Sociological studies bla, bla - TL;DR: You are more civil when people recognize you. You are more likely to act in the "interest of the group" when you sign stuff with your real name. At least that's the state of the research to my best knowledge.
This paper [0] compares newspaper comment systems that allow anonymity against others that require names, and finds more civil discourse on named discussions - the assumption seems to be that people are not picking their newspaper site based on comments protocol, therefore the anonymity is causing the uncivility. There is surprisingly little research visible when I googled just now.
