MosT workers in the field used to believe that little could be done to cure or ameliorate mental retardation. Some authors even included the notion of incurability in their definition of mental retardation (e.g., Doll, 1941). Recently, more and more authors have expressed the view that retardation is sometimes remediable through educational, psychological, and medical treatment (e.g., Kirk, 1958; Sarason and Gladwin, 1958). Whether this current optimism is factually based or not, the belief that retardation may be curable does raise interesting questions about the contributions of environmental conditions to retarded persons' development.