Obviously it's really hard to choose nature or nurture when considering violence. I'm don't do research in the area, so all i have to go on is my personal experiences.

Starting with myself. I used to be a very violent person. I would never order so much fast food that I would order them by a number, but if I did get the wrong order. I would retaliate in one way or another [probably violently]. That was when I was quite a bit younger. Now, through the aid of a bleeding ulser, I've learned just to eat what I get and be happy that I'm eating.

If one were to analyze this aspect of my live it would appear that I was naturally violent. Then through sercumstances, I learned to be peaceful.

Another experience is raising my children. They didn't come out hitting people. They were nice and cuddley at first. They learned to hit from watching movies, and playing with other children.

I would have to lean towards the notion that we learn to be violent, but that we instinctually learn to be violent because self preservation is our number one objective.