Toddlers vary widely in the rate at which they develop vocabulary. This variation predicts later language development and school success at the group level; however, we cannot determine which children with slower vocabulary development in the second year will continue to have difficulty. In this article, I argue that this is because we lack…

Extending new verbs is important in becoming a productive speaker of a language. Prior results show children have difficulty extending verbs when they have seen events with varied agents. This study further examines the impact of variability on verb learning and asks whether variability interacts with event complexity or differs by language.…

Young children are able to categorize animals on the basis of unobservable features such as shared biological properties (e.g., bones). For the most part, children learn about these properties through explicit verbalizations from others. The present study examined how such input impacts children's learning about the properties of categories. In a…

We explored whether a rising trend to blindly "overcopy" a model's causally irrelevant actions between 3 and 5 years of age, found in previous studies, predicts a more circumspect disposition in much younger children. Children between 23 and 30 months of age observed a model use a tool to retrieve a reward from either a transparent or opaque…

Investigated development of working memory in the transitional period from infancy to preschool years. The age-related increase in scores on the Imitation Sorting Task (IST) appeared to be about one unit every six months. Results suggest that the IST has a good construct validity. (AA)

Examined the use by children of the Novel Name-Nameless Category principle, under the framework that lexical principles are acquired in a developmental sequence. Results indicated that the particular principle was not available at the start of lexical acquisition but that exhaustive categorization ability and a vocabulary spurt occur…