Abstract
The goal of a micro-macro social psychology proposed here is to study macro behavior (as distinct from micro or individual behavior) as an unintended consequence of individuals' social action. The “unintendedess” of macro behavior relevant to micro-macro social psychology emerges from the interdependent nature of social action. It is suggested that the rational choice theoretical framework provides a useful conceptual tool to analyze this interdependence responsible for the“unintendedness” of macro behavior, since individuals' action can be analyzed as conditions for others' rational choice.