Disagreement reduces overconfidence and prompts exploration in young children.

Can the experience of disagreement lead young children to reason in more sophisticated ways? Across two preregistered studies, four- to six-year-old US children (N = 136, 50% female, mixed ethnicities, data collected 2020-2022) experienced either a disagreement or an agreement with a confederate about a causal mechanism after being presented with ambiguous evidence. We measured (1) children's confidence in their belief before and after the (dis)agreement, and (2) how long children searched for information about the correct answer. Disagreement, especially with an expert (Experiment 2), reduced overconfidence and prompted children to search longer for information, compared to agreement. Together, our findings suggest possibilities for interventions aimed at fostering humility and learning across the lifespan.