Determining whether a sample provides a good basis for broader generalizations is a basic challenge of inductive reasoning. Adults apply a diversity-based strategy to this challenge, expecting diverse samples to be a better basis for generalization than homogeneous samples. For example, adults expect that a property shared by two diverse mammals…

Reviews selected research on children's early formation of categories. Finds sophistication in how children group objects and think about those groupings. Notes findings related to type of grouping (thematic or taxonomic), multiple classifications, overgeneralization, the role of background knowledge on classification abilities, the…