Sleep deprivation increases chances of false crime confessions, study finds
Sleep deprivation greatly increases the chances of an innocent suspect confessing to a crime, a study has found.
Tests on volunteers showed that participants who had been kept awake for 24 hours were 4.5 times more likely to sign a false confession than those who had enjoyed eight hours' sleep.
The findings have far-reaching implications for police forces, military authorities and other agencies that engage in questionable interrogation techniques.
Lead researcher Dr Kimberly Fenn, a psychologist from Michigan State University in the US, said: "This is the first direct evidence that sleep deprivation increases the likelihood that a person will falsely confess to wrongdoing that never occurred.
"It's a crucial first step toward 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."
In the US, false confessions are thought to account for 15-25% of wrongful convictions.
For the study, 88 volunteers undertook various computer tasks and a mental test over the course of a week.
Participants were warned not to hit the "escape" key because it could cause the computer to "lose valuable data".
At the end of the experiment, half the volunteers slept for eight hours while the other half spent the night awake.
The next morning, each participant was shown a statement falsely alleging that he or she had hit the escape key. Every volunteer was asked to check the statement for accuracy and sign it.
Strikingly, half the sleep-deprived participants signed the false confession compared to only 18% of those who had been allowed to rest.
Those volunteers who achieved lower scores in the mental ability test were much more likely to sign.
Writing in the journal Proceedings of the National Academy of Sciences, the authors conclude: "A false admission of wrongdoing can have disastrous consequences in a legal system already fraught with miscarriages of justice.
"We are hopeful that our study is the first of many to uncover the sleep-related factors that influence processes related to false confession."