This study is a comparison of 2 versions of an internet-based tutorial that teaches the behavior-analysis concept of positive reinforcement. A fixed-item group of students studied a version of the tutorial that included 14 interactive examples and nonexamples of the concept. A response-sensitive group of students studied a different version of the tutorial in which, after an initial round of 10 example and nonexample items, the computer readministered item types the students had answered incorrectly until the students responded correctly to each of 5 example and 5 nonexample item subtypes. A control group studied an online tutorial in biological psychology. Students in all 3 groups took a 10-item pretest and posttest over positive reinforcement. An analysis of the students' change scores indicated that the students learned more using the response-sensitive tutorial than the fixed-item tutorial. Scores of students using both versions of the tutorial were superior to those of the control group. Students using the response-sensitive and fixed-item tutorials required the same amount of study time. Students rated both versions of the positive reinforcement tutorial favorably on several dimensions.Online tutorials and demonstrations have become widely available to educators as a source of computer-based instructional materials (e.g., Davidson, 2004;Krantz, 2004; National institutes of Health, 2004). These resources provide the advantages of computer-based instruction (Alessi & Trollip, 2001;Kulik, 1986;Kulik & Kulik, 1991) to online users at no cost beyond internet access charges. Many of these online tutorials are not interactive because there is no opportunity to respond to the content and receive guidance or feedback (Alessi & Trollip, 2001). When opportunities for interaction are provided, tutorial exercises often consist of a fixed number of items or problems that the students answer. This use of a fixed number of items does not give students an opportunity for Please address correspondence concerning this manuscript to Lyle K. Grant, Psychology Centre, Athabasca University, 1 University Drive, Athabasca, Alberta, Canada, T9S 3A3. (E-mail: lyle@athabascau.ca). We thank Dean Mah for his assistance with the computer programming for this study.