According to Charles Ma's 2007 esaay, Deja vu is caused by mis-timing neuronal system or multiverse. For real, i don't even know what i am talking about in that essay. I spent hours on searching the internet, and i only found these two ideas make sense to me. I only have two body paragraphes because i certainly can not find enough information for anonther one. Even in my essay, the second reason for deja vu is ridicules, and even in Word computer keep saying that the spelling of multiverse is wrong. Multiverse is the hypothetic theory that the reality is comprised by many multiple possible universes, and they are parallel. If you want to know more details about multiverse, please go to wikipedia and search. You will not find the information about deja vu in that reading because i connectted them which means i made it up. Want to why multiverse cause deja vu? To watch a movie which called 'Deja Vu', and there are some crazy scientists will explain to you.