Differential Operant Conditioning of Heart Rate

&NA; Five normal female subjects (Ss) were taught to increase and decrease cyclically their heart rate (HR) by means of a differential operant conditioning technique. Discrimination between slowing and speeding was easily demonstrated; however, the ability significantly to increase and decrease HR relative to resting rate was less apparent. Although each S could do this on at least one occasion, only 2 Ss did so with consistency. Breathing or musculoskeletal responses did not seem to mediate the learned responses.