Cross-classification and category representation in children's concepts.

Items commonly belong to many categories. Cross-classification is the classification of a single item into more than one category. This research explored 2- to 6-year-old children's use of 2 different category systems for cross-classification: script (e.g., school-time items, birthday party items) and taxonomic (e.g., animals, clothes). The results of Experiments 1 and 2 show that by a young age, children are able to cross-classify items into both category systems. Experiment 3 found that children mentally represent cross-classified items as simultaneously belonging to both taxonomic and script categories. Experiment 4 found that children often, but do not always, spontaneously activate taxonomic and script cross-classifications. Overall, the results demonstrate that from an early age children form and use both taxonomic and script categories for cross-classification.