The importance of the smallest effect size of interest in expert witness testimony on alcohol and memory

The influence of acute alcohol intoxication and hair visibility on delayed face recall

Many witnesses are intoxicated at crime scenes, yet little is known of their ability to accurately describe perpetrators to police. We therefore explored the impact of alcohol on delayed verbal face recall across two experiments. Participants were administered an alcoholic or non-alcoholic beverage prior to viewing either one or two unfamiliar female faces, which they described from memory the following day while in a sober state. Each to-be-remembered model had long hair worn either loose (i.e., visible), or tied behind the head (i.e., concealed). Testing the hypothesis that alcohol narrows the focus of attention to the external (hairstyle) region of faces, we expected intoxicated participants to have poorer memory of internal face features (eyes, nose, mouth) than sober controls for stimulus faces with visibly long hair. Results revealed poorer recall accuracy for internal face details following alcohol consumption (Exp. 2), but the effect was uninfluenced by hairstyle. Findings are therefore consistent with the more general view that alcohol is associated with a bias to the external (hairstyle) region of faces during face learning, irrespective of hair visibility.

Time and memory distrust shape the dynamics of recollection and belief-in-occurrence

The current study examined how people's metamemory judgments of recollection and belief-in-occurrence change over time. Furthermore, we examined to what extent these judgments are affected by memory distrust - the subjective appraisal of one's memory functioning - as measured by the Memory Distrust Scale (MDS) and the Squire Subjective Memory Scale (SSMQ). Participants (N = 234) studied pictorial stimuli and were tested on some of these stimuli later in the same session, but were tested on other stimuli 1, 2, 4, 8, and 17 days later. Recollection and belief ratings were correlated highly and followed similar declining patterns over time. However, belief decreased relatively more slowly than recollection, such that the discrepancy between recollection and belief increased over time. Memory distrust moderated the association between recollection and belief, with this association being weaker among people who reported greater (versus lower) memory distrust. Memory distrust also interacted with retention period to predict memory judgments. Two measures of memory distrust diverged in their predictive power. In particular, only the MDS predicted the spontaneous reporting of nonbelieved memories. Our results provide support to the theoretical perspective that belief-in-occurrence is a summative judgment informed not only by recollective phenomenology but also by metamemorial beliefs.

Self-relevance enhances susceptibility to false memory

Eyewitness testimony serves as important evidence in the legal system. Eyewitnesses of a crime can be either the victims themselves-for whom the experience is highly self-referential-or can be bystanders who witness and thus encode the crime in relation to others. There is a gap in past research investigating whether processing information in relation to oneself versus others would later impact people's suggestibility to misleading information. In two experiments (Ns = 68 and 122) with Dutch and Chinese samples, we assessed whether self-reference of a crime event (i.e., victim vs. bystander) affected their susceptibility to false memory creation. Using a misinformation procedure, we photoshopped half of the participants' photographs into a crime slideshow so that they saw themselves as victims of a nonviolent crime, while others watched the slideshow as mock bystander witnesses. In both experiments, participants displayed a self-enhanced suggestibility effect: Participants who viewed themselves as victims created more false memories after receiving misinformation than those who witnessed the same crime as bystanders. These findings suggest that self-reference might constitute a hitherto new risk factor in the formation of false memories when evaluating eyewitness memory reports.

Look into my eyes: a "faceless" avatar interviewer lowers reporting threshold for adult eyewitnesses

Evidential interviewing is often used to gather important information, which can determine the outcome of a criminal case. An interviewer's facial features, however, may impact reporting during this task. Here, we investigated adults' interview performance using a novel tool-a faceless avatar interviewer-designed to minimize the impact of an interviewer's visual communication signals, potentially enhancing memory performance. Adults were interviewed about the details of a video by (1) a human-appearing avatar or a human interviewer (Experiment 1; N = 105) or (2) a human-appearing avatar or a faceless avatar interviewer (Experiment 2; N = 109). Participants assigned to the avatar interviewer condition were (1) asked whether they thought the interviewer was either computer or human operated (Experiment 1) or (2) explicitly told that the interviewer was either computer or human operated (Experiment 2). Adults' memory performance was statistically equivalent when they were interviewed by a human-appearing avatar or a human interviewer, but, relative to the human-appearing avatar, adults who were interviewed by a faceless avatar reported more correct (but also incorrect) details in response to free-recall questions. Participants who indicated that the avatar interviewer was computer operated-as opposed to human operated-provided more accurate memory reports, but specifically telling participants that the avatar was computer operated or human operated had no influence on their memory reports. The present study introduced a novel interviewing tool and highlighted the possible cognitive and social influences of an interviewer's facial features on adults' report of a witnessed event.