Statistical regularities in vocabulary guide language acquisition in connectionist models and 15-20-month-olds.

This research tested the hypothesis that young children's bias to generalize names for solid objects by shape is the product of statistical regularities among nouns in the early productive vocabulary. Data from a 4-layer Hopfield network suggested that the statistical regularities in the early noun vocabulary are strong enough to create a shape bias, and that the shape bias is overgeneralized to nonsolid stimuli. A 2nd simulation suggested that this overgeneralization is due to the dominance of names for shape-based categories in the early noun vocabulary. Two subsequent longitudinal experiments tested whether it is possible to create word learning biases in children. Children 15-20 months old were given intensive naming experiences with 12 noun categories typical of the types of categories children learn to name early. The children developed a precocious shape bias that was overgeneralized to naming nonsolid substances; they also showed accelerated vocabulary development. Children taught an atypical set of nouns or no new nouns did not develop a shape bias and did not show accelerated vocabulary development.