J. J. Gibson initially developed his theory of the perceptual control of action with an eye toward the perceptual control of locomotion. Subsequently, his theory has been generalized to many other tasks. Recent research has shown the importance of perceptual control skills in computer-based cognitive tasks. These results suggest that the problem of computer-interface design may be not only challenging in its own right but also theoretically promising as a way to investigate the exploratory learning of perceptual control skills. To test this premise, we used an existing instructional interface to capture the exploratory activities of novices as they learned to use a computer program. The aim of the research was to test a diffuse-control model of exploratory learning and a new evaluation methodology based on the model. Our results suggest that the model, which is based on ecological psychology principles, enhances our understanding of exploratory learning. Furthermore, the measures derived from the model provide a more detailed analysis of exploratory learning than current measures. Finally, the diffuse-control model and its derived measures proved to be an effective way to evaluate computer-interface design.