‘Sleep on it. Things will look better in the morning.’
It is an old wives tale and an advice many parents give to their children lovingly. There are countless anecdotes from famous scientists, artists and philosophers who problem-solved or had new bursts of ideas after sleep.
How accurate is this advice?
The Science of It
Numerous studies in humans and other animals show better memory after sleep compared with a similar time awake. We know that we are able to consolidate and organise memories while we sleep.
A team of researchers led by Kristin Sanders of Northwestern University* took this further seeking to find out whether we have the ability to problem-solve the same way we organise memory during sleep. They did this by testing whether cueing music associated with unsolved brain puzzles during sleep increased people’s ability to solve these brain teasers the next morning.
With 57 participants in a course of three days and two nights, the researchers found that participants were 55 percent more likely to solve puzzles on their second try when the corresponding sound clip was played while they slept.
They concluded that “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.”