Distributions of body-rocking manifested by severely mentally deficient adults in ward environments

Systematic observations were made of the stereotyped body-rocking engaged in by twenty-seven mentally deficient adults in ward environments. A significant decline in amount of body-rocking across the session was observed in each of the patients and other evidence suggested that this was an effect of fatigue. For eleven of the patients there was significant evidence of a 90--110 minute ultradian bio-rhythm in the amount of body-rocking. Rates of body-rocking showed less variation during the sessions. It was suggested that these results, plus other cited evidence, make it less likely that body-rocking in experimental, and in natural, environments are the same operants.