Christopher Boehm suggests that morality (self control) evolved as a response to our ancestors depending on big game hunting. In order to fairly divide a big kill, alpha male tendencies had to be suppressed for the hunting group to survive.
My book is the first to actually try to look at the natural history of moral evolution. At what time and how did developments take place which led us to become moral? In a way, this is a new field of study.
What I have done is to look at all of the possible hunter-gatherer societies that have been studied. I simply got rid of all of those that could have never existed in the Pleistocene... Then, I project the patterns of shared behavior back into the period when humans were culturally modern.
But my theory is that you cannot have alpha males if you are going to have a hunting team that shares the meat fairly evenhandedly, so that the entire team stays nourished.
My hypothesis is that when they started large game hunting, they had to start really punishing alpha males and holding them down. That set up a selection pressurein the sense that, if you couldn’t control your alpha tendencies, you were going to get killed or run out of the group...
Therefore, self-control became an important feature for individuals who were reproductively successful. And self-control translates into conscience. [emphasis mine]