The Swiss psychologist and educator Jean Piaget (1896-1980) is famous for his learning theories based on identifiable stages in the development of children's intelligence.

Jean Piaget was born on August 9, 1896, in Neuchâtel, Switzerland, the son of a historian. When he was 11, his notes on a rare part-albino sparrow were published, the first of hundreds of articles and over 50 books. His help in classifying Neuchâtel's natural-history museum collection stimulated his study of mollusks (shellfish). One article, written when he was 15, led to a job offer at Geneva's natural-history museum; he declined in order to continue his education. At Neuchâtel University he finished natural-science studies in 1916 and earned the doctoral degree for research on mollusks in 1918.

Piaget's godfather introduced him to philosophy. Biology (life) was thus merged with epistemology (knowledge), both basic to his later learning theories. Work in two psychological laboratories in Zurich...