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

Abstract

Regarding police procedures with alcohol-intoxicated witnesses, Swedish police officers have previously reported inconsistent and subjective decisions when interviewing these potentially vulnerable witnesses. Most officers have also highlighted the need for national policy guidelines aiding in conducting investigative interviews with intoxicated witnesses. The aims of the two studies presented here were to investigate whether (1) police officers’ inconsistent interview decisions are attributable to a lack of research-based knowledge; (2) their decision to interview, as well as their perceptions of the witnesses’ credibility could be influenced by scientific research; and (3) police officers decision-making and perceptions of witness credibility are biased by pre-existing social norms. In two separate randomized online experiments, police professionals and recruits (Study 1, N = 43; Study 2, N = 214) watched a recorded fictive witness interview to which they were asked to rate the probability of interviewing the witness, the witness’ credibility, and to estimate the witness’ level of intoxication. Results showed that interview probability and perceived witness credibility were affected by witness intoxication level. While it cannot be stated definitely from the present research, these findings provided indications that police officers and recruits lacked research-based knowledge. Results also showed that interview probability, but not perceptions of credibility, was influenced by a research-based message. In line with research, interview probability for the most intoxicated witness increased after reading the message. Unexpectedly, neither interview probability nor witness credibility was affected by social norms. The current findings added to the legal psychology literature by showing that a breath alcohol concentration (BrAC) as low as .04% was enough for police officers and recruits to consider intoxicated witnesses less credible than sober witnesses. Findings also indicated that, despite the lower credibility assessment, police may have some understanding that these witnesses can be interviewed at low intoxication levels (i.e., around .04%). However, this willingness to interview intoxicated witnesses ceased at a BrAC lower than the levels where research has found intoxicated witnesses as reliable as sober witnesses (i.e., BrAC < .10%). Future directions for research and policy development as well as theoretical and practical implications of the present findings are discussed.

Police–suspect interactions and confession rates are affected by suspects’ alcohol and drug use status in low-stakes crime interrogations

“…To date, interrogators and interviewers must use their own judgment when deciding how to conduct interrogations with intoxicated persons as the research on alcohol/drugs and cognition in the legal context is still limited. Furthermore, many countries lack evidence-based guidelines for interviews with intoxicated and substance using persons (see Evans et al, 2009 ; Crossland et al, 2018 ; Monds et al, 2021 ; Hagsand et al, 2022a , b ; Pettersson et al, 2022 ). As the first novel study on interrogations concerning low-stakes crimes related to alcohol and/or drugs, the present study provides useful information about current Swedish interrogation practices and areas for improvement.…”

“…The lack of national policy guidelines in some countries results in different interrogation practices across police stations and investigators within stations. In the case of drug- and alcohol-related crimes, police officers must use their own judgment when deciding when, how and where to interrogate/interview sober, alcohol- or drug-intoxicated suspects, witnesses and victims (see Evans et al, 2009 ; Crossland et al, 2018 ; Hagsand et al, 2022a , b ; Pettersson et al, 2022 ). Sweden currently differs from the neighboring Norway, as well as United Kingdom, in that there is no clear national policy for how interrogations should be carried out by the police.…”

The interrogator‐suspect dynamic in custodial interrogations for high‐stakes crimes in Sweden: An application of the interrogation taxonomy framework

“…In line with the current absence of a national policy on interrogation and investigative interview methods, samples of Swedish police officers recently self‐reported in surveys that they use their own subjective judgement when deciding on when, how, and where to interrogate suspects, witnesses, and victims of crimes (Hagsand, Evans, Pettersson & Schreiber Compo, 2022; Hagsand, Pettersson, Evans & Schreiber Compo, 2022; Pettersson, Bergquist & Hagsand, 2022). Further, a Scandinavian police survey on interrogations with suspects of child sexual abuse showed that the type of emotion interrogators experienced during an interview affected which interrogation tactics they used (Magnusson, Joleby, Luke, Ask & Lefsaker Sakrisvold, 2021).…”