This article concisely describes the psychology of motivation and the basic underlying factors that increase or decrease it.
According to Ryan and Deci (2000) motivation can be broken down into three factors:
Click the link to read more. Also included are links to other related articles on motivation.
Richard M. Ryan, Edward L. Deci, Intrinsic and Extrinsic Motivations: Classic Definitions and New Directions, Contemporary Educational Psychology, Volume 25, Issue 1, January 2000, Pages 54-67, ISSN 0361-476X, 10.1006/ceps.1999.1020.(http://www.sciencedirect.com/science/article/pii/S0361476X99910202)