The Influence of Lineup Procedures on Eyewitness Decision Making

Eyewitness misidentifications are a leading cause of wrongful convictions in the United States justice system. In the present research, two experiments were designed to determine how lineup procedures impact identification rates. In Experiment 1, participants were either given a warning about the adverse consequences of a misidentification, or no warning at all, and were subsequently presented with either a culprit-absent or culprit-present lineup. While people were more likely to reject the lineup when the culprit was absent, and more likely to make a suspect identification when the culprit was present, there was no impact of consequence information on identification rates. Experiment 2 examined the impact of unbiased instructions, which inform mock eyewitnesses that the perpetrator could be or could potentially not be in the lineup, and the inclusion or exclusion of an explicit “not there” option at the time of lineup on choosing rates in target absent lineups. The “not there” option was more effective at reducing false identifications than unbiased instructions. These experiments can help researchers and lineup administrators understand the impact procedures have on identification rates, as well as potentially direct the development of recommendations for these procedures