Insufficient Sleep May Cause False Memories

Being deprived of sleep or sleeping too little impaired memory in recent study

(RxWiki News) People often feel foggy when they haven't gotten enough sleep, and new research suggests a lack of sleep could significantly impair memory.

Lacking sleep can distort people’s memories, causing them to imagine some events and misremember what really happened, new research shows.

"Seek medical care if you have consistent trouble sleeping at night."

This research was conducted by Kimberly Fenn, PhD, associate psychology professor at Michigan State University, and colleagues.

The researchers conducted two experiments comparing memories in those who slept at night and those who either did not sleep at all or slept fewer than six hours. They found that people who slept less were not as likely to remember events as accurately as those who had adequate sleep.

In the first experiment, researchers asked 194 students at the University of California in Irvine to participate in two parts. These students reported on how much sleep they had and then took part in the tests. The 28 students who reported five hours of sleep or fewer were in one group, and the remaining participants were in the other.

In the first part, the students read about a plane that crashed and watched videos depicting the crash site but not the actual crash. They were later asked if they had seen video footage of the plane crashing.

Those who had not slept more than five hours were more likely to say they had seen the video when they had not, compared the well-rested participants (54 percent versus 33 percent). In a follow-up interview, however, similar numbers of people in both groups reported they had seen the video.

In the second part of the experiment, participants looked at photos of two crimes and, about 40 minutes later, read two texts about what they had seen, with some misinformation.

Finally, participants answered multiple-choice questions (with three possible answers for each) about what they had seen in the photos.

Those who had slept little incorporated misinformation into what they recalled of the photos they had seen 38 percent of the time, which was more than those who were rested (28 percent of the time).

For the second experiment, 104 students at Michigan State University took part in a study where they were either deprived of sleep for 24 hours or permitted to sleep for eight hours in the lab. They took part in the same tests as the students in California — but with a twist.

Part of the group did part of the tests in the evening, where they were not given misinformation but read the news item or saw the pictures. In the morning, they were given misinformation and completed the tests. The other part of the group did the entire test in the morning.

Those who did part of the test the night before, when rested, did as well as those who had slept the night when they completed the tests in the morning. However, those who had not done any of the test the night before and were deprived of sleep performed worse on the test than everyone else.

Those who had not slept incorporated more false suggestions into their memories, suggesting that sleep deprivation may prevent events from making a lasting impression on the brain.

In all the experiments, sleep deprivation appeared to increase the risk of false memories, the researchers concluded.

“People who repeatedly get low amounts of sleep every night could be more prone in the long run to develop these forms of memory distortion,” Dr. Fenn said in a press release. “It’s not just a full night of sleep deprivation that puts them at risk.”

This study appeared in the July issue of Psychological ScienceThe authors did not disclose any conflicts of interest.

Review Date: 
July 23, 2014