It was originated by the Swiss developmental psychologist Jean Piaget (1896–1980). The theory deals with the nature of knowledge itself and how humans gradually come to acquire, construct, and use it.

Jean Piaget (1896-1980) always considered himself a natural scientist, not a psychologist. As a boy he quickly gave up play and pretend to take refuge in "work" -- exploring internal combustion ...

Jean Piaget's ideas about child development continue ... Piaget conducted a well-known experiment where children had to ...