Not getting enough sleep could lead to the formation of false memories.

Sleep-deprived people who viewed photographs of a crime being committed and read false information about them were more likely to report remembering the false details compared with those who got a good night's sleep, the Association for Psychological Science reported. The findings were published recently in the journal Psychological Science.

"Over the years I noticed that whenever I had a bad night's sleep, my perception and memory seemed to get fuzzy until I had a good recovery sleep," Steven J. Frenda of the University of California said. "I was surprised to find that there were so few empirical studies connecting sleep deprivation with memory distortion in an eyewitness context. 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."

A preliminary study suggested getting five hours of sleep or less was associated with the formation of false memories. The team then decided to see how pulling an all-nighter changed these results.

In the more recent study 104 college-age participants were assigned to one of four groups: two were presented with crime photos as soon as they entered the lab. One group was then allowed to sleep while the other had to stay up all night in the lab. The other two groups did this in the reverse order, viewing the photographs in the morning.

In the second part of the experiment the participants read narrative statements that contradicted what the photos showed. The team found only the students had been sleep deprived before viewing the photos were more likely to report the false details instead of what they had actually seen.

"Recent studies are suggesting that people are getting fewer hours of sleep on average, and chronic sleep deprivation is on the rise," Frenda said. "Our findings have implications for the reliability of eyewitnesses who may have experienced long periods of restricted or deprived sleep."

"We are running new experiments now, in order to better understand the influence of sleep deprivation on processes related to false memory," he concluded.