Elaborating further on this theory, Whittington and Evans (2005) stated that "each of these needs operates at all times, although one deficient set dominates the individual at any one time and circumstance" . The motivation experienced by humans to fulfill these needs is either derived from internal or external factors. Intrinsic motivation is found in people who are influenced by factors that cause a sense of accomplishment and pleasure, while extrinsically motivated people are commonly influenced by factors controlled by others, such as money and praise.