Extinction and DRO in the treatment of aggression in a boy with severe mental retardation.

A novel use of extinction was applied in combination with differential reinforcement of other behavior to reduce dangerous levels of aggression displayed by an 11-year-old boy with severe mental retardation and cerebral palsy. Data taken during actual treatment sessions and in the client's "natural" environment (classroom and dormitory) suggest that the intervention was immediately effective and that the improvements were maintained and generalized.