Perhaps the most prominent instance of this new guise, and of the way educational practice - formal and informal - has been redefined and reconfigured, is the growing acceptance of the constructivist theory of learning. In the 1990s, constructivist theories of learning, developed from sociology, gained ground, proffering as they did a radically differ- ent concept of knowledge acquisition from that of the transmission model - but drawing on theories already in common currency (from Dewey, Piaget, Vygotsky and others).