Sleep learning, or hypnopaedia, is the theory that one can learn during sleep using taped recordings, or even by placing a book under your pillow and hoping for the best. Broadly speaking, research has been inconclusive. However, sleep and learning are definitely linked.

Aldous Huxley explored sleep learning in his 1932 novel Brave New World when Reuben Rabinovitch fell asleep next to a radio. When he woke up he was able to recite the entire broadcast, unfortunately for the Polish character, the broadcast was all in English.

In the 1950s, researchers ran an experiment where subjects were played recordings of trivial facts about sport, history and science while they slept. When they woke they were tested and, unsurprisingly, performed poorly when asked about the trivia.

Image of a baby sleeping

Sleep learning is not all hokum

However, sleep has been associated with learning. In 2014, a Swiss research team ran an experiment called ‘Boosting Vocabulary Learning by Verbal Cueing During Sleep‘, testing whether sleep enhances our ability to learn foreign languages. Subjects were given Dutch to German word pairs at 10 pm and listened to audio recordings of these pairings until 2 am. Half the group was allowed to sleep during the four-hour period. Researchers discovered that those who slept recalled significantly more than those who didn’t.

Read More: 7 Sleep Mistakes You Don’t Know You’re Making And How To Fix Them

Sleep learning consolidates memory

The research says that the brain is able to recall and retain information during sleep – or perform memory consolidation. This happens during the deep sleep, or the slow waves period of our sleep. Deep sleep consolidates short-term memory into long-term memory and originates in the neocortex and makes a circuit with the hippocampus – the brain’s hard drive. Scientists believe that this circuit allows for newly-learned information to be repeated and memorised during the deep sleep cycle, typically in the first half of the night. It’s been shown that patients with insomnia, who fail to reach the deep sleep stage of sleep, suffer from impaired memory consolidation.

Sleeping learning student

So how can you learn in your sleep?

Unfortunately, your teachers and parents were right. The best way to take advantage of this memory consolidation is to read and get enough good sleep to allow your brain to retain what has been read. Much of sleep learning is limited to making subconscious associations, such as pairing Dutch words to German words which have already been read while conscious.

Dr Susan Biali wrote 6 tips for the night before and the day of an exam, and touched upon some great advice for memory consolidation.

Sleep, particularly deep sleep, is critical for memory formation. New connections between brain cells form while you are sleeping, creating memories from your day. In order to reach the optimal number of cycles of memory-promoting deep sleep, aim to get a full eight hours before the big day. Make it a practice to get a good night’s rest after any intense day of learning and studying, as that will help your brain to retain as much information as possible.

Are you a sleep learning expert? Share your sleeping tips in the comments below!