The Impact of Threat, Unusualness and Weapon Focus on Memory and Eyewitness Identifications

Abstract

The Weapon Focus Effect (WFE) is an eyewitness’ decreased ability to accurately recall details of a crime and identify a perpetrator when a weapon or unusual object is used compared to not used. Threat and unusualness are two of the mechanisms underlying the WFE, therefore, we examine different ways of creating threat and unusualness. Participants watched a mock- crime video where we manipulated object (i.e. gun, newspaper, Millwall Brick) and function (i.e. usual or unusual). Participants were then asked to answer a series of free recall, cued recall and recognition questions based on the video. They were then asked to rate threat and unusualness for each object, then to identify the target from a lineup and how confident they were in their decision. We found a WFE of the main effects, threat and unusualness. For free recall of the perpetrator we found a WFE for the main effect but not for that of the crime scene. We also found an effect on cued recall and recognition for the interaction effect only. Lastly, we found a WFE effect for target-present and target-absent lineups for the interaction effect of object and function only and not the main effects. Results may have an impact on real life investigations as lack of significant evidence on the effects of weapon focus on eyewitness statements and identifications may make it difficult for prosecutors to determine reliable evidence to be used in courtrooms.