The chapter outlines a general model of intrinsic and extrinsic motivation, the Hierarchical model. This model serves two objectives. First, the model provides a framework to organize the literature on intrinsic and extrinsic motivation, as well as to identify the psychological mechanisms underlying motivational changes. Intrinsic and extrinsic motivation represents a substantial portion of people's experiences when involved in activities. Furthermore, conceptual and methodological advances are presented supporting a multidimensional approach to the study of motivational phenomena. Such an approach has been found useful—for instance, for distinguishing nonintrinsic but internalized motivational forces that promote adaptive consequences such as persisting at difficult tasks from other internalized forces that compromise adaptive adjustment. A second objective of the hierarchical model is to lead to novel and testable hypotheses. Moreover, other aspects of the model also appear as prime candidates for future research. Such a model serves to integrate the literature and points toward new research. It is within such a contextually situated perspective that the model shows its greatest promise of usefulness.