This experiment was designed to clarify the referential status of infants’ newly learned words. We introduced 15- and 17-month-olds to a novel noun, presented in conjunction with pictures of two whisks that differed in color. We asked whether infants would extend this newly learned noun to other members of the same kind (other whisks), one differing only in color and another differing in both color and representational medium. Fifteen- and 17-month-olds’ interpretation of the novel noun was not tethered tightly to the perceptual features with which the word had previously been paired. Instead, their interpretation was sufficiently abstract to include a new member of the same object category, although it differed in color and representational medium. Thus, by 15 months, infants appreciate the referential status of words and extend their meaning flexibly from pictures to objects.
Our results demonstrate that for infants as young as 15 months, words refer to categories of objects, their meaning extending beyond the particular items with which they were introduced. Armed with this early appreciation that nouns refer to object categories, infants attend carefully to the range of application for a novel noun and integrate this understanding with their concepts of individuals and kinds to discover the meaning of a word. Our findings also provide good news about reading picture books to infants and toddlers: Infants glean information from two-dimensional representations and apply that information systematically to real three-dimensional objects when they encounter them.