In the last decade, researchers have increasingly acknowledged the impor tance of social interaction for the development of the individual’s cognition. Theorists of different schools, however, suggest different mechanisms for the process, and debate over findings that support one theory or another. In contrast, several researchers view different theories —mainly those of Piaget and Vygotsky-as complementing each other. This chapter follows the latter approach. It attempts to construct a theoretical framework for categorizing and analyzing interactions of different types, while integrating different theories. The study reported here suggests a multifaceted view of interactions and their cognitive effects, and has implications for questions that cognitive researchers commonly ask.