As far as i know MULTIPLE IDENTITY DISORDER is a mental disorder where there are different identities in one body which in most cases is caused by child trauma when your mental is not yet developed and you face a trauma leading your brain to confusion and end up creating multiple identities. So when one identity takes over the other it is impossible to remember. You will only remember what you do in your main identity so that's why people with this mental disorder finds themselves in places where they don't know and have no memory of. What happens to you is just you trying to fit with different groups which have different meanings to you so you act accordingly. So as a human I can say it's every human behavior. It's every human's default function. We are influenced easily so we act different under different influences. Plus you should never self-diagnose. It may cause other serious mental illnesses like anxiety, depression, panic attack and several cases. So never self-diagnose if you feel uncertain about yourself make sure to go check a doctor and be sure of what is happening to you be it physically or mentally.