On the evolution of male competitiveness

Since a man's reproductive success depends on his ability to outcompete other men, male competitiveness may be expected to have been exposed to strong selective pressure throughout human history. Accordingly, the relatively low level of physical violence observed between men has been viewed as a puzzle. What could have limited the eagerness of men to out-compete each other? I study the evolution of male competitiveness in a model where men compete for both reproductive and productive resources. I show that high levels of male competitiveness are then consistent with evolution by natural selection if (a) the ecology is generous enough for men to supply little or no food to their children, (b) competing is not too costly in terms of productive resources, and (c) relatedness among males is low enough. While the main analysis takes women to passively accept the husband that emerges from the male-male competition, the results are qualitatively robust to allowing for female mate choice following the male-male competition game. Possible implications for our understanding of the evolution of marriage systems are discussed.