I recall from primatology lectures that a majority of violence is not triggered by a scarcity of resources but by friction in social ranking. I also recall a lecture by Sapolsky where he talk about this successful peace negotiator which focused on mutual respect, understanding and a feeling of kinship rather than negotiating about borders and resources.
In a book called The Happiness Hypothesis, the author made the interesting claim that violence is often cause by an attack on a person's self-image, and that it was indeed thus heavily linked to social friction.
