“Sleeping on it” really does help people solve problems, a new study has found.

It’s long been theorised that sleep can help bring on “eureka” moments of insight or realisation, but now a group of scientists have put it to the test.

They were all given instructions that involved responding to the dots on a keyboard, but were not told about a trick that could make the task easier.

After four sets of trials, all the participants took a 20-minute nap, while scientists tracked their sleep patterns.

After their nap, the subjects were tested again, and 70.6 per cent of them were able to figure out the unmentioned “trick” that made their task easier.

The study found that 85.7 per cent of those who had achieved the first deeper sleep phase – or N2 sleep – had their “aha” moment, compared to 55.5 per cent of those who stayed away, and 63.6 per cent of those who dropped into lighter, N1 sleep.

In a group given the same task, but who did not get a chance to nap, only 49.6 per cent had a “breakthrough” moment.

“It’s really intriguing that a short period of sleep can help humans make connections they didn’t see before,” study co-author Nicholas Schuck said.

“The next big question is why this happens.”

Fellow co-author Anika Löwe said it was good to establish solid data around what had been a subjective, if widely known, experience.

“What really struck me when telling people in my environment – particularly creatives – about these findings was how much they resonated with people,” Löwe said.

“Many of them could relate to our results with a personal experience of having a (creative) breakthrough after a nap.”