According to a new research on the positive benefits of napping, Rapid Eye Movement (REM) sleep can enhance the creative problem-solving ability of people. This research was conducted at the University of California, San Diego School of Medicine, by Sara Mednick, assistant professor of psychiatry at UC San Diego and the VA San Diego Healthcare System and first author Denise Cai, graduate student in the UC San Diego Department of Psychology. The findings of the study are published in the June 8, 2009, online edition of the Proceedings of the National Academy of Sciences (PNAS).

Highlights of the study
a. This study was conducted on 77 volunteers.
b. Researchers used a creativity task called a Remote Associates Test (RAT) in this study.
c. Participants were shown multiple groups of three words (like cookie, heart and sixteen) and asked to find a fourth word that can be associated to all three words (sweet, in this instance).
d. Participants were tested in the morning and again in the afternoon after either a nap with REM sleep, one without REM or a quiet rest period.
e. Various conditions of prior exposure to elements of the creative problem were manipulated by the researchers and controlled for memory.
f. It was seen that participants grouped by REM sleep, non-REM sleep and quiet rest were indistinguishable on measures of memory.
g. 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.
h. However, the Improvement of the REM sleep group was almost 40 per cent when compared to their morning performances.
i. This, researchers believe, is due to the fact that REM sleep allows the brain to form new nerve connections without the interference of other thought pathways that occur when we are awake or in non-dream-state sleep.