Piaget's Stage Theory

The Piaget's Stage Theory was developed by doctor Jean Piaget, a Swiss developmental psychologist and philosopher. He founded that children were not less intelligent than adults, they simply think differently. The Theory describes the cognitive development of children, which involves changes in cognitive process and abilities. Piaget believes that early cognitive development involves processes based upon the actions and later progresses into changes in mental operations.

Key concepts of Piaget's Theory are: Schemas, Assimilation, Accommodation, and Equilibration.

Schemas are categories of knowledge that help to interpret and understand the world, and the process of Assimilation is to take in new information into previously existing schema. Then Accommodation is the process of adaptation, involving changing and alternating existing schemas after acquiring new information.  And finally Equilibration is the process of balancing Assimilation (information acquired) and Accommodation (information changed).

The key idea of Piaget's stage Theory are divided into 4 stages:

1. Sensorimotor Stage: From birth to 2 years of age, the infant builds an understanding of him or herself and reality through interactions with the environment.

2. Preoperational Stage: From the ages of 2 to 4, the child would classify objects in simple ways.

3. Concrete Operations: From the ages of 7 to 11, the child begins to think abstractly and conceptualize.

4. Formal Operations: From the ages of 11 to 15, the child is capable of deductive and hypothetical reasoning, similar to that of an adult.

But there were some major criticisms in his theory and research. The problem in his research "Method" was in that he only tested on his 3 children, and children of well educated family thats of high socio-economic status. Another problem was in the systematical structure and operation of the theory, in that the children would automatically move to the next stage at the specific ages. And also, recent research found that children even at the age of 4 and 5, could develop very sophisticated thoughts, which according to Piaget, would occur at the ages of 7 to 11.