A mathematical model that describes attitude change in human communication networks is developed in this paper. The parameters of the model are drawn from a review of the literature related to network analysis, small group influence, mass communication, and attitude change. The literature review identifies key variables that influence attitude change in social networks, including those of valuation, strength, apprehension, rate of contact, accumulated information, and the discrepancy between the initial attitudes of two communicators. Including these variables, the final mathematical model ultimately predicts that in most social systems there will be "pools" of disparate attitudes that are a result of group influence processes, out-group communication, and the relative rates of communication in a human communication network. The paper concludes with a discussion of the importance of these findings for organizational communication, mass communication, diffusion, and small group research. An extensive bibliography is also provided. (HOD)