Experts still aren't sure what causes déjà vu, where it seems like something's happened before. It could be a glitch in how our brain processes memories . . . or it could be a glitch in the "matrix." But what we do know is it's very common.
A recent poll found nine out of 10 people have experienced déjà vu before. Only 6% said they never have, and 4% weren't sure.
You'd think it would happen to older people more, because they've been around longer and experienced more. But people over 55 were much more likely to say it's never happened. And young people were almost five times more likely to say it happens a lot.
Image source: Getty Images