“I am a constructivist. I think that knowledge is a matter of constant new construction, by its interaction with reality, and that it is not pre-formed. There is continuous creativity.”

Jean Piaget was a Swiss Psychologist and developmental psychologist. He studied the nature of children of different ages which were a tremendous benefit to teachers. His genetic epistemology is devoted to a study of the innate developmental stages of children as they relate to their acquisition of knowledge.

Piaget contended that the mental development of children consists of a succession of three stages: sensorimotor (birth to 18 months) symbolic or preconcrete operational (18 months to 7/8) concrete operational (7/8 to 12). Finally during adolescence the formal operational stage occurs when children are able to think about their thoughts, construct ideals, reason realistically about the future, reason about contrary-to-fact propositions....

His researches in developmental psychology and genetic epistemology had one unique goal: how does knowledge grow? His answer is that the growth of knowledge is a progressive construction of logically embedded structures superseding one another by a process of inclusion of lower less powerful logical means into higher and more powerful ones up to adulthood. Therefore, children's logic and modes of thinking are initially entirely different from those of adults.

Jean Piaget has influenced a great many educators, psychologists, sociologists, for example Jerome Bruner and Seymour Papert. Piaget had a remarkable career, long and prolific. Successively or simultaneously, Piaget occupied several chairs: psychology, sociology and history of science at Neuchâtel from 1925 to 1929; history of scientific thinking at Geneva from 1929 to 1939; the International Bureau of Education from 1929 to 1967; psychology and sociology at Lausanne from 1938 to 1951; sociology at Geneva from 1939 to 1952, then genetic and experimental psychology from 1940 to 1971. He was, reportedly, the only Swiss to be invited at the Sorbonne from 1952 to 1963.

Interestingly, Piaget published his first paper on zoology at the age of 10. This he did because the university librarian treated him as a child, and he hoped this discovery (the sighting of an albino sparrow) would give him greater credibility with the librarian. Although he went on to receive a doctorate in zoology, his primary research interest was in psychoanalysis studying children, particularly his own. Many contend that Piaget was the first to take children’s thinking seriously.

At the time of his death at the age of 84 Piaget has developed several new fields of scientific research: developmental psychology, cognitive theory and genetic epistemology.
Recently, Time magazine named Piaget as one of its 100 most influential people of the past century.