JARON LANIER: I'd like to hypothesize one civilizing force, which is the perception of multiple overlapping hierarchies of status. I've observed this to be helpful in work dealing with rehabilitating gang members in Oakland. When there are multiple overlapping hierarchies of status there is more of a chance of people not fighting their superior within the status chain. And the more severe the imposition of the single hierarchy in people's lives, the more likely they are to engage in conflict with one another. Part of America's success is the confusion factor of understanding how to assess somebody's status.
STEVEN PINKER: That's a profound observation. 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.
Every time we read about a workplace shooting, it's difficult to imagine that these men (almost invariably) are well-connected socially outside their office or plant, in sports or family or civic service groups. Pinker's full discussion here; he also points out the decline in autocracies, which also bodes well for decreased violence.