Cognitive development is defined as gradual orderly changes by which mental processes become more complex and sophisticated, or the scientific study of how human beings develop in certain orderly stages as they get older. The actual study of cognition refers to the process of knowing; it is the study of all mental activities related to acquiring, storing, and using knowledge (Microsoft, 2001, p.3). How we as humans develop cognitively has been thoroughly observed and researched by Jean Piaget. He was a cognitivist: he believed that our environment stimulates us to learn on our own (make our own intelligence).
Piaget was a Swiss psychologist who had a major impact on educational theory in the early 20th century. He called himself a "cognitive biologist." He was considered a boy genius, publishing his first paper at the age of ten. By the age of fifteen, he had written and published more than twenty articles. He received his doctorate in biology at the age of twenty-two from the University of Neuchatel (Microsoft, 2001, p.5). When Piaget became interested in cognitive development, he started studies and did research and writing on his theories of cognitive development. Piaget wrote extensively on the development of thought and language patterns in children. He examined children 's conceptions of numbers, space, logic, geometry, physical reality, and moral judgment (Microsoft, 2001, p.1).
Piaget was one of the first child psychologists who worked one-on-one with children instead of with a group study. During the one-on-one time he spent with the children, Piaget noticed that at different ages, specifically as they got older, children were
able to learn more and understand more complex concepts. This is when he came up with his four stages of cognitive development. He said that we, even as adults, attain intelligence at different levels. He referred to this as hierarchical fashion and said that learning is