Children and adults often encounter counterintuitive claims that defy their perceptions. We examined factors that influence children's acceptance of such claims. Children ages 3-6 years were shown familiar objects (e.g., a rock), were asked to identify the objects, and were then told that each object was something else (e.g., that the rock was soap). For some children, informants explicitly stated that the objects were different from what they appeared to be, whereas other children received testimony about the objects' identities without any reference to the discrepancy between appearance and reality. Children also completed standard tasks measuring appearance-reality understanding. When later asked about the objects' identities and properties, children who had a firm understanding of the appearance-reality distinction and those who heard informants mention that distinction were more accepting of the informants' counterintuitive claims. Thus, receptivity to counterintuitive claims can reflect conceptual growth rather than simple deference or conformity.