It's true - you can practice in your sleep

Northwestern University researchers are validating procrasti-nappers everywhere – they say a 90-minute nap can actually help in learning a new skill.

At least when that skill is remembering a musical tune.

Participants in the study, published June 26 in the scientific journal Nature Neuroscience, learned two different musical sequences on a computer screen while watching moving circles that went along with them, similar to video games such as Guitar Hero and Dance Dance Revolution.

After practicing for 25 minutes, the participants took a 90-minute nap. The researchers monitored the participants’ brain activity, and when they entered the “slow wave sleep stage” - a period of deep sleep with occasional intervening periods of REM sleep - the psychologists played one of the two sequences quietly.

Before nap time, the participants performed equally on both sequences. The researchers purposely made the sequences difficult so practice would become important, and the subjects could potentially show improvement. When they woke up, participants were re-tested and performed better on the sequence that had been played during their nap.

The researchers concluded the participants’ exposure to musical cues played during their slow wave sleep stage helped them make fewer errors when re-tested.

Similar research has been conducted in the past, said James Antony, the lead author of the study. But this finding is new because it relates to perfecting a skill, rather than remembering learned information, he said.

Previously in a Northwestern laboratory, subjects had participated in studies based on spatial memory, by placing objects on a screen in their proper locations.

In the musical sequences’ case, that would mean “you could know the sequence but not be able to play it,” Antony said.

That’s why the new study is important, he said, because it emphasizes the participants’ ability to perform what they learned.

The study results also help explain the previously accepted idea that practice helped improve a skill, said Paul Reber, an associate professor of psychology at Northwestern and co-author of the study. Though this concept was acknowledged, researchers didn’t know exactly why practice made perfect, he said, but this study’s results show the process can be influenced even while sleeping.

It is important to remember the study does not suggest someone can learn new information while sleeping, Reber said. But the process could be useful to help the brain “do a better job of remembering things that are really important,” he said.

Though the researchers have not developed any tools to assist in memory based on these results, Reber said he has thought of a few potential applications of the information, including supplementing students’ learning of a new language by listening to an audio recording of previously introduced lecture notes while sleeping.

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