Of guns and geese: a meta-analytic review of the ‘weapon focus’ literature

Weapon focus is frequently cited as a factor in eyewitness testimony, and is broadly defined as a weapon-related decrease in performance on subsequent tests of memory for those elements of an event or visual scene concurrent to the weapon. This effect has been attributed to either (a) physiological or emotional arousal that narrows the attentional beam (arousal/threat hypothesis), or (b) the cognitive demands inherent in processing an unusual object (e.g. weapon) that is incongruent with the schema representing the visual scene (unusual item hypothesis). Meta-analytical techniques were applied to test these theories as well as to evaluate the prospect of weapon focus in real-world criminal investigations. Our findings indicated an effect of weapon presence overall (g= 0.53) that was significantly influenced by retention interval, exposure duration, and threat but unaffected by whether the event occurred in a laboratory, simulation, or real-world environment.