Why Do You Feel Déjà Vu?

Imagine you walk into a room and suddenly feel like you have been there before. It is not magic. Your brain is just being a bit slow with its paperwork.

Your eyes see a scene and your ears hear sounds. These go to two different departments in your head. Sometimes one department finishes its job a split second faster than the other. When they meet, the 'finished' report looks like it was filed long ago. You think you remember walking into that room yesterday, but you really just walked in five seconds ago.

It is like hearing an echo slightly later than the shout.