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.