Are you ever doing something and suddenly have a feeling that you’ve already experienced or done that thing before, even though you haven’t? Do you ever recognize the situation you’re in, although you’ve never encountered it? For example, when you walk into a house you’ve never seen and been in but you feel as if you remember that place. If this has ever happened to you, you’re experiencing déjà vu.

What happens in the brain during déjà vu?

Although there isn’t a definitive answer as to what happens in the brain during déjà vu, scientists have researched and tested this, leading to many closely related guesses. One thing that might be happening in your brain is that the frontal areas of your brain are more active than the hippocampus (the part of your brain in charge of memory) during déjà vu. What are the frontal areas of my brain? Frontal areas, or also called the frontal lobe, is as its name suggests: it’s in the front part of your brain. It is mainly in charge of your reasoning and judgment. This basically means that during déjà vu, your memory is weak while your decision making is strong. It’s hard for the brain to figure out if the memory you were experiencing was a real or fake memory because, at the moment, your memory ability is very weak.

Why does déjà vu happen?

Just as scientists don’t know for sure what happens in the brain during déjà vu, why déjà vu happens is still a mystery.

EPILEPSY

One reason for déjà vu is epilepsy, a disorder that causes seizures. Many people with temporal lobe epilepsy, a hard word that basically means a type of epilepsy that affects your hippocampus, say that they often have déjà vu right before they have a seizure. Once again, the hippocampus helps you with your memory. This means that déjà vu is somehow connected to memory.

UH-OH! BRAIN GLITCH?

You might not have epilepsy but maybe your brain might be “glitching”. No, I don’t mean that your brain is crashing or shutting down like a video game that glitches. I mean that your brain is probably experiencing something that usually happens before seizures, causing that “glitch”. So even if you’re healthy with no epilepsy, you still have this seizure-like glitch in your brain. This glitch causes your brain to activate both your past and present memories, leading it to confuse and mix them up. Because of this, you might suddenly be “remembering your past memories”. Wow! Who knew? That déjà vu could simply be created by your brain’s mistakes.

YOUNG PEOPLE...

As scientists have said, “Young people, between the ages of 15-25, are more likely to get déjà vu than older people.” It’s hard to find out exactly why this happens but this might be because, at those ages, your brain is more precise and is able to detect your brain’s trip-ups and mistakes more easily. As you’re growing older, your brain starts making many memory errors, therefore, it’s more difficult for the brain to detect certain, specific errors that lead to déjà vu.

SLEEPY AND STRESSED

The last and most relatable reason might be because you’re tired or stressed. When you’re tired or stressed, you’re definitely less likely to remember things. It’s also more difficult for you to learn and absorb new information. Think about how you might be stressed during a super hard test or maybe when your teacher calls on you randomly. Doesn’t your mind often go blank during these times? This is because you were so stressed out that you couldn’t recall things even though you knew them. Or maybe you were studying late at night but when you woke up, you remembered very little of what you studied. You might have moments of déjà vu at these times.