Decision Variables in the Case of Police Lineup Rejections

Though high-confidence identifications from a police lineup can provide strong evidence of guilt, confidence in a lineup rejection often provides little additional information beyond the rejection itself. Here, we investigate whether participants use different decision rules for positive identifications vs. lineup rejections. In this experiment, we compared confidence ratings from a standard simultaneous lineup (where confidence in the lineup rejection is not applied to any particular face) to the confidence ratings from a rate-them-all simultaneous lineup (where confidence that a person is or is not the perpetrator is applied to every face in the lineup). We hypothesize that, in the case of a lineup rejection, confidence in the standard condition will be best predicted by the average memory signal in the rate-them-all condition. The possible reliance on an average memory signal could help to explain why previous research has not found a strong confidence-accuracy relationship for lineup rejections