More than meets the eye: Co-witness misinformation about a target's appearance can impair target-absent lineup performance

Abstract

Past research has demonstrated that co-witness misinformation may impair not only eyewitness testimony, but also eyewitness identification (Zajac & Henderson, 2009). The present study aimed to replicate the findings of Zajac and Henderson (2009) using between-subjects manipulations of exposure to discussion, exposure to misinformation, and lineup composition. We expected that co-witness misinformation would be incorporated into participants’ verbal reports and would impair the ability to reject a target-absent lineup in which the members’ eye-colour was consistent with the misinformation. We also expected that misinformation imparted directly by a co-witness would be more powerful than misinformation imparted indirectly by the experimenter. Participants viewed a film of a simulated theft in pairs, one member of which was an experimental confederate. Half of the participants were exposed to misinformation about the accomplice’s eye colour; remaining participants were not exposed to this misinformation. Half of the participants also engaged in discussion; remaining participants did not engage in discussion. Participants then provided a description of the accomplice and completed a target-absent photographic lineup. Half of the participants were exposed to a lineup in which the members had blue eyes; remaining participants were exposed to a lineup in which the members had brown eyes. As expected, participants exposed to misinformation during co-witness discussion were more likely to report the misinformation relative to participants who were not exposed to misinformation and relative to those who were exposed to misinformation without co-witness discussion. Contrary to our hypothesis, participants exposed to co-witness misinformation were no more likely than participants not exposed to misinformation to identify a member from the lineup in which the eye-colour of the lineup members was consistent with the misinformation. They were, however, less likely than participants not exposed to misinformation to identify a member from the lineup in which the eye-colour of the lineup members was inconsistent with the misinformation. These findings have implications for police investigations and for identification procedures.