Proceedings of the Annual Meeting of the Cognitive Science Society

Central to rationality is the ability to think about our beliefs, and make sure they are based on good reasons. If we have several conflicting reasons to believe something, we wait for more information before making a decision, perhaps rechecking our original reasons before proceeding. In these studies, we presented great apes and young children with conflicting evidence about the location of a reward. We found that apes double-checked the evidence for their original choice before making a final decision, revealing an awareness of their own beliefs and reasoning not hitherto documented. Young children, in contrast, were more sensitive to peer disagreement than conflicting physical evidence, illustrating the distinctively social nature of human rationality.