Reorganizing the lexicon by learning a new word: Japanese children's interpretation of the meaning of a new word for a familiar artifact

This research investigated how children interpret the meaning of a new word associated with a familiar artifact. The existing literature has shown that syntactic form-class information plays an important role in making this kind of inference. However, this information is not available to Japanese children, because Japanese language does not have a grammatical distinction between count nouns and mass nouns, proper nouns and common nouns, or singular and plural. In Study 1, 12 three-year-old monolingual Japanese children were tested to examine whether they interpreted a new noun associated with a familiar artifact to be a material name or a new label for the object. They interpreted the new word as a new category label for the object, rather than as a name for the material. How children related the new category to the old familiar one was then examined in Studies 2 and 3. The results of Study 2, in which 24 three-year-olds participated, showed that children could flexibly shift between two interpretations using shape information. When the named object had a typical shape for the familiar category, they mapped the new word to a subordinate category. In contrast, when the shape of the named object was atypical, they mapped the new word to a new category that was mutually exclusive to the familiar category by excluding the named object from the familiar category. In Study 3, 12 three-year-olds were tested to examine relative importance of shape and functional information in this inference process. The results of the three studies suggest that children flexibly recruit clues from multiple sources, but the clues are weighed in hierarchical order so that they can determine the single most plausible solution in a given situation when different clues suggest different solutions.