What does the next generation think of today’s issues? As part of The Big Smoke’s Next Gen program, Zain Hamdia (age 13) explores déjà vu, that sense you get when you think you’re re-experiencing something familiar again. 

The sun has nearly set in the chaotic city. Horns can be heard over loud conversations. I am walking down the street and feel thirsty, so I go in search of water. I eventually stumble upon a little convenience store. A convenience store that seems all too familiar. The sign above the building, “Liberty Mart,” is something I swear I’ve seen before. One letter slightly tilted and another completely missing, as it flashes in various neon colors. I sprint inside and get my water. While walking to the cashier, I get that feeling again. The cashier is wearing a white coffee-stained tank top that I have seen somewhere. The stain resembles the shape of Mickey Mouse. The bags of chips are arranged very specifically on the shelves by color. Also, familiar. Have I been here before? That’s impossible. I’ve never even been to this city before.

The experience described above is what’s known as “déjà vu,” which is actually a French term. Its literal translation appropriately means “already seen.” Déjà vu describes the feeling of looking at something and recognizing it, even though you’ve never actually seen it before.

This eerie sensation is something that 60-70% of the population has experienced at least once in their lifetime, with many experiencing it several times. It also tends to happen more frequently with younger age groups than older. But why does it happen? Is it science? Or science fiction?

Almost all the plausible and varied theories seem to lead us back to the most mysterious organ in our body—the brain.

Déjà vu describes the feeling of looking at something and recognizing it, even though you’ve never actually seen it before. … This eerie sensation is something that 60-70% of the population has experienced at least once …

There are some things about the brain we know for certain—like what areas control movement, sight, or speech—yet there are many other functions and occurrences that still elude us. One of them being déjà vu.

This strange phenomenon could have many causes and, while we don’t have one solid answer, there are many theories that attempt to explain why it happens. However, what we do know for certain is that déjà vu is not a glitch in the simulation—sorry, Hollywood.

One possible theory is something called “split perception.” Split perception explains that if you see something out of the corner of your eye, or you see something that you aren’t paying specific attention to, your brain immediately stores that object as a memory in the temporal lobe (one of four lobes in the brain that is responsible for processing input and translating into memory). Moments later, if your attention is then focused on that object, your brain retrieves it as a memory, creating the illusion of déjà vu.

Another theory sounds a bit like a computer error and is called “minor brain circuit malfunction.” While the name does sound a bit alarming, there is no need for concern. What happens is your brain’s electrical signals get crossed and falsely interpret what you are presently seeing as a memory, or something from the past. And, while we are on the subject of memory, this leads us to our next theory.

Also on The Big Smoke

• The Big Smoke Next Gen: Virtual Reality, Just What the Doctor Ordered
• The Big Smoke Next Gen: The Clandestine Side of 3D Printing
• The Big Smoke Next Gen: From COVID-19 to Zainiac 19

“Memory recall” describes what happens when your brain sees something similar to a past memory and fills the gaps with what is in front of you, thus giving the effect of déjà vu. The way it was found is very fascinating. Scientists put test subjects into a virtual world using virtual reality and let them explore. Some areas of the world were identical to others, except certain parts had been changed. For example, a trash bag in place of a bush, or a chair instead of a stool. This would make the test subjects believe they had seen this new area before because the two areas were so similar; the memory of the first and the second started to blur. Essentially, the brain retrieves a similar past memory and gives you the feeling you have experienced it before, even though you haven’t.

Aside from these, there are dozens of other theories being explored, with still no solid answers. Ultimately, we may never know the real reason for déjà vu.

Maybe Dr. Sheldon Cooper on The Big Bang Theory had it right all along.

Amy: “Wow. Déjà vu.”

Sheldon: “Amy, you’re a neuroscientist, you know the latest research into déjà vu suggests it’s nothing but the frontal regions of the brain attempting to correct an inaccurate memory.”

Amy: You telling me stuff I already know is definitely déjà vu.