Interviewing intoxicated witnesses: Memory performance in theory and practice

The impact of post-encoding alcohol consumption on episodic memory recall and remember-know responses in heavy drinkers

Introduction

People often consume alcohol following trauma, particularly in response to distressing memories. To date, little is known about how post-encoding alcohol consumption influences episodic memory recall for negative events. Understanding these effects may help to improve support for trauma victims - for example, witnesses and victims of crimes.

Methods

We tested 60 participants who self-described as heavy drinkers. After watching an analog trauma film, half were allocated to consuming a moderate dose of alcohol (Alcohol-Exposed group), while half received a placebo drink (Placebo-Control group). Immediately and after a one-week delay, participants recalled the event via free and cued recall tasks. Participants also gave remember-know responses and confidence ratings, elucidating alcohol's effect on experiential memory.

Results

Free recall performance was similar for the Alcohol-Exposed group and the Placebo-Control group during Sessions 1 and 2. The Alcohol-Exposed group benefitted more from the delayed repeated retrieval attempt. For the cued recall task, the Alcohol-Exposed group provided more "Do not Know" responses compared to the Placebo-Control group in both sessions. For the Alcohol-Exposed group only "Correct Know" responses increased from Session 1 to 2. Although memory performance improved across sessions, confidence levels decreased from Session 1 to 2 in the Alcohol-Exposed group.

Discussion

Post-encoding alcohol consumption appears to impact immediate episodic memory retrieval; however, this effect is only temporary in nature. No evidence was found that alcohol primarily reduces remembering responses. Much like previous findings focusing on pre-encoding alcohol consumption (Hagsand et al., 2017), current findings suggest that providing individuals who drank alcohol after witnessing an incident with a delayed repeated retrieval attempt can lead to more complete and accurate testimonies.

Improving intoxicated witness recall with the Enhanced Cognitive Interview

RATIONALE

Witnesses and victims typically provide the central leads in police investigations, yet statistics from past research indicates in many instances these individuals are intoxicated.

OBJECTIVES

To date, however, no research has looked at how best to interview such witnesses to maximise the amount of accurate information they recall.

METHODS

In the present research, whilst on a night out, participants watched a videoed theft whilst either sober or moderately (MBAC = 0.05%) or severely (MBAC = 0.14%) intoxicated. A week later, in a different location, participants were interviewed using either the Enhanced Cognitive (ECI) or Structured Interview.

RESULTS

The ECI was found to improve the recall accuracy and completeness of witness accounts across all three drinking conditions. However, no significant interaction was indicated between alcohol and interview condition.

CONCLUSIONS

The study findings are discussed in terms of their real-world value in aiding police officers to elicit as complete and as accurate an account as possible from intoxicated witnesses.

Observing Alcohol Myopia in the Context of a Trauma Film Paradigm: Differential Recall of Central and Peripheral Details

BACKGROUND

A major tenet of the alcohol myopia model is that intoxication results in a narrowing of attention to the most central environmental cues, at the cost of more peripheral information. Though long hypothesized, no known study of alcohol myopia has demonstrated differential immediate recall of central and peripheral cues using a standardized task. To address this gap, we conducted an alcohol administration study with a clear, standardized focus-a trauma film.

METHODS

Ninety-eight female social drinkers completed self-report measures, and then were randomized to consume a placebo beverage, a low dose of alcohol (mean breath alcohol concentration [BrAC] = 0.04%), or a high dose of alcohol (mean BrAC = 0.11%). Participants then moved to a staged room where they viewed a film clip depicting a sexual assault. After leaving the room, participants completed a written free recall task of the film and the room.

RESULTS

The distinction between recall of central and peripheral details was supported by confirmatory factor analysis. Consistent with the alcohol myopia model, relative to placebo, a high dose of alcohol led to impaired recall of peripheral (but not central) details. Although the interaction between BrAC and information type (central vs. peripheral) was not statistically significant, simple effects revealed a strong association between BrAC and peripheral information, and no association between BrAC and central information. Bolstering myopia as an explanation for our findings, neither central nor peripheral information correlated with self-reported tendencies to dissociate or distract oneself, or typical alcohol consumption or expectancies.

CONCLUSIONS

Alcohol myopia can be observed through an immediate free recall task following a stressful film. Additional research is needed to continue evaluating dose-dependent differential recall in larger samples. This task may be useful for clarifying the role of alcohol myopia in clinical phenomena, such as aggressive behavior and processing traumatic events.

Do intoxicated witnesses produce poor facial composite images?

RATIONALE

The effect of alcohol intoxication on witness memory and performance has been the subject of research for some time, however, whether intoxication affects facial composite construction has not been investigated.

OBJECTIVES

Intoxication was predicted to adversely affect facial composite construction.

METHODS

Thirty-two participants were allocated to one of four beverage conditions consisting of factorial combinations of alcohol or placebo at face encoding, and later construction. Participants viewed a video of a target person and constructed a composite of this target the following day. The resulting images were presented as a full face composite, or a part face consisting of either internal or external facial features to a second sample of participants who provided likeness ratings as a measure of facial composite quality.

RESULTS

Intoxication at face encoding had a detrimental impact on the quality of facial composites produced the following day, suggesting that alcohol impaired the encoding of the target faces. The common finding that external compared to internal features are more accurately represented was demonstrated, even following alcohol at encoding. This finding was moderated by alcohol and target face gender such that alcohol at face encoding resulted in reduced likeness of external features for male composite faces only.

CONCLUSIONS

Moderate alcohol intoxication impairs the quality of facial composites, adding to existing literature demonstrating little effect of alcohol on line-up studies. The impact of intoxication on face perception mechanisms, and the apparent narrowing of processing to external face areas such as hair, is discussed in the context of alcohol myopia theory.