Liberals and Conservatives Rely on Very Similar Sets of Foundations When Comparing Moral Violations

Applications of moral foundations theory in political science have revealed differences in the degree to which liberals and conservatives explicitly endorse five core moral foundations of care, fairness, authority, loyalty, and sanctity. We argue that differences between liberals and conservatives in their explicit ratings of abstract and generalized moral principles do not imply that citizens with different political orientations have fundamentally different moral intuitions. We introduce a new approach for measuring the importance of the five moral foundations by asking U.K. and U.S. survey respondents to compare pairs of vignettes describing violations relevant to each foundation. We analyze responses to these comparisons using a hierarchical Bradley-Terry model which allows us to evaluate the relative importance of each foundation to individuals with different political perspectives. Our results suggest that, despite prominent claims to the contrary, voters on the left and the right of politics share broadly similar moral intuitions.