There’s a habit I’ve had for years, but it recently struck me that I’m not sure if it’s actually a good one.
If I have a tricky problem to work on, I first try to get to the point where I’ve outlined various possible options to solve it. Then immediately before bed, I’ll glance through these options, and sleep on it. I do the same if I have to prepare a talk. I’ll rehearse before I go to sleep, then turn the practice over to my sleeping brain. After all, my conscious mind works hard enough on problem solving during the day, so why shouldn’t my subconscious pull its weight too?
That being said, there seems to be an optimal middle ground when it comes to sleepy problem solving. It doesn’t work well to go to bed while frustrated with seemingly insurmountable obstacle, or wired from working on the final stretch of an idea. Elusive coding bugs and excited brain activity aren’t very conducive to rest.
It seems I’m not alone. Reid Hoffman, co-founder of LinkedIn, is reportedly a fan of the ‘give the mind an overnight task’ approach. Then there’s Otto Loewi, who won the 1938 Nobel Prize in Physiology or Medicine, and attributes his winning experiment to an idea that came to him while sleeping. Thomas Edison slept little at night, and instead kept beds around his workplace so he could power-nap then return to work invigorated. As one account put it, ‘he awakes in immediate and full possession of his faculties, arising from the cot and going directly “back to the job” without a moment’s hesitation’.
But is all this actually effective? Or have people just convinced themselves it’s useful?
The stereotypical approach to learning in your sleep, e.g. by putting on a tape to learn a new language, seems to have limited evidence behind it – although it’s been suggested that more nuanced approaches to triggering memory via smells and sounds can be more productive.
So, what about using sleep to solve a problem, like I’ve been doing? Biologically, there is some sense behind the idea: when we go to sleep, the brain goes through a process of triage, sorting all the information and memories we’ve accrued during the day. The potential for making creative associations appears to be greatest during the period of rapid eye movement (REM) sleep, where dreams are common. REM sleep is noisier that other types of consciousness, with random activation of neural pathways. (Writers like Tim Harford have similarly noted the potential for chaos to spark creativity when we’re awake.) Going to bed with mental jigsaw pieces could therefore be making use of this routine REM creative sorting, to produce a clearer picture by morning.
One 2013 study got some university students to sleep on problems, and others to remain awake. Based on the differences between groups, they concluded that sleep can facilitate problem solving, but only if the problems were relatively difficult. Another study suggested that using sounds associated with different problems could allow targeted ‘reactivation’ of specific problems while sleeping.
So perhaps my habit isn’t that ridiculous after all. Although, it may be best to sleep on it first.
Thanks for this post which resonated with me, because I just finished reading In a Flight of Starlings by Giorgio Parisi.
In it he has the following paragraph:
“It is a very interesting description of the process, and one that assigns a prominent role to unconscious thinking. Even Einstein was in agreement with this. On various occasions, he underlined how important unconscious thinking was to him. Pausing one's concentration on a difficult problem—to allow ideas to settle, and to face that problem again with a fresh mind—is no doubt very common. The Italian phrase La notte porta consiglio has counterparts in so many languages: In nocte consilium ("Night is the time for counsel"- or, more colloquially, "Sleep on it"; Die nacht bringt rat ("Night brings advice"); Il est utile de consulter l'oreiller and Antes de hacer nada, consúltado con la almohala (where l'oreiller and almohada both mean "pillow," so literally "It is useful to consult your pillow"); La note xe la mare d'i pensieri ("Night is the sea of thought").”