Cognition is the study of the mind works. When we study cognitive development, we are acknowledging the fact that changes occur in how we think and learn as we grow. There is a very big difference in the way that children and adults think about and understand their environment. Jean Piaget (1896-1980), a biology student did extensive research work in the area of child development and is attributed with the development of the theory of cognitive development which has played a major role in this field (child development). His approach of studying the development of the human mind was a synthesis of ideas drawn from biology and philosophy. He looked at human beings as biological organisms who must adapt successively to their environment. Piaget’s theory of cognitive development revolutionized the study of children’s cognitive development and it has undergone some revisions over the years. It also provides a set of basic principles to guide our understanding of cognitive development that are found in most recent theories. Piaget believed that in order to adapt successively to our changing environment, we are always actively trying to make sense of our experiments. Active learning (organizing by schema): gives us a chance to explore the different ways that objects can be organized depending on the concept used. At 5 years old, children are at the preoperational stage of cognitive development. Piaget defined this second stage by what it lacks: operations rather than what it has.