Thinking of things unseen: infants' use of language to update mental representations.

One of the most distinctive characteristics of humans is the capacity to learn from what other people tell them. Often new information is provided about an entity that is not present, requiring incorporation of that information into one's mental representation of the absent object. Here we present evidence regarding the emergence of this vital ability. Nineteen- and 22-month-old infants first learned a name for a toy and later were told that the toy had undergone a change in state (it had become wet) while out of view. The 22-month-olds (but not the 19-month-olds) subsequently identified the toy solely on the basis of the property that they were told about but had never seen. Thus, before the end of their 2nd year, infants can use verbal information to update their representation of an absent object. This developmental advance inaugurates a uniquely human and immensely powerful form of learning about the world.