Jean Piaget is Swiss biologist and psychologist who established the discipline called genetic epistemology. Genetic epistemology is the study of the origins of knowledge. He took particular interest in how human intelligence develops by studying how children learn. Studying cognitive development is studying how children process information, use observational skills, learn a language and develop skills.
Piaget theorized that there are four stages of development: sensorimotor stage, preoperational stage, concrete operational stage and formal operational stage. Human beings go through each stage by a process of assimilation and accommodation. Assimilation is the process how a child perceives and familiarizes with different concepts presented. When a child encounters new concepts, it is processed in the brain by searching through previously learn concepts and associating the new one with it. Assimilation is incorporating new ideas and relating them to one that already exists in the brain. Accommodation is the fitting the new concepts into the mold to allow in to be part of the thought process. When a child learns new concepts and the child cannot relate it to the existing ones, there will be changes in the thought process to accommodate the new concepts.
Piaget believes that each child goes through the four stages of development. The sensorimotor stage occurs from birth to 2 years old. In this stage, an infant gains knowledge of the environment what the senses perceive. By seeing how an object looks, the movement and hearing the sound associated with, the child acquires knowledge by the physical movement in the environment. The preoperational stage occurs from 2 to 7 years old. In this stage, the child gains knowledge by representing ideas with symbols, words and drawing. The child’s imagination develops by the replacing object with symbols and knowing how make-believe. The third theory is the concrete operational stage which occurs from 7 to 11 years old. In this stage, the child now has a logical way to solve a problem that is not hypothetical. The last stage is formal operational stage which happens from adolescence to adulthood. In this stage, the child can now use logical reasoning to answer hypothetical questions. The thought process has developed into complex understanding by involving a systematic way of reasoning.
There are criticisms to the theory. One of them is having fixed ages when it comes to development. Others suggest that culture should be factored in the stages. Whatever new theories that will come up, Piaget’s theory of cognitive development surely pioneered these kinds of studies.