The Relationship Between Autonomic Indicators of Psychological Stress: Heart Rate and Skin Conductance

Repeated research has failed for a long time to establish significant correlations between autonomic nervous system indices of arousal or stress. This has resulted from the use of inappropriate methods of obtaining the correlations--specifically, from interindividual (across subjects) procedures. When intraindividual approaches were employed, substantial relationships were found between heart rate and skin conductance. The data came from an extensive study of the autonomic effects of a benign and a stressor motion picture film. One intraindividual approach led to a correlation of 0.5 under the stressor condition. The average curvilinear correlation under stress was 0.4. Thus, there is evidence of a generalized autonomic reaction when the appropriate methods of correlation are used. Moreover, the magnitude of the intraindividual relationship between heart rate and skin conductance was significantly higher under the stressor film than under the control.