A person who has been awake for 24 hours is 4.5 times more likely to falsely confess to a crime than a fully-rested person who had a proper eight hours of sleep, a new study has found.
The study, led by Michigan State University's Kimberly M. Fenn, was published Feb. 8 in the Proceedings of the National Academy of Sciences, an academic journal.
"This is the first direct evidence that sleep deprivation increases the likelihood that a person will falsely confess to wrongdoing that never occurred," Fenn said, according to Science Daily. "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."
Fenn's findings mirror a 2014 study that showed sleep deprivation can lead to the creation of false memories. In that study, researchers found that people didn't need to miss a night of sleep for their memories to become more pliable -- participants who slept five hours or less were susceptible to having their memories warped, said Steven Frenda, a psychologist at the UC Irvine who led that study.
"Sometimes memory distortions are trivial and don't matter, but there are contexts (e.g., eyewitnesses in court, clinicians making medical decisions) where errors have serious consequences, so we need to be concerned about factors that make memory less reliable, and more vulnerable to distortion," Frenda wrote in an email to the Huffington Post.
As the New Scientist points out, pliable memories can have disastrous consequences in criminal courts. The publication cited the case of Damon Thibodeaux, who spent 15 years on death row after he was wrongfully convicted of raping and killing a 14-year-old girl. Although DNA evidence eventually freed him, police were able to convince Thibodeaux to confess to the crime after long hours of interrogation.
“To the average person it’s inconceivable how a false confession can happen,” Saul Kassin, a criminologist at John Jay College of Criminal Justice in New York, told the New Scientist.
Depriving suspects of sleep is a standard interrogation tool used by police and military interrogators. Sleep-deprived suspects who confess to crimes see their confessions as temporary measures, Kassin said, buying them time away from the interrogation after long hours of questioning.
“They believe that in the end they won’t have to pay for the confession," Kassin said.