Homophily, Proximity, and Social Support Theories

This chapter discusses three families of theoretical mechanisms—homophily, proximity (physical and electronic), and social support—that have been identified by social scientists as important motivations for why we create, maintain, dissolve, and reconstitute our communication networks. While much of this research is conducted in nonorganizational settings, this chapter focuses on the theory and research that we consider to be most germane to communication and other organizational networks. Several researchers have attempted to explain communication networks on the basis of homophily, that is, the selection of others who are similar. Brass (1995a, p. 51) notes that “similarity is thought to ease communication, increase predictability of behavior, and foster trust and reciprocity.” Homophily has been studied on the basis of similarity in age, gender, education, prestige, social class, tenure, and occupation (Carley, 1991; Coleman, 1957; Ibarra, 1993b, 1995; Laumann, 1966; Marsden, 1988; McPherson & Smith-Lovin, 1987). Several lines of reasoning provide support for the homophily hypothesis. These fall into two general categories: the similarity-attraction hypothesis (Byrne, 1971) and the theory of self-categorization (Turner, 1987). The similarity-attraction hypothesis is exemplified in the work of Heider (1958) who posited that homophily reduces the psychological discomfort that may arise from cognitive or emotional inconsistency. Similarly, Sherif (1958) suggested that individuals were more likely to select similar others because by doing so they reduce the potential areas of conflict in the relationship. The theory of self-categorization (Turner & Oakes, 1986) suggests that individuals define their social identity through a process of self-categorization during which they classify themselves and others using categories such as age, race, gender. Schachter (1959) argued that similarity provided individuals with a basis for legitimizing their own social identity. The manner in which individuals categorize themselves influences the extent to which they associate with others who are seen as falling into the same category. It is easy to see that the theoretical mechanism by which homophily influences the likelihood of a communication relation is based on the similarity among specific attributes of the actors.