In recent years, the theory that humans can remember information and even learn in their sleep has gained popularity. We decided to check whether this hypothesis has scientific basis.

Publications with offers to help start sleep learning appeared on many resources. In a dream they offer to master foreign languages, learn to play musical instruments and even tighten up mathematics. The question of the possibility of learning in a dream has been repeatedly asked by users "Yandex.Zena", the editors also tried to answer it "TASS.Science"

According to scientists, people carry out in sleep for about a third of my life. Now, in the age of productivity and time management becoming increasingly popular, theories have emerged about how you can make the most of this time, learning something new in the process. Learning a poem, memorizing a dozen new words in a foreign language, preparing for an exam while you sleep - all this sounds very tempting for any person living in the fast pace of a big city. Sleep learning process called "hypnopaedia".

It is known that sleep shares into two stages: slow-wave sleep (orthodox) and fast sleep (paradoxical). The first stage occurs after falling asleep and lasts from 60 to 90 minutes. During it, metabolism slows down, muscles relax and body temperature drops. Slow-wave sleep is replaced by rapid sleep, which is also paradoxical. Its duration is much shorter - only 10 to 20 minutes. This stage is characterized by increased heart rate, increased temperature, and contraction of facial muscles and limb muscles.

Investigating these stages, scientists conducted experiment. Sleeping volunteers were given electroencephalograms to show what happens to brain activity during sleep, electrooculography to track eye movements and electrical activity of the eye muscles, and electromyography to track the state of skeletal muscles. As a result, scientists have found that the processing of external information is blocked during slow-wave sleep due to its depth. However, in the fast phase, everything was the other way around: the motor cortex, also known as the motor cortex of the brain, gave the necessary signals so that a person could make a finger movement in response to a certain word. True, such a reaction was only possible if the person already knew this word. The study confirmed the assumption that the human brain during the rapid stages of sleep can not only perceive information, but also analyze it. The same experiment completely refuted the claim that sleepers are isolated from the environment.

With the analysis of information, everything is more or less clear. But can it linger for a long time in a person’s memory? In 2017 in the magazine Nature An article was published whose authors reported that people can actually remember information they hear in a dream. The only condition for remembering it is to be in that very rapid stage of sleep at the time of its perception. Scientists have demonstrated that at this moment waves appear in the human brain indicating the learning process, that is, during the rapid, or paradoxical, phase of sleep, a person is able to continuously absorb information.

As for learning foreign languages in your sleep, this is definitely impossible today. Scientists have not yet found a way that will allow you to remember new words while in a state of sleep. When learning a foreign language, neurons throughout the brain are activated, so the most that the human brain is capable of during REM sleep is processing words that have already been learned. Therefore, for productive learning advise learn 10–20 new words half an hour before bedtime.

Thus, based on scientific research and experiments, the following conclusion can be drawn. In the fast phase of sleep, a person can actually analyze, remember and retain in memory what he hears in a dream (if among this stream there are no words previously unknown to him), as well as process information already received and remember it more deeply. At the same time, the capabilities of our brain do not allow us to study something fundamentally new in any phase of sleep, or we do not yet know how to activate them for this purpose.