We demonstrate how altruism can flourish in a population of nonaltruists. We assume that each individual plays a one-shot prisoner's dilemma game with his or her sibling and that the probability than an individual survives to reproduce is proportional to his or her payoff in this game. We model...

The large amount of equal division of bequests by parents who otherwise would have compensated the earning differences among their children is attributed to the cost associated with unequal bequests. This paper identifies a source of this cost and explains why equal bequests to children whose...

We demonstrate how altruism can surge in a population of nonaltruists. We assume that each individual plays a one-shot prisoner's dilemma game with his or her sibling, or with a stranger, and that the probability that an individual survives to reproduce is proportional to his or her payoff in...

We relate to others in two important ways: we care about others, and we care about how we fare in comparison to others. In some contexts, these two forms of relatedness interact. Caring about others can conveniently be labeled altruism. Caring about how we fare in comparison with others who fare...