We systematically compared beliefs about animal (e.g., "lion"), artifactual (e.g., "hammer"), and institutional (e.g., "police officer") categories, aiming to identify whether people draw different inferences about which categories are subjective and which are socially constituted. We conducted two studies with 270 American children, ages 4 through 10: 140 girls, 129 boys, one not reported; 59% White, 3% Black, 10% Asian, one Native American, 17% multiracial or another race, 11% unreported. We also conducted two studies with 360 American adults recruited from Amazon mechanical Turk. In all four studies we found that children and adults judged institutional categories as more socially constituted than artifactual categories (in all studies) but as less subjective (in three of four studies). Whereas younger and older children's beliefs about subjectivity were similar, younger and older children expressed different beliefs about social constitution. Young children judged none of the category domains as socially constituted; older children differentiated between the three domains. These results support the conceptual independence of subjectivity and social constitution and suggest that concepts of institutions and artifacts differ.