Swiss developmental psychologist and epistemologist Jean Piaget is one of the most influential figures in the history of psychology. His four-stage theory of cognitive development identified play as a central vehicle through which children construct knowledge of the world. He described three progressive stages of play — functional, symbolic, and rule-based — that mirror broader cognitive development, and argued that children learn through active, hands-on engagement with their environment rather than passive instruction. He founded the International Center for Genetic Epistemology in Geneva in 1955. Decades after his death in 1980, his framework continues to underpin early childhood education worldwide.
