Standing on principle: How moral principles can excuse disloyalty

How do we judge someone who must decide between loyalty to their friends and adherence to moral principles? Across seven experiments (four in the main text, three in the supplemental materials), participants read scenarios in which a person's friend becomes embroiled in a conflict with an acquaintance, and the person must decide whose side to take. We systematically varied whether the friend was morally right or wrong and whether side-takers opposed friends based on moral principles or had alternative motivations for their opposition, both altruistic and self-interested. Across experiments, we find that people consistently excuse disloyalty when opposing a friend is grounded in moral principles (e.g., the friend violated the side-taker's moral principle) but not when it reflects other motives. Further, we find this effect is specific to the side-taker's own moral principles: Neither alternative motives nor the moral judgments of others excuse disloyalty. These results align with the side-taking theory of morality, which holds that moral judgment functions to coordinate side-takers in a conflict. More broadly, they shed light on an underexplored feature of morality: its power to excuse disloyalty.