Lack of sleep 'increases risk of false memories'

Past research has claimed lack of sleep can cause memory loss. Now, in what is deemed a first-of-its-kind study, researchers from the University of California-Irvine and Michigan State University suggest sleep deprivation could increase susceptibility to false memories.

Sleep deprivation could increase the risk of false memory formation - the recall of an event that never occurred - according to researchers.

The research team of the Department of Psychology and Social Behavior at UCI, recently published their findings in the journal Psychological Science.

The researchers note that although lack of sleep has been associated with impaired cognitive functioning, very few studies have investigated whether sleep deprivation contributes to false memories - the recall of an event that never happened.

The team 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.

In a preliminary study, the research team found that sleeping for 5 hours or less a night was linked to false memory formation. But the team wanted to delve deeper. They developed a test to investigate how getting no sleep at all affected the formation of false memories.

24-hour sleep deprivation 'led to false memory formation' on misinformation test

The research team enrolled 104 participants of college age to a misinformation test and divided them into four groups.

For the first part of the test, a variety of photos showing a crime taking place was shown to two of the groups upon arrival at a laboratory late at night. One of the groups was allowed to sleep, while the other group was required to stay awake throughout the night.

The other two groups - one of which was allowed to sleep while the other was required to stay awake - reviewed the crime photos the morning after rather than the night before.

The next part of the experiment required all participants to read narratives of eyewitness statements that gave different information to what the crime photos showed. For example, one of the statements said a thief put a stolen wallet in the pocket of his pants, when the photo showed he put it in his jacket. Participants were then asked to recall what was shown in the photos.

The researchers found that the group who looked at the photos, read the narratives and attempted to recall the photos after staying awake all night, were more likely to say that the details in the narratives were present in the photos - indicating false memory formation.

However, the participants who looked at the photos prior to staying awake all night were found to be no more likely to report false memories than the groups that were allowed to sleep.

The team's findings could have important implications for legal matters:

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

However, the researchers note that before researchers can present such findings to law enforcers and recommend ways to ensure the accuracy of eyewitnesses' memories, further research is warranted - something he says is currently under way.

Another team of researchers recently reported on a study that suggested lack of sleep can speed up the aging brain in older individuals.