This study defined a type of information-processing task analysis and an index relating different instructional sequences to this analysis. One hundred sixty-four college students were taught, with computer-assisted instruction, an imaginary science by various instructional sequences or by selecting their own sequence. A program-controlled instructional sequence conforming to the sequence defined by the task analysis was most effective. Learner-controlled sequences yielded poor performance. The contributions of the cognitive abilities of induction, associative memory, and general reasoning to performance under learner and program-controlled sequence and the ability by sequence interactions were shown. (Author)