Two studies are reported. The first is based on Piaget's assertion that the child's representation of his world is dependent on the level of cognitive development at which he is currently functioning. Forty-eight normals and 48 retardates were given a visual memory task. They were asked to recall a configural presentation in a number of ways, immediately, one week after, and 6 months after the initial presentation. Piaget's proposition that memory is an integral part of intelligence is given support. Normals were found to be superior to retardates on the task. Similar findings are reported in a 2nd study which focused on a seriation task: (1) significant improvement did not occur in the performances of the youngest group, suggesting that the schema of seriation was incompletely developed; and (2) overall, the performance of normals exceeded that of retardates over time, even though the groups had been matched for MA and CA. It is suggested that conditions present in the mentally retarded preclude the improvement noted in normals of equivalent mental ages. (TL)