A small but intriguing study published in the journal Nature Communications suggests that our brains can create new memories while we sleep, the Washington Post reports. It’s preliminary research, but it’s an interesting new step in understanding the relationship between sleep and memory.

Study author Thomas Andrillon, PhD, a neuroscientist at PSL Research University in Paris, and his colleagues monitored 20 people while they slept. During the night, the researchers played clips of mostly random noise. Within that sound clutter, they hid a more complex sequence of white noise that repeated five times, according to the Washington Post.

The next morning, the researchers played back the recording and found that the subjects were able to identify that hidden pattern—something Andrillon told the Washington Post writer Ben Guarino would be very hard to do unless you somehow remembered the pattern that was played while you were sleeping. Interestingly, the researchers found that specific stages of sleep were more conducive to learning: participants remembered the pattern better if it was played during light or REM sleep compared to deeper, non-REM sleep, according to the Washington Post.

“We proved that you can learn during sleep,” Andrillon told the Washington Post, “which has been a topic debated for years.”

The debate centers around two competing theories about sleep and memory storage, Andrillon told Guarino. One theory suggests that during sleep, our brains replay what happened during the day and strengthens those memories, while the other theory proposes we prune out weaker memories as we sleep. Andrillon’s research may show that these theories aren’t mutually exclusive: “they might simply occur at separate moments in the sleep cycle, strengthening fresh memories followed by culling,” Guarino writes.

While the findings are encouraging, this doesn’t mean that you can play a language tape while you sleep and wake up with a few key phrases in your back pocket. That hasn’t stopped people from trying though: even in the 1920s people proclaimed the power of listening to something overnight and waking with newfound knowledge, the Washington Post points out. (And it’s still happening—check out the App Store for the wide and strange array of “sleep learning” offerings to see for yourself.) Plus, Andrillon suggests that trying to learn something that requires complex thought processing overnight, like a language, won’t result in you waking up an expert.

So sleep learning could come in handy for that upcoming “recall acoustic white noise patterns” exam, but isn’t so helpful for becoming fluent in French overnight. But with sleep being such a critical part of our lives and overall well-being, the more we understand about it, the better.

Read more on the Washington Post.