The social filtering of reason quality: Evidence from a partisan penalty

When people evaluate another person's view, they sometimes evaluate not only the belief but the reasons offered in its support. These evaluations can come apart: two people can agree on a conclusion and still dismiss each other's reasons as weak or unserious. We tested whether judgments of reason quality are socially filtered, such that reasons associated with political opponents are evaluated less favorably than reasons associated with political allies. Across four preregistered studies (N = 4,049), we used contemporary partisanship in the United States as a test case. Participants rated the quality of political reasons supporting or opposing positions they had endorsed or rejected. Studies 1a and 2 established a partisan penalty: reasons associated with participants’ own party received higher ratings than reasons associated with the opposing party, even when the reasons supported positions participants shared. Study 1b showed that unlabeled reasons carried reliable partisan signals. Study 3 linked each participant’s source inferences to that participant’s evaluations of the same reasons. Reasons inferred to come from a contrapartisan received lower ratings, and this association remained after adjusting for perceived factual accuracy and shared values. These findings suggest that perceived partisan affiliation is associated with reason-quality judgments beyond differences in participants’ stated positions.