Preinstitutional social deprivation, responsiveness to social reinforcement, and IQ change in institutionalized retarded individuals.

Mentally retarded individuals who had been examined on a task measuring responsiveness to social reinforcement after 3 weeks and after 3 years of institutionalization were examined after 6 years of institutionalization. IQ changes were also examined. For familially retarded subjects, a linear decrease in responsiveness to social reinforcement and a linear increase in IQ was found from the 1st to the 6th year of institutional life. No changes in responsiveness to social reinforcement or IQ were found over the 6 years for nonfamilially retarded subjects.