UC Berkeley

This article reconciles two seemingly incompatible expectations about interpersonal interaction and social influence. One theoretical perspective predicts that an increase in interaction between two actors will promote subsequent convergence in their attitudes and behaviors, whereas another view anticipates divergence. We examine the role of political identity in moderating the effects of interaction on influence. Our investigation takes place in the U.S. Senate—a setting in which actors forge political identities for public consumption based on the external constraints, normative obligations, and reputational concerns they face. We argue that interaction between senators who share the same political identity will promote convergence in their voting behavior, whereas interaction between actors with opposing political identities will lead to divergence. Moreover, we theorize that the consequences of political identity for interpersonal influence depend on the local interaction context. Political identity’s effects on influence will be greater in more divided Senate committees than in less divided ones. We find support for these hypotheses in analyses of data, spanning over three decades, on voting behavior, interaction, and political identity in the Senate. These findings contribute to research on social influence; elite integration and political polarization; and identity theory.