<P> Piaget's theory of cognitive development is a comprehensive theory about the nature and development of human intelligence . It was first created by the Swiss developmental psychologist Jean Piaget (1896--1980). The theory deals with the nature of knowledge itself and how humans gradually come to acquire, construct, and use it . Piaget's theory is mainly known as a developmental stage theory . </P> <P> To Piaget, cognitive development was a progressive reorganization of mental processes resulting from biological maturation and environmental experience . He believed that children construct an understanding of the world around them, experience discrepancies between what they already know and what they discover in their environment, then adjust their ideas accordingly . Moreover, Piaget claimed that cognitive development is at the center of the human organism, and language is contingent on knowledge and understanding acquired through cognitive development . Piaget's earlier work received the greatest attention . </P>

Cognitive-developmental theory has influenced our ways of thinking about