Mom was wrong, UCLA/VA researcher concludes sleep not essential for learning

Following popular advice to sleep rather than study is unlikely to help a student ace the big exam, according to conclusions in a new review of REM sleep studies.

REM (rapid eye movement) sleep, or dreaming, plays little role in memory formation, according to a review of human and animal studies by UCLA/VA neuroscientist Dr. Jerome Siegel. The article appears in the Nov. 2 edition of the peer-reviewed journal Science.

“Sleep loss interferes with concentration. For this reason, cramming for exams during periods of sleep loss is not a good academic strategy. Similarly, taking exams while sleepy will interfere with performance. However, it does not appear that sleep is required for memory formation,” said Siegel, professor of psychiatry at UCLA and chief of neurobiology research at the VA Greater Los Angeles Healthcare System Sepulveda in North Hills, Calif.

“Glib advice to sleep rather than study may not improve learning,” Siegel said.

Scientists and sage parents long have hypothesized that REM sleep has an important role in memory consolidation. Siegel reviewed the scientific community’s evidence on this hypothesis and found that depriving animals and humans of REM sleep by awakening them or by drug treatments does not impair their ability to form long-term memories.

In particular, humans taking a class of drugs called MAO inhibitors that eliminate REM sleep for periods of months or years have unimpaired or even improved memory. Humans with brain damage that prevents REM sleep have normal memory.

In addition, the time spent in REM sleep does not correlate with learning ability across humans, nor is there a positive relation between amount or intensity of REM sleep and learning ability across species.

Animals with high amounts of REM sleep, such as the duck-billed platypus, are not especially smart. Conversely, some animals that are known to have impressive intellectual abilities, such as dolphins and whales, have little or no REM sleep. Humans do not have particularly high or low amounts of REM sleep, compared with other species.

There are many good reasons to sleep, before and after learning. Without sleep you may not safely make it to the exam or be able to concentrate during it. However, sleep does not appear to be essential to the learning process itself.

Sleep Patterns

Here is a comparison of number of hours of REM sleep and total sleep across the 24-hour cycle among various animals. Despite our unique learning capabilities, human REM and non-REM sleep parameters are not unusual and are in accord with our size and level of maturity at birth relative to other mammalian species.

SOURCE: Science, Nov. 2, 2001