Recent Issues in the Developmental Approach to Mental Retardation

Abstract

A two-group approach to the range of intellect was explained to account for irregularities in the ``normal'' IQ curve. Organically retarded persons would be represented by one curve at the lowest end of the distribution. Familial retarded persons would be grouped with the rest of the population---their lower IQs considered a part of the normal variation dictated by the diversity of human genetic inheritance. The extreme environmental approach to mental retardation was summarized, as were the difference and general-developmental positions. Behavioral differences between mildly retarded and nonretarded persons of the same MA were explained in terms of environmentally-based motivational differences, including such factors as social deprivation, expectancy of success, optimal reinforcers, outerdirectedness, and institutionalization.