Proof of things you already suspected: Human society is not more violent today than in the past. Quite the opposite, in fact. (At least, as measured by statistics based on Western European historical records.) Vaughn Bell of MindHacks turned up this fascinating story from 2003, in which sociologists and historians debate what, exactly, caused the precipitous drop off in the European murder rate that happened over the course of the 17th, 18th, and 19th centuries. Theories include "The Rise of Courtly Manners" and "The Establishment of the Modern State".