Sleep deprived people are more likely to falsely confess to wrongdoings that never occurred, according to a new groundbreaking study that has important implications for police interrogation practices.
The odds of signing a false confession were 4.5 times higher for participants who had been awake for 24 hours than for those who had slept eight hours the night before, researchers found. “This is the first direct evidence that sleep deprivation increases the likelihood that a person will falsely confess to wrongdoing that never occurred,” said Kimberly M Fenn, associate professor at Michigan State University.
“It’s a crucial first step towards understanding the role of sleep deprivation in false confessions and, in turn, raises complex questions about the use of sleep deprivation in the interrogation of innocent and guilty suspects,” Fenn said. False confessions in the US are thought to account for 15-25 per cent of wrongful convictions. Previous research has indicated that the interrogation of unrested, possibly
sleep-deprived suspects is commonplace.
For the study, 88 participants completed various computer activities and a cognitive test during several laboratory sessions over a week-long period. Participants were given several warnings not to hit the “escape” key because “this could cause the computer to lose valuable data.” Participants were monitored during the tasks. On the final day of the experiment, half of the participants slept for eight hours while the other half stayed awake overnight.
The next morning before leaving the lab, each participant was shown a statement summarising their activities and falsely alleging the participant had pressed the escape key. Participants were asked to sign the statement, check a box confirming its accuracy and sign their name. The results were striking: 50 per cent of sleep-deprived participants signed the false confession, while only 18 per cent of rested participants signed it.
Further, sleep deprivation had a significant effect on participants who scored lower on the Cognitive Reflection Test, which is related to intelligence. Those participants were much more likely to sign the false confession. The study was published in the journal PNAS.