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...