The purpose of this study was to determine the effect of computer assisted instruction (CAI) on the cognitive and affective development of college students enrolled in a principles of macroeconomics course. The hypotheses of the experiment were stated as follows: In relation to the traditional principles course, the experimental treatment will result in (1) no loss in general cognitive capabilities of the students; (2) superior analytical capability; (3) and more favorable student attitudes toward economics. The experimental design for the course emphasized the substitution of CAI for the traditional lecture-textbook approach. It involved two instructors each teaching a control and an experimental section. The experimental sections differed from the control sections in that the students were exposed to CAI materials which included tutorial lessons and simulations. The results indicated that exposure to integrated CAI materials had a significant positive effect on basic analytical ability. However, the materials were not able to produce significant results across all question types on a general cognitive instrument. Furthermore, the affective results clearly indicated no effect. In accounting for these results, it is pointed out that the CAI materials were not uniform, that they were optional, and that the data base was relatively small. (Author/JK)