EMG and cardiovascular responses to emotionally provocative photographs and text

Previous studies on the psychophysiology of human emotion have repeatedly shown general and occasionally specific facial EMG (mu v) and covert cardiovascular response relationships to emotionally provocative photographs. Less clear are the relationships between psychophysiological response indices measured during the silent reading of emotionally charged versus emotionally neutral text. In this study, 12 adult subjects were presented two emotionally loaded color and black-and-white photographs and two brief newspaper articles, one emotionally charged and the other emotionally neutral in content. Each independent stimulus was presented for 1 min., preceded by a rest according to a multiple baseline-reversal design. Subjects evaluated each pictorial and textual stimulus condition according to adjective dimensions on 7-point rating scales. Mean values for corrugator supercilii EMG (mu v), upper trapezius EMG (mu v), surface temperature (degrees F), and heart rate (bpm) measured by finger photoplethysmography were measured during each rest and test period. Significant increases in the subjects' mean corrugator supercilii EMG (mu v) measures were observed during all color and black-and-white photograph presentations for both emotional and neutral content. As predicted, the subjects' mean corrugator supercilii EMG (mu v) measures increased significantly while silently reading text with an obvious unpleasant emotional tone. A significant positive relationship was observed between the subjects' mean ratings and mean corrugator EMG (mu v) difference values for the emotionally loaded color photographs.