Political partisanship and perceived partisan threat relate to simple trust decisions.

Affective polarization in the USA is an ongoing and pervasive problem eroding cooperation and productive debate related to partisan and non-partisan topics. Such findings signal an inherent mistrust of opposing partisans that is likely related to the extent of threat people believe opposing partisans pose to them. Whereas past work has examined the mistrust and threat characteristic of affective polarization in complex social environments as well as in social perception, no work to date has examined their effects in the context of simple everyday decisions. The current work filled this gap in the literature by examining effects of political partisanship and perceived partisan threat on trust behavior indexed by a trust game widely used in decision-making research. Across two studies using college-aged adults (Study 1) and adults across the lifespan (Study 2), participant and target partisanship interacted to affect trust. Across studies, more liberal participants exhibited lower trust toward Republicans than Democrats. However, more conservative participants' trust either remained stable across party lines (Study 1) or exhibited lower trust toward Democrats than Republicans (Study 2). In Study 1, these patterns were paralleled when substituting perceived partisan threat toward Republicans and Democrats for political ideology. Study 2 manipulated partisan threat to show larger participant-based partisan differences in trust when partisan partners were more versus less threatening. These findings in part support threat-related affective polarization in trust decisions and have implications for intergroup interactions along partisan lines in everyday life.