Georgetown philosopher Jason Brennan describes political “hooligans” in this way:
Hooligans are the rabid sports fan of politics. They have strong and largely fixed worldviews. They can present arguments for their beliefs, but they cannot explain alternative points of view in a way that people with other views would find satisfactory. Hooligans consume political information, although in a biased way. They tend to seek out information that confirms their preexisting political opinions, but ignore, evade, and reject out of hand evidence that contradicts or disconfirms their preexisting opinions. They may have some trust in the social sciences, but cherry-pick data and tend only to learn about research that supports their own views. They are overconfident in themselves and what they know. Their political opinions form part of their identity, and they are proud to be a member of their political team…Most regular voters, active political participants, activists, registered party members, and politicians are hooligans.1
Across five studies, we find that people overestimate the degree to which partisans belong to party-stereotypical groups, often vastly so. Even in cases where these groups comprise just a sliver of the population, people report that these groups constitute upwards of 40% of the party they “fit.” And when people are given information about these groups’ shares in the population, the bias in their estimates doesn’t decline, suggesting that people rely on representativeness when making judgments about party composition.
Republicans, Democrats, and Independents, all overestimate the share of party-stereotypical groups in both the major parties. Partisan differences, although statistically significant, are relatively small compared to the overall magnitude of these misperceptions. Even more strikingly, those most interested in politics hold the most skewed perceptions of party composition. One plausible explanation for both of these results is that mediated, impersonal information drives these misperceptions. However, all the evidence we have presented on this point is descriptive. Additional research is needed to assess the extent to which media shape these perceptions.
These misperceptions are also consequential. Experimental evidence suggests that beliefs about out-party composition affect perceptions of where opposing-party supporters stand on the issues. These findings provide a potential explanation for why people tend to overestimate the extremity of opposing partisans. In future extensions, we plan to further investigate whether beliefs about party composition explain the striking finding that people also overestimate the extremity of co-partisans (Ahler 2014; Levendusky and Malhotra 2015). Misperceptions about out-party composition also lead partisans to feel more socially distant from the opposing party. Building on work by Hetherington and Weiler (2009) and Mason and Davis (2015), who find that partisan animus is related to party composition, we experimentally show that people’s beliefs about party composition affect their feelings towards the opposing party.
…The experimental findings support the notion that orientations toward constituent social groups affect how people feel toward the parties, among other things. However, they also show that beliefs about shares of various groups in the parties matter. Thus, while the group identity account makes a compelling case that partisanship is a relatively stable, affective attachment, work in this tradition must grapple more thoroughly with the social cognitions (and cognitive biases) that are relevant to how people reason about politics.
This is especially the case because partisans overestimate the share of party-stereotypical groups in their own party. For instance, many lower- and middle-class Republicans think that their party contains far more rich people than it actually does. This suggests that many partisans like their own parties to the extent they do—a great deal, with average ratings exceeding 80 on the thermometer scale (Iyengar, Sood and Lelkes 2012)—despite believing that the party has a greater share of groups to which they tend not to belong than it actually does. Green, Palmquist and Schickler (2002, p. 8) suggest that partisans choose parties based on “which assemblage of groups” looks like them. While this may still be true, the data suggest that people identify with parties based on which groups they like.
Finally, and most broadly, this research furthers our understanding of people’s perceptions of mass collectives and how these perceptions shape individuals’ own political attitudes. Mutz (1998) describes impersonal influence as the effect of people’s perceptions of what others are experiencing, or what others believe, on their own attitudes and behaviors. We take this one step further and assert that people’s perceptions merely of who belongs to a collective can be a source of impersonal influence—and in this case, a catalyst for partisanship in American politics (pg. 27-28).