Improving Eyewitness-Identification Evidence Through Double-Blind Lineup Administration

Abstract

Lineups and photo arrays are often presented to witnesses by police officers who know which lineup member is the suspect (single-blind lineup administration) rather than by officers who do not know (double-blind administration). Administrators who are not blind to which lineup member is the suspect are more likely than blind administrators to emit behavioral cues that steer witnesses toward choosing the suspect and away from choosing fillers (i.e., a lineup member who is not the suspect). Moreover, nonblind administrators may provide confirmatory feedback to witnesses who identify the suspect, increasing their confidence in the accuracy of their identification and weakening the correlation between witness confidence and accuracy. Nonblind administrators are also more likely to interpret witnesses’ tentative statements about a suspect than about a filler as a positive identification. Because of these findings that single-blind administration biases identifications against suspects, even when they are innocent, evidence-based recommendations for best practices in the collection of eyewitness-identification evidence call for the use of double-blind lineup-administration procedures.