Developmental psychologists have a long history of using triangle metaphors to conceptualise the social constitution of psychological development. In this paper, we present a genealogy of triadic theories, to clarify their origins, distinctions between them, and to identify key themes for theoretical development. The analysis identifies three core…

Maintains that, although Leontiev's sociocultural orientation and its activity emphasis were inherited from Vygotsky's theory, the two men's theoretical motives and goals differed. Vygotsky's focus on symbolic mediation transforming psychological processes and Leontiev's on activities leading to internalization of action in mental processes were…

Contrasts work of Leontiev and Vygotsky. Suggests that Leontiev concentrated on social activity as a whole, whereas Vygotsky made semiotic mediation through culturally developed symbols a central aspect of his analysis. Maintains that they shared a philosophical base and that Leontiev used Vygotsky's ideas as a starting point to explore human…