How to sleep your way to the top of Spanish class

You’ll only need three things: headphones, an audio version of your textbook, and a comfy bed. Because according to a recently unveiled preprint study, humans can learn foreign words while we’re sleeping.

Though this does come with a caveat – you can’t exactly become fluent in a new language just by listening to words in your sleep. But it sure does seem to help.

💤 A sleeper, ehrm, deeper dive… The study’s researchers monitored 30 German speakers as they slept in a lab, focusing on each participant during their first cycle of deep sleep. This cycle consists of peaks and troughs of brain activity each lasting around half a second, New Scientist reports (hold onto that fact for a sec).

The sleeping participants were then broken up into two groups. Half simultaneously heard simple (and completely made-up) foreign words + their translations during the peaks of brain activity, while the other half were fed this information during the troughs. Each word corresponded to one of three categories: animals, places, or tools.

• 12 hours later – and awake this time – the participants were told the made-up words and asked to recall their respective categories. The peak group answered correctly no better than chance (33% of the time), while the trough group was right 37% of the time, a figure that could also be attributed to chance.

🧠📈 But, but, but: In another test, performed 36 hours after hearing the words in their sleep, those in the trough group were able to answer correctly 41% of the time, with a statistical analysis suggesting this wasn’t a chance finding. The peak group still scored no greater than chance.