  The game-theoretic literature contains numerous solution concepts that either generalize or refine Nash equilibrium. Various commentators suggest that a proper analysis of convention requires one of these alternate solution concepts. For instance, Robert Sugden (1986/2004) analyzes convention as a system of evolutionarily stable strategies. On this approach, not only are conventions self-enforcing, but they have an additional stability property: once established, they can resist invasion by deviant agents trying to establish a new convention. Sugden argues that this approach illuminates a wide range of social phenomena, including familiar examples such as money and property.