If the principles of languages are applied to the learning of arithmetic, it appears that elementary grade pupils are being introduced to mathematical symbols at too early an age. (MP)

Explores two hypotheses about the effect of symbolic systems on psychological functions: (1) culturally elaborated systems of signs affect psychological functioning in a general way; and (2) systems of signs, when used to support skilled action, affect the organization of human activity. Reviews research that supports the second hypothesis. (LB)

This paper examines sixth-grade children's thinking related to solving ratio and proportion problems before these children had received any instruction in the domain. It explores unitizing and norming, one of the processes identified by both content analyses (Behr, Harel, Post, & Lesh, 1990); Harel, Behr, Post & Lesh, 1990) and research in…