Jean Piaget (1896 - 1980) is a Swiss born biologist but because of his mother's poor mental health, Piaget became interested in psychopathology.
In 1919, he became interested in why children repeatedly choose the same incorrect answers to the intelligence tests, this motivated him to begin his studies of cognitive development in children. His studies of human cognitive development help us to understand how children percieve the world around them. Through his interest of children, he became one of this centuries most influential observers of children. He died in 1980 after spending years of experimenting and teaching.
Other definition:
Jean Piaget was born in 1896 at Neuchatel, Switzerland and died in 980 at Geneva, Switzerland . She got her Ph.D. in Biology at the University of Neuchatel. Famous achievements: Pioneered research on the cognitive development of children. Received honorary degrees from 30 universities, including Harvard and Cambridge.