Wait, haven’t you asked us this before?
About three out of four people have experienced déjà vu, yet it’s not well understood. The most common theory: an experience you have that’s similar to a previous one activates the earlier event in your brain. “it’s just an association with already stored information,” says Dr Larry Squire, a neuropsychologist at UC San Diego and co-author of Memory: From Mind to Molecules (R1 617, Kalahari).
The eerie feeling simply stems from your inability to identify the source of similarity.