It is often said that the best way to get to the bottom of a hard problem is to sleep on it. But how accurate is this advice?

关于如何追根究底找到解决问题的方法，通常有个普遍的说法——最好先睡上一觉，或许会找到解决方案。不过这个说法到底有几分可信度呢？

A new study forthcoming in the journal Psychological Science may have the answer.

A team of researchers led by Kristin Sanders of Northwestern University designed an experiment to test whether cueing music associated with unsolved brain teasers during sleep increased people's ability to solve those same brain teasers the next morning. Fascinatingly, they found that it did.

"Numerous studies in humans and other animals demonstrate better memory after sleep compared with a similar time awake," state the researchers. "Sleep-related memory processes not only strengthen but also can optimize, organize, and transform information."

Over the course of the two experimental sessions, the researchers found that participants were 55 percent more likely to solve puzzles on their second try when the corresponding sound clip was surreptitiously played while they slept. They also reported that the effect was not dependent on the type of puzzle; solve rates for both spatial and verbal puzzles increased when cued during sleep.

The authors conclude, "By demonstrating for the first time that targeted reactivation of puzzle memories during sleep improves problem-solving the following morning, we add to a growing literature recognizing sleep as useful for both strengthening and reorganizing memory."

So, the next time you're faced with a difficult problem, sleep on it...and play some music to remind yourself of the challenge.