Accommodation and assimilation are processes of adaptation in the theory of cognitive development proposed by the Swiss psychologist Jean Piaget. Although Piaget’s theory is considered a grand theory of cognitive development, he also wrote about social and emotional development. Assimilation and accommodation are learning mechanisms that are relevant to cognitive, social, and physical development because all human learning happens in the mind.

Infants begin to build mental structures, or schemas, in the mind as they interact with and adapt to the world. Older children and adults continue to build and revise schemas as they develop. The mind achieves a balance between assimilation and accommodation through what Piaget called “equilibration.” The mind organizes itself and achieves balance beginning in infancy and throughout the lifespan. This entry is ...