Social information can potentiate understanding despite inhibiting cognitive effort.

Both reasoning ability and social learning play a crucial role in human adaptation. Cognitive abilities like enhanced reasoning skills have combined with cumulative cultural adaptation to allow our species to dominate the world like no other. Thus, understanding how social learning interacts with individual reasoning ability is crucial for unravelling our evolutionary history. Here we describe a laboratory experiment designed to investigate the effect of social learning on individuals' ability to infer a general rule about unfamiliar problems. In this experiment, social information had both positive and negative effects on individuals' likelihood of inferring the rule. Social learners required more evidence to infer the rule than did individual learners, suggesting that social learning inhibits cognitive effort but social learning provided individuals with information that individual learners were unlikely to gather on their own, especially as the task became more difficult. When individuals are unlikely to discover useful information by themselves, social learning can potentiate understanding even though it reduces individual cognitive effort.