Research suggests that liberals and conservatives use different moral foundations to reason about moral issues (moral divide hypothesis). An alternative prediction is that observed ideological differences in moral foundations are instead driven by ingroup-versus-outgroup categorizations of competing political groups (political group conflict hypothesis). In two preregistered experiments (total N = 958), using experimentally manipulated measures of moral foundations, we test strong versions of both hypotheses and find partial support for both. Supporting the moral divide hypothesis, conservatives endorsed the binding foundations more strongly than liberals even when a moderate target group was explicitly specified. Supporting the political group conflict hypothesis, both conservatives and liberals endorsed moral foundations more when moral acts targeted ingroup versus outgroup members. These results have implications for improving measures of moral values and judgments and point to ways to enhance the effectiveness of strategies aimed at building bridges between people from different political camps.
Keywords: ideological identification; ideology; moral foundations; morality; political psychology.