This chapter examines how psychological essentialism poses a set of conceptual obstacles to a full grasp of evolutionary theory for ordinary (non-expert) children and adults. Specifically, this chapter describes five essentialist assumptions that are common in everyday thought and are inconsistent with evolutionary theory, including: assumption of category stability and immutability, assumption that category boundaries are strict and impermeable, failure to understand within-category variability, by either denying its existence or treating it as ‘noise’, treating causes as inhering in...

This chapter examines how psychological essentialism poses a set of conceptual obstacles to a full grasp of evolutionary theory for ordinary (non-expert) children and adults. Specifically, this chapter describes five essentialist assumptions that are common in everyday thought and are inconsistent with evolutionary theory, including: assumption of category stability and immutability, assumption that category boundaries are strict and impermeable, failure to understand within-category variability, by either denying its existence or treating it as ‘noise’, treating causes as inhering in individuals rather than resulting from population-level forces, and viewing categories as progressing toward an ideal state. Some of these obstacles impede acceptance of evolutionary theory; others impede understanding evolutionary theory. The chapter concludes with speculations about implications for science education.