A large number of individuals are randomly matched into groups, where each group plays a finite symmetric game. Individuals breed true. The expected number of surviving offspring depends on own material payoff, but may also, due to cooperative breeding and/or reproductive competition, depend on...

We look at gender differences among adolescents in Sweden in preferences for altruism, risk and competition. We find that girls are more altruistic and less risk taking than boys. No gender differences are found comparing competitive performance with non-competitive performance in either a...