Dr Oliver Scott Curry from Oxford's Institute of Cognitive and Evolutionary Anthropology came and gave a really interesting talk to my reading group last week. Curry defends the claim that morality is best understood as being all about cooperation.
Here is a video of the talk.(The audio is rather low I'm afraid, but should be okay for headphones.)
The thesis was that morality is a set of instincts, customs, preferences and behaviours unified by their common function of facilitating for-the-good-of-the-group, cooperative behaviour. The morals themselves are best revealed by empirical techniques including ethnographic survey, Curry claimed, and the functions of the morals are best elucidated using game theory. When we survey moral attitudes and behaviours, we will see that we tend to consider as moral only those acts which are best for the group.