A deja vu is the feeling you get when a situation feels familiar, almost like you have been through it before… but you actually never have.
Let’s say you go to a restaurant and the waitress spills the coffee on their hand. The scene plays out just as you remembered but that is the first time you are eating there. Congratulations! You are experiencing deja vu.
This weird feeling has been an inspiration for many famous movies and songs. The reason why there are so many speculations about deja vu is the lack of hard evidence caused by the fact that the experience is brief. Scientists cannot just sit and wait for it to happen to them or just record it the moment it happened. But a professor in CSU’s Department of Psychology, Anne M. Cleary, was able to recreate deja vu in human subjects with the help of visual reality. By making candidates go through the same moment in both reality and visual reality, she had the chance to examine their brains during the feeling of premonition during the deja vu state.
In another research, researchers showed candidates 24 common, basic words and then hypnotized them to trigger the second part of the recognition process. When the candidates were shown the same words after the hypnosis, they said that these words feel familiar although they do not know when they have seen them before. Out of the 18 people studied, 10 of them reported that they felt like deja vu.
But still, we do not have any single explanation of deja vu that just solves the misery. Our memory is way more complicated than we would think. It is not only the feeling of deja vu but also the times that we are sure we lived a certain moment that is unreliable. Our brain is constantly playing with one of the theories that explain the deja vu we are about to dive in:
1- Completing The Uncertain Memory:
Let's assume you are in Toronto for the first time in your life. You are all happy watching the CN Tower when all of a sudden, you see a little girl falling to the ground, crying because she hurt her hands. It is weird because you feel like you have seen this happening before, but you have probably never even seen this girl.
Then why do you feel this way?
Your brain gets frustrated when memory is incomplete. So, when you remember the abstract of something, but you don’t remember any of the details, your brain will add those details.
In some cases, it is personal, and it is motivated by your bias. A child who has been bullied throughout kindergarten can later remember it as if they were the bully. It is an extreme example, yet it is completely natural.
In some other cases, where it is not personal, your brain can try to complete the old uncertain memory with a new, similar one. Yes, you may have not seen that little girl before. But let’s say years ago, you have seen a girl falling who looks just like her or perhaps who was wearing clothes that have the same pattern as her. Yes, even a pattern or a color could work.
This is called the hologram theory. When you see that girl in Toronto, an old memory swims up from your unconscious memory. Your brain has summed up this girl you see with the girl you saw years ago who you cannot completely recall. But since you cannot clearly remember that event from years ago, your brain supplements the old memory without you identifying it. And now, the situation feels familiar, but you have no idea where you remember it from.
The dual-processing theory assumes that deja vu happens when cognitive processes lose synchronization. Your brain is processing many different elements, like smells and sounds and, colors at a time. When one of these elements is processed later or earlier than the others, your brain can try to store this event twice. Making you feel like you have lived that moment before.
3- Attentional Theory
According to this theory, the things we perceive under full awareness can cause deja vu once we actually pay attention to them.
Before we go deep into this theory, I want to introduce you to the phenomenon “inattentional blindness”:
Daniel J. Simons, an experimental psychologist and professor at the University of Illinois, defines this as “The failure to notice a fully visible but unexpected object because attention was engaged on another task, event or object.”
It is a nice autumn day. You are on the bus, watching the rain slowly fall. You are focused on the sound of the rain, but you are still able to hear the old ladies in front of you chit-chatting. So, your flanker stimulus (below conscious awareness) is processing the chat.
But when the driver suddenly blows the horn and you bring your attention back to the bus, you notice the ladies. So, your focal stimulus takes over.
And certainly, you are feeling deja vu!
Our ability to process information during inattentional blindness but our inability to save it as a decent memory makes us feel like we have gone through this scene before when we actually start paying attention to it and process the memory properly.
4- Memory Confusion
This theory explains deja vu with a brain malfunction.
Normally, when your brain absorbs information, it follows a specific path from your short-term memory to your long-term memory.
This theory suggests that sometimes an event you are currently experiencing accidentally goes into your long-term memory instead of your short-term memory, making you feel like you are living in an old scene, an old experience.
This theory is also accepted by many people although there are not many pieces of research that explain why and how this confusion occurs.
Last but not least…
About two-thirds of people experience deja vu. It is mostly seen in young people and the frequency decreases with age. Research and surveys show that drug use, however, increases the frequency of deja vu experiences.
People with epilepsy and schizophrenia are feeling deja vu more often. This data caused scientists to link it with these diseases at first but now there is no compelling evidence of such a connection.
Later, this speculated link to pathology was explained by some scientists as people without these diseases were just afraid to admit they have experienced déjà vu – something that has only recently been accepted as something normal.
This theory makes sense since there are a lot of science-unrelated, fictional explanations of deja vu that could make some people believe that the feeling is also fictional.
Speaking of which, the famous series Matrix has the most popular and interesting explanation of déjà vu.
In the first movie, the main character Neo sees the same cat moving a certain way for the second time and tells his friend Trinity that he is experiencing deja vu. Trinity, who knows about the way our world runs – the way it is conducted would make a better definition – tells him that something had been changed in our simulation. She says that every time they change something in the simulation that we are living in, we experience deja vu.
Later, they add a new character to the series. A lady who gets deja vu all the time and she’s able to tell the future with the help of this feeling. It turns out that it was caused by a mistake they made in Matrix. The augurs and deja vu stories were gone when the mistake was fixed.
There are also a lot of people in real life who say they know what is about to happen when they are having deja vu. In reality, it is just a coincidence. The chances of you guessing your future when you are having deja vu are equal to the chances that you are not.