A deep nap could improve one’s capacity for creative problem-solving.

A recent study revealed that individuals are more likely to experience a “Eureka” moment after entering the second stage of sleep—characterized by slower brain activity and bursts of electrical discharges known as sleep spindles—compared to those who have light sleep.

The results suggest that brief, deep naps can lead to valuable insights. Annika Rowe from the Max Planck Institute in Berlin notes, “We are uncovering what actually occurs during sleep, which I believe is quite beneficial.” She added, “During deep sleep, our brains may process irrelevant information related to the problem, enabling us to have these insightful moments upon waking.”

While previous research highlights that naps can enhance creativity and problem-solving, opinions vary regarding which sleep stages are most beneficial. Some argue that the lightest non-REM stage, N1, is best—citing how Thomas Edison embraced ideas while holding a steel ball that would audibly drop, waking him from deeper slumber. In contrast, some studies advocate that deeper N2 sleep (even lighter N3) fosters greater innovation.

To explore this further, Löwe and her team engaged 90 healthy participants aged 18-35 in a task where they classified the movement direction of rapidly flashing dot patterns on a screen, without informing them that the dot colors would gradually hint at correct answers.

Fifteen participants chose shortcuts in the first 25 minutes, while the remaining 75 were invited to take a 20-minute nap in a quiet setting, monitoring their brain activity with an EEG.

After napping, participants revisited the task. This time, most recognized color-based shortcuts, although the likelihood of a “Eureka” moment appeared to hinge on having napped. Among the 68 participants yielding quality EEG data, 85.7% who entered deeper N2 sleep recognized shortcuts.

This research distinctly illustrates that deeper sleep can trigger “Eureka” moments—at least for the specific task used. Itamar Rana from the University of Texas, San Antonio states, “The task type heavily influences whether sleep enhances performance.” ”

Delphine Oudiette from the Paris Brain Institute mentions that varying task designs might explain their findings of significant problem-solving post N1 sleep. “Both sleep stages could be significant, but different cognitive processes may necessitate isolation for a clearer understanding,” she points out.

Björn Rasch at the University of Fribourg in Switzerland notes that the findings support the notion that deeper sleep aids problem-solving, but cautions that the study’s design complicates distinguishing between causation and coincidence. Participants were not randomly assigned to sleep stages and were not studied across various sleep scenarios; thus, those who napped comfortably might simply possess a higher insight capacity.