Jean Piaget (August 9, 1896 - September 16, 1980) was a Swiss philosopher, natural scientist and developmental psychologist, well known for his work studying children and his theory of cognitive development. According to Ernst von Glasersfeld, Jean Piaget is also "the great pioneer of the constructivist theory of knowing" Wikipedia
The definitive Wikipedia entry for Jean Piaget. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Jean_Piaget
Source : Genetic Epistemology , a series of lectures delivered by Piaget at Columbia University, Published by Columbia Univesity Press, translated by Eleanor Duckworth. marxists.org/reference/subject/philosophy/works/fr/piaget...
Concluding chapter of Piaget's definitive description of how chldren form their elementary concepts genetically marxists.org/reference/subject/philosophy/works/fr/piaget...
... Cognitive Development Jean Piaget (1896-1980) was a biologist who originally studied molluscs (publishing twenty scientific papers on them by the time he was 21) but moved into ... www.learningandteaching.info/learning/piaget.htm
Having studied such problems at first hand, [Piaget and Szeminska, The Childs Conception of Number, Ch. www.marxists.org/archive/vygotsky/works/comment/piaget.htm
Jean Piaget was born in Switzerland and by age 10 had already begun his professional career as a researcher and writer. He was interested in biology and wrote a paper on the sighting of an albino sparrow that propelled his interest in the scientific stud allpsych.com/biographies/piaget.html