ABSTRACT
This chapter focuses two experiments. In Experiment 1, participants judged the category membership of artifacts and natural kinds, and also rated their confidence in those category judgments. Results indicated that artifact categories were more graded than natural categories. Experiment 2 attempted to predict an individual’s tendency to give graded membership ratings, on the basis of his or her epistemic beliefs. People tend to believe that membership in an artifact category is a subjectively decided matter of opinion, while membership in a natural category is an objectively determined matter of fact. If membership in a natural category is objective, then it is possible for the category judgment to be incorrect, and therefore people may sometimes lack confidence in their category judgments. Psychological Essentialism posits that people hold essentialist beliefs, and that these beliefs affect cognition.
