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Jean Piaget (August 9, 1896 – September 16, 1980) was a Swiss philosopher, natural scientist and developmental psychologist, well known for his work studying children, his theory of cognitive development and for his epistemologic view called "genetic epistemology". He created in 1955 the International Centre for Genetic Epistemology in Geneva and directed it until 1980. According to Ernst von Glasersfeld, Jean Piaget is "the great pioneer of the constructivist theory of knowing". (wikipedia)