Labelling patterns and object naming

We examined the effects of different labelling patterns on the generalization of object names. Two-year-olds, three-year-olds and adults were shown two 'standard' objects, which were named with the same label, or with two different labels, or with no label at all. Participants were then asked whether objects morphed to be intermediate to the standards belonged to one of the labelled categories or, in the No Label condition, were 'like' one of the standards. The Same Label condition showed generalization to all intermediates, whereas the Different Label and No Label conditions showed division of the intermediates into two separate categories, with somewhat sharper division under Different Label. These results suggest two possible mechanisms of lexical learning: 'boosting' the equivalence of different exemplars through label identity, and 'differentiating' the exemplars through differences in labelling. The studies provided strong evidence for boosting. Learners are sensitive to the distribution of labels across exemplars, and they hold powerful assumptions about the relationship between these distributions and the underlying naming space. These findings have implications for the early emergence of cross-linguistic differences in lexical learning.