 It is important to understand that conformity to a social norm is always conditional on the expectations of what the relevant other/s will do. We prefer to comply with the norm as we have certain expectations. To make this point clear, think of the player who is facing a typical one-shot prisoner’s dilemma with an unknown opponent. Suppose the player knows a norm of cooperation exists and is generally followed, but she is uncertain as to whether the opponent is a norm-follower. In this case the player is facing the following situation  (Figure 2).