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...

The intersection of the standard altruism hypothesis with the quite strong evidence that bequests tend to be equal suggests that inter-vivos transfers should be strongly compensatory. Yet the available evidence is not in congruence with this implication. It has therefore been inferred that the...