Quite often established migrants offer assistance and support that facilitate the arrival of new migrants. Why would migrants want other migrants to join them - so much so as to be willing to pay for them to come? We suggest a rationale. Our modeling framework is capable of explaining several...

We model group formation as a response to relative deprivation. We employ a simple measure of relative deprivation. We show that the process of deprivation-induced self-selection into groups reaches a unique steady state. We study the social welfare implications of the deprivation-induced...

We offer a game-theoretic proof of Hamilton's rule for the spread of altruism. For a simple case of siblings, we show that the rule can be derived as the outcome of a one-shot prisoner's dilemma game between siblings.