Intoxicated Eyewitnesses: The Effects of Alcohol on Eyewitness Recall across Repeated Interviews

Abstract

The study evaluated the usefulness of repeat-interviewing of witnesses to crimes who were intoxicated by alcohol at the time of the incident and their first interview, and then re-interviewed when not intoxicated the following day. Sixty young, social drinkers were divided into three groups. One group was given a "placebo" (alcohol-like) beverage, a second was given a "low dose" of alcohol (0.2 g/kg men; 0.17 g/kg women), and a third was given a "high dose" of alcohol (0.6 g/kg men; 0.52 g/kg women) over a 15 minute period. Twenty minutes later they viewed a 4-minute video of a crime, and afterwards they were given two opportunities to recall everything that they could remember from the incident; the first opportunity was immediately after the event, and the second was 24 hours later. Analyses of the quantity and accuracy of the details recalled revealed no overall increase in the total amount of information recalled between the first and second recall opportunities. However, on average, 18% of the details recalled by participants in the second test were new and accurate. The incidence of contradictions between the first and second recall opportunities was less than 1%. Surprisingly, none of the effects were influenced by alcohol, even at the highest dose. The results imply that 1) memory for at least some incidents observed under the influence of alcohol is resilient even up to relatively high blood-alcohol levels; and 2) the repeated interviewing of witnesses who were intoxicated at the time of the crime can reveal additional, reliable information that is not present at the initial interview, just as is the case for non-intoxicated witnesses.

Interviewing intoxicated witnesses: Memory performance in theory and practice

“…The third study (La Rooy, Nicol & Terry, ) found that alcohol intoxication (low dose 0.2g/kg and high dose 0.6g/kg) did not affect the completeness or accuracy of reports made by witnesses to an unsuccessful robbery viewed on video. Interview time had no effect in this study, but it should be noted that all witnesses were interviewed twice, immediately after the event (during intoxication), and then again 24 hours later (when sober).…”

“…However, it is also possible that they instead may reminisce or be able to maintain fragmented memory sequences without filling the gaps with information suggested by the interviewer. So far, accuracy rates in the first and second interview have not differed among intoxicated witnesses (Hagsand et al ., ; La Rooy et al ., ). Regarding suggestibility, if previous research is an indicator, the level of suggestibility should depend on how certain they are of their memories’ accuracy.…”

“…Also, accuracy rate was somewhat lower in reports given one week later compared to in reports given immediately after the event, for both intoxicated and sober witnesses (Hagsand et al ., ; Hildebrand Karlén et al ., ; Yuille & Tollestrup, ). Interestingly, effect sizes in these studies indicate that the negative effect on report completeness in free recall due to interview delay seems to be more comprehensive than the corresponding negative impact of alcohol in an immediate interview (Hagsand et al ., ; Hildebrand Karlén et al ., ; LaRooy et al ., ; Yuille & Tollestrup, ). In other words, at these BAC‐levels, an intoxicated witness interviewed immediately after the event provided more information than a sober witness who was interviewed one week later.…”

“…This result has been replicated in previous research on alcohol intoxicated and sober persons within and outside a witness context (i.e., with material that is meaningful and experienced during arousal and during pharmacological influence) (for a discussion, Christianson, ; Hildebrand Karlén, ). Specifically, four studies have shown a beneficial effect of an immediate interview on amount of reported information in subsequent recall for intoxicated witnesses and their sober counterparts, with more complete reports given one week later (Hagsand et al ., ; Hildebrand Karlén, ; LaRooy et al ., ; Yuille & Tollestrup, ). Also, repetition (i.e., having given an interview immediately after the event) slightly increased the accuracy rate of reports given one week later for all witnesses, sober as well as intoxicated, in these studies.…”

“…(), intoxicated and sober witnesses interviewed immediately after the event reported an equal number of new details, at a similar accuracy rate, in the second interview one week later. The other studies (LaRooy et al ., ; Hildebrand Karlén et al ., ; Yuille & Tollestrup, ) did not report presence of old/new information separately in their results. Therefore, it is not clear whether the larger amount of information found in the reports given one week later by witnesses who also had been interviewed immediately after the event was due to the fact that: (1) new information was added one week later (i.e., the group interviewed repeatedly remembered and reported new information in their second interview); or (2) information was retained better over time by persons in the repeated interview groups compared to those in the delayed interview groups (i.e., the repeated interview group did not forget as much information over time as the delayed interview group did).…”