I was working on homework the other day and I got up to get a bottle of water out of my fridge when I got a feeling as if I had been in this exact spot doing the exact same thing before. It was deja vu for me and it was a weird sensation that I wanted to more about.
The feeling that I had of familiarity is called déjà vu which is a French word that means “already seen” (Real Clear Science). From this same article, it goes on to say that this sensation occurs randomly to around 60-80% of people. This is very hard to study because it happens randomly and the only information knowing about this is the people who report that they had deja vu.
Although deja vu is difficult to study, testing familiarity with faces or people can be tested. In a study, researchers found that when people were exposed to people and places that seemed familiar to them, the part of the brain that was being used was the perirhinal cortex (Brain Facts). Adding to this, when people are able to decipher whether they have seen these people or places before, the part of the brain being used is the parahippocampal cortex. Thus the linking factor between the two is the hippocampus, where both of the two parts of the brain relay messages. Scientists believe this is where we get the feeling of deja vu from (Brain Facts).
As to why deja vu actually occurs, scientists are not completely sure, but they do know that it most likely has to do with certain links between parts of the brain. So, maybe you know the people and places you are seeing and maybe you are just having a deja vu!