Identifying profoundly mentally retarded subtypes as a means of institutional grouping.

While the profoundly mentally retarded social group is behaviorally heterogeneous, this knowledge appears to be of more theoretical than practical interest. The behavioral identification of functional profoundly retarded subtypes derived from ethological analysis may supply the structure necessary to utilize this behavioral variability. Institutional groupings based on dominant and subordinate subtypes may prove to be efficacious in increasing programming efficiency. A study of profoundly retarded persons' territoriality was discussed as it relates to new grouping procedures based on behaviorally identified subtypes. Implications with respect to the control of aggression, stereotypic activity, and behavior modification for functional subtypes were discussed.