Why do we experience déjà vu and how does the brain explain it?

We feel déjà vu when our brain thinks it’s seeing something new but actually remembers it from before, like thinking you just met your friend at school, but suddenly you’re sure you’ve seen them somewhere else.

Imagine you're eating your favorite snack, and all of a sudden, you feel like you've already eaten this exact same snack in the same spot. That's déjà vu, it’s when something feels super familiar, even though it's happening right now.

Your brain has two parts that work together to help you remember things: one part checks what is happening right now, and another part checks your memories. Sometimes, the memory part gets a little confused, it thinks something happened before, but actually, it’s just happening now.

It's like when you're playing with building blocks and think you've seen that tower somewhere else, maybe in a toy commercial or at a friend’s house. Your brain is trying to match what you’re seeing with your memories, and sometimes it makes a little mistake, poof, déjà vu!