Why do we experience Déjà Vu?

By: Alyssa Shi ’26 Opinions:

When you walk into a new place, have you ever been overwhelmed by the feeling that you have been to this place before? Approximately 97% of people have experienced Déjà vu at least once in their lifetime, and 67% experience it regularly, most commonly between the ages of 15 to 25 (1).

Déjà Vu is a French term that refers to “already seen”, describing the feeling of having already been to one place before, and it is the conflict between the false eerie familiarity and the awareness that the familiarity is incorrect There have always been multiple explanations and misunderstandings of déjà vu, some people think of it as the leakage of memory from past lives, and others think of it as the guidance of the future. What is the unsettling truth behind déjà vu scientifically? What happens in the brain during déjà vu?

Since déjà vu occurs unexpectedly and rapidly, it is difficult to study and recreate it in a lab setting. Therefore, multiple parapsychologists have developed different speculations of déjà vu Neurologist Dr Khoury speculated that déjà vu is induced by malfunctioning connections between the parts of your brain that serve in memory recollection and familiarity (2) Human brains have two temporal lobes on each side, and the hippocampus inside is responsible for short-memory storage When experiencing seizures, the malfunctioning neurons that are in charge of recognition and familiarity (3), uncontrollably fire electric signals to affect and activate the hippocampus and surrounding brain tissues, causing experiences such as déjà vu to happen. In short, memory systems are disrupted by electric signals to induce a false sense of familiarity, mistakenly mixing the present with the past

A related theory suggests that déjà vu is caused by malfunction between short and long-term circuits in the brain (4). When traveling along the circuit of short to longterm memory, information from surroundings accidentally leaks out, bypassing the storage transfer mechanism and avoiding the short-memory bank completely Therefore, it feels like memories from the past are dug out when a new moment is experienced - which is supposed to be in the short-term memory.

Additional researchers postulated that déjà vu is caused by delayed processing Delayed processing means that when humans perceive something, the sensory information simultaneously runs to two separate pathways The pace of the information running is different, one could run more rapidly than the other, and the brain could break the same event into two separate events, thereby causing delayed memory.

Dr Alira O’Connor, a senior psychology lecturer at St Andrews University, proposes that déjà vu might be caused by memory reaffirmation and correction “For the vast majority of people, experiencing déjà vu is probably a good thing. It's a sign that the fact-checking brain regions are working well, preventing you from misremembering events,” Dr. O’Connor says (5). The frontal decision-making areas are affecting ascertaining between actual experiences and made-up experiences O’Connor’s study used Magnetic Resonance Imaging (MRI) to scan the brain as the 21 participants experienced lab-induced déjà vu

The results support the hypothesis that déjà vu was triggered by the decision-making areas of the brain instead of the areas pertaining to memory, such as the hippocampus O’Conner’s team concludes that the brain was conducting conflict resolution to reaffirm what has actually happened.

Déjà Vu has intrigued scientists for hundreds of years, and it is still not fully understood and remains with a great possibility of new theories Whether it is caused by neuron firing, delayed processing, or conflict resolution, déjà vu, the unsettling and incredibly mysterious phenomenon, constantly reminds us of how sophisticated and fascinating our brains are.

Works Cited

1

Lewis, J (2012, August 14) https://wwwpsychologytodaycom/us/blog/brainbabble/201208/the-neuroscience-d-j-vu Psychology Today Retrieved January 22, 2024, from https://wwwpsychologytodaycom/us/blog/brainbabble/201208/the-neuroscience-d-j-vu

Clinic, C (2023, December 13) Deja vu: what it is and why it happens Cleveland Clinic https://healthclevelandclinicorg/deja-vu-what-it-is-and-when-it-may-because-for-concern

3

BuzzFeed Unsolved Network (2021, April 9) The Science of Déjà vu [Video]

YouTube https://wwwyoutubecom/watch?v=OLTPAa MNuk

4

Lewis, J (2012, August 14) https://wwwpsychologytodaycom/us/blog/brainbabble/201208/the-neuroscience-d-j-vu Psychology Today Retrieved January 22, 2024, from https://wwwpsychologytodaycom/us/blog/brainbabble/201208/the-neuroscience-d-j-v https://wwwsciencefocuscom/the-human-body/deja-vu 5

Ling, T (nd) What causes déjà vu? The quirky neuroscience behind the memory illusion BBC Science Focus Magazine