Why ‘Sleep on It’ is the Most Useful Advice for Learning — and Also the Most Neglected

The role of the unconscious in problem solving

As a strategy for raising educational achievement, sleep has to rank highly. Yet you will hear scant mention of sleep in the education discourse. For all the debate on curriculum and assessment, pedagogy and behaviour management, so little attention is given to an issue that literally impacts our everyday lives.

By the time you’re done with Matthew Walker’s Why we sleep, you’ll be asking why not? Sleep, it appears, is vital to every aspect of our mental and physical wellbeing. Walker’s expertise lies in neuroscience, and he draws on a wealth of research to expose the fallacy in thinking we can get by with compromising on our sleep — not just the amount of sleep we get, but also the consistency of our sleep patterns. I was even left persuaded that I have chronic sleep deprivation. By making me reflect on my morning coffee routine, as well as the occasional snooze, Walker’s book has been—that’s right — a wake-up call.

The result of a good night’s sleep (image source)

Sleep is also critical to problem solving. When my students are stuck on a maths problem, sleep on it is often the only wisdom I have to offer. This adage has served me well in the past and now enjoys a strong neurological basis thanks to the research Walker draws on. Walker relates problem solving to the REM phase of sleep, demonstrating that it is in this critical stage of unconsciousness that we form novel connections between individual chunks of knowledge. REM sleep is where our ideas crystallise and recombine into new, creative thoughts. The link is so pervasive that the phrase sleep on it exists in most languages.

Walker is only confirming what problem solvers have long understood.

Thomas Edison is known to have turned power napping into a craft by seeking a sweet spot between conscious and unconscious states, where he believed his deepest insights originated from. His method: holding a bunch of ball-bearings so that they would clatter onto the floor just as he drifted into slumber, awaking him at the opportune moment.

Less dramatic were the reflections of placing French polymath Henri Poincare, who articulated the nature of invention thus: “The role of this unconscious work in mathematical invention appears to me incontestable.” Jacques Hadamard later backed up his compatriot by making note of how he alternated between conscious and unconscious thought when working of mathematics.

Responding to Hadamard, one Albert Einstein spoke of the “combinatory play” that is “the essential feature in productive thought”, concluding: It seems to me that what you call full consciousness is a limit case which can never be fully accomplished.” No wonder that George Polya, in his classic How to Solve It, advised maths students to “take counsel of your pillow” when caught in the web of a problem.

Bringing the discussion to the present day, mathematician Andrew Wiles devotes one of the Bs of his “3B” mantra to Bed (along with Bus and Bath), in homage to the importance of switching off from problems to allow creative insights to make their way in.

Thomas Edison. Asleep. (image source)

Sleep on it would pass as folk wisdom, except that it heralds from some of the most creative thinkers of recent times, and is now reinforced by neuroscience. The link between deliberate sleep patterns and core tenets of mathematical thinking such as problem solving and creativity is inescapable.

So why has education not embraced sleep as a central part of its design? To answer that, just consider the implications.

The education system would have to adapt to the varied sleeping patterns of students. The most important concept I took away from Matthew Walker’s book is circadian rhythm — body clock. Our body is attuned to rising and sleeping at different hours, depending on our state of biological development. Adolescents, for example, struggle to switch on early morning compared to children and young adults. It is not that adolescents are lazy; their tendency to drift off mid-morning is partly a consequence of being denied their natural sleeping routine. For education to meet the needs of its students, it would have to adapt its timetables — later starts and finishes for high schoolers, and so on. The premise of adaptive timetabling does not fit will with a standardised model that runs on a fixed clock.

Sleep does not lend itself to the measurement paradigms of today’s education system. Education is mired in empiricist dogma, hell-bent on measuring whatever it can, and then assigning importance only to what has been measured. It should be evident that the nature of problem solving, so much of which is rooted in unconscious thought, is holistic and beyond the blunt tools of written assessment. Any timed exam that seeks to capture students’ problem solving skills within a fixed period (looking at you, PISA) is, by the findings of neuroscience, a contradiction in terms. Embracing sleep means letting go of futile efforts to measure every nuance of students’ thinking. If education is to truly become evidence-based, it cannot, in good conscience (or should that be unconscience?) afford to ignore emerging insights from neuroscience.

The importance of sleep is by now irrefutable — the onus is on education policy, practice and research to adapt. And if you’re still in doubt of the power of the unconscious, I can only advise you to, well, sleep on it. The penny will hopefully drop by the time you awake.


I am a research mathematician turned educator. Say hello on Twitter or LinkedIn and sign up below to receive more content like this.
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