Learn It With Your Eyes Closed

Wish you could learn a musical instrument but have too little time? Only in your dreams, you say? Well, you’re in luck. Recent findings show you can learn it in your sleep. A team of researchers at Northwestern University has now demonstrated that learning to play a simple melody can be fine-tuned by listening to recordings of it while you snooze.

In a small but well-designed study, the researchers trained subjects to play two simple melodies on a keyboard. Subjects then took a well-deserved afternoon nap. Unbeknownst to them, as the subjects entered slow wave sleep, the researchers selected one of the two melodies and played a recording of it twenty times — loud enough to hear but not enough to awaken them. The recordings lasted only four minutes. Before and after the nap, subjects attempted to play the melody; performance was measured in terms of number of mistakes.

While performance of both melodies improved following sleep, the improvement was significantly greater in the melody replayed during the snooze session.

One of the factors in how much of an effect the music cues had was the percentage of the nap spent in slow wave sleep, or deep sleep. Subjects with a higher percentage of slow wave sleep tended to improve more in response to the recordings. Slow wave sleep is important for memory consolidation and sensorimotor integration.

The idea that we can learn while we sleep is not completely new; similar studies have used odor cues and sound cues to enhance declarative memory formation and spatial learning, respectively. This study extends these findings to auditory tones and sensorimotor performance.

Just what can’t we learn while sleeping? Fortunately for the researchers, there are countless ways future studies could tinker with the type of cue/amount/volume/time exposed/phase of sleep/etc. to attempt to further improve learning and define the limits of this approach.

So if you fall asleep to Chopin, will you wake up with piano chops? Probably not. Should you start voice-recording the Krebs cycle to cram for your biology exam? Whispering times tables to your second-grader while she tosses and turns? French and Italian lessons for your slumbering newborn? Not yet.

First, this was a sensorimotor task, not a linguistic or arithmetic challenge.

Second, this study doesn’t demonstrate new learning in sleep as much as memory reactivation—the subjects learned the melody with good old practice and hard work. By listening to it during nap time they simply reinforced what they’d already practiced. And while this study does show that replaying the melodies tweaked performance within an individual, the effect wasn’t large enough to carry over to a significant difference in performance between the music-listening nappers and those who napped in silence.

Perhaps most importantly, outside of the sleep lab this couldn’t be practically applied to only slow wave sleep, so it’s important to know how it would impact your other sleep cycles if you pressed repeat on your ipod and nodded off. Sleep is critical for learning and, more importantly, for overall well-being, and the authors do point out that their findings do not lend any insight into the potential negative impact auditory cues may have on getting a good night’s sleep.

While the practical implications of this study may be limited, understanding how we learn during sleep will lend insight into learning and memory during waking hours, and — since we do spend a third of our life in dreamland and sleep disruption is a key feature of many neurological and psychological disorders—understanding the biological value of sleep is a major challenge for neuroscience today.

Now go tell your boss you have a legitimate excuse for drooling on your desk earlier this morning!

References

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Image via Zadorozhnyi Viktor / Shutterstock.