Piaget's Theory of Cognitive Development Jean Piaget, a Swiss psychologist who began his research in the 1920s and continued through the 1970s, had an enormous impact on the field of cognitive development. Piaget's theory of development was based on his observations of young children. Although Piaget's writings were complex, his conclusions about the nature of development can be summarized in two parts. A set of fixed stages, and a pair of processes that led the …showed first 75 words of 837 total…

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