Why do we experience déjà vu and what causes it to happen?

We experience déjà vu when our brain thinks it’s seeing something new, but actually remembers it from before, like a puzzle piece that fits in two places.

Imagine you're playing with your favorite building blocks. You stack them up and look at the tower, poof! It feels like you've seen this tower before, even though you just built it. That's déjà vu!

Your brain has two parts that work together: one that takes in what you see (like your eyes reading a book), and another that checks if it’s familiar (like remembering the story you read yesterday). Sometimes, the part that checks for familiarity gets a little ahead of itself, it thinks it knows what's coming before the other part has finished sending the message. That mismatch makes your brain go, “Wait… I know this already!”

It’s like when you're listening to a song and then hear it again, it feels extra familiar because your brain remembered it from before. Déjà vu happens for similar reasons: your brain is trying to remember something, but it gets a little confused about the timing.

So next time you feel like you've seen something before, just smile, your brain is playing a fun trick on you!