Accordingto Hamilton’s(1964a, b) rule,a cost lyaction will be undertaken if its fitness cost to the actor falls short of the discounted benefit to the recipient,where the discount factor is Wright’s index of relatedness between the two. We propose a generalization of this rule,and show that...

What preferences will prevail in a society of rational individuals when preference evolution is driven by their success in terms of resulting payoffs? We show that when individuals’ preferences are their private information, a convex combinations of selfishness and morality stand out as...

We analyze the effects of family ties on the incentives for production of effort, where family ties are defined as a mixture of true and coerced altruism between family members. We model families as pairs of siblings. Each sibling exerts effort in order to obtain output under uncertainty. A...