Given geographical constraints, the ability of humans to be aware of or establish contact with others falls off rapidly with physical distance. Indeed, problems as diverse as the spread of disease within human populations, the diffusion of cultural norms, migration, racial/ethnic segregation, and susceptibility to panic or revolution have all been linked to the distance-based structure of human relations. Yet, this spatial element of social network formation has received little attention. This project therefore develops mathematical network models based on physical distance, evaluates competing network models using published data on interpersonal relations across space, and presents measures of network structures. Using simulation methods, it identifies the linkages between large-scale social processes, such as those described above, and the social networks that span social groups and organizations. The mathematical methods thus provide insights into the general structures of human interaction that shape the more specific experiences and behaviors of individuals in a variety of types of groups.
