Scientists have successfully “chatted” in real time with a sleeping person, invading their dreams, shows a new study. The researchers say it’s like trying to communicate with an astronaut in another world.
Dreamers can follow instructions, solve simple math problems and answer yes-no questions without ever waking up, according to the results of four experiments described on Thursday (February 18) in the newspaper Current Biology.
The researchers communicated directly with the sleeping participants, asking them questions and getting them to respond with eye or facial movements during lucid dreaming – when people are at least aware that they are dreaming. (Some lucid dreamers can control what happens in their dreams.)
“You could expect that if you tried to communicate with someone who was asleep, they just wouldn’t respond,” study lead author Karen Konkoly, a cognitive neuroscientist at Northwestern University in Illinois, told Live Science. Although Konkoly hoped that real-time communication would work, she said she “didn’t believe it” when someone first answered her dream questions.
Related: 7 mind-blowing facts about dreams
People dream every night, but scientists don’t fully understand why we dream. Studying dreams is difficult because people often forget or distort details after waking up. This is partly because the brain does not form many new memories while sleeping and has a limited ability to store information accurately after the dream ends, according to the study.
To overcome this limitation, the researchers tried to communicate with people while they were still dreaming. As the study participants were having lucid dreams, this meant that they could make a conscious effort to respond to cues from the outside world, the researchers raised the hypothesis.
The researchers placed electrodes on the participants’ heads to measure their brain waves; beside your eyes, to track eye movements; and on the chin, to measure muscle activity. They used this data to determine when participants entered rapid eye movement (REM) sleep stage, when lucid dreams are more likely to occur, explained Konkoly.
Four groups of independent laboratories in the United States, Germany, France and the Netherlands conducted four separate experiments. The researchers used various techniques in the experiments to communicate with dreamers during REM sleep, including asking spoken questions and giving them messages encoded in flashing lights, beeps and physical touches, which dreamers were trained to decipher. If the dreamers received and understood the question or message during a lucid dream, they responded with a set of distinctive eye or facial movements that were interpreted by the electrodes.
“This two-way communication – from outside to inside the dream and vice versa – is something that may seem to belong in the realm of science fiction,” Pilleriin Sikka, senior professor of cognitive neuroscience at Sweden’s Skövde University and postdoctoral researcher in University of Turku, Finland, told Live Science by email. “Given how challenging it is to induce lucid dreams in the laboratory and the study was carried out by four groups of independent laboratories, the researchers’ effort is remarkable,” she said.
Sikka, however, notes that it was very difficult for experiments to achieve this communication successfully – it was obtained from only six of 36 participants in many attempts – which raises questions about the extent to which the findings can be generalized and replicated.
About 23% of people have a lucid dream once a month or more, according to a 2016 research article published in the journal Consciousness and Cognition. Konkoly helped to induce lucid dreams in his experiments by training participants to associate a sound with a lucid state of mind and then introducing them to that sound, or hint, again during sleep. (Those who want to experience lucid dreams for themselves can download an app called Lucid, developed by students in the Northwestern University lab, said Konkoly.)
The researchers suggest that the method in the experiments could be adapted to help adapt a person’s dream to a specific need, such as learning or dealing with emotional trauma, according to the study.
Robert Stickgold, professor of psychiatry at Harvard Medical School and director of the Center for Sleep and Cognition at Beth Israel Deaconess Medical Center, said the results of the study were “groundbreaking” in an email to Live Science.
“The retrospective nature of dream reports presents a challenge for the study of dreams. Two-way real-time communication between researchers and lucid dreamers immersed in REM sleep offers a new and exciting window into the study of dreams and dreams,” said Stickgold. Still, it is unclear “how easily these early discoveries can be extended to real-life applications or to answer more complex questions about the nature and function of dreams.”
Some images of the lucid dreaming experiments were captured for an online NOVA, a PBS documentary called “Dream hackers: bridge to your hidden brain“which is available to watch on YouTube from February 18th.
Originally published on Live Science.