Rapid Eye Movement (REM) sleep enhances creative problem-solving says a leading expert on the positive benefits of napping.
Dr. Sara Mednick, assistant professor of psychiatry at UC San Diego and the VA San Diego Healthcare System, says that these findings may have important implications for how sleep, specifically REM sleep, fosters the formation of associative networks in the brain.
Working with Denise Cai, graduate student in the UC San Diego Department of Psychology, Mednick has shown that REM directly enhances creative processing more than any other sleep or wake state.
"We found that, for creative problems that you've already been working on, the passage of time is enough to find solutions. However, for new problems, only REM sleep enhances creativity," said Mednick.
The researcher further said that it appeared that REM sleep helps achieve such solutions by stimulating associative networks, allowing the brain to make new and useful associations between unrelated ideas.
Importantly, added the researcher, the study showed that these improvements are not due to selective memory enhancements.
During the study, the research team used a creativity task called a Remote Associates Test (RAT) to show the subjects multiple groups of three words-for example, cookie, heart, sixteen-and asked them to find a fourth word that could be associated to all three words-sweet, in this instance.
The researchers tested the participants in the morning, and again in the afternoon, after either a nap with REM sleep, one without REM or a quiet rest period. They manipulated various conditions of prior exposure to elements of the creative problem, and controlled for memory.
"Participants grouped by REM sleep, non-REM sleep and quiet rest were indistinguishable on measures of memory. Although the quiet rest and non-REM sleep groups received the same prior exposure to the task, they displayed no improvement on the RAT test. Strikingly, however, the REM sleep group improved by almost 40 percent over their morning performances," said Cai.
The authors hypothesize that the formation of associative networks from previously unassociated information in the brain, leading to creative problem-solving, is facilitated by changes to neurotransmitter systems during REM sleep.
The findings have been published in the online edition of the Proceedings of the National Academy of Sciences (PNAS).