The famous Swiss psychologist and educationalist had a long, prolific scientific career in France and Switzerland and is known as the founder of constructivism, a major theory of cognitive development, and genetic epistemology.
Piaget's theory of developmental psychology involves stages of development (from infancy to adolescence) and processes of constructing knowledge (adaptation: assimilation and/or accommodation).
His observation that a child's knowledge about the world appears to grow in stages which correspond to growth in cognitive capacities underpins his theory of genetic epistemology.
With Vygotsky, Piaget has had a major influence on our understanding of cognitive development, orienting educators towards active, creative models of learning.
Watch: Piagetian learning