Essentialist to some degree: beliefs about the structure of natural kind categories.

Previous research has provided conflicting evidence regarding the hypothesis that people are essentialists. Much of the evidence in favor of essentialism is based on demonstrating that categories are thought to have absolute membership. Although the hypothesis is often framed as an absolute claim about all categories of a certain type (e.g., natural kinds), it has generally been tested by making relative comparisons with a select sample. The present study assesses judgments of absolute structure across a range of categories. A further condition for essentialism is that the criteria for category identity be seen as objective rather than conventional. The results of three experiments based on these considerations do not provide support for essentialist claims. Few categories were judged to have essentialist structure, in terms of either absolute membership or objective criteria. Results are discussed in light of an alternative to the essentialist hypothesis that emphasizes a pragmatic view of categories.