What exactly is Deja vu? Everyone experiences and it can be an odd feeling. According to Business Insider, scientists at the Leeds Memory Group, conducted an “experiment… based on the theory that two key processes happen in the brain when we recognise something or someone familiar. Firstly, our brains search through our memorize to see we’ve observed the scene before, and if it comes up with a match, a separate area of the brain identifies it as familiar.