Social Influence in Eyewitness Recall: A Meta-Analytic Review of Lineup Instruction Effects

Past research has considered the impact of biased police lineup instructions upon eyewitness lineup performance. Biased instructions either suggest to the eyewitness that the perpetrator is in the lineup or otherwise discourage a no choice response. A meta-analysis of 18 studies was employed to review the hypothesis that biased instructions lead to greater willingness to choose and less accurate lineup identifications than do unbiased instructions. The role of moderating variables in the instruction procedure was also considered. In support of the hypothesis, a significantly higher level of choosing followed biased instructions. Lineup type moderated performance accuracy, however. For target-absent lineups the increased level of choosing following biased instructions resulted in reduced identification accuracy. Biased instructions within a target-present lineup generated a higher level of confidence, but had minimal impact on accuracy. Implications for police practice are discussed.