Explicit Heuristic Training as a Variable in Problem-Solving Performance**Chapter 6 is an expanded and revised version of Schoenfeld (1979b). Permission from the Journal for Research in Mathematics Education to reproduce parts of the article is gratefully acknowledged.

This chapter presents the results of a small-scale research study conducted at Berkeley in 1977–1978 to explore students' mastery of five heuristic strategies. It describes the problem-solving processes of seven upper-division college students working a series of problems that can be solved by the application of one or more heuristic strategies. In the study, two small groups of students were given practice on and shown the solutions to a set of problems that could be solved by heuristic methods. The amount of time working the problems was identical for the two groups and the solutions they were shown were nearly identical. Pretests and post-tests were given individually and the students were recorded as they worked the problems out loud. Two comparisons of pretest-to-post-test gains, with regard to two different scoring procedures, indicated that the experimental group significantly outperformed the control group. More important, however, are the results provided by the protocol data. Explicit heuristic instruction makes or can make a difference with regard to problem-solving performance.