THE SCIENCE BEHIND DEJA VU

Why Does it Happen to You?

by Kyle Banker Design: Isabella M. Lozano

Introduction Have you ever walked into a restaurant in Key Biscayne for the first time that you swore you had already visited? What about having a conversation about the emerging University of Miami football team that you felt sounded familiar? You suddenly feel convinced that you have been in this situation, but you are unsure why. When you tell your friends, “I swear we have done this before,” they will likely give a confused look and respond, “What are you talking about?” From this, you feel bewildered and wonder why you had an eerie sensation as if that experience had previously occurred. This typical and trending feeling across college students is known as déjà vu, or “already seen” in French. Almost two out of three people worldwide have experienced déjà vu, with rates being the highest among people between the ages of 15 and 25. As a college student, and someone that falls between the prevalent age range, it is likely that you have had this experience throughout your time at the University of Miami. However, it is still somewhat misunderstood why déjà vu happens and what triggers this experience in our brain. As a result, let us understand why we thought we already talked about Sebastian the Ibis at Smoothie King or how we listened to the same song in the car while driving past the exact same Publix. After this article, you will understand why déjà vu exists and its role at the University of Miami.

What is Déjà Vu?

The expression “déjà vu” originated from the French philosopher Émile Boirac in 1876, where Boirac had a similar experience as one you may have in a few weeks. After using the term in his book L’Avenir des sciences psychiques in 1917, the concept of déjà vu has since been applied internationally. In the present day, we use the following universal definition to describe déjà vu: “any subjectively inappropriate impression of familiarity of the present experience with an undefined past.” To expand on this definition, there is no issue with your brain if you occasionally experience déjà vu. Most individuals experiencing these illusions are entirely healthy; only in rare cases does déjà vu indicate a neurological disorder. According to multiple studies done in the past few decades, people who report experiencing déjà vu experience it about once a year. The frequency of déjà vu is also experienced equally by both men and women, and its occurrence has been found to decrease with age. Another interesting finding is that those who are more educated or have higher socioeconomic status are more likely to experience déjà vu. Despite many studies involving déjà vu, it is very difficult to study the phenomenon as the feeling occurs randomly. Some scientists have even tried using hypnosis or virtual reality as a method of influence; unfortunately, these researchers did not achieve obtainable results. This fleeting and unpredictable time block makes déjà vu a very intriguing area of research. While we cannot understand everything about this feeling, scientists have generated strong reasoning behind its occurrence through neuroscience and psychology.

Explanation Through Neuroscience & Psychology

Scientists have found that feelings of exhaustion and stress tend to

result in experiences of déjà vu, but questions remain as to why our brains respond to those areas of fatigue with feelings of déjà vu. While there are multiple theories explaining déjà vu, they all share a common theme: the temporal lobe. The temporal lobe is the section of the brain that controls memory, and when your body is under immense amounts of stress, the temporal lobe cannot function properly. As a result, the hindrance of the temporal lobe can cause these episodes or feelings of déjà vu to occur. While connecting déjà vu to memory retention still needs further research, scientists developed this shared understanding from people who suffer from temporal lobe epilepsy. Temporal lobe epilepsy is a condition where nerve cell activity in the brain is disturbed. Results from these studies suggest that déjà vu events may be caused by an electrical malfunction in the brain. For those with temporal lobe epilepsy, clinical reports show that some of these patients experience déjà vu before an epileptic seizure event. It is found that seizure discharges from the temporal cortex simultaneously activate two circuits in the hippocampus. One of these circuits represents our ongoing experience of the present world while the other retrieves memories. By activating both these circuits at the same time, it is possible that these two brain functions colliding cause us to remember the present situation, or, in other words, experience déjà vu. While these overall findings between déjà vu and memory are not concrete and solidified within the scientific world, they are a significant first step toward our understanding of the origin of déjà vu. However, it is interesting to see why this feeling frequently occurs among college students, as our fatigue can cloud short and long-term memory in the frontal lobe. This is very apparent at the University of Miami, where students are typically exhausted due to exams, a late football game, or other events. I was inspired to do further research into the connection of déjà vu within the University of Miami undergraduate student body.

Initial Research at the University of Miami

While gathering data from University of Miami students, I wanted to target three areas of interest: (1) student demographics that affect episodes of déjà vu, (2) how often a University of Miami student experiences déjà vu, and (3) where respondents experience déjà vu. To collect all this data, I sent out a Google Form on September 13th, 2022, to over 200 undergraduate students at the University of Miami. The Google Form contained a few questions aiming to answer the goals mentioned above, and I received 57 responses on this day. Based on this preliminary data set, I could extract some key findings from my research. The respondents were aged 18-22 years old, ranging from freshmen to seniors at the University of Miami. About 95 percent of the respondents (54 of 57) said they experienced déjà vu at some point in their life, and 82 percent (47 of 57 respondents) estimated that they had this eerie feeling anywhere from 2 to 5+ times a year. Specifically to University of Miami students, about 83 percent of respondents have experienced déjà vu while at the University of Miami, including at The Rat, Herbert Wellness Center, and in various classes. Due to the small and convenient sample size, it is challenging to extrapolate whether these results apply to the entire University of Miami student body; but based on survey results, it appears that University of Miami students frequently experience déjà vu. We should consider that some respondents who replied “no” may not have remembered these experiences if they had occurred a few months or years prior. It is also significant to point out that experiences of déjà vu can be easily forgotten over time. As a result, the responses involving the frequency of déjà vu experiences from the surveyed University of Miami students are purely estimated and are not

exact. Nevertheless, these responses provide a limited yet intriguing range of how often University of Miami students personally experience déjà vu on an annual basis.

Next Steps

There is more research needed to solidify our understanding of déjà vu, both from a neurological and psychological perspective. Nevertheless, it is an interesting trend to keep an eye on, both in pop culture and in the scientific world. Why does déjà vu occur more frequently for college students than for older populations? What is the best theory for describing déjà vu? What triggers a random déjà vu reaction? These questions will likely remain unanswered for the short term, as the difficulties of researching a random neurological process is not time efficient nor easily replicated in a study environment. However, after reviewing available findings from primary and secondary sources, we can now better understand why the human brain is sometimes “tricked” by memory. That, Scientifica readers, is the power of déjà vu.