Studies suggest that children’s exploratory behavior is sensitive to uncertainty; however, few have approached thiswith sufficient precision to model quantitatively. Across three experiments, children (mean age=70 months) were asked to shakea box to identify which of two sets of marbles, differing in numerosity, were hidden inside. The sets’ numerosities varied in theirdiscriminability indices – the degree to which listeners can distinguish the sets based on the acoustic information generated.The time children spent shaking the box varied systematically with the discriminability of the alternative hypotheses they wereasked to distinguish, even though they heard only one set for each contrast. This suggests that children represent the uncertaintyin their own perceptual discrimination abilities (an ability we refer to as an intuitive psychophysics) and their exploratorybehavior is precisely calibrated to their degree of uncertainty about alternative hypotheses that might explain unobserved causesof perceptual data.

In cooperative activities, all parties have a shared goalbut may not have the same set of skills. The currentstudy considers whether preschoolers are sensitive toprobable differences in individuals’ competence whenallocating roles. We found that 3.5- to 5.5-year-olds userelative competence, as indexed by the age of theirintended partner, to determine who should do the harderand easier of two tasks in a cooperative interaction. Asecond experiment demonstrated that children allocateroles differently in a competitive context. Youngchildren infer differences in others’ ability and candivide labor efficiently to achieve their goals.