Sleep On It

Have you ever been told, when confronted with a tough decision or a difficult problem to solve, to “sleep on it”? Take a moment to consider this common suggestion. Does it make sense? Or have you ever wondered why sleep would be a logical next step in such a situation?

After all, don’t you think you’d be more capable of weighing the pros and cons of your options or working through the steps of an equation if, oh, I don’t know, you actually remained conscious?

Even if the phrase sounds silly on one level, we can still generate a few possibilities as to why “sleeping on it” might be beneficial. For one, a stressed out, overtired individual will have fewer cognitive resources at his or her disposal than a relaxed, well-rested individual. Another possibility–maybe you consider yourself a “morning person,” so you want to wait until your system is functioning optimally before taxing your brain. Maybe you are in a horrible mood and you don’t think you have the willpower or the attentional capacity to take on a challenge, so you decide to wait and see if a good night’s sleep will give you a boost. Maybe you are just hoping that you will have forgotten about the problem completely by the time you wake up—and then you can live in ignorant bliss!

Regardless of the method to your madness, the overall goal remains the same: make the decision, solve the problem. So how can sleep help, and how does this relate to creativity?

In their article, “To sleep, perchance to gain creative insight?” authors Robert Stickgold and Matthew Walker state that central to the meaning of “creativity” is “the ability to take existing pieces of information and combine them in novel ways that lead to greater understanding and suggest new behaviors and responses” (p. 191). There is anecdotal evidence to suggest that there is a link between creative problem solving and sleep. For example, Dmitry Mendeleyev, who laid out the periodic table of elements, reported that the rule governing the table’s structure came to him in a dream. Loewi, a Nobel Prize winner, claimed that “he woke up with the essential idea for an experimental confirmation of his theory of chemical neurotransmission” (Wagner et al., 2004, p. 352). And I’m sure many of you have had similar experiences, though maybe on a slightly smaller scale–falling asleep unsure of how you are going to pull off a surprise party for your loved one, and then waking up with an ingenious idea. Or, maybe you spent the night unsuccessfully trying to figure out how to get the kids to all of their after-school activities, only to come up with the perfect carpooling plan first thing in the morning. 

Sleep has actually been shown to inspire “insight,” with insight being defined as “a mental restructuring that leads to a sudden gain of explicit knowledge allowing qualitatively changed behavior” (Wagner et al., 2004, p. 352). More simply put, sleep makes it more likely that you will have one of those “AHA!” moments, where you suddenly reach the solution to a problem without being able to describe exactly how you got there.

Wagner and colleagues (2004) provided evidence supporting the idea that sleep facilitates creative insight. Participants performed a cognitive task, and response speed increased gradually with practice. However, the task was designed so that it was also possible for participants to show sudden, substantial performance improvements with a burst of insight–i.e. by discovering a hidden abstract rule underlying the task demands. There were three conditions in the study, where an initial task training session was followed by 8 hours of nocturnal sleep, nocturnal wakefulness, or daytime wakefulness. Then, participants were given the cognitive task again. The researchers found that more than twice as many participants “gained insight into the hidden rule after sleep as after wakefulness, regardless of the time of day” (Wagner et al., 2004, p. 352).  But why?

In general, sleep is important for the consolidation of memories, a process that oftentimes is likened to the drying of cement. While wet, cement is still vulnerable to alterations (e.g. footprints). When dry, the surface remains smooth and unchanged, even when stepped upon. A memory, before “consolidated,” is also particularly susceptible to interference from a variety of sources. Sleep, therefore, protects this consolidation process from external interference and can result in “delayed learning without the need for further practice or task engagement” (Stickgold & Walker, 2004, p. 191). Further, in the study described above, Wagner and colleagues hypothesized that sleep might “set the stage” for insight by changing the representational structure of these memories–in other words, by changing how memories of the training session are stored in the brain (Wagner et al., 2004). Upon awakening, then, you would literally be seeing the problem in a “whole new light,” thereby increasing the chances that you will gain insight into the solution.

This is good news for me–I’m currently in the planning stages for my next experiment, and I’m hitting a few road bumps in my stimuli generation process.

I guess it’s time for a nap.



Stickgold, R., & Walker, M. (2004). To sleep, perchance to gain creative insight? Trends in Cognitive Sciences, 8(5), 191-192.

Wagner, U., Gais, S., Haider, H., Verleger, R., & Born, J. (2004). Sleep inspires insight. Nature, 427, 352-355.

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