Peer influence on event reports among adolescents and young adults

When two or more people witness an event together, the event report from one person can influence others’ reports. In the current study we examined the role of age and motivational factors on peer influence regarding event reports in adolescents and young adults. Participants (N=249) watched a short video of a robbery then answered questions with no co-witness information or with information believed to be from a co-witness. Public and private response conditions were included to explore motivations for peer influence. Co-witness information influenced participants’ responses, although the effect was equally strong in the private and the public co-witness conditions. Peer influence on event reports was steady across a large age range (11- to 25-year-olds).     

A Developmental Evaluation of Frequency Memory for Actions Presented in Lists,Scripts, and Stories

Although some research suggests that misinformation provided by a co-witness could be more influential than that obtained from other sources, most of this research has compared the effect of co-witness information against non-social forms of misinformation only. To better understand the influence of co-witnesses we compared the influence of co-witness misinformation with the influence of misinformation provided by an interviewer. Across two experiments using the MORI paradigm we found no evidence that a co-witness is particularly influential relative to another social source of post-event misinformation. In fact, the source of the misinformation delivered by our interviewer was less likely to be correctly recalled than the source of the misinformation delivered by a co-witness. There was some evidence that misinformation delivered by both a co-witness and an interviewer has a stronger effect on witnesses' accuracy and confidence than misinformation obtained from either source alone. Finally, our results suggest that the opportunity to provide an early individual memory account might protect against the effect of subsequently-encountered co-witness misinformation. These results have important implications for the way that criminal investigations are conducted.     

Don't it make my brown eyes blue: Co-witness misinformation about a target's appearance can impair target-absent line-up performance

Misinformation from another witness has been shown to impair eyewitness reports, but little is known about how it may influence eyewitness identification. In Experiment 1, adult pairs comprising one participant and one experimental confederate viewed a video clip of a staged theft. Half of the participants were then misinformed by the confederate that the thief's accomplice had blue eyes (in fact, they were brown). Next, individual participants described the accomplice and completed a target-absent photographic line-up task comprising blue-eyed members. Misinformed participants were several times more likely than controls to describe the accomplice as having blue eyes, and twice as likely to identify someone from the line-up. In Experiment 2, when line-up members’ eye colour was digitally altered from blue to brown, the line-up effect disappeared, suggesting that the increase in identifications in Experiment 1 was not a generalised increase in willingness to choose from the line-up. In Experiment 3, we discounted the possibility that discussion alone could account for the line-up misinformation effect, by subjecting all participants to co-witness discussion.