Police perceptions of eyewitness impairment due to alcohol and other drug use: a cross-cultural comparison

Abstract

Police perceptions of eyewitness impairment due to alcohol and other drug use: a cross-cultural comparison.Victims, witnesses, and suspects of crime are frequently intoxicated by Alcohol or Other Drugs (AOD) during the event. How intoxication is perceived by investigating officers, and the manner in which this is handled during interview procedures, can affect the quality of information obtained and therefore investigative outcomes. Various factors are likely to contribute to how intoxication is handled during the investigation of a crime, including standard procedures, familiarity with the effects of different substances, and cultural attitudes. While findings with respect to the effect of different substances on memory are still emerging, it is important to investigate whether police beliefs are consistent with available evidence. In this study, Australian and Indonesian police officers were surveyed about their perceptions of memory accuracy and credibility of victims and witnesses intoxicated with various substances (e.g., alcohol, cannabis, amphetamines, and opioids). A higher proportion of Australian police identified larger negative memory effects associated with alcohol intoxication. At the same time, Indonesian police were found to be more likely to report that intoxication with alcohol would make a victim or witness less credible.With regard to timing, across multiple substances, larger proportions of Australian police reported believing that information obtained from witnesses that were still intoxicated would be more accurate than if interviewed after they became sober. It is concluded that, in order to rectify misconceptions about the impact of AOD intoxication on memory and improve investigative practices, both Australian and Indonesian police would benefit from additional training on the effects of intoxication.

Police Decision-Making in the Absence of Evidence-Based Guidelines: Assessment of Alcohol-Intoxicated Eyewitnesses

“…Based on previous research (Evans et al, 2009;Crossland et al, 2018;Monds et al, 2021a;, we expected interview probability (H1a) and perceived witness credibility (H1b) to decrease as witness intoxication level increased. Due to potential lack of scientific knowledge among police officers, as suggested previously (e.g., , we expected to find an effect of the research-based message on both interview probability (H2a) and perceived witness credibility (H2b).…”

“…From these studies, several contributing factors to the officers' inconsistent decisions can be derived. Firstly, many police officers perceived intoxicated witnesses as less credible than sober witnesses, which may have rendered them reluctant to interview these individuals (Evans et al, 2009;Crossland et al, 2018;Monds et al, 2021a;. As the research described above has proposed otherwise, these findings suggested that police officers perhaps lacked research-based knowledge, highlighting the need for guidelines regarding intoxicated witnesses' ability to accurately recall criminal events .…”

“…In the past, the alcohol and memory literature have often found evidence of detrimental memory impairments being caused by alcohol-intoxication (e.g., Parker et al, 1976;Mintzer, 2007). This provides a rationale for the prevalent perception among legal practitioners (Kassin et al, 2001;Evans et al, 2009;Crossland et al, 2018;Hagsand et al, 2021Monds et al, 2021a) and lay people (Evans and Schreiber Compo, 2010;Monds et al, 2021b) that intoxicated witnesses are less credible than sober witnesses. However, the effects of memory impairments caused by alcohol-intoxication have often not been replicated within the applied legal context of eyewitness memory (see Altman et al, 2019, for a review).…”

“…Complete and accurate statements of eyewitnesses can be of central importance in criminal investigations (Kebbell and Milne, 1998), where criminal charges as well as subsequent court convictions often rely on evidence gathered from police interviews (Howe and Knott, 2015). Despite the known importance of obtaining information from witness interviews, police officers have reported inconsistent decisions to interview intoxicated witnesses and furthermore report varying procedures of engaging with them (i.e., waiting until witness is sober vs. interviewing immediately; Evans et al, 2009;Crossland et al, 2018;Monds et al, 2021a;.…”

“…One way to further understand police officers' inconsistent decisions to interview intoxicated witnesses has been studied through police surveys which were conducted both in Sweden and internationally (Evans et al, 2009;Crossland et al, 2018;Monds et al, 2021a;. From these studies, several contributing factors to the officers' inconsistent decisions can be derived.…”