What causes déjà vu and how does it work?

You get déjà vu when your brain thinks it’s seeing something new, but it actually feels like you’ve seen it before, just like when you walk into a room and think you've been there a million times.

Your brain has two parts that work together to help you understand what's going on around you. One part is fast, it sees things right away. The other part is slower, it takes a little more time to process everything.

Sometimes, the slow part catches up just a tiny bit late, like when you're eating a sandwich and suddenly think you've already had that exact sandwich before. It's like your brain said, “Wait! I saw this earlier!”, but only after you’ve already started enjoying it.

Imagine you’re playing with building blocks. You stack them up, and then you look at them again a little later. Your brain says, “Oh, I remember that tower! It looks just like this one.” But the tower is brand new, your brain just forgot it was still building.

That’s déjà vu, your brain mixing up when things happened, making you feel like you've seen them before when you haven’t quite yet. You get déjà vu when your brain thinks it’s seeing something new, but it actually feels like you’ve seen it before, just like when you walk into a room and think you've been there a million times.

Your brain has two parts that work together to help you understand what's going on around you. One part is fast, it sees things right away. The other part is slower, it takes a little more time to process everything.

Sometimes, the slow part catches up just a tiny bit late, like when you're eating a sandwich and suddenly think you've already had that exact sandwich before. It's like your brain said, “Wait! I saw this earlier!”, but only after you’ve already started enjoying it.