Science suggests sleep can spark inspiration

Leonardo da Vinci had a rather unique napping routine. It is thought that the Mona Lisa artist used to sleep 20 minutes every four hours throughout the day. The Surrealist artist Salvador Dalí did something similar, taking micro-naps while clutching a handful of pencils. Despite being separated by centuries, the two had both recognized the power of the nap, using it to mine inspiration.

Dalí and Da Vinci were not the only ones to work this out. A new study from the journal PLOS Biology suggests that reaching the first stage of deep sleep – or N2 – during a nap can help us have an “aha” moment. Just close your eyes and disconnect for a while. Neuroscience is beginning to confirm what some artists have practiced in an almost ritualistic way.

Anika Löwe and Maria Tzegka, researchers at the University of Hamburg in Germany, designed an experiment using 90 volunteers between the ages of 18 and 35. The participants were asked to follow a series of dots on a screen and respond by pressing a keyboard. What the participants didn’t know is that, after completing 40% of the exercise, the scientists would introduce a trick that made the task easier. After four rounds of trials, some of the subjects were told to take a 20-minute nap, while their brains were monitored using an electroencephalogram (EEG).

Upon waking, all groups showed an improvement in their performance, but 85.7% of those who achieved the N2 sleep phase had their insight moment. In contrast, 55.5% of those who stayed awake and 63.6% of those who dropped into light, N1 sleep experienced only a brief moment of insight.

“The result is a brain that is more plastic and receptive to new ideas, which could explain why so many people discover the hidden trick after napping,” Anika Löwe, lead author of the research told EL PAÍS. In other words, their minds are able to see what previously went unnoticed.

Most sleep studies focus on oscillatory activity. In other words, they look at sleep spindles and slow waves – prominent EEG patterns during non-REM sleep – which are rhythmic and show clear peaks. In this case, the scientists focused on aperiodic activity, which consists of electrical patterns in the brain that do not repeat in a regular manner. That kind of neural “background noise” seems to play a key role in how our neurons turn on and off, and make new connections.

“We found that it provided additional predictive power, possibly because it reflects a more continuous dimension of sleep depth and brain flexibility, which goes beyond the traditional phases of sleep,” Löwe told EL PAÍS.

Delphine Oudiette, a neuroscientist at the Paris Brain Institute in France, believes that more studies are still needed to understand how these mechanisms work. “It is a challenge for specialists to discover the neural processes involved,” says Oudiette who did not participate in the research. The lack of clarity about cognitive processes, according to Oudiette, makes it difficult to know exactly “which part of the task or stage of sleep produces the effect.”

One of the biggest limitations of the experiment is that the scientists did not monitor brain activity during the task, only during naptime. “An interesting next step would be to examine whether some of the learned content is reactivated during sleep and how this relates to a moment of revelation,” Oudiette says. The German researchers hope that their findings, which could be linked to the power of EEG brain waves, is a “good first clue.”

Resetting the brain

When they sleep, people go through a two-phase cycle: rapid eye movement (REM) and non-REM sleep. During the slow-wave phase, the brain reduces the strength of synaptic connections by decreasing the strength of less relevant chemical connections and signals. This helps maintain balance and prepares the brain to learn new information upon waking.

Anika Löwe explains that there are two theories. The first suggests that only irrelevant synapses are weakened, while important connections are retained. The other proposes a generalized reduction of all synapses, which is designed to “reset” the system. It is the cognitive and neural mechanisms underlying intuition, however, that is attracting the interest of researchers.

Oudiette participated in a study similar to that undertaken in Germany in 2021. Hers aimed to show that the light sleep that precedes deep sleep can help solve problems. The scientists were inspired by Dalí and Thomas Edison, who believed that creativity could be enhanced by sitting comfortably in a chair with an object in hand, which falls to the floor waking them up as soon as they fall asleep. Although they found a significant effect for N1 sleep, they did not establish that N2 aided in task resolution. Other research from 2018 and 2020, by contrast, found that neither N1 nor N2 sleep phases necessarily led to aha moments.

One thing both experiments coincided on, according to Oudiette, is that “if you want to use a micro-nap in your life, it can help you in at least two types of creative tasks, even if you don’t know what stage [of sleep] you are in.” Perhaps that is why Da Vinci slept in snatches. Or Dalí worked out to get to the brink of sleep and pull back. They were not escaping from the world. They may have been simply looking for another way to look at it.

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