Researchers analyzed the brain signals and eye and face movements of people who are dreaming clear conversations.
K. Konkoly
By Sofia Moutinho
In the movie Getting Started, Leonardo DiCaprio enters other people’s dreams to communicate with them and steal secrets from their subconscious. This science fiction plot seems to be a baby closer to reality. For the first time, researchers were having ‘conversations’ with new questions and math problems with lucid dreamers – people who are aware that they are dreaming. The findings, from four laboratories and 36 participants, suggest that humans can receive and process complex external information while sleeping.
“This work challenges the definitions of sleep,” says cognitive neuroscientist Benjamin Baird of the University of Wisconsin, Madison, who studied sleep and dreams but was not part of the study. Traditionally, he says, sleep has been defined as a condition in which the brain is disconnected and unaware of the outside world.
Lucid dreaming made one of its first mention in the writings of the Greek philosopher Aristotle in the fourth century BC, and scientists have observed it since the 1970s in experiments on the rapid eye movement phase (REM) of sleep, when most dreams occur. One in two people has had at least one lucid dream, about 10% of people experience it once a month or more. While rare, this ability to recognize yourself in a dream – and even control some aspects of it – can be enhanced with training. A few studies have tried to communicate with lucid dreamers by using stimuli such as lights, shocks and sounds to “enter” people’s dreams. But it recorded only minimal responses from the sleepers and did not involve complicated transfer of information.
During independent dreams, four independent teams in France, Germany, the Netherlands and the United States tried to go further and bring about complex two-way communication using speech and asking questions that the transversalists had never heard in their training. They recruited 36 volunteers, including experienced lucid dreamers and others who had never experienced a lucid dream but remembered at least one dream per week.
The researchers first trained participants to recognize when they are dreaming, by explaining how bright dreams work and showing directions – sounds, lights or finger-tapping – that they would present while dreaming. The idea was that the directions to the participants would indicate that they were dreaming.
Nap sessions are planned at different times: some at night, when people go to bed regularly, and others early in the morning. Each lab uses a different way of communicating with the sleeper, from spoken questions to flashing lights. Sleepers were told to indicate that they had come into a lucid dream and to answer questions by moving their eyes and face in certain ways – by, for example, moving their eyes three times to the left.
While the participants fell asleep, the scientists monitored their brain activity, eye movement and contractions in the face – common indicators of REM sleep – with electro-encephalogram helmets with electrodes. Out of a total of 57 sleep sessions, six individuals indicated that in 15 of them they dreamed clearly. In those tests, researchers asked the dreamers simple yes or no questions or math problems, such as eight minus six. To answer, dreamers use the signals they learned before falling asleep, which included smiling or frowning, moving their eyes several times to indicate a sum, or, in the German laboratory, moving their eyes in patterns corresponding to the Morse code.
The researchers asked 158 questions to the lucid dreamers, who responded correctly 18.6% of the time, the researchers reported today Current biology. The dreamers gave only 3.2% of the questions the wrong answer; 17.7% of their answers were not clear and 60.8% of the questions received no answer. The researchers say that these numbers show that communication is possible, even if it is difficult. “It’s a proof of understanding,” Baird says. “And the fact that different labs have used all these different ways to prove that it’s possible to have this kind of two-way communication … makes it stronger.”
After several questions, the dreamers were awakened and asked to describe their dreams. Some remembered the questions as part of a dream: One dreamer reported that math problems came from a car radio. Another was at a party when he heard the researcher interrupt his dream, like a narrator in a movie, to ask him if he spoke Spanish.
The experiment provides a better way to study dreams, says lead author Karen Konkoly, a cognitive neuroscientist at Northwestern University. “Almost everything known about dreams depends on retrospective reports given when the person is awake and it can be distorted.” Konkoly hopes that this technique can be used therapeutically in the future to influence people’s dreams, so that they can better deal with trauma, anxiety and depression.
Sleeping ‘conversations’ can also help the dreamer solve problems, learn new skills or even come up with creative ideas, Baird says. “The dream is a very associative state that can have benefits when it comes to creativity.”
Rochester University cognitive neuroscientist Michelle Carr, who was not involved in the study, says she is excited about such future applications. But she stresses that retrospective dream reports cannot be replaced. “If you’m in a dream, your reporting ability is pretty limited,” she says.
Changing people’s minds during dreams is still science fiction, emphasizes co-author and cognitive neuroscientist Ken Paller, also in the Northwest. Nevertheless, he thinks the experiment is an important first step in communicating with dreamers; he compares it to the first conversation using a telephone or talking to an astronaut on another planet. Dreamers live in a ‘world completely made up of memories stored in the brain’, he says. Now it seems that researchers have found a way to communicate with people in that world.