Kimberly Fenn, associate professor at Michigan State University, and lead author of the study. Photo credit: G.L. Kohuth.You’ve been up all night – your mind is reeling. You’re getting asked questions, again and again, about something you didn’t do. The fatigue is agonizing. Do you tell your interrogators what they want to hear – just to make it all stop?

Sleep deprivation leads to increased rates of false confessions, according to a new study by a team of psychologists. Subjects who were kept up 24 hours were 4.5 times more likely to sign a false confession than those who had a full night’s sleep, according to the paper, in the latest Proceedings of the National Academy of Sciences.

The social experiment is the first of its kind to demonstrate how extreme fatigue may lead to false confessions – thought to account for between 15 and 25 percent of wrongful convictions in the United States.

“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 Fenn, associate professor of psychology at Michigan State University, and lead author. “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.”

Read more: The Truth behind False Confessions: An Interview with Saul Kassin

The experiment involved a much-smaller scale of confession. Eighty-eight participants were given various computer activities and cognitive tests over the course of a week. Over the days they were continually warned not to press the “escape” key – since it would erase valuable data for the project.

Before the final day of the experiments, half the subjects were kept awake overnight, while the other half received a full eight hours of sleep. All were then confronted with a bogus charge: that they had pressed the forbidden key. They were given a statement to sign confessing to the act.

Half of the sleep-deprived people signed that document, compared with only 18 percent of the subject who slept the night before, they found.

Although the stakes for the escape key experiment are completely different than that of a serious crime accusation meaning years in prison, the experiments show a microcosm of pressures at play in the real interrogations, said Steven Frenda, one of the authors from New School for Social Research. He said the same processes are at play in extreme situations: compliance, suggestibility, and impulsivity.

"We recognize that this scenario may differ in important ways from teh situation a suspect may face in an interrogation room," the authors write. "Nonetheless, to the extent that the same psychological processes are implicated both by laboratory studies and real-life interrogations, our findings have important implications for policies and procedures related to interrogations, particularly those involving innocent suspects."

A noted confession expert told Forensic Magazine about the phenomenon of false confessions last year. Saul Kassin, of the John Jay College of Criminal Justice, spoke about how the Reid Technique of getting suspects to confess crimes involves a process of diminishing the anxiety of confessing, while increasing the anxiety of continuing to hold out against questions. The Reid Technique, which was first published in a textbook in 1962, doesn’t involve physical violence – but can incorporate long hours of questioning without rest, said Kassin (who also happened to be a reviewer of the latest study).

“People are responsive to reward and punishment, and are likely to choose an immediate reward. Getting out of a bad situation now becomes more impactful than what is going to happen to me down the road,” Kassin told Forensic. “Interrogators minimize what’s going to happen to the suspect to them in the future and focus on the immediate reward,”

Sleep deprivation has been used for centuries as a mechanism of interrogation. The CIA’s “enhanced interrogation techniques” were recently revealed to include keeping prisoners awake for long periods, in addition to waterboarding and rectal feeding.

Fenn and her co-authors from the New School for Social Research, California State University, and the University of California, Irvine, had several recommendations. Foremost among them was videotaping full interrogations to give judges and juries a full view of the subject’s mental and physical state at the moment of confession.

“A false admission of wrongdoing can have disastrous consequences,” the authors write. “We are hopeful our study is the first of many to uncover the sleep-related factors that influence processes related to false confession.”