The twilight time between full wakefulness and being sound asleep may be packed with creative potential. In a new experiment, people who drifted into a light sleep were better problem solvers later.
Scientists shared those findings December 8 in Science Advances. The results help demystify the fleeting early moments of sleep. They may even point out ways to boost creativity.
Thomas Edison inspired the new study. Rumor has it that the famous inventor used to chase the twilight moments between wakefulness and sleep. Supposedly, he used to fall asleep in a chair holding two steel balls. As he drifted off, the balls fell into metal pans. The resulting clatter woke him. Then, he could write down his inventive ideas before he fell into a deep sleep and forgot them.
Researchers tested Edison’s method of cultivating creativity with 103 healthy people. Volunteers came to the lab to solve a tricky number problem. They were asked to convert a string of numbers into a shorter sequence. They were told to follow two simple rules. What the volunteers weren’t told was that there was an easy trick to do this task. The second number in the sequence would always be the correct final number, too. Once discovered, this trick dramatically cut the solving time.
After doing this task 60 times, the volunteers earned a 20-minute break. This downtime was spent in a quiet, dark room. Volunteers reclined in chairs and held a version of the steel balls that Edison used as “alarm clocks” — it was a light drinking bottle in one dangling hand. The researchers told participants to close their eyes and rest or sleep if they desired. All the while, electrodes monitored their brain waves.
About half of the participants stayed awake. Twenty-four fell asleep and stayed in the shallow, fleeting stage of sleep called N1. Fourteen others progressed to N2, a deeper stage of sleep.
After their rest, participants returned to their number problem. The researchers saw a stark difference between the groups. People who had fallen into a shallow, early sleep were 2.7 times as likely to spot the hidden trick as people who stayed awake. Shallow sleepers were 5.8 times as likely to spot the trick as people who reached the deeper N2 stage.
Such drastic differences in such experiments are rare, says Delphine Oudiette. She’s a cognitive neuroscientist at the Paris Brain Institute in France. “We were quite astonished by the extent of the results,” she says.
Her team also turned up a “creative cocktail of brain waves,” as Oudiette puts it. These seemed to accompany the twilight stage of sleep. That cocktail was a mixture of alpha brain waves and delta waves. Alpha waves usually mark relaxation. Delta waves are a sign of deeper sleep.
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The study doesn’t prove that the time spent in N1 actually triggered later creativity, says John Kounios. He’s a cognitive neuroscientist, too. But he wasn’t involved in the study. He works at Drexel University in Philadelphia, Pa. Stewing over the problem may have just caused these volunteers to both nod off and to have their later insight, he says. In that case, N1 sleep would be a “by-product of the processes that caused insight rather than the cause.”
More work is needed to untangle the link between N1 and creativity, Oudiette says. But the results raise an interesting possibility. People may be able to learn to reach that twilight stage of sleep — or to produce the cocktail of brain waves associated with creativity — on demand.
It seems Edison was onto something about the creative powers of nodding off. But don’t put too much stock in his habits. He also is said to have considered sleep “a criminal waste of time.”