The psychological dimensions hypothesized to describe common instructional treatments and materials, and the relevant psychological characteristics assumed to describe students are discussed in their relationship to studies of aptitude-treatment interaction (ATI). The Annehurst Curriculum Classification System is described as a practical model that is currently available for ATI studies. It may be used to classify learning media as being high or low in experiential, intellectual, motivational, creative, emotional-personal, or social levels of content, design, format, application, or evoked responses. An experiment is described in which 96 ninth-grade students were tested for verbal ability, creativity, and field independence and then asked to express their preferences between pairs of contrasted items representing a variety of learning materials, the Langrehr Annehurst Materials Preference Scale (LAMPS). LAMPS consists of 33 items measuring 11 constructs. A factor analysis of the tests and scales resulted in six factors, and suggested that verbal ability and field independence were statistically significantly related to some of the performances measured by the scale. (Author/CTM)