What method did Jean Piaget primarily use to gather information for his theories on cognitive development?

Jean Piaget primarily used the method of observing his own children to gather information for his theories on cognitive development. Through this direct observation, he was able to gain insights into how children think, learn, and develop cognitive abilities at different stages. This hands-on approach allowed him to track the natural progression of cognitive skills, leading to his formulation of the stages of cognitive development: sensorimotor, preoperational, concrete operational, and formal operational stages.

By spending time with his children, Piaget could witness firsthand how they interacted with the world, solved problems, and understood concepts, which provided a rich basis for his theories. This observational method is particularly valuable in developmental psychology because it captures behaviors and processes as they unfold in real-time, leading to a more nuanced understanding of cognitive growth.

While other research methods, such as surveying children or conducting experiments in laboratories, can provide useful data, Piaget's emphasis on observation highlighted the importance of understanding cognitive development in a naturalistic context. This helps underscore his belief that learning is an active process where children construct their understanding through experiences, rather than simply receiving information passively.