What increases the likelihood of signing a false confession? Sleep is key, say Michigan State University researchers. In their new study, sleep-deprived participants were 4.5 times more likely than those who slept to sign untrue allegations.

“False confessions are thought to account for approximately 15 to 25 percent of wrongful convictions in the United States,” wrote Psychologist Kimberly M. Fenn, associate professor, and her colleagues. By their definition, a false confession occurs whenever “an innocent person makes a false admission of guilt and subsequently produces a postadmission narrative, which includes details about how or why the crime was committed.” A confession is a powerful form of evidence with serious consequences, even without an accompanying narrative. According to Fenn, even when jurors understand a confession has been coerced, the taint of self-incrimination lingers.

To study this phenomenon more closely, Fenn and her colleagues encouraged 88 undergraduates to participate in their study. Following cognitive testing, participants completed various computer activities during several laboratory sessions conducted throughout a single week. The students were given several warnings not to hit the “escape” key because “this could cause the computer to lose valuable data.”

During the final 24 hours, half of the participants stayed awake overnight performing tasks on the computer, while the other half slept for eight hours. The next morning, participants were shown summaries of their activities, which included a false allegation that they'd pressed the escape key. After reading this misrepresentation, each student was asked to check a box confirming the statement's accuracy and then sign their name.

Dramatically, half the sleep-deprived participants signed the false confession, while only 18 percent of rested participants did so.

Requested once again to sign the false statement, nine additional rested participants signed (for a total of 39 percent) and eight additional sleep-deprived participants did so (for a total of 68 percent).

Real World

The researchers note their experiment cannot equal what a suspect may face in an interrogation room. At the same time, they noted "sleep deprivation may increase confession rates of both innocent and guilty suspects." This being the case, the team suggests law enforcement officials carefully weigh possible benefits and possible risks of these interrogation room tactics. However, no matter whether participants were in the sleep-deprived group or not, anyone who indicated fatigue on the Stanford Sleepiness Scale were significantly more likely to sign off on the false allegation, Fenn and her colleagues say. They recommend this simple, one-question-tool be used in real-world interrogations to designate those who might be at heightened risk of compromising their own testimony.

A 2007 survey of 631 police investigators working in Los Angeles, Boston, Miami, Tampa, counties in Texas, and Quebec revealed not only their interrogation practices but also their personal beliefs. As many as 17 percent of interrogations, which last, on average, 1.6 hours, occur overnight during typical sleep hours, the results indicated. Investigators said they elicit self-incriminating statements from 68 percent of suspects including nearly 5 percent who are innocent.

Overall, 81 percent of these professionals believe interrogations should always be recorded, according to the Law and Human Behavior survey.

Source: Frenda SJ, Berkowitz SR, Loftus EF, Fenn KM. Sleep deprivation and false confessions. Proceedings of the National Academy of Sciences. 2016.