Improving Eyewitness-Identification Evidence Through Double-Blind Lineup Administration

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.

警察通常会让证人辨认嫌疑人队列和照片组，实施辨认的警察往往知道队列中的哪个成员是嫌疑人（单盲队列管理），而不是由不知道的警察（双盲管理）来进行。知道队列中哪个成员是嫌疑人的管理人员比不知情的管理人员更有可能发出行为暗示，引导证人选择嫌疑人而不选陪衬者（即不是嫌疑人的队列成员）。此外，非盲管理人员可能会向指认嫌疑人的证人提供确认性反馈，增加他们对自己辨认准确性的信心，并削弱证人信心与准确性之间的相关性。非盲管理人员也更有可能将证人对嫌疑人的试探性陈述（而非对陪衬者的陈述）解释为肯定的指认。由于这些发现表明单盲管理会使辨认对嫌疑人产生偏见，即使他们是无辜的，基于证据的关于收集目击证人辨认证据的最佳实践建议要求使用双盲队列管理程序。