Jean Piaget was born on August 9, 1896, in Neuchâtel, Switzerland. Over the course of his career in child psychology, he identified four stages of mental development, called “schema.” He also developed new fields of scientific study, including cognitive theory and developmental psychology. Piaget received the Erasmus Prize in 1972 and the Balzan Prize in 1978. He died on September 16, 1980, in Geneva, Switzerland.