The core idea of Piaget's theory is that children develop by acting as “little scientists” who explore and interact with their world to understand people, objects, and concepts. They do this naturally, even without the help of an adult. The theory consists of four stages.
One of the major limitations of Piaget"s theory of cognitive development
Research has disputed Piaget's argument that all children will automatically move to the next stage of development as they mature. Some data suggest that environmental factors may play a role in the development of formal operations.
The theory seems to suggest that reaching the formal operational stage is the end goal of development, yet it is not clear if all people actually fully achieve the developmental tasks that are the hallmark of formal operations. Even as adults, people may struggle to think abstractly about situations.