Yawning much? Is it time for another coffee break? Not sleeping enough doesn’t just hurt your focus and productivity, turns out, it could hurt your memory too. Sleep-deprived people may think they’ve witnessed something that never happened, according to a study published in Psychological Science.
In case you missed this video from a few days ago, seven to eight hours a night is about right for most people. There’s overwhelming evidence that the lack of sleep impairs cognitive function, though few have investigated the role of sleep deprivation in the formation of false memories. “I was surprised to find that there were so few empirical studies connecting sleep deprivation with memory distortion in an eyewitness context,” Steven Frenda from University of California, Irvine, says in a news release. “The studies that do exist look mostly at sleep deprived people’s ability to accurately remember lists of words -- not real people, places and events.”
To gauge the effect of insufficient sleep on memory, Frenda and colleagues kept college students awake for 24 hours to see how likely they’d mix up event details. They assigned 104 volunteers into one of four groups late one evening. Two groups were shown a series of photos depicting a crime being committed: a man stealing a wallet. One of those groups got to go to bed right away, while the other group stayed awake all night in the lab. The remaining two groups did it in reverse: One slept as the other stayed awake, and they all viewed the crime photos in the morning.
In the next part of the experiment, the participants read narratives containing statements that contradicted what the photographs showed. A description might, for example, say that the thief put the stolen wallet in his pants pocket -- but the photos showed him putting it in his jacket.
Students who had been sleep deprived for the entire experiment -- viewing the photos and reading accounts of the crime -- were more likely to report the false details from the narrative as having happened in the crime photos. Those who viewed the photos before staying up all night, however, were no more susceptible to false memories than the students who had been allowed to sleep.
“We found memory distortion is greater after sleep deprivation,” says study coauthor Kimberly Fenn from Michigan State in a university release. “And people are getting less sleep each night than they ever have.”
According to the Centers for Disease Control and Prevention, insufficient sleep is a public health epidemic, linked to vehicle crashes, industrial accidents, medical errors, and chronic diseases like high blood pressure and diabetes. Sleep deprivation, these findings indicate, could make you remember fake details as actually having happened -- distorting your memories and making you a bad eyewitness.