There are studies showing that violence is more common when people are confined to one pecking order, and all of their social worth depends on where they are in that hierarchy, whereas if they belong to multiple overlapping groups, they can always seek affirmations of worth elsewhere. For example, if I do something stupid when I’m driving, and someone gives me the finger and calls me an asshole, it’s not the end of the world: I think to myself, I’m a tenured professor at Harvard. On the other hand, if status among men in the street was my only source of worth in life, I might have road rage and pull out a gun.

Steven Pinker, A history of violence: Edge master class 2011, Edge.org.