The Sleepy Eyewitness: Self-Reported Sleep Predicts Eyewitness Memory

• Published in: Journal of applied research in memory and cognition Vol. 12; no. 4; pp. 513 - 530
• Main Authors: Carlson, Maria A., Carlson, Curt A., Fitzsimmons, Corinne L.
• Format: Journal Article
• Language: English
• Published: Washigton Educational Publishing Foundation 01.12.2023; Society for Applied Research in Memory and Cognition
• Subjects: Crime; Female; Human; Male; Memory; Recall (Learning); Self-Report; Sleep; Sleepiness; Witnesses; sleep; eyewitness identification; eyewitness recall; discriminability; confidence-accuracy relationship
• ISSN: 2211-3681; 2211-369X
• DOI: 10.1037/mac0000076

Sleep is critical for memory, but research indicates that eyewitness identification may be an exception. We conducted three experiments to assess the effect of self-reported sleep duration and quality the night before a mock-crime video, and current sleepiness, on eyewitness recall and identification. We found that duration and quality strongly predicted the recall of central details, but only weakly predicted the recall of peripheral details. Those reporting long duration or high quality had higher discriminability than those reporting short duration or low quality, for both lineups and showups in single-session experiments. Based on a two-part experiment, we found that poor sleep the night before a crime may be more impactful than sleep the night before an ID procedure. We conclude that self-reported sleep could be an important individual difference variable for eyewitness memory. General Audience Summary It is well-known that sleep is important for memory, but it is unclear how important it is for eyewitness memory. Could police ask eyewitnesses how well they slept the night before a crime, with the answers predicting their ability to accurately recall crime details and to make a correct identification decision later from a showup or lineup? We addressed this question across three experiments with large demographically diverse online samples. Participants viewed a mock-crime video then were asked about the duration and quality of sleep the night before and also how sleepy they were. Later, they were asked to recall details about the video and also to make an identification decision from a lineup (Experiments 1 and 3) or showup (Experiment 2). When everything took place in a single session (Experiments 1 and 2), those reporting better sleep the night before were better able to recall important crime details, such as what the perpetrator was wearing and what he was doing with his hands. Moreover, well-rested participants were more likely to correctly identify the perpetrator from a lineup or showup and were especially more likely to reject a lineup or showup containing an innocent suspect instead of the perpetrator. Experiment 3 presented the recall questions and lineup 2 days after the mock-crime video, and though there was still an effect of sleep the night before the lineup on recall, there was no longer any effect on identification accuracy. This informs us that sleep the night before a crime may be especially important, more so than sleep the night before police present an identification procedure like a lineup. We conclude that it may be beneficial for police to ask eyewitnesses simple sleep questions after a crime, as their answers could be predictive of the quality of eyewitness evidence they provide.