Is the most representative skunk the average or the stinkiest? Developmental changes in representations of biological categories

•Biological category representations change gradually across development.•Younger children think of familiar animals in terms of category ideals.•Adults think of familiar animals in terms of averages.•Participants of all ages are sensitive to adaptive ideals for novel animals.•Suggests an early and persistent role for ideals in biological category structure. People often think of categories in terms of their most representative examples (e.g., robin for BIRD). Thus, determining which exemplars are most representative is a fundamental cognitive process that shapes how people use concepts to navigate the world. The present studies (N = 669; ages 5 years – adulthood) revealed developmental change in this important component of cognition. Studies 1–2 found that young children view exemplars with extreme values of characteristic features (e.g., the very fastest cheetah) as most representative of familiar biological categories; the tendency to view average exemplars in this manner (e.g., the average-speeded cheetah) emerged slowly across age. Study 3 examined the mechanisms underlying these judgments, and found that participants of all ages viewed extreme exemplars as representative of novel animal categories when they learned that the variable features fulfilled category-specific adaptive needs, but not otherwise. Implications for developmental changes in conceptual structure and biological reasoning are discussed.