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Interviewees: Matt Hall, Sleep Study Volunteer and Sara Mednick
In Your Dreams
Now new research is illuminating the role of REM sleep — the sleep stage in which dreams occur– in creative problem solving.
In their study of 77 healthy volunteers, University of California, San Diego sleep researchers researchers Sara Mednick, Denise Cai, and their colleagues found that a daytime nap boosts performance on a standard test of creative problem solving, but only if the nap includes REM, or rapid-eye-movement sleep.
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"This is the first time that REM sleep has ever been shown to be directly connected to a boost in creativity, and also that this is done in a daytime nap," says Mednick.
She hopes the study adds some insight into insight for scientists and the public.
"If REM sleep is helping solve creative problems, then there’s something specific about the associative networks that occurs during REM sleep that allows these unconnected bits of information to finally connect and associate," she says. "That’s interesting from its own basic science perspective."
From a more applied way, we’re at a university where we’re always trying to be more creative, we’re always trying to reach a new interesting solution to science or whatever it is that you’re studying, and I think when you get to have a piece of data that shows if you take a nap with REM sleep, you’re actually going to be boosting your ability to make these new associations in creative ways, I find that to be very exciting to be able to share that with people."
The researchers gave volunteers a standard test of creative problem solving in the morning and again in the afternoon.
Called the "Remote Associates Test," or "RAT" for short, its problems consist of sets of three unrelated words, like "cookie, heart, and sixteen." The solution is a fourth word that relates them– in this example, "sweet."
"So you’re making a new and useful association which is the definition of creativity." Mednick explains.
In between tests, volunteers were wired with electrodes to reveal their brainwaves, which characterize our sleep stages. Then they got to visit the nap lab, but not everybody got a nap. Some sat in a recliner for some quiet meditation but were not allowed to nod off. Others got a nap, but were not allowed to reach REM, which only occurs after 60 minutes of sleep. A third group got a 90-minute nap that included REM sleep.
As the researchers wrote in the Proceedings of the National Academy of Sciences early online edition, only those who got REM sleep improved their performance in the later test session.
The researchers had all of the volunteers wear watch like devices called actigraphs to make sure their sleep cycles were normal leading up to the experiment. They also ruled out differences in memory.
"We examined whether people in the REM sleep group had better memory for what they saw in the morning than the non-REM or quiet rest group, and there was no difference in memory between the three groups," says Mednick. "So it looked as though, even though there was no difference in memory, the people in the REM group were more able to utilize information from the morning to answer their creativity problems in the afternoon."
Mednick says during REM, information can flow freely among different brain networks involved in learning and memory.
"Specifically, with REM sleep, there seems to be information flow between an area called the hippocampus, which is very important for learning or (episodic) memories of our own experiences… and the neocortex, which is more for the associative processes," Mednick explains.
She says this research supports the hypothesis that "during REM sleep, you actually have a change in the transfer of information from the hippocampus to the neocortex, and it actually shuts down the hippocampus. And so you have this free-flowing information system in the neocortex where these new associations can be made without necessarily knowing that they’re from some sort of experience in your life. They’re just now becoming part of an associative network."
"This is very similar to what occurs during dreams," she says. "You have these kind of fanciful dreams, very bizarre, you can’t quite figure out how these different ideas are connected. But it’s likely that this is the same process."
Mednick, who tries to nap at least three times a week amid her hectic schedule, points out that only naps longer than 60 minutes will have REM sleep.
Her personal reaction to this new result was to try it on herself.
"I’ve been studying naps for a long time and have shown so many different levels of improvement in memory and different kinds of performance with napping, but when I first got this result for the REM sleep… I actually decided I was going to give it a test of my own," she reports.
In my free time, I write songs, and I decided I was going to write a new song… and I was going to use a nap. And I thought about what the song was, and the words I wanted to have in there, and I was decided to take a 90-minute nap. When I woke up, in fact I had the song ready," she says.
"This is something that, anecdotally, you hear a lot about people who’ve been working on a problem, they put it aside, they go they take a nap or they fall asleep… and suddenly they have this insight. And I thought, great, I got to experience that!"
This research was published in PNAS early online edition for the week of June 8 - 12, 2009, and was funded by the National Institutes of Health (NIH).
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