The malleability of eyewitnesses: investigating the external predictors for eyewitness suggestibility

Introduction. A series of experiments were conducted to identify the salient characteristics within a post-event discussion that could increase the suggestibility of an eyewitnesses to misinformation from co-witnesses. The effects of the majority size (number of eyewitnesses presenting the misinformation), target group (number of eyewitnesses exposed to misinformation) and unanimity of misinformation amongst co-witnesses were explored.

Method Five hundred fifty-six participants took part in an eyewitness simulation experiment. Participants were placed into groups and viewed video footage of a bar fight taking place. After witnessing the event, participants discussed the event with group members before giving individual statements privately. Through the use of confederates, the participants were exposed to misinformation. A mixed design was employed, with target group size and confederate size acting as the independent variables within the study.
Results. The results indicated that misinformation size, as well as the unanimity of misinformation, were significant predictors for eyewitness suggestibility (P<.001). However, target group size was not able to predict for eyewitness suggestibility.

Discussion. The findings indicated that an increase in the size of the misinformation source had a strong positive relationship with eyewitness suggestibility, with the rate of increase in eyewitness suggestibility remaining relatively constant as the misinformation size increased. Furthermore, despite the target group size showing no direct relationship with eyewitness suggestibility, the results indicated that if the misinformation was not unanimously held by all co-witnesses, the target would be significantly less likely to conform to the false information.