Grooming movements as operants in the rat

Two experiments investigated the effect of contingent food deliveries on grooming movements in rats. The grooming sequence was divided into three topographically distinct behaviors: paw washing, face washing, and body washing. The first experiment found that rates of paw washing and body washing increased reliably under a food contingency, but face washing did not. A second experiment replicated these findings, and, in addition, showed that the average duration of paw washing and body washing decreased in length when followed by food. Placing a contingency on face washing, however, produced an increase in the rate of paw washing but no increase in face washing. It was concluded that, on the one hand, paw washing and body washing may be influenced by operant contingencies in the same way as behaviors such as lever pressing. On the other hand, increases in paw washing under the face washing contingency suggested that increases in the rate of grooming movements may occur by means other than operant relations.