Can only one person be right? The development of objectivism and social preferences regarding widely shared and controversial moral beliefs.

Prior work has established that children and adults distinguish moral norms (e.g., hitting is wrong) from conventional norms (e.g., wearing pajamas to school is wrong). Specifically, moral norms are generally perceived as universal across time and space, similar to objective facts. We examined preschoolers' and adults' perceptions of moral beliefs alongside facts and opinions by asking whether only one person could be right in the case of disagreements. We also compared perceptions of widely shared moral beliefs (e.g., whether it is better to pull someone's hair or share with someone) and controversial moral beliefs (e.g., whether it is better to help someone with a project or make cookies for someone). In Studies 1 and 2, preschoolers and adults were more likely to judge that only one person could be right in the case of widely shared versus controversial moral beliefs, treating the former as more objective or fact-like. Children were also more likely than adults to say that only one person could be right in a moral disagreement. Study 2 additionally revealed that adults were more likely than children to report preferring individuals who shared their controversial moral beliefs. Study 3 replicated these patterns using a different sample of widely shared beliefs (e.g., whether it is okay to mock a poor classmate) and controversial moral beliefs (e.g., whether it is okay to tell small, prosocial lies). While some aspects of moral cognition may depend on abundant social learning and cognitive development, the perception that disagreements about widely shared moral beliefs have only one right answer while disagreements about controversial moral beliefs do not emerges relatively early. We discuss implications for moral learning and social preferences.