Social versus dietary control of ruminating by mentally retarded persons.

The effects of social and nonsocial environments on the maintenance of ruminating were compared. There was no decrease in ruminating in the nonsocial condition for the 4 mentally retarded subjects tested. In addition, results of Rast, Johnston, Drum, and Conrin (1981) and Rast, Johnston, and Drum (1984), who manipulated the quantity of food available to 2 subjects, were replicated. Satiation quantities of starches produced immediate and large decreases in the frequency of ruminating compared to ruminating under standard meal sizes. Parametric decreases in food intake by one subject resulted in increases in ruminating at each food volume.