The Social Structure Of Political Echo Chambers: Ideology Leads To Asymmetries in Online Political Communication Networks
Abstract
ABSTRACT. We investigate the possibility that people with different political orientations may exhibit different levels of political homophily, the tendency to preferentially interact with those who share one’s political beliefs. In the case of political groups, greater homophily is likely to result in ideological amplification, as members of the more homophilous group will be exposed to more messages reinforcing their worldview than members of the less homophilous group. A set of findings on differences in cognitive styles across the political spectrum leads us to expect that the levels of political homophily should vary between ideologies. A long-running research program spanning multiple disciplines has documented systematic variation across the political spectrum in the aversion to unknown, ambiguous, uncertain or threatening situations, and in the desire to reach cognitive closure. Two readings of these findings exist. In a recent meta-analysis, Jost and colleagues argue that such tendencies are generally more pronounced in individuals on the political right than on the left (Jost 2003a). An alternate interpretation holds that these results instead track the differences between the political center and the ideological extremes (Greenberg and Jonas 2003). We reason that individuals with greater aversion to ambiguous or threatening stimuli should be more averse to dissent and disagreement, causing them to have stronger preferences for interaction with others who share their views. Drawing on this line of research, we make two competing (though potentially complementary) predictions. We expect that individuals who are (1) further to the ideological right or (2) further from the ideological center should exhibit greater levels of political homophily. With either prediction, we expect that the emergent networks of people with different ideologies systematically differ in how much they resemble an “echo chamber”—that is, vary in how much their members are shielded from disagreement and provided with reaffirmation. In this paper, we test our hypotheses on a dataset of 237,244 personal networks belonging to American users of Twitter, which is an online communications network used by over 6% of adult Americans (Pew 2010). Our results indicate that individuals who follow politicians or think tanks further to the ideological right are connected to each other at greater rates than those that follow politicians and think tanks on the ideological left. However, we fail to find a parallel effect for differences between the ideological center and ideological extremes.