Relation of Experimental Tachycardia to Amplitude of Motor Activity and Intensity of the Motivating Stimulus

¹ From the Pavlovian Laboratory, Phipps Psychiatric Clinic, Johns Hopkins Medical School, Baltimore, Maryland

The heart rates accompanying three auditory signals for three different intensities of electric shock are proportional to these three intensities and also parallel to the amplitudes of the motor responses (Crs) and inversely proportional to the latent period of the motor Crs. There is thus a close relationship between the intensity of the reenforcing shock and the learned responses to the signals for the shocks, whether the response be in the ‘voluntary’ motor system or in the ‘involuntary’ autonomic (cardiac) system. Since the intensity of the shock (unconditional stimulus) is analogous to ‘motivation,’ we see here that the acquired change in heart rate (tachycardia) in such an experiment where the stress is not sufficient to produce pathology and chaotic relations, and where the conditions are kept constant, is proportional to the intensity of the motivation.