Preschoolers' use of superordinate relations in classification and language

Preschoolers' difficulty in accessing superordinate relations in classification contrasts sharply with their facility in accessing superordinate relations in language use. We consider two hypotheses regarding this discrepancy. First, certain aspects of classification tasks may obscure superordinate relations. In free classification tasks, the open-ended instructions leave the choice among possible organization schemes unconstrained, allowing for virtually any grouping (e.g., thematic, idiosyncratic), not necessarily a taxonomic grouping. Second, children's facility with superordinate relations in language may be due to a language-specific constraint in development: Children may interpret novel labels as referring to taxonomic (as opposed to thematic or idiosyncratic) relations. In Experiment I, we used 'clues' to focus preschoolers' attention on superordinate relations. Clues were (1) superordinate category labels (Label condition); (2) sets of typical category instances (Instance condition); or (3) typical instances with instructions to consider the instances as a group (Group condition). Four-year-olds classified successfully in all conditions. Three-year-olds classified well with labels, but not with instances; their performance in the Group condition was intermediate. In Experiment II, we focus on the role of labels in superordinate classification. If labels highlight taxonomic relations, then a set of category instances paired with a novel label should serve as an especially effective taxonomic clue. With the introduction of a novel word, 3-year-olds classified as successfully as children provided with known English labels. The powerful relation between language and classification is discussed.