Gollwitzer, P. M., & Oettingen, G. (2015). Motivation, History of the concept. In James D. Wright (Ed.), International encyclopedia of Social and Behavioral Sciences. 2nd edition, Vol 15. Oxford: Elsevier. pp. 936–939.
Originally, motivation was analyzed as a singular determinant of human thoughts, feelings, and actions. It was quickly recognized, however, that motivation operates in concert with other determinants (e.g., cognition, affect, habits). This insight has allowed the psychology of motivation to progress to a very sophisticated level to answer to the question as to which of the human needs are to be differentiated and how these needs manage to guide and energize people. It has also promoted considering the concept of goals (on top of incentives and expectations) which allowed a better understanding of action control; willpower is nowadays analyzed in terms of the effective (effortful and/or automatic) self-regulation of goal pursuit.