Randall Parker over at FuturePundit points to an interesting Erin Anderssen and Anne McIlroy article in the Canadian Globe And Mail that summarizes recent research on child development and human violence. They report that Richard Tremblay has found that two year old babies are more physically aggressive than teenagers or adults but are simply too uncoordinated to do much damage to others:

Consequently, are human beings born pure, as Rousseau argued, and tainted by the world around them? Or do babies arrive bad, as St. Augustine wrote, and learn, for their own good, how to behave in society?
Richard Tremblay, an affable researcher at the University of Montreal who is considered one of the world leaders in aggression studies, sides with St. Augustine, whom he is fond of quoting.
Dr. Tremblay has thousands of research subjects, many studied over decades, to back him up: Aggressive behaviour, except in the rarest circumstances, is not acquired from life experience. It is a remnant of our evolutionary struggle to survive, a force we learn, with time and careful teaching, to master. And as if by some ideal plan, human beings are at their worst when they are at their weakest.
St. Augustine was obviously much closer to the truth.

Read the entire post, as Mr. Parker includes a number of interesting links relating to the subject of this research. Hat tip to Tyler Cowan at Marginal Revolutions for the link.