Sleep can sometimes feel like a waste of time, which is one of the reasons why it is hard not to be jealous of those lucky few individuals who only require a few short hours of it per night. The feeling becomes especially strong when you spend too much time reading about the cult of productivity: Why waste time sleeping when you could be multitasking? This is probably why the Apple and Android app markets are flooded with sleep-learning apps offering to teach you an eclectic range of new talents — a foreign language, money management, social skills — all while you doze. They’re like the modernized version of the subliminal-message cassette tapes of the ‘80s and ‘90s. But the question remains: Do they actually work?
Jordan Gaines Lewis, who studies sleep at Penn State College of Medicine (and is a friend of Science of Us), addresses this over at The Guardian this week. As it turns out, it’s not exactly a new question, and there even exists a 60-year-old experiment suggesting that, no, you probably can’t memorize new facts in your sleep. The researchers in that study played an audio recording that listed Trivial Pursuit–style factoids, drawing from sports, science, and history, among other things. “The subjects were asked trivia questions after awakening, but there was no evidence that they’d retained any of the information that was played to them,” Lewis writes. “The researchers concluded that sleep-learning was ‘impractical, and probably impossible.’”
But sleep does play an important role in learning, Lewis explains. Maybe we can’t easily learn new facts as we sleep, but sleep does play a huge role in learning, in that it helps consolidate the information we learned throughout our days. Lewis explains:
[S]low-wave or deep sleep has been recognised for some time as critical for memory consolidation – the stabilisation of memory from short-term to long-term. During slow-wave sleep, which tends to happen during the first half of the night, the firing of our brain cells is highly synchronised. When we measure sleep using electrodes attached to the scalp, slow-wave sleep appears as slow, high-amplitude oscillations.
These “slow waves” originate in the neocortex and make a circuit with the hippocampus, the brain structure which encodes new memories. Scientists believe that this connection allows for newly-learned information to be repeatedly activated with each oscillation. It’s been shown that patients with insomnia, who experience less slow-wave sleep than normal sleepers, show impaired memory consolidation.
Sleep can and does help you learn, but probably not in a way that makes it worth it to spend $9.99 on an app promising to help you do so.