The context of learning with computers is different from that of more traditional educational media because the computer is a new medium whose interactivity supports dynamic, evident, and malleable representations of abstract ideas. The model proposed addresses some mediating factors of the environment in which computers are used that affect learners' cognitive processes. The thesis is based on work conducted by a research group on large scale computer-based instructional systems to teach basic skills, instructional design for teaching computer implementations, and teaching problem solving using Logo. It is noted that: (1) programs are improved when they are structured to utilize other media in addition to computers; (2) computer training materials should support inferential learning; and (3) within computer environments, mediated learning approaches are more effective methodologies than either strict instruction or discovery-oriented approaches. (14 references) (Author/DB)