Jean Piaget By asifa Aug 9, 1896 Born in Neuchatel, Switzerland Period: Jan 1, 1906 to Jan 2, 1906 1906 Published first scientific paper Jan 1, 1919 In Paris, started to study language development in children Jan 1, 1919 In Paris, started to study language development in children Jan 1, 1958 Published The Growth of Logical Thinking From Childhood to Adolescence Jan 1, 1972 defined the four stages of intellectual development Sep 17, 1980 Died