In this article I focus on the mediational role of communicative activity in the co-construction of meaning involved when pupils write collaboratively. I explore the developmental nature of peer intermental or social activity within a Zone of Proximal Development (ZPD) by drawing on perspectives from sociocultural theory and the dialogical aspects of some classroom activity. Vygotsky's concept of the ZPD is viewed as a tool used to produce forms of instruction that lead pupils' psychological ...