The argument advanced in this article is that interaction in social networks has a strong, though often overlooked, influence on the propensity to participate in politics. Specifically, I argue that social interaction creates opportunities for individuals to gather information about politics that allows them to live beyond personal resource constraints, thereby supporting the political activity of many people. Using relational data from the South Bend Election Study, this article provides evidence that the effect of social interaction on participation is contingent on the amount of political discussion that occurs in social networks. Additional analysis shows the substantive and theoretical importance of such interaction by explaining how it is distinct from the effect of social group memberships and how it enhances the effect of individual education on the probability of participation. This key contribution of this article is to show that models of political participation that do not account for informal social interaction will be theoretically underspecified. It also shows that such interactions play a crucial role in explicating the role of other factors that predict participation, such as group membership and individual resources.
Given the central role that scholars and casual observers attribute to citizen participation in American democracy, it is no surprise that a great deal of effort has been spent examining the causes of such activity But untangling the theoretical thicket surrounding participation has proved to be a trying task, with recent reviews of the field observing that we have much left to learn about the causes of political involvement (Leighley 1995; Schlozman 2002; Rosenstone and Hansen 1993). In response to such observations, the analytic focus of participation scholars has started to move beyond a narrow concentration on the individual characteristics and resources associated with participation, specifically by devoting greater attention to the role of the environmental determinants of involvement. Despite this trend, one area that still receives little attention is the influence of interaction in social networks on individual levels of participation.
One reason for this inattention is that social interaction is seemingly ubiquitous and may not provide much leverage in sorting participants out from non-participants. Another reason is that existing scholarship highlights the importance of formal social interaction, such as membership in voluntary groups, as a cause of involvement. Consequently, there may be a tendency to assume that the social underpinnings of participation are effectively "controlled for" once formal group memberships are accounted for in empirical analyses.
This article seeks to rectify this shortcoming by testing the implications of a social network model of political involvement. Three questions are addressed. First, when and how do social networks make people politically active? Second, is the impact of informal interaction in those networks distinct from that of formal social organizations? Finally, how much does a social network model of involvement add to our theoretical and substantive understanding of how people become involved in politics?
To address these questions, I first outline a social network model of participation that emphasizes the substance-rather than the form-of social interaction as the key to unlocking social network influences on participation. This model is then used to outline predictions about the circumstances under which informal interaction should influence participation, thereby highlighting the usefulness of social interaction as a theoretical tool for studying involvement. The model is also used to demonstrate that social interaction has a value-added effect that helps us better understand when personal characteristics and resources contribute to involvement. Using relational data from the South Bend election survey, this article provides evidence that social networks only influence participation when they carry political substance, that this effect exists even when controlling for membership in formal social institutions, and that even the effect of individual resources cannot be fully understood without accounting for this process. …