Proceedings of the Annual Meeting of the Cognitive Science Society

This paper describes the implementation and quasiexperimental evaluation of a three-week instructional project designed in accordance with theories and assumptions of constructivism and socially situated cognition. Our goal was to develop students' ability to reason about real-life problems, where "good reasoning" was conceptualized in terms of a normative thinking model derived from cognitive research in decision making, probabilistic reasoning, and argumentation. In the spring of 1994, students in two middle school classrooms worked in teams that collected evidence, constructed arguments, and prepared presentations while engaged in activities that culminated in a mock legislative hearing. Through instruction and mentoring, students were encouraged to use statistics and probability as tools for reasoning. The effectiveness of the program was evaluated by comparing the written arguments of students from the two treatment classrooms with those of students from eight comparison classrooms. Students' arguments were scored in terms of how well they captured essential features of model reasoning and avoided particular thinking fallacies. That the reasoning abilities of students developed through social negotiation and shared problem solving was su