Study shows sleep helps improve memory

Forget about pulling an all-nighter before an exam -- a study suggests it's more important to get a good night's rest. Harvard Medical School researchers, led by assistant professor of psychiatry Robert Stickgold, found that people who slept after learning and practicing a new task remembered more about it the next day than people who stayed up all night after learning the same thing. The study will be published in the December 2000 issue of Nature Neuroscience, was released today.

The study is another piece in a growing body of evidence that suggests proper rest is necessary for learning. "We think getting that first night's sleep starts the process of memory consolidation," Stickgold said. "It seems that memories normally wash out of the brain unless some process nails them down." The 24 participants were trained to identify the orientation of three diagonal bars flashed for one-sixtieth of a second on a horizontal-striped computer screen. Half of the participants went to sleep that night. The others were kept awake until the second night of the study. Both groups were allowed to sleep on the second and third nights.

On the fourth day, both groups were tested on how proficient they had become at identifying the orientation of the diagonal bars. Those who slept on the first night performed better than they had the first day. Those who didn't sleep did not improve "We don't know a lot about sleep, but we do know that it's useful in terms of deciding what information is useful and what's superfluous and can be discarded," said Joseph Modrack, an assistant professor of sleep medicine at the University of Rochester. "This study makes a lot of sense."