Reduction of stereotyped body-rocking using variable time reinforcement: practical and theoretical implications.

The first experiment assessed the effectiveness of two schedules of reinforcement in reducing stereotypy engaged in profoundly retarded patients in ward environments. These schedules were the differential reinforcement of other behaviour (DRO) and variable time reinforcement (VT). This experiment was terminated prematurely because of problems in implementing the DRO contingencies. However, the VT contingency appeared to reduce stereotypy. The second experiment evaluated the VT schedule of reinforcement alone. Significant decreases in amounts of stereotypy from baseline measures were observed in all five profoundly retarded female subjects. It is tentatively concluded that stereotypies in ward and laboratory environments differ in function. This has implications for the treatment of patients who engage in stereotyped behaviour.