Environmental problems can be viewed as a failure of cooperation: individual choices are seemingly made based on individual benefits, rather than benefits for all. The game-theoretic structure of these problems thus resembles commons dilemmas or similar multiplayer strategic choices, in which the incentives to eschew cooperation can lead to unfavorable outcomes for all the players. Such problems can sometimes be restructured by punishing noncooperators. However, cooperation can also be enhanced when individuals adopt intrinsic values, such as cooperation, as a result of social goals to affiliate with a group. We define a social goal as any goal to affiliate with a group, and also any goal that derives from any group affiliation.