Psychological essentialism has been subject to much debate. Yet a key implication – that people should defer to experts in categorizing natural kinds – has not been widely examined. Three experiments examine deference in the categorization of chemical kinds. The first establishes borderline cases used in the second and third. These latter show limited deference to experts, and some deference to non-experts. These data are consistent with a perspectival framework for concepts in which categorization is sometimes based on micro-structural properties and sometimes on appearance and function
