Motivation theories attempt to do no less than explain why humans think and behave as they do. It needs little justification that this issue is immensely complex and that various schools of thought in psychology will address the question in very different ways. Indeed, all the prominent psychological directions and subfields (i.e., psychoanalytic theory, behaviorist psychology, humanistic psychology, cognitive psychology, social psychology) contain specific theories explaining human motivation and action (for reviews, see Eccles, Wigfield & Schiefele 1998; Graham & Weiner 1996) and the scope of motivation research centered around educational topics – primarily around student motivation and the motivation to learn – is also wide (for comprehensive summaries, see Pintrich & Schunk 1996; Stipek 1996; Wigfield, Eccles & Rodriguez 1998). However, in spite of the wide conceptual differences, most researchers would agree that motivation theories in general explain three interrelated aspects of human behavior: the choice of a particular action, persistence with it, and effort expended on it. That is, motivation is responsible for why people decide to do something, how long they are willing to sustain the activity, and how hard they are going to pursue it.