The psychology of mental retardation

Abstract

Mental retardation is a deficit in intellectual or cognitive functioning. The IQ test, developed at the beginning of this century, made diagnosis possible.The little cognitive research conducted up to about 1960 was largely descriptive and exploratory. After 1960, the majority of research was conducted to find the major cognitive deficit that caused mental retardation. The results of that research indicated that nearly every cognitive process studied was deficient in persons with mental retardation. A system theory of intelligence and mental retardation is described.This theory explains why all cognitive processes appear impaired in persons with mental retardation even though only some central cognitive processes are actually deficient. Identification of impaired processes will require a fuller understanding of the relationship between intelligence and brain functioning.