One more prominent psychological theory of socialization is cognitive development theory. Jean Piaget; a Swiss psychologist is the pioneer of this theory. Cognitive development theory was developed by jean Piaget via observing normal children. According to Piaget, children go through four series of stages for the acquisition of knowledge. However, the knowledge acquired by the children in the four stages differ in quantity, quality and understanding. Children move from one stage to another, when reach to a certain level of maturity and exposed to the new experiences. Piaget believed that, children cannot reach the highest level of cognitive growth, until and unless they are not exposed to new experiences. Proposed four stages of cognitive development are as follow, sensorimotor stage, preoperational stage, concrete operational stage and formal operational stage.
Sensorimotor Stage
This stage occur during first two year when a child is born. In this stage child understanding of world is based on touching chewing, sucking, shaking and by manipulating the objects. In the early part of sensorimotor stage, children lack object permanence; which means the existence of object and people. Until the age of 9 month child will not notice his missing toy and does not search for it. After 9 months child will start noticing object and people and if something is missing he/she will look for it. The critical development in sensorimotor stage is object permanence.
Preoperational Stage
In this stage children starts the use of language and symbols to describe events, people and feelings. They even use symbols while playing, for example pushing a book on the floor represents a car. In this stage child use egocentric thoughts which is looking at the world from their own perspective, they think that everyone perceive the world as they do.
Concrete Operational Stage
During this stage children let go some of their egocentric thoughts and develop to think in a logical way. One of the vital thing children learn in this stage is reversibility, which means that, something can be changed or undone by reversing an earlier action. For example if someone change the shape of clay ball by rolling it, they understand that it can be back in to shape of ball. In this stage child can understand the physical world however, they still lack the capabilities of understanding the questions of abstract and hypothetical nature.
Formal Operational Stage
In formal operational stage child begins to think abstract, formal and logical. Thinking of child is no longer limited to the observation of events however, they begin to use logical techniques for resolving problems. Piaget devised a pendulum problem and asked the children which variable determine how fast the pendulum swing? Weight of the pendulum or length of the string or the force which is applied to pendulum. The children started to manipulate all the variable one by one to seek the answer of the question. This ability of sorting out the possibilities is know as formal operational thoughts.
