Children's developing capacity to calibrate the verbal testimony of others with observed evidence when inferring causal relations.

Across two studies (N = 120), we investigated the development of children's ability to calibrate the certainty of verbal testimony with observable data that varied in the degree of predictive causal accuracy. In Study 1, 4- and 5-year-olds heard a certain explanation or an uncertain explanation about deterministic causal relations. The 5-year-olds made more accurate causal inferences when the informant provided a certain and more calibrated explanation. In Study 2, children heard similar explanations about probabilistic relations, making the uncertain informant more calibrated. The 5-year-olds were more likely to infer the correct causal relations when the informant was uncertain, but only when the explanation was attuned to the stochasticity of the individual causal events (or outcomes that sometimes occur). These findings imply that the capacity to integrate, and make efficient inferences, from distinct sources of knowledge emerges during the preschool years.