Everyone is familiar with the state in which we feel as if we have been in a similar situation or a similar place before. This state, which is not always pleasant, lasts a few seconds and passes quickly, leaving us wondering: when could this have happened to me?

Surprisingly, scientists still do not have a clear explanation of how and why the phenomenon of deja vu arises (translated from French — “already seen”). In total, there are about 40 hypotheses, however, many of them are associated with religious beliefs and supernatural phenomena. Professor of Cognitive Psychology at Colorado State University (USA) Ann Cleary tested in experiments one of the most popular hypotheses of the origin of the déjà vu effect. She shared the results in an article posted on The Conversation portal.

It could be due to stress or fatigue.

Theories explaining deja vu began to appear from the end of the 19th century. People thought that the occurrence of this mental state could be the result of mental disorders, some kind of problems with the brain, or perhaps a temporary malfunction in the normal functioning of human memory. But scientists took up this topic seriously quite recently, only at the beginning of the third millennium.

American psychologist Alan Brown collected everything that was written by researchers of the phenomenon of deja vu before him. Much of what he managed to find had a paranormal flavor and was associated with supernatural phenomena — such as reincarnation or psychic abilities. But the scientist also came across studies in the form of surveys, where ordinary people were asked to talk about their experience of experiencing deja vu.

From all these works, Brown drew the basic information about the unusual mental state. So, he determined that two-thirds of people experience deja vu at some point in their lives. The most common trigger (provoking factor) for this sensation is the scene or place that the person enters, and the next most common is the conversation in which he participates or hears. Brown also noted that in the medical literature of the twentieth century there are suggestions about a possible connection between the effects of déjà vu and certain types of convulsive activity in the brain. But, in addition to biological disorders like epilepsy, stress or banal fatigue can be the cause of this condition.

In total, Brown counted thirty different explanations for déjà vu. His extensive review took this topic to the scientific plane — publications began to appear in peer-reviewed journals that scientists read and which they focus on in their work. In the end, it came down to experiments.

Gestalt hypothesis of acquaintance

Anne Cleary, a professor of cognitive psychology, and her colleagues decided to test one of the theories explaining this phenomenon in the laboratory.

“Inspired by Brown’s work, my own research group began to conduct experiments aimed at testing hypotheses about the possible mechanisms of déjà vu,” she writes. “We explored a hypothesis almost a century old that suggested that déjà vu could occur when there is a spatial similarity between the current scene and one that the person cannot remember. Psychologists call this theory the Gestalt Acquaintance Hypothesis.

For example, imagine that you are passing by an infirmary in a hospital ward on your way to visit a sick friend. Although you have never visited this place before, you were struck by the feeling that you have been here. The main reason for the experience may be that the layout of the scene you are in, including the placement of furniture and specific objects in the space, has the same configuration as another scene you have seen in the past.

For example, the way the infirmary is laid out (furniture, items on the counter), the way it connects to the corridor, mimics the arrangement of tables and items at the entrance to a school event you attended a year earlier. According to the Gestalt Familiarity Hypothesis, unless it occurs to you that a previous situation is similar to the current one, you can only have a vague sense of familiarity with it.”

To test the hypothesis, Anne Cleary’s research team used virtual reality technology. People were placed in scenes with different spatial structures, some of them had the same configuration. As expected, déjà vu was more likely to occur when a person was in a scene that contained the same spatial arrangement of elements as one of the previous ones shown to him. The subject saw it, but could not remember. In other words, it simply did not occur to him.

“However, this does not mean that spatial similarity is the only cause of déjà vu,” Cleary concludes. — It is very likely that many factors can influence the fact that a scene or situation seems familiar to us. Additional research is currently underway to explore possible factors playing a role in this mysterious phenomenon.”

brain trick

It is worth saying that the hypothesis tested by American psychologists is the most common of those proposed by scientists to explain the phenomenon of deja vu. It was stated earlier in an interview with aif.ru by the head of the laboratory of the Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, Doctor of Biological Sciences, Academician Pavel Balaban: “All our memories are associated with the environment in which we once received them. Moreover, memories are stored in a complex, we remember the situation with the help of all the senses — how the birds chirped at that moment, how the sun shone, what the smell was, etc. Our memory simply cannot exist in isolation from these nuances. And when we find ourselves in an environment where there is some element from our memory (for example, the color of the walls in the room coincided), the rest seems to be drawn out after it. There is such an completion of the situation, we begin to recognize it.

But it’s one thing when we find out the real situation that we’ve been in before, and another thing when the brain deceives us. The phenomenon of deja vu is just the wrong completion of the brain, deception. How it happens is still a mystery to science.”