How Good Are Students at Testing Alternative Explanations of Unseen Entities?

THE purpose of the present study is to test the hypothesis that a fifth stage of intellectual development characterized by the ability to test alternative explanations involving unseen theoretical entities exists. This fifth-stage hypothesis will be tested in the context of a nonmajors, college-level biology course in which the assumption is made that some, but by no means all, students have acquired stage-five reasoning skills. Jean Piaget’s...