Using cognitive dissonance theory as a model in the experimental design, the author investigates the effects on student attitudes of Black ethnic culture materials included in speech classes. One hundred eighty students in all-white speech classes from four Illinois high schools were placed in three categories--prejudiced, moderate, and favorable-on the basis of pretest attitude assessment. Subjects were randomly assigned from the three categories to four experimental groups and a control group. Treatment folders containing the same Black culture materials but with different instructions were distributed to the four experimental groups--(1) Exposure (reading of materials), (2) Forced Compliance (writing a pro-black persuasive speech), (3) Forced Choice Affirmative (writing an affirmative debate brief), (4) Forced Choice Negative (writing a negative debate brief). The control group received unrelated materials and wrote a speech. Comparing pretest and post-test results, the experimenter concluded that no speech activity was clearly superior to others in causing attitude change and that Black Studies materials were most successful in changing attitudes of the most highly prejudiced students. (Author/LG)