how does piaget describe development
According to Piaget, cognitive development involves an ongoing attempt to achieve a balance between assimilation and accommodation that he termed equilibration. At the center of Piaget's theory is the principle that cognitive development occurs in a series of four distinct, universal stages, each characterized by increasingly sophisticated and abstract levels of thought. 1  These stages always occur in the same order, and each builds on what was learned in the previous stage. They are as follows: