Political outgroups as monoliths: evidence of perceived political outgroup homogeneity

The outgroup homogeneity effect describes a tendency for people to perceive outgroup members as more similar to one another than ingroup members. This pattern has been found for various attributes (e.g., faces, preferences, and personality) and with respect to various outgroup types (e.g., gender, nationality, minimal groups). Four pre-registered studies (total N = 3243) using three distinct measures of perceived homogeneity replicated the basic effect: American Democrats and Republicans consistently perceived their political outgroup to have more homogenous political views than their ingroup. Extending beyond previous findings, this effect was mediated by the belief that their political outgroup has less informed views than their ingroup, and having less emotional vigilance toward ingroup dissent. As well, participants who perceived more threat perceived higher outgroup homogeneity. Participants who perceived their outgroups as more homogenous also perceived them as having more intention and being more capable of taking coordinated action to further the group’s interests, indicative of higher threat. These findings suggest that perceived threat may function as a cause or consequence of political outgroup homogeneity, leading to further political animosity.