Disagreement, justification, and equitable moral judgments: A brief training study.

Although theorists agree that social interactions play a major role in moral development, previous research has not experimentally assessed how specific features of social interactions affect children's moral judgments and reasoning. The current study assessed two features: disagreement and justification. In a brief training phase, children aged 4-5.5 years (N = 129) discussed simple moral scenarios about issues of fairness (how to allocate things between individuals) with a puppet who, in a between-participants factorial design, either agreed or disagreed with the children's ideas and either asked or did not ask the children to justify their ideas. Children then responded to another set of moral scenarios in a test phase that was the same for all children. Children in the "agree and do not justify" baseline condition showed an inflexible equality bias (preferring only equal allocations regardless of context), but children who had experiences of disagreement or experiences of being asked to justify themselves shifted toward making equitable decisions based on common ground norms and values. Furthermore, false belief competence was related to children's decisions and justifications. These findings support the classic Piagetian hypothesis that social interactions are a catalyst of cognitive disequilibrium and moral development.