Lexical form class information guides word-to-object mapping in preschoolers

We demonstrate that lexical form class information can play a powerful role in directing the establishment of word-to-object mappings in referentially ambiguous situations. A total of 144 3- and 4-year-olds heard a novel label, modeled syntactically as either a proper name or an adjective, for a stuffed animal of a familiar kind. We then added a second object of the same kind and asked children (1) to choose one of the two objects as the referent of a second novel label, also presented syntactically as either a proper name or an adjective, and (2) to decide whether this second label could also apply to the object they did not choose. In each of three experiments, preschoolers were most Likely to reject two words for the same object if both words were proper names (as if one dog could not be both "Fido" and "Rover"). They were significantly less likely to do so if both were adjectives (as if one dog could be both "spotted" and "furry") or if one was a proper name and the other was an adjective (as if one dog could be both "Fido" and "furry"). Information about lexical form class thus contributed significantly to the formation of linkages between words and objects.