What area is Piaget primarily associated with researching?

Piaget is primarily associated with the research of cognitive development, which focuses on how individuals, particularly children, acquire knowledge and the processes involved in the understanding and processing of information. His theory outlines distinct stages of cognitive development—sensorimotor, preoperational, concrete operational, and formal operational—which describe how children's thinking evolves and becomes more complex over time.

Piaget's work emphasizes the importance of interaction with the environment and the role of language in cognitive development, illustrating how kids move from concrete thinking to more abstract reasoning. This foundational perspective has had significant implications in education and child psychology, helping educators tailor their approaches to suit the cognitive capabilities of students at various developmental stages.