Americans perceived political ingroups as more prototypical of Americans; perceiving the outgroup as poorly fitting the prototype of the superordinate group predicted opposition to bipartisan cooperation and a lower likelihood of bipartisan behavior

Ingroup Projection in American Politics: An Obstacle to Bipartisanship. Angela C. Bell et al. Social Psychological and Personality Science, October 5, 2021. https://doi.org/10.1177/19485506211046788

Abstract: One potential obstacle to cooperation between political parties is ingroup projection, the tendency for members of subgroups to define superordinate groups based on characteristics of their own ingroups. In five studies spanning 11 years and three presidential administrations, we demonstrated that ingroup projection can be an obstacle that prevents bipartisanship between Republicans and Democrats. Study 1 showed that Americans perceived political ingroups as more prototypical of Americans than outgroups and that the degree of mismatch between the outgroup and the superordinate group was associated with ingroup bias. Studies 2–5 demonstrated that perceiving the outgroup as poorly fitting the prototype of the superordinate group predicted opposition to bipartisan cooperation and a lower likelihood of having engaged in bipartisan behavior (Studies 4 and 5). These studies provide evidence for ingroup projection among American political parties and suggest that it contributes to political polarization.

Keywords: bipartisanship, ingroup projection, polarization, common ingroup identity, social identity theory