Novel Evidence, Partisan Signalling and Divergent Political Beliefs

Amid increasing political polarization, individuals can signal adherence to partisan norms to engender trust among peers. On politically contested subjects, we hypothesise that this incentive to signal will: i.) bias how novel information is processed and ii.) bias the updating of beliefs with iii.) the effect of the latter mediated by the former. We test these hypotheses with two pre-registered online experiments utilizing a trust game. Respondents play as receivers and can signal trustworthiness to senders by evaluating a description of a study on a politicised issue. We manipulate respondents’ knowledge of their peer's partisan identity, with a subset aware of that identity and another unaware. We find those aware of their peer's partisanship give evaluations more aligned with that partisanship, compared to those unaware. Moreover, those aware also maintain more aligned political beliefs after the exchange, an effect potentially mediated through the evaluation of evidence.