Experiment contradicts assumptions about sleep loss and criminal interrogations

Preliminary results show that even mildly sleep-restricted participants provided around 7% less information during their initial disclosure. Sleep-restricted individuals also reported less overall motivation to recall information.

"Historically, sleep has been used as a tool to compel disclosure or confessions, while sleep loss remains common among interview subjects such as victims or witnesses," said lead author Zlatan Krizan, who has a doctorate in personality and social psychology and is a professor of psychology at Iowa State University in Ames, Iowa. "However, there was little direct, scientific evidence on whether sleep enhances or inhibits intelligence disclosures during investigative interviews prior to this study. These findings carry direct implications for science and practice of investigative interviewing and contradict longstanding assumptions about the role of sleep in gathering human intelligence."

The study involved 120 healthy participants who were recruited from the university community. They were assigned to maintain or restrict their sleep for two days, with objective estimates of sleep duration gathered using actigraphy. Sleep-restricted participants slept 4.5 hours less on average, losing about one night of sleep over two days. Following the sleep manipulation, participants were interviewed about past illegal acts they admitted to.

According to the authors, the results suggest that even moderate sleep loss can inhibit criminal disclosure during interviews.

The research abstract was published recently in an online supplement of the journal Sleep and will be presented as a poster Aug. 28-30 during Virtual SLEEP 2020. SLEEP is the annual meeting of the Associated Professional Sleep Societies, a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.