It’s long been understood that sleep helps us reflect on our days, solidify memory and sometimes problem-solve. While research shows that this occurs, we don’t exactly know why or how. What exactly causes epiphanies post-sleep? How does it happen? And, most importantly, how long do we need to sleep in order to wake up with a solution to a problem?
Penelope Lewis, a neuroscientist from Cardiff University who has been studying the way people process information during sleep for years and even pioneered the idea of “sleep engineering” in a TEDx Talk, has come out with a new hypothesis. Though some of her conclusions are ultimately conjectures at this point, she did unveil some interesting insights into why and how “sleeping on it” is crucial to mulling over important decisions and parsing problems that need to be solved.
Her theory breaks down sleep processes to understand each stage’s role in comprehending and consolidating the various bits of information and memories we experience during the day. In the article, her overarching question is: “How can sleep both promote the construction of general knowledge frameworks and facilitate the creative leaps, which such knowledge actively suppresses?” The preceding question was formed from the idea that non-REM sleep is the stage in which we extract concepts to find patterns and rules within our experiences (creating generalities or gathering the gist of an experience), while REM sleep is the stage in which we are able to see beyond such rules and form more creative conclusions. Lewis is less interested in the debate over which stage is more important to meaning-making and more interested in how the two might work together.
According to Lewis, the key to how we solve problems after a restful night is the way in which these two stages work in concert to help us unpack difficult problems. She claims that, “the answer lies in the heterogeneity of sleep stages, as REM and non-REM are iteratively interleaved throughout the night in cycles of about 90 min.” So, the process of moving in and out of the two stages allows us to see things we may have missed in our waking lives because during sleep our brains to meditate on the same memory from two vastly different angles. She and her team elaborate later in the article, “We posit that the iterative alternation between generating cortically represented schemas in non-REM, and forming links between these and other cortically represented information in REM, is critical to the formation of the rich, highly interconnected representations that characterise human thought.”
Following this thread of thought, we looked at another, older study comparing napping with caffeine and a placebo to measure the benefits of each as they pertain to verbal, motor and perceptual memory. In this study, participants engaged in verbal, motor and perceptual memory tasks that were punctuated with a 60 to 90 minute napping session or drug intervention. The study found that those who napped did better on verbal and motor tasks and much better on perceptual tasks than those who used a placebo but about the same as participants who used caffeine.
What’s interesting here is the amount of time the nappers napped. If Lewis’ theory is indeed true, it also supports and explains the idea that a 60-90 minute nap is valuable to working through a problem. A 90 minute snooze would theoretically be enough time for our brains to do what Lewis claims is the crucial step: pop in and out of the two stages (non-REM and REM) which together promote the type of reflection that often yields a solution.
While much of this is still theoretical, it seems Lewis is onto something. Anecdotally, we’ve all likely woken up only to find that a previously challenging problem now seemed ridiculously clear in those moments. It would be amazing to more deeply understand this phenomena that often feels like magic and learn how to strategically harness it to untangle our daily dilemmas. Thanks to this new research, we could be almost there.
This article originally appeared in Sleep Retailer eNews on May 24, 2018.
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