Scientists are closer to understanding the mystery of déjà vu thanks to new virtual reality research

Have you ever had that strange feeling that you’ve been through the exact same situation before, even though it’s impossible? Sometimes it may even seem like you are reliving something that has already happened. This phenomenon, known as déjà vu, has puzzled philosophers, neuroscientists and writers for a very long time.

From the late 1800s, many theories began to emerge as to what might cause déjà vu, which means “already seen” in French. People thought maybe it stemmed from a mental dysfunction or maybe some kind of brain problem. Or perhaps it was a temporary hiccup in the otherwise normal operation of human memory. But the subject did not reach the realm of science until very recently.

Moving from the paranormal to the scientific

At the beginning of this millennium, a scientist named Alan Brown decided to review everything that researchers had written about déjà vu up to that point. Much of what he could discover had a paranormal flavor to it, related to the supernatural – things like past lives or psychic abilities. But he also found studies that polled ordinary people about their experiences of déjà vu. From all of these papers, Brown was able to extract some basic findings about the déjà vu phenomenon.

For example, Brown found that roughly two-thirds of people experience déjà vu at some point in their lives. He determined that the most common trigger for déjà vu was a scene or place, and the next most common trigger was a conversation. He also reports hints over a century or more in the medical literature of a possible connection between déjà vu and certain types of seizures in the brain.

Brown’s review brought the topic of déjà vu into the realm of more mainstream science because it appeared both in a scientific journal that cognitive scientists tend to read and in a book aimed at scientists. His work served as a catalyst for scientists to design experiments to study déjà vu.

Testing déjà vu in the psychological laboratory

Prompted by Brown’s work, my own research team began conducting experiments aimed at testing hypotheses about the possible mechanisms of déjà vu. We investigated a nearly century-old hypothesis that suggests déjà vu can occur when there is a spatial similarity between a current scene and an unrecalled scene in your memory. Psychologists have called this the Gestalt Cognition Hypothesis.

For example, imagine you are passing the medical station in a hospital ward on your way to visit a sick friend. Even though you’ve never been to this hospital before, you’re overwhelmed with the feeling that you have. The main reason for this experience of déjà vu may be that the layout of the scene, including the placement of furniture and specific objects in the space, has the same layout as a different scene that you have experienced in the past.

Perhaps the way the nursing station is laid out—the furniture, the items on the counter, the way it connects to the corners of the hallway—is the same as a set of welcome tables in terms of signs and furniture in the hallway at the school entrance. an event you attended a year earlier. According to the gestalt familiarity hypothesis, if this previous situation with a similar layout to the current one does not come to mind, you may be left with only a strong sense of familiarity with the current one.

To explore this idea in the lab, my team used virtual reality to place people in scenes. In this way, we could manipulate the environment people were in – some scenes shared the same spatial layout, while otherwise they were different. As predicted, déjà vu was more likely to occur when people were in a scene that contained the same spatial arrangement of elements as an earlier scene that they had seen but did not remember.

This research suggests that one factor contributing to déjà vu may be the spatial similarity of a new scene to one in memory that fails to be consciously recalled in the moment. However, this does not mean that spatial similarity is the only cause of déjà vu. Quite possibly many factors can contribute to what makes a scene or situation feel familiar. More research is underway to investigate additional possible factors in this mysterious phenomenon.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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