Levy, Amnon and Romm, Tsilia, Need satisfaction motivated behaviour: static and dynamic aspects, Department of Economics, University of Wollongong, Working Paper 90-10, 1990, 21.
Recent reviews of the literature on motivation (Luthans, Mitchell, Arnold and Feldman, 1985; Arnold and Feldman, 1986; Mitchell, 1983) categorize the theoretical models in this area into two types: content, and process theories. Content theories are characterized by their emphasis on needs as motivators of human behaviour. They differ in the type of needs that each considers central, and in the inter-relationship that is assumed to exist between these needs. The most well known theoretical model of this category is Maslow's (1943; and 1965). This model specifies five needs: physiological, safety, belonging, esteem and self-actualization. The model assumes a hierarchical relationship between these needs, so that gratification of a lower need is considered necessary for a higher need to be activated. Another widely quoted content model is Herzberg's (1966). In contrast to Maslow's this model perceives motivation as a product of an inter-relationship between two clusters of needs or two factors. The first cluster is defined as external, or hygiene needs.