The intent of this study was to explore the intrinsic aspects of motivation, and to see if the design of instruction could positively affect learners' levels of intrinsic motivation toward the subject matter. The following questions were addressed: (1) Will different computer-based instructional treatments which have been designed to reflect principles of intrinsic motivation to varying degrees produce measurably different levels of intrinsic motivation in learners? (2) Can the data from this study be explained in terms of the flow model? (3) Are higher levels of intrinsic motivation associated with higher learning scores? and (4) Are prior learning and prior interest related to different levels of intrinsic motivation? The flow phenomenon is described in terms of its two parameters, challenge and skills. When these two factors are in balance, people feel that they have the skills necessary to achieve a challenging but realistic goal. Instructional materials for the study consisted of three computer-assisted instructional programs on the topic of the relationship of aperture and shutter speed to exposure, depth-of-field, and image blur. Treatment #1 utilized a linear design with a fixed sequence of topics. Treatment #2 contained the same content material, but was organized into a hypermedia style structure, giving subjects a choice over the sequencing of instruction. Treatment #3 utilized a series of camera simulators with embedded instructional sequences for both presentation of the material and opportunities for practice, and with a "Jeopardy" style game at the end in lieu of embedded questions. Measures of intrinsic motivation were gathered from 121 subjects through the use of the Experience Sampling Form (ESF) and the Intrinsic Motivation Inventory (IMI). Results suggest that attempting to increase intrinsic motivation through the design of instructional materials is more difficult than the literature would indicate. The following subdimension score results are discussed: activation (alertness, involvement, excitement); affect (happiness, sociability, relaxation); cognitive efficiency (concentration, expectation, satisfaction); motivation (sense of control; success, satisfaction, importance of activity to the subject); perceived confidence (respondent's sense of competence, skill, and confidence). Results are illustrated in eight tables. (Contains 22 references.) (MAS)