The effects of self-pacing versus system-pacing were examined in different versions of a computer-based learning environment (static pictures/animations). The role of cognitive style was also considered. While the variables investigated did not have a direct impact on either learning outcome or cognitive load, significant interaction effects were found. Concerning the difference between self- and system-pacing, results suggested that for animations, self-pacing was--as expected--effective, while for static pictures, the opposite was true. With respect to the difference between animations and static pictures, analyses showed that learners tending toward a visual cognitive style learned significantly better with animations than with static pictures. For learners tending toward a verbal style, learning outcomes were descriptively better with static pictures, although in that case the difference between animations and static pictures did not reach significance. The results indicate that self-pacing as a feature of learning environments is not universally advantageous, and highlight the importance of considering the role of individual learning differences such as cognitive style when choosing or developing computer-based learning environments. The findings are discussed considering contemporary theories of cognitive load and multimedia learning. (Contains 3 tables and 4 figures.)