MONDAY, June 30, 2025 (HealthDay News) — Do you enjoy “eureka” moments, when sudden insight or inspiration strikes seemingly from nowhere?

Then you definitely need to sleep on it, a new study says.

People are more likely to have sudden “eureka” moments on nagging problems if they can reach a deeper phase of sleep during a nap, researchers reported June 26 in the journal PLOS Biology.

Folks who reached this deeper sleep during a 20-minute nap were more likely to figure out a trick to make a problem-solving task easier to complete, researchers found.

“It’s really intriguing that a short period of sleep can help humans make connections they didn’t see before,” senior researcher Nicolas Schuck, a professor of psychology at the University of Hamburg in Germany, said in a news release. “The next big question is why this happens.”

For the study, researchers asked 90 participants to track a series of dots across a screen. The subjects were given basic instructions on performing the task, but researchers left out a trick that would make it easier.

After performing the task four times, participants then took a 20-minute nap while an EEG tracked their sleep.

After their nap, about 71% of participants had a “eureka” moment, figuring out the trick that would make the task easier.

Nearly 86% of those who entered deeper stage 2 sleep during their nap experienced this moment, compared with 56% of those who stayed awake and 64% who dropped into light stage 1 sleep, results show.

EEG patterns also showed that a steeper spectral slope — a measurement linked to deeper sleep — was also associated with sudden inspiration.

“The EEG spectral slope has only recently been considered as a factor in cognitive processes during sleep,” said lead researcher Anika Löwe, who was a doctoral candidate at the University of Hamburg during the study.

“I think a lot of us have made the subjective experience of having important realizations after a short nap,” she added in a news release. “It’s really nice to not only have data on that, but also a first direction of what processes are behind this phenomenon.”

Interestingly, the study did not provide subjects the opportunity to go into the deeper realms of stage 3 (deep) sleep or stage 4 (REM dreaming) sleep.

Future studies should look more closely into how EEG activity during awake “eureka” moments relates to EEG readings during sleep, researchers said.

How the brain’s networks function during a steeper EEG spectral slope is another good avenue of research, they added. 

More information

The Sleep Foundation has more on the stages of sleep.

SOURCE: PLOS, news release, June 26, 2025