The central claim of this paper is that radical behaviorism and cognitive psychology can both make important contributions to an experimental analysis of a cognitive skill such as memory performance. Though they currently differ in what constitutes an explanation of many phenomena, behaviorists and cognitive psychologists share interests in such human activities as problem solving and memory. We show how the behavioral approach may apply to one case that seems to epitomize cognition—the dramatic improvement in the memory span performance of (...) one individual on a task often used by cognitive psychologists to assess short-term memory. After 230 hours of practice, ability to recall random digits improved from a span of 7 digits to a span of 80. Although a detailed account of the mechanisms that mediated such improvement has been given, we show that the acquisition of such exceptional memory skill can also be explained within the framework of behavior analysis. (shrink)