Although children often believe an adult’s claims, they may have opportunities to check these claims by gathering relevant empirical evidence themselves. Here, we examine whether children seize such opportunities, especially when the claim is counterintuitive. Chinese preschool and elementary schoolchildren were presented with five different-sized Russian dolls and asked to indicate the heaviest doll. Almost all children selected the biggest doll. Half of the children then heard a false, counterintuitive claim (i.e., smallest = heaviest). The remaining children heard a claim confirming their initial intuition (i.e., biggest = heaviest). Children in both age groups typically endorsed the experimenter’s claim even when it was counterintuitive. However, during the experimenter’s subsequent absence, elementary schoolchildren explored the dolls more if they had received counterintuitive rather than confirming testimony whereas preschool children rarely explored, no matter what testimony they had received. Thus, with increasing age, children seize opportunities to test counterintuitive claims.