This paper describes an emerging approach to the design of task sequences and the theory that undergirds it. The approach aims at promoting particular mathematical concepts, understood as the result of reflective abstraction. Central to this approach is the identification of available student activities from which students can abstract the…

Research conducted at the Institute of General and Pedagogical Psychology of Moscow, and based on the premise that the development of thought processes is a direct product of the social environment, is described. As a corollary to this premise, Piaget's view that the development of the thinking process occurs in orderly fashion is questioned.…