Editing Social norm (section)

===Game theory===
{{Main|Game theory}}
Another general formal framework that can be used to represent the essential elements of the social situation surrounding a norm is the [[repeated game]] of game theory. Rational choice, a branch of game theory, deals with the relations and actions socially committed among rational agents.<ref>Voss, Thomas. Game-Theoretical Perspectives on the Emergence of Social Norms. Social Norms, 2001, p.105.</ref> A norm gives a person a [[rule of thumb]] for how they should behave. However, a [[rationality|rational]] person acts according to the rule only if it is beneficial for them. The situation can be described as follows. A norm gives an [[Expectation (epistemic)|expectation]] of how other people act in a given situation (macro). A person acts optimally given the expectation (micro). For a norm to be [[Structural stability|stable]], people's actions must reconstitute the expectation without change (micro-macro feedback loop). A set of such correct stable expectations is known as a [[Nash equilibrium]]. Thus, a stable norm must constitute a Nash equilibrium.<ref>[[Cristina Bicchieri|Bicchieri, Cristina]]. 2006. The Grammar of Society: The Nature and Dynamics of Social Norms, New York: Cambridge University Press, Ch. 1</ref> In the Nash equilibrium, no one actor has any positive incentive in individually deviating from a certain action.<ref name=":0" /> Social norms will be implemented if the actions of that specific norm come into agreement by the support of the Nash equilibrium in the majority of the game theoretical approaches.<ref name=":0">Voss 2001, p. 105</ref>

From a game-theoretical point of view, there are two [[explanation]]s for the vast variety of norms that exist throughout the world. One is the difference in games. Different parts of the world may give different environmental contexts and different people may have different values, which may result in a difference in games. The other is [[equilibrium selection]] not explicable by the game itself. Equilibrium selection is closely related to [[Coordination game|coordination]]. For a simple example, driving is common throughout the world, but in some countries people drive on the right and in other countries people drive on the left (see [[coordination game]]). A framework called comparative [[institutional analysis]] is proposed to deal with the game theoretical structural understanding of the variety of social norms.