Forget all-nighters: Cram for that exam while you sleep

June 29, 2012 at 11:30 AM ET

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If you want to learn something new, it's better to sleep on it than pull an all-nighter, researchers say.

It sounds like the answer to every college student’s dream: New research suggests you may be able to cram for the exam while you sleep.

Researchers have found that under the right conditions, memory can be bolstered during sleep, according to a report published in Nature Neuroscience.

While the new study focused on something fairly simple — learning a new tune — its implications may be much broader, says co-author Paul Reber, an associate professor at Northwestern University.

“We’ve talked about whether it might be feasible to make auditory recordings and put them on an iPod next to the bed,” Reber says. “Would that get you any benefit? Our results suggest you would. But we haven’t tried anything like that yet.”

One thing researchers do know is that pulling all-nighters doesn’t help, Reber says. “There’s lots of evidence that cramming instead of sleeping is not the right strategy,” he adds.

That’s because you need to sleep on something for your brain to shift it into long-term memory.

Reber’s study is intriguing because it showed that people could actually get better at something if they “practiced” while sleeping.

To see if people could study while asleep, Reber and his colleagues rounded up 16 volunteers and asked them to learn to play two novel tunes on a device with four keys that could be played with one hand.

Then the volunteers were asked to take a 90-minute nap while having their brain waves monitored with an EEG. That way, the researchers knew whether the volunteers had reached slow wave sleep and whether they stayed asleep for the entire nap.

During the nap, Reber and his colleagues played one of the tunes at a volume quiet enough not to wake the volunteers.

After the nap, the volunteers were asked to try to reproduce the two tunes. Sure enough, they had learned the tune played during the nap much better than they had before they fell asleep. And they had learned it much better than the tune they had only heard during practice before the nap.

Reber suspects that there may be a limit to how much you can accomplish while you’re asleep, and that there may be a cost. In other words, when you boost your memory regarding one thing, you might forget something else. Ultimately, though, studying while you sleep may give you the option of choosing what you remember best, he says.

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