Explain Piaget’s stages and their major milestones.

Jean Piaget, a psychologist and a genetic epistemologist, was keen on understanding the intellectual development of children. This interest led him to investigate the cognitive processes of children and gave birth to the theory of cognitive development. With this theory, he argues that children think differently from others and acquire their knowledge through schemas. Furthermore, he also stated that in the process of growing older, individuals use their experiences in the real world to construct knowledge of the world, also known as the constructivist theory.