What causes deja vu and how does our brain process it?

You get déjà vu when your brain thinks it’s remembering something that just happened, like seeing a friend at the park and suddenly thinking you already met them there before.

Imagine you have a toy box full of different toys. When you open it, sometimes you pick out a red ball without looking, but then you think, “Wait! I had this red ball just now!” That’s déjà vu, your brain is confused because it thinks something happened twice when it really only happened once.

Your brain has two parts working at the same time: one that remembers things and another that notices what's happening right then. Sometimes these two parts get out of sync, like two kids playing a game but counting on different numbers.

When your brain sees or hears something familiar, it thinks, “I’ve been here before!” But really, you’re just in a place you know, like your favorite playground. Your brain gets mixed up and gives you that strange feeling of déjà vu. It’s like when you put your socks on backward and don’t realize it until you look down!