Jean Piaget was born on August 9th, 1896 and died on September 16th, 1980. Jean was a professor of pyschology at the University of Geneva from 1929 to 1954.

Piaget argued that cognitive growth occurs through a series of states, known as 'stages in developement. Some of Piaget's important concepts include schemes, assimilation, accomodation, and equilibration.