The Relation Between Heart Rate and Electromyographic Activity in a Discriminated Escape‐Avoidance Paradigm

Experiment I attempted to train both increases and decreases in heart rate using a discriminated escape‐avoidance paradigm. Noncontingent control S s were yoked to both experimental groups. Subjects were given 64 training trials and 16 extinction trials. Experiment II employed essentially the same design except that the contingent response was a specific amount of muscular tension (either 40 to 60 microvolts, or 90 to 110 microvolts) from the chin area. Seven S s were run in each group. Heart rate, chin electromyogram (EMG), and respiration were continuously monitored during each study. The results of Experiment I indicated that the response contingencies produced significant heart rate increases and decreases in the appropriate experimental groups. Neither yoked control group showed a significant heart rate change. No group exhibited any significant EMG activity. Respiration amplitude increased significantly only in the heart rate increase group. Both experimental groups in Experiment II learned to emit the correct EMG response. However, only the group in the 40 to 60 microvolt range showed a relationship between heart rate and EMG changes.