cognitive developmental theory

jean piaget, a swiss biologist and philosopher,was most interested in the child's development of intellectual organization,how we think. He created a theory of cognitive development,which include four periods and recognizes that children move through these specific periods at different rates but in the same sequence or order. His theory was built on years of observing children as they explored,manipulated,and tried to make sense out of the world in which they lived. In piaget's theory external or internal forces did not shape thinking,although he acknowledged their presense in the process. Piaget's theory includes four general periods of development with a number of stages each period:period I,sensorimotor intelligence,period II,preoperational thought,period III,concrete operations,period IV,formal operations.