Biofeedback control of skin potential level.

This study explored the possibility of using biofeedback to arrest spontaneous declines in tonic electrodermal levels. For 3 days, 10 subjects (S) received 20 minutes of training in increasing skin potential level (SPL) negativity (arrested declines), followed by 20 minutes of training in decreasing SPL negativity (facilitating declines), with reverse order for half of the Ss. Simultaneous analogue and binary feedback of SPL were used. Training in the direction of SPL increases resulted in arrest of spontaneous declines in SPL negativity but did not result in large-magnitude increases above baseline. Training in the direction of SPL decreases facilitated declines in SPL. The absolute mean difference between the increase condition and the decrease condition on the 3rd day was 8.28 mV. Correlations suggested that considerable intraindividual variability may have been independently related to the Locus of Control personality dimension and to a Law of Initial Values limitation on SPL change. It was concluded that SPL was controllable to the extent of facilitating or arresting spontaneous declines.