He says something to this regard in the following video: http://archive.org/details/StevenPinker_2007 See 11:00ff forward. He also says that anarchy is an excentive for violence. I haven't fact checked everything, but I am actually pretty skeptical about this. He also gives other reasons.
It took me quite a bit of time and effort to make this. I'd appreciate your feedback. :) http://www.youtube.com/watch?v=KXNRzI64L9Q