase in ecphoric similarity...