Witnesses stumbling down memory lane: The effects of alcohol intoxication, retention interval, and repeated interviewing

Abstract

Intoxicated eyewitnesses are often discredited by investigators and in court, but few studies have examined how alcohol affects witnesses' memory. The primary aim of the present study was to examine how intoxication (alcohol vs. control), retention interval (immediate vs. one week delay), and number of interviews (one vs. two interviews) affect witnesses' memory. The participants (N = 99) were randomly assigned to consume either orange juice or alcohol mixed with orange juice, and they all witnessed a filmed mock crime afterwards. The recall took place either (a) immediately and after a one week delay or (b) after a one week delay only. No main effect of alcohol was found on the quantity or quality of the witnesses' statements. Both intoxicated and sober witnesses recalled more details, and were more accurate, during immediate compared to delayed recall. For witnesses interviewed twice, an average of 30% new details were provided in the second compared to the first interview, and these were highly accurate. In sum, contrary to what one can expect, intoxicated witnesses with a low to moderate blood alcohol concentration (below 0.10%) were reliable witnesses.

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

“…However, a similar study by Schreiber Compo et al () showed a reduction in memory accuracy only among participants who had consumed alcohol just prior to encoding, then the same quantity again (M BAC = 0.08%) just prior to their retrieval attempts a week later. In terms of test format, open response tests such as the free recall task have elicited more complete and accurate memory responses from alcohol participants than cued questions in some studies (Altman et al, ; Hagsand, Roos af Hjelmsäter, Granhag, Fahlke, & Söderpalm Gordh, ; Schreiber Compo et al, ), but not all (Crossland, Kneller, & Wilcock, ). Crossland et al (, Experiment 2) played a video of a mock‐crime to inebriated bar patrons and tested their recall and recognition of the event 1 week later when all were sober.…”

Mind the Gap: The Key to Advancing the Science and Policy on Alcohol-Intoxicated Witnesses is to expand the Study Population and Bridge the Researcher-Practitioner Gap

“…Given the current research findings, witnesses with low-to-moderate intoxication levels at the event are often as reliable as sober witnesses [9], which mean that they also could be perceived as a credible source of information in the investigation. In order to have an objective measure of the witnesses' intoxication levels, recommendations have been made in the past that police officers should try to measure witnesses' intoxication levels with a portable breathalyzer at the scene of the crime [27].…”

“…After reaching this intoxication level, the participants witnessed a filmed mockcrime in the laboratory followed by several recall tasks (in this study: questioning similar to a police interview). The method in the study by Hagsand et al [9] is a good example of the most commonly used experimental procedure employed in laboratories in the UK, USA and Sweden with respect to this new emerging research topic. Similar methods were employed in other studies in the field [10][11][12][13][14][15][16].…”

“…Of course, in this context it is important to highlight that memory does not function like a recording device. In other words -both sober and intoxicated witnesses can misremember, which can lead the criminal investigation in the wrong direction [9].…”

“…For example, a recently published laboratory study [9] used low-to-moderate doses of alcohol with the aim of allowing the witnesses to reach a BAC of around 0.08%. After reaching this intoxication level, the participants witnessed a filmed mockcrime in the laboratory followed by several recall tasks (in this study: questioning similar to a police interview).…”