Every teacher and every parent faces the question of how to foster more versus less motivation in students. Theories of motivation, accordingly, must be able to both describe the nature of human motivation, and prescribe methods by which it can be fostered or undermined. However, because most prior theories of motivation have conceptualized motivation as a unitary phenomenon, one that varies from very little motivation to act to a great deal of it, they have been critically hamstrung in providing any practical advice to educators and parents.