The Malleability of Eyewitness Confidence: Co-Witness and Perseverance Effects

A theft was staged 70 times for pairs of eyewitnesses ( N = 140) who then made a photo-lineup identification. Witnesses then received 1 of 9 types of information regarding the alleged identification decision of their co-witness. Witnesses told that their co-witness identified the same person whom they had identified showed an increase in the confidence they expressed to a confederate police officer. Confidence deflation occurred among witnesses who thought their co-witness either identified another person or had stated that the thief was not in the lineup. Initial co-witness information was not mitigated by subsequent changes to that information. A second study showed videotapes of these witnesses' testimonies to observers ( n = 378) whose credibility ratings of the testimony paralleled the witnesses' self-rated confidence. Eyewitness identification confidence is highly malleable after the identification has been made despite the fact that physical resemblance between the culprit and person identified has not changed.