Continuation support is requested for a research center on mental retardation and related aspects of human development. The research program encompasses four research institutes: the Institute on Mental Retardation and Intellectual Development, the Demonstration and Research Center for Early Education, the Center for Community Studies, and the Institute on Teaching and Learning. In these component research institutes, work groups of faculty scientists and assistants conduct studies that range from basic to clearly applied. Research programs will be continued in the following areas: early education of mentally retarded and culturally disadvantaged children; comparative development; individual differences in the development of personality and motivational traits, and their relationship to learning and performance efficiency; concept formation and abstracting abilities; acquisition and elaboration of language structures; follow-ups of the subjects of preschool education programs for children from poor families; learning and its facilitation; parent training through home visiting; community adjustment of children and youth; development of curriculum and educational material for preschool and school-age retarded children; development of symbolic processes in retarded and normally developing children; social ecology of families; community residential facilities and arrangements for mentally retarded persons. The research is organized around a social ecology conceptual orientaton, with strong emphasis on person-setting interactions, development of individuals within the social context of families and family-like social structures. As often as possible, the research methods include observational methods and research in relatively natural settings.