Piaget described cognitive development as occurring

The correct answer is in four qualitatively different stages.

Jean Piaget's theory of cognitive development proposes that children progress through four distinct, qualitatively different stages of intellectual growth. Rather than viewing cognitive development as a continuous, gradual increase in the quantity of information or skills, Piaget argued that children's thinking undergoes fundamental, qualitative shifts as they transition from one stage to the next. At each stage, the child understands the world in a structurally different way.

These four stages are:
1. Sensorimotor Stage (Birth to 2 years): The infant constructs an understanding of the world by coordinating sensory experiences with physical motor actions.
2. Preoperational Stage (2 to 7 years): The child begins to represent the world with words and images, showing an increase in symbolic thinking that goes beyond the connection of sensory information and physical action.
3. Concrete Operational Stage (7 to 11 years): The child can now reason logically about concrete events and classify objects into different sets.
4. Formal Operational Stage (11 years through adulthood): The adolescent reasons in more abstract, idealistic, and logical ways.