Social essentialism, the belief that members of certain social categories share unobservable properties, licenses expectations that those categories are natural and a good basis for inference. A challenge for cognitive developmental theory is to give an account of how children come to develop essentialist beliefs about socially important…

Children, 4-6 years of age, in special education kindergartens were randomly assigned to a classification training (n 45) and a comparison (n 49) group. Children in the training group were taught the Classification unit of Bright Start, whereas those in the comparison group received a regular content-oriented curriculum. Both groups were given…