Contemporary accounts of cognitive development have emphasized that children build up a conception of the world on the basis of their own personal observation. The extent to which children also make use of testimony provided by other people, especially adults, has rarely been systematically examined. I argue that children are well equipped to make use of such information. Evidence for children's early use of testimony emerges from research on their understanding of the shape of the earth, the relationship between mind and body, and the origin of species. By implication, adult testimony helps children to construct a more objective or ‘scientific’ conception of the world. However, further evidence also illustrates that children also use adult testimony in developing various metaphysical ideas, for example concerning the special powers of God.

Two views of children's use of testimony are then considered. On the ‘amplification’ view, adult testimony is a useful supplement to children's personal observation but does not fundamentally alter the nature of the information that children gather. On the ‘transcendence’ view, adult testimony is not just a supplement to personal observation. It can provide children with a new type of information – information that is not grounded in direct observation. Children's receptivity to such information raises the question of when and how they begin to differentiate between different bodies of belief, notably between science and religion.