The patriarch of cognitive theory was Jean Piaget(1896-1980). Piaget was a biologist, who became interested in human thinking while working to evaluate the results of child intelligence tests. As Piaget worked he noted the correlation between the child's age and the type of error they made. Intrigued by the discovery that certain errors occurred predictably at certain age, he began to focus his time and energy to the further investigation of his findings. Starting with his children and moving on to other students, Piaget developed what is known as the Cognitive theory, a behaviorism theory which emphasizes the structure and development of thought processes. The theory says that thoughts and expectations have a direct affect on beliefs, attitudes, values, assumptions, and actions. Cognitive theory was the utmost studied theory in the later decades of the twentieth century. The theory consists of four main stages of development.
The sensorimotor stage is first and takes place from the time the baby is born to the time the baby turns two. This is the stage where an infant’s knowledge of the world is limited to their sensory perceptions and motor activities. the infants behavior is limited to simple motor responses caused by sensory stimuli. Children utilize skills and abilities they were born with, such as looking, sucking, grasping, and listening, to learn more about the environment.
According to Piaget the development of object permanence is key to this stage of development. Object permanence is a child's understanding that objects continue to exist even though they cannot be seen or heard, for example toys or food.
Once the baby turns two he or she enters the Preoperational stage of their lives. During this stage of Piaget’s theory the child does not understand common logic and language is a big part of the stage as well. In addition children are expected to be egocentric;