Topics to be added
Useful summaries:
Piaget believed that cognitive development has to come before learning -- the child had to be cognitively "ready" to learn. "Learning is subordinated to development and not vice-versa".
Vygotsky on the other hand believed that learning was an active process that does not have to wait for readiness. In fact, "properly organized learning results in mental development and sets in motion a variety of developmental processes that would be impossible apart from learning". (from Woolfolk's book)