Piaget

Jean Piaget (1896–1980) was a Swiss psychologist whose work on cognitive development reshaped the understanding of how children think. He trained in biology and philosophy at the University of Neuchâtel and later worked at the University of Geneva, where he developed a theory of cognitive development and the concept of genetic epistemology, the study of the origins and growth of knowledge.

Piaget proposed that children are active learners whose intellect develops through qualitative stages. His stage theory identifies four periods: sensorimotor (birth to about 2 years), preoperational (2–7), concrete operational (7–11), and formal operational (11 and up). He argued that thinking progresses through the formation and revision of schemas via assimilation and accommodation, with equilibration driving advancement. The theory emphasizes maturation, interaction with the environment, and the child’s own discovery of how the world works.

The theory influenced education by promoting constructivist, learner-centered approaches that encourage hands-on exploration and developmentally appropriate activities. Notable works include The Language and Thought of the Child (1926) and The Origins of Intelligence in the Child (1952; originally published in French in 1936). Piaget’s ideas have shaped discussions on maturation, discovery learning, and the balance between individual exploration and social context in learning.

Piaget’s work has faced criticisms for underestimating younger children's abilities, downplaying cultural and social influences, and presenting development as overly stage-like. Nevertheless, his emphasis on active learning and the processes of assimilation, accommodation, and equilibration remains foundational in developmental psychology and education.