The Sleeping Witness – Sleep’s Effect on Memory in a Witness Situation

Sammanfattning: Previous studies have shown that sleep strengthens memory. The current study has put this into a real-life context and study sleep’s effect on witness testimony. The 18 participants watched a video of a fictitious assault, and after a 12-hour delay, where half stayed awake during the day, and half slept during the night. They answered a questionnaire about the video, as a memory test. The questions were divided into different categories of interest such as facts surrounding the assault, time estimation of e.g. the duration of the assault, and the aggressiveness of the perpetrators. The participants were then asked to identify a perpetrator in a picture line-up. They also reported their confidence estimation for each answer they gave. The results showed that there was no significant difference between the groups’ memory performance for fact questions, time estimations, aggressiveness estimations or the ability to identify a perpetrator in a line-up. Even though sleep did not improve overall memory performance, it made the participants who slept rate their confidence in their answers higher. Conclusion: sleep did not improve memory, affect the perceived aggressiveness, or identification in the line-up, but it did increase the confidence estimation of the sleeping participants’ answers.