An aspect of adaptation proposed by French psychologist Jean Piaget.

In the cognitive development theory of Jean Piaget, assimilation is one of two complementary activities involved in adaptation, the process of learning from and adjusting to one's environment. Assimilation consists of taking in new information and incorporating it into existing ways of thinking about the world. Conversely, accommodation is the process of changing one's existing ideas to adapt to new information. When an infant first learns to drink milk from a cup, for example, she tries to assimilate the new experience (the...