Little is known about the teaching effectiveness of instructional media, particularly film and television. Accumulated research evidence applies to a generalized "average student," and thus to no one. There has been little concern for individual differences in interaction with instructional-media variables. The problem lies with the design of experiments. In the animal lab, treatment averages are meaningful since deviations from the average are small and background variables are constant. In the case of a heterogeneous group, however, random division maintains heterogeneity, and treatment averages are therefore meaningless. Some improvement is brought to the situation if individuals are first separated into aptitude subgroups. Two major questions should be considered: 1) What aptitude variables are particularly relevant for filmed and/or televised instruction? and 2) What media attributes under what task requirements are particularly likely to interact with aptitudes? Past research has pitted one instructional medium against another without concern for differing individual responses to those media. An alternative approach would consider aptitude interactions with media variables, thus pointing up appropriate treatments for different kinds of students. (LS)