While the focus of this study has been on the identification of hyperactivity in children, this chapter is an excursus into etiology. Although grounded in data collected, it is the most speculative and theoretical chapter in this book. Here I outline a social system approach to hyperactivity as a contrasting model to the medical-clinical approach, which is the predominant model for explaining the causes of hyperactivity. In presenting this approach, a concept of "situational hyperactivity" will be developed with examples from the research. In short, this is a first statement towards a sociology of hyperactivity.