 Thibaut and Kelley’s (1959) view of norms as substitutes for informal influence has a similar functionalist flavor. As an example, they consider a repeated battle of the sexes game. In this game, some bargaining is necessary for each party to obtain, at least occasionally, the preferred outcome. The parties can engage in a costly sequence of threats and promises, but it seems better to agree beforehand on a rule of behavior, such as alternating between the respectively preferred outcomes. Rules emerge because they reduce the costs involved in face-to-face personal influence.