The Effects of Group Discussion on Eyewitness Accuracy

Previous research on group performance in judgmental tasks reveals that groups are rarely inferior, and often superior, to the average individual. The present study examined whether this pattern of results extends to the accuracy of eyewitness reports of a crime. It was found that group discussion led to accounts that were significantly more accurate than the average individual. A requirement to reach a unanimous decision did not alter any of the effects of group discussion. Group superiority was especially clear in terms of the completeness of the reports and in estimations of the duration of the incident. The discussion considered the implications of the present results for the current practice of prohibiting group discussion as an aid to the preparation of testimony.