Conventions and Norms (Philosophical Aspects)

Abstract

This entry defines and distinguishes the concepts of convention and norm. Both terms refer to behavioral regularities. Lewis (1969) provisionally (and roughly) defined a convention as the set of coordinated expectations that solve a recurrent coordination problem. More recent game theory implies a broader definition: that a convention is a prevailing Nash equilibrium, and its attendant expectations, in a situation with at least one alternative equilibrium. The existence of multiple equilibria captures the intuition that conventions are arbitrary. By contrast, the central feature of a norm is that the behavioral regularity is supported, at least in part, by the fact that most or all individuals in the relevant population approve of conformity to the regularity and/or disapprove of non-conformity. The existence of normative approval or disapproval captures the intuition that norms are obligatory. Conventions and norms are distinct because norms need not be arbitrary (there may be no other possible equilibrium) and conventions need not be supported by approval or disapproval. Nonetheless, many actual behavioral regularities are both conventions and norms.

Keywords: convention, norm