Who is Jean Piaget and why is he considered to be an important educational psychologist?

Jean Piaget was a Swiss psychologist who observed the intellectual development of children during childhood. He is referred to as the father of cognitive development. According to him, “Cognitive development is a progressive reorganization of mental processes as a result of biological maturation and environmental experience.” He studied the intellectual development of his three children. He is an important educational psychologist because he propagated four main stages of cognitive development which are the sensorimotor stage, the preoperational stage, the concrete operational stage, and the formal operational stage.