The Piagetian theory of cognitive development espouses an individual constructivist theory of cognitive development in which there is no formal role for anyone apart from the child.
In sharp contrast, Vygotsky espoused a social constructivist theory of cognitive development in which the child's interaction with others (especially those who are more knowledgeable) is key, even integral, to development.
Of the two theories, only the Vygotskian perspective espouses a formal instructional role for teachers who scaffold students' learning with the lessons they teach.
Here is a key phrase from the Seifert and Sutton textbook: “Piaget was more interested in what children and youth could figure out on their own, so to speak, than in how teachers or parents might be able to help the young to figure out.” (p. 38).
