PIAGET-COGNITIVE PSYCHOLOGY/ORIGIN: Jean Piaget believied children think differently as they undergo four stages of cognitive development. EXPLANATION: "Schemas" are one's units of knowledge; that is a dog. "Assimilation" is when new knowledge is added to a schema; dogs have fur and bark. "Accommodation" is when new information alters or creates new schema; that is similar to a dog but it is a cat. EXAMPLE: Jill manipulated little Joe's dog Schema by making him believe mice were also dogs.