We developed an assignment that required introductory psychology students to read and evaluate the quality of several sources of information about the causal link between vaccines and autism. To evaluate the effects of this assignment, students in several different introductory courses completed a pretest and posttest in which they evaluated the quality of information from a website promoting a pseudoscientific therapy. Students who completed the assignment decreased their ratings of the quality of the information from the website (from pretest to posttest), were better able to identify specific problems with the information, and were less likely to recommend the therapy to a friend. Students who did not complete the assignment exhibited no changes in the dependent measures.