Robots and rodents: children's inferences about living and nonliving kinds.

This study tests the firm distinction children are said to make between living and nonliving kinds. Three, 4-, and 5-year-old children and adults reasoned about whether items that varied on 3 dimensions (alive, face, behavior) had a range of properties (biological, psychological, perceptual, artifact, novel, proper names). Findings demonstrate that by 4 years of age, children make clear distinctions between prototypical living and nonliving kinds regardless of the property under consideration. Even 3-year-olds distinguish prototypical living and nonliving kinds when asked about biological properties. When reasoning about nonbiological properties for the full range of items, however, even 5-year-olds and adults occasionally rely on facial features. Thus, the living/nonliving distinction may have more narrow consequences than previously acknowledged.