While REM sleep gets all the attention, sleep researchers in Paris have discovered a connection between “twilight zone” sleep and creativity.
According to the study, which was published in December in the journal Science Advances, spending at least 15 seconds in the first stage of sleep, or nonrapid eye movement, tripled creative problem solving.
In the study, more than 100 participants were given several eight-digit number sequences and asked to find the final solution as quickly as possible by applying two rules. They were not told the second number in each sequence was always the final solution, which would allow them to solve the problem much faster.
After the exercises, participants took 20-minute breaks in a semi-reclined position with their eyes closed. Each person held an object in their right hand and, if the object fell, participants were to report their thoughts immediately before dropping.
Researchers reported 38 participants fell asleep, with 24 staying in hypnagogia or N1 before they were awakened by the object falling out of their hand, and 14 people progressed to a deeper stage of sleep. N1 often is characterized by vivid dreams, which most people tend to forget as they progress into a deeper sleep. The cognitive role of N1 is largely unknown, as most existing research focuses on the role of rapid eye movement, or REM, sleep.
At the conclusion of each break, participants who remained in N1 were nearly three times as likely to discover the number sequences’ hidden rule compared with those who stayed awake. And they were about six times as likely compared to participants who reached a deeper stage of sleep.
“Our findings suggest that there is a creative sweet spot within the sleep-onset period, and hitting it requires individuals balancing falling asleep easily against falling asleep too deeply,” researchers wrote.