Why study this?
Scientists disagree about the role of dreams in our health. There is a hypothesis that dreams are important for preserving the memory that has accumulated during the day. However, it is difficult to confirm due to the limited possibilities for studying dreams. Another question scientists want to answer is what is the nature of the images and experiences that are reflected in dreams.
“We are researching dreams to learn more about why we dream and how they can be beneficial for the mental function upon awakening. In our previous research, we suggested that the process of cognition during sleep may be beneficial for memory function, ”Ken Paller of Northwestern University in Chicago told Gizmodo. He and his colleagues have been studying the relationship between sleep and memory for many years.
Upon awakening, people retell dreams in fragments and, apparently, in a distorted form. In sleep, people’s ability to form new clear memories is impaired. Communicating with a sleeping person in real time – so that they can relay information about dreams before waking up – would give scientists new opportunities for research.
Lucid sleep is a state in which a sleeping person is aware that he is sleeping, but this does not lead to an instant awakening. This condition is possible mainly during the REM sleep phase. Experts note that this is a rare phenomenon.
Previously, scientists have learned to recognize lucid sleep by the nature of eye movement (1, 2). Paller and his co-authors used sounds to induce lucid sleep in sleeping people. In previous studies, interaction with sleeping people was one-way: they perceived stimuli from the “outside world”, but did not respond to them.
Two-way communication with sleeping
In the new study, scientists from different countries, including Paller’s group, set out to establish two-way communication with a sleeping person. “Many will assume that this is not possible – that people are more likely to wake up from questions or not answer, and will definitely misunderstand the question,” Paller explained the complexity of the tasks they posed.
The new scientific article includes data that were independently obtained by four different groups of scientists in different countries – the United States, France, the Netherlands and Germany. They pursued the same goal, but took slightly different approaches. The researchers decided to combine their data into one publication. An excerpt from a documentary based on this data is available online in English.
The study involved 36 people, some of whom already had lucid dreaming experiences. The scientists used different stimuli to put the participants in a state of lucid sleep: sounds, touches, speech, flashing lights. The researchers used electroencephalography to assess brain activity and determine sleep patterns.
A total of 57 sleep sessions were held, in 26% of them, scientists were able to see signs of lucid sleep. During successful communication, sleeping people could follow instructions: with the help of eye movements and facial muscle contractions, answer “yes” and “no”, distinguish between sensations, and do simple mathematical actions. Scientists have called this “interactive dreaming.”
There were 158 attempts to “get in touch” with people in a state of lucid dream. In 18% of cases, the participants gave correct answers, in 60% of cases there was no response.
After lucid sleep, study participants reported that they could recall instructions they received before going to bed and tried to follow them. Some remembered the questions asked, although sometimes they were distorted. Some of the participants perceived in a dream the words of scientists that they came from another reality, others “heard them on the radio” or through other means of communication. In some cases, people did not remember the questions or remembered the wrong questions.
One of the participants recounted how he received the question “Do you speak Spanish?” From scientists in a dream: “I was at a party with friends. Your voice sounded outside, like a voiceover in a movie. I decided to answer no [при помощи сокращения мышц лица]… “When I touched my finger, I was fighting goblins. I remember being surprised that I could do so many things at the same time, ”said another participant.
“We found that during rapid eye movement sleep, people can interact with the experimenter and communicate in real time. We also showed that sleepers can understand questions, use working memory and provide answers, ”said Paller.
This is a small study, so scientists point out that its results should be viewed with caution. However, they are convinced that the work demonstrates the possibility of two-way communication with the sleeper. In addition, it is noteworthy that several groups of scientists in different countries came to this conclusion independently, using different methods.