Why do we get déjà vu, and how does it happen?

We get déjà vu when our brain thinks it’s remembering something that just happened, like a fun surprise from a familiar toy.

Imagine you’re playing with your favorite building blocks. You stack them up, and poof! It feels like you’ve seen this exact tower before, even though it's brand new. That’s déjà vu!

Your brain has two parts working together: one that notices things (like when you see your blocks), and another that remembers (like when you recall stacking them yesterday). Sometimes these parts get confused, the remembering part thinks it saw something new, but actually, it just saw something similar.

It’s like when you wear a shirt you’ve worn before, but on a different day. Your brain says, “Wait! I remember this shirt!” even though it's not the same moment. That mix-up is what causes déjà vu, your brain thinks it’s remembering, but it's just recognizing something familiar.