The influence of alcohol and weapon presence on eyewitness memory and confidence

Abstract

Summary In this quasi‐experimental field study, bar drinkers (0.00–0.23% blood alcohol content) viewed a photographic sequence in which a male took a laptop from a helpdesk assistant, either on loan or at gunpoint. Following a brief retention period, participants answered 20 multiple‐choice questions about the male, his actions, and details of the scene, then attempted to identify him from a simultaneous target‐present or target‐absent line‐up. Alcohol was associated with a reduction in correct identifications and an increase in false identifications. Surprisingly, the presence of a weapon in the scene enhanced identification accuracy, though wider scene memory was not influenced by alcohol or the weapon. Findings offer some support for the view that alcohol restricts face encoding, perhaps through the narrowing of attention to salient external features (e.g., hair). We also suggest that curiosity about mock‐crime perpetrators may produce weapon focus reversals, although the factors that might elicit such curiosity remain unclear.

Evidence of alcohol induced weapon focus in eyewitness memory

“…That Harvey et al (2020) found no effect of witness intoxication on scene memory was not a big surprise as such null effects are relatively common in the applied alcohol and memory literature. The absence of a WF effect is more unusual, particularly as the design of that study was a replication of the seminal Loftus et al (1987) WF demonstration.…”

“…The absence of a WF effect is more unusual, particularly as the design of that study was a replication of the seminal Loftus et al (1987) WF demonstration. Here, we test the possibility that both null effects are attributable to three limitations of the Harvey et al (2020) design. First, the multiple‐choice memory questionnaire was limited by the absence of a “do not know” response option for each item.…”

“…At present, data from the applied psychology literature provide no clear answer. Studies of alcohol on face identification in a forensically meaningful context such as an identification parade show little effect of the drug, at least at low to moderate blood alcohol concentrations (BACs) of around 0.03–0.08% (Altman et al, 2018; Colloff & Flowe, 2016; Dysart et al, 2002; Flowe et al, 2017; Hagsand et al, 2013; Harvey et al, 2013a; Kneller & Harvey, 2016; Read et al, 1992; Yuille & Tollestrup, 1990), although a few authors have found identification impairments (e.g., Dysart et al, 2002; Harvey et al, 2020; Read et al, 1992). Conclusions regarding the impact of alcohol on memory for wider scene features are similarly difficult to draw (for reviews see Altman et al, 2019; Jores et al, 2019).…”

“…The combined effects of alcohol intoxication and WF on witness memory have so far been explicitly examined in only one study (Harvey et al, 2020). Harvey and colleagues had a group of sober and alcohol‐intoxicated (BAC range = 0.04–0.23%) bar drinkers view one of two slideshows depicting a young male queuing for assistance at a university help desk.…”

“…This is important because Crossland et al (2016) found highly intoxicated witnesses who viewed a mock theft made significantly more “do not know” responses to cued recall questions than sober responders, and these memory gaps were primarily for questions concerning peripheral scene features of low salience (i.e., those not spatially or semantically connected to the target “thief” and his actions). As the multiple‐choice questionnaire of Harvey et al (2020) included only four response options per item (1 correct, 3 incorrect), correct guessing may have inflated accuracy for the tougher “peripheral” questions rendering their questionnaire insensitive for the detection of alcohol narrowing effects.…”