Mental retardation in the United States is currently defined as " ... signif­ icantly subaverage general intellectual functioning existing concurrently with deficits in adaptive behavior, and manifested during the development period" (Grossman, 1977). Of the estimated six million plus mentally retarded individuals in this country fully 75 to 85% are considered to be "func­ tionally" retarded (Edgerton, 1984). That is, they are mildly retarded persons with no evident organic etiology or demonstrable brain pathology. Despite the relatively recent addition of adaptive behavior as a factor in the definition of retardation, 1.0. still remains as the essential diagnostic criterion (Edgerton, 1984: 26). An 1.0. below 70 indicates subaverage functioning. However, even such an "objective" measure as 1.0. is prob­ lematic since a variety of data indicate quite clearly