Early in this century, most empirically oriented psychologists believed
that all motivation was based in the physiology of a set of non-nervous-
system tissue needs. The theories of that era reflected this belief and
used it in an attempt to explain an increasing number of phenomena. It
was not until the 1950s that it became irrefutably clear that much of
human motivation is based not in these drives, but rather in a set of
innate psychological needs. Their physiological basis is less
understood; and as concepts, these needs lend themselves more easily to
psycho- logical than to physiological theorizing. The convergence of
evidence from a variety of scholarly efforts suggests that there are
three such needs: self-determination, competence, and interpersonal
relatedness. This book is primarily about self-determination and
competence (with particular emphasis on the former), and about the
processes and structures that relate to these needs. The need for
interpersonal relat- edness, while no less important, remains to be
explored, and the findings from those explorations will need to be
integrated with the present theory to develop a broad, organismic theory
of human motivation. Thus far, we have articulated self-determination
theory, which is offered as a working theory-a theory in the making. To
stimulate the research that will allow it to evolve further, we have
stated self-determination theory in the form of minitheories that relate
to more circumscribed domains, and we have developed paradigms for
testing predictions from the various minitheories.