Words and gestures: infants' interpretations of different forms of symbolic reference.

In 3 experiments, we examine the relation between language acquisition and other symbolic abilities in the early stages of language acquisition. We introduce 18- and 26-month-olds to object categories (e.g., fruit, vehicles) using a novel word or a novel symbolic gesture to name the objects. We compare the influence of these two symbolic forms on infants' object categorization. Children at both ages interpreted novel words as names for object categories. However, infants' interpretations of gestures changed over development. At 18 months, infants spontaneously interpreted gestures, like words, as names for object categories; at 26 months, infants spontaneously interpreted words but not gestures as names. The older infants succeeded in interpreting novel gestures as names only when given additional practice with the gestural medium. This clear developmental pattern supports the prediction that an initial general ability to learn symbols (both words and gestures) develops into a more focused tendency to use words as the predominant symbolic form.