The scientists answer: rather not, if you want to remember something completely new. But it is possible to consolidate the already studied material in a dream. Details are in a new study by psycholinguists from France.
It is known that during sleep the brain is not in a completely “off” state. He retains the ability to respond to what is happening outside. For example, if someone nearby says our name, we wake up faster. In the same way, a mother wakes up from the cry of her child, no matter how soundly she sleeps. Until recently, the reactions of the sleeping brain were considered something of a reflex. A team of psycholinguists led by Sid Kouider found that during sleep, the brain is able to make decisions and even plan what to do.
The researchers conducted several experiments. In the first, volunteers had to listen to the words and determine which of them denoted an animal and which denoted an object. To make a choice, they had to press a button located to their left or right. The organizers at this time measured their brain activity. As a result, Kuider and his colleagues were able to track the moment of making a decision and preparing a response (pressing a button) – when a participant decided that he should use his left or right hand, electrical activity arose in his motor cortex.
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The participants were then invited into a room with a relaxing environment (comfortable chair, dimmed light) and subjected to the same test. Soon some of them fell asleep (their brain activity corresponded to the state of sleep), but their brain continued to generate activity in the area that was responsible for making decisions and pressing the button*. The researchers deliberately used new words to make sure that the brain was solving the problem of analyzing their meaning, and not reproducing the answers already given. When they woke up, the participants did not remember the words. But it is obvious that their brain continued to make decisions without the participation of consciousness.
According to Kuider, this is due to the fact that in sleep our brain is, as it were, in autopilot mode: it is able to perform (or rather, plan) actions brought to automatism without involving the prefrontal cortex, which is responsible for concentration and conscious behavior (during sleep its activity is suppressed). For the same reason, for example, sleepwalking patients may prepare simple meals like sandwiches or drive a car in their sleep: these are actions that they usually perform mechanically without thinking.
So, in a dream, we can perform actions that we managed to hone in advance in the waking state. Does this mean that with the right technique, sleep learning can be successful, at least for practicing simple skills (for example, identifying errors in recently learned words)? “There is such a possibility, but you need to understand that the effect will still be weak,” Kuider explains. “During sleep, we cannot fully control our cognitive processes. In particular, to track errors. So there is a high chance of distortion. In addition, in a dream, the brain solves its own problems – in particular, the organization of the experience accumulated during the day. By intervening in this process, we risk harming ourselves.”
* Current biology, online publication September 11, 2014.