In this paper, we consider an intergroup contest game with intragroup altruism. We show that more altruism within a group increases conflict intensity by increasing total groups' efforts. Moreover, we show that, unlike the celebrated Olson's group size paradox, group size increases the probability of winning the contest provided that intragroup altruism is high enough.
Economics Bulletin, vol. 38, n° 2, avril 2018, p. 720–724