Expertise and Bias in Political Communication Networks


  • Mayer was supported by a National Science Foundation Graduate Research Fellowship.

T. K. Ahn is Professor of Political Science and International Relations, Seoul National University, Seoul, Korea 151-742 ( Robert Huckfeldt is Professor of Political Science, University of California, Davis, CA 95616 ( Alexander K. Mayer is a Research Associate at MDRC, 475 14th Street, Suite 750, Oakland, CA 94612-1900 ( John Barry Ryan is Assistant Professor of Political Science, Florida State University, Tallahassee, FL 32306-2230 (


Citizens minimize information costs by obtaining political guidance from others who have already assumed the costs of acquiring and processing political information. A problem occurs because ideal informants, typically characterized by the joint presence of political expertise and shared viewpoints, are frequently unavailable or rare within the groups where individuals are located. Hence, individuals must often look beyond their own group boundaries to find such informants. The problem is that obtaining information from individuals located beyond their own groups produces additional costs. Moreover, the availability of ideal informants varies across groups and settings, with the potential to produce (1) context-dependent patterns of informant centrality, which in turn generate (2) varying levels of polarization among groups and (3) biases in favor of some groups at the expense of others. The article's analysis is based on a series of small-group experiments, with aggregate implications addressed using a simple agent-based model.