遇到难题解决不了？科学告诉你，不妨先睡一觉再说！

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.

一项即将在《心理科学期刊》刊登的最新研究报告或许能给出答案。

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.

美国西北大学克里斯汀·桑德斯领导的一组研究人员设计了一个实验。在测试者睡眠期间，播放与尚未解决脑筋急转弯相关的提示音乐，研究他们在次日早晨解决同样问题的能力是否有所提高。实验结果令人惊喜，测试者次日解决问题的能力确实得到了提高。

"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."

研究人员称：“根据对人类和其他动物的大量研究，在相似的时间段，睡眠之后的记忆力比清醒时效果更佳。与睡眠相关的记忆形成过程，不仅能在睡眠中得到加强的效果，还起到组织、优化、和转换信息的作用.”

 To arrive at this conclusion, the researchers invited 57 students at Northwestern University to participate in a three-day, two-night study. On the first day, participants were presented with a series of difficult spatial and verbal puzzles. Here is one example. (The answer is provided at the end of this article.)

为了证实这个结论，研究人员邀请美国西北大学57名学生参与三天两夜的实验研究。第一天，测试者需要解决一系列的空间和文字难题。举个例子：（答案于本文文末）

On a wall outside a closet door are three standard on/off switches. One (and only one) controls a light bulb inside the light-tight, well-insulated closet. The other two switches do nothing. You can only open the closet door once, and cannot change any switches after the door is open (or re-closed, for that matter). Damaging or disassembling the door, walls, or switches is against the rules. Within these constraints, how can you determine with certainty which switch controls the light bulb?  — Sanders et al. (2019)

壁橱门外的墙上有三个同样规格的标准开关。其中有且仅有一个开关控制壁橱内的一个灯泡，壁橱密不透光、完全隔绝。其余两个开关不起任何作用。你有且仅有一次机会可以打开壁橱门，确定你选择的开关是否是控制该灯泡。门开之后或重新关闭前，都不可更改任何开关。禁止损毁或拆卸壁橱门、墙以及开关，否则作违规处理。在这些约束条件下，你是如何确定灯泡的开关呢？—— 桑德森等（2019）

 Forty-two puzzles like the one presented above were used in the experiment. Importantly, each puzzle was paired with a sound clip. The experimenters encouraged participants to try to solve the puzzles as well as to remember the different sound clips associated with each puzzle. Participants worked through the brain teasers until a total of six puzzles remained unsolved.

实验中测试者需解决42道类似上述的智力题。值得一提的是，每个智力题都配备一个声音文件。研究人员鼓励测试者在解决智力题的同时，尽可能地记住与每个智力题相关的声音片段。最后测试者成功解决这些问题，但还有六道尚未找到解决方法。

Next, participants took home a sleep monitoring device and sound cueing system that gathered data and played music while they slept. For instance, every time the machine detected slow-wave sleep(i.e., the type of sleep in which dreaming and memory re-organization is thought to occur), the machine cued music associated with some, but not all, of the unsolved brain teasers.

随后，测试者带回家一个睡眠监测设备和一个声音提示系统设备。在他们睡眠期间，设备可收集与睡眠相关的数据以及播放音乐。例如，当机器检测到慢波睡眠时（该睡眠状态被认为梦和记忆会出现重组的情况），机器便会播放部分与尚未解决的脑筋急转弯相关的声音片段。

 The next morning, participants were asked to try to figure out the puzzles they were not able to solve the day before. The experiment was repeated later that day and night, and participants again attempted to solve the unsolved puzzles the next morning.

次日早上，再要求测试者解决前一天尚未解决的智力题，同时在当天重复前一天的实验；到第三天早上，测试者再一次解决未解决的智力题。

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.

通过这两次实验，研究人员发现，在测试者睡觉时偷偷播放与未解智力题相应的声音片段，他们在第二次解决问题的可能性高达55%。研究报告还指出这种效应与智力题的类型无关，如果测试者在睡眠期间接收到相关声音的提示，空间和文字问题的解决率都有所提高。

 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.”

研究人员总结说：“这次实验首次证明，在睡眠期间，有针对性地重新激活未解难题的记忆，有助于提高解决该问题的能力。我们为这方面的研究增加了有科学依据的参考文献，让人们认识到睡眠对于增强和重组记忆是有效果的。”

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

因此，不论你遇到什么难题，不妨先睡一觉，同时播放一些能够提示你解决该问题的音乐，或许醒来后你就找到了解决方案。