Categories convey prescriptive information across domains and development.

Young children display a pervasive bias to assume that what they observe in the world reflects how things are supposed to be. The current studies examined the nature of this bias by testing whether it reflects a particular form of reasoning about human social behaviors or a more general feature of category representations. Children aged 4 to 9 years and adults (N = 747) evaluated instances of nonconformity among members of novel biological and human social kinds. Children held prescriptive expectations for both animal and human categories; in both cases, they said it was wrong for a category member to engage in category-atypical behavior. These prescriptive judgments about categories depended on the extent to which people saw the pictured individual examples as representative of coherent categories. Thus, early prescriptive judgments appear to rely on the interplay between general conceptual biases and domain-specific beliefs about category structure.