By Gabriella DeLuca, ’27

Staff Writer

Have you ever walked into a room and had the strange sensation that you had already been there before? Or turned the corner while visiting a new city and gotten the overwhelming feeling that you had been in that exact same spot before, only you know there is no possible way you could have? This sensation is known as Déjà Vu, the French word for “already seen.” Nearly 97 percent of people will experience this phenomenon at least once in their lifetime. But what causes it? And what does it mean?

Déjà Vu is the fleeting sensation that you have already lived in a totally identical situation at some point in your life, only you haven’t. This conflict between false familiarity and rational knowledge feels as if your memory is telling you one thing, while your brain is saying something different. In fact, this conclusion is not as far off as you may think.

The concept of Déjà Vu has fascinated scientists for many years, and even now the true cause of this “glitch in the matrix,” as the popular movie franchise calls it, is still yet unknown. Some people have proposed that Déjà Vu could be a sign that you are recalling an experience from a past life or experiencing a paranormal event; however, after increased research and experimentation, scientists have developed scientifically proven theories to explain the reasons behind this uncanny sensation. Through the use of insights into neuroscience, scientists have proposed that Déjà Vu is likely the result of dysfunctional connections between the parts of the brain that have a crucial role in memory and familiarity.

According to Dr. O’Connor, a senior lecturer in the School of Psychology and Neuroscience at the University of St. Andrews, this miscommunication arises between two parts of the brain, namely the medial temporal lobe that is associated with recollecting memories and the frontal cortex that is responsible for higher order cognition and fact-checking. Déjà Vu may occur when the temporal lobe sends signals to the frontal cortex to indicate a familiarity with the experience at hand. The frontal cortex region then evaluates whether this signal is consistent with a prior experience. If a prior experience is not identified, the sensation of Déjà Vu occurs and you are left with the conscious feeling of familiarity without evidence to back it up; in other words, false memories.

In 2006, a group of medical researchers led by Leeds Memory Group conducted an experiment in an attempt to recreate Déjà Vu in a lab setting. First, the patients were presented with a simple memory while under hypnosis, such as playing a game or seeing a certain color. The test subjects were then given the suggestion to either forget or hold on to the memory. The experiment showed that this later triggered the sense of Déjà Vu when the patients were presented with a situation that reminded them of the memory they were introduced to while under hypnosis. The results of this confirmed to scientists the belief that Déjà Vu is a memory phenomenon, a feeling of familiarity that cannot be placed.

What does it mean if you experience Déjà Vu?

Although this memory quirk may seem as a sign your brain is working improperly, it actually indicates the opposite. The sensation of Déjà Vu demonstrates that the fact-checking brain regions are functioning correctly to prevent you from incorrectly remembering events. Having this feeling of false familiarity is a sign that your brain is functioning properly to accurately remember situations and events, and is overall a sign of a healthy brain and mind.

Through recent studies and experimentation, scientists have discovered specific situations that can increase the probability of experiencing Déjà Vu. For example, age can have an effect on whether you are more likely to experience Déjà Vu. Young people between the ages of 5 to mid-20s tend to experience more frequent instances of Déjà Vu due to the fact of healthier fact-checking frontal regions in younger brains. As you age, the brain’s ability to detect memory errors declines, and the instances of Déjà Vu become less common.

So, if you experience Déjà Vu in the future, do not worry – instead, view it as proof of a well-functioning brain and a healthy mind.

Works Cited:

“Can Science Explain Déjà Vu?” BBC Bitesize, Apr. 2024, http://www.bbc.co.uk/bitesize/articles/zdpbwsg.

Cleveland Clinic. “Why Does Déjà vu Happen?” Cleveland Clinic, 23 Oct. 2022, health.clevelandclinic.org/deja-vu-what-it-is-and-when-it-may-be-cause-for-concern.

Kennedy, Justin. “The Fascinating Science of Déjà vu | Psychology Today.” 20 Dec. 2023, http://www.psychologytoday.com/us/blog/brain reboot/202312/the-fascinating-science-of-deja-vu.

Stierwalt, Sabrina. “Can Science Explain Deja Vu?” Scientific American, 23 Mar. 2020, http://www.scientificamerican.com/article/can-science-explain-deja-vu/.