The monograph reviews federal research activities and progress in biomedical and behavioral/social science research in mental retardation. Activities represent the National Institute of Child Health and Human Development and the Mental Retardation and Developmental Disabilities branch. The following categories are addressed in terms of biomedical research: genetics and genetic disorders (cytogenetics, inborn errors of metabolism); infection; toxicology and environmental factors (fetal alcohol syndrome, low level lead exposure); and congenital hypothyroidism. Areas of behavioral and social science research addressed are individual processes (cognition and learning, memory, perception, language, personality); family processes (parent-child interaction, parental attitudes, adaptive behavior); and residential and educational settings (social interaction, educational settings, research in institutions, group homes). Concluding sections consider research training and future research emphases in genetics/Down Syndrome, developmental neurobiology, high-risk infancy, and amelioration/rehabilitation. (CL)