Children's understanding of natural language hierarchies

Three experiments examined young children's ability to evaluate the relationship between concepts as one of inclusion. In Experiment 1, the same group of 4-to 7-year-old children were given three tasks: one in which they made judgments about whether “all” or “some” members of a category were included in another category, and two tasks in which they made inferences based on knowledge of inclusion relations. The majority of children succeeded on at least one of the tasks, thereby implying that they could evaluate inclusion relations. Two further experiments provided more evidence for this hypothesis: Experiment 2 confirmed that nursery children could answer quantitative questions about conceptual interrelationts; Experiment 3 demonstrated that nursery schoolers could solve certain inference problems involving the construction and evaluation of hierarchies.