The effects of instruction in forming generalizations on high school students’ critical thinking in world history

Abstract The development of critical thinking is an ongoing concern in education. One critical thinking skill that is frequently listed is forming generalizations, although specific definitions of the term are lacking. This study provides a conceptual framework for the definition of this and related critical thinking terms and describes the results of an experimental study designed to improve high school students’ abilities to clearly state and adequately defend generalizations. Two intact world history classes received three days of traditional instruction on the history of the Renaissance and Reformation. For the remainder of two weeks, the experimental class received explicit instruction in the formation of generalizations in history while the control class received additional traditional instruction. Results of delayed post‐tests, controlling for pretest differences and reading achievement, indicated that students in the experimental class wrote essays assessed for quality and quantity of generalizations significantly better than controls and retained as much content knowledge from the unit as the controls. No significant differences were found between groups on the Cornell Critical Thinking Test (Ennis, Millman, & Tomko, 1985) but the test was found to be moderately reading‐dependent. The results suggest a useful conceptual framework and instructional format for teaching aspects of critical thinking in literacy situations.