An evaluation of frontal EMG as an index of general arousal

Two experiments were conducted to investigate the sensitivity of frontal EMG to increased arousal. In Experiment 1 subjects who were aroused by a physical threat (electric shock) showed changes in skin temperature and self-report of arousal, but did not show changes in frontal EMG. In Experiment 2 subjects who were aroused by an evaluative threat (poor performance on an important intelligence test) showed changes in skin temperature, pulse rate, finger pulse volume, and self-report of arousal, but again failed to show changes in frontal EMG. The finding that frontal EMG was not sensitive to increases in arousal is inconsistent with what has generally been assumed and suggests that frontal EMG biofeedback training may not be effective for teaching persons to reduce high levels of arousal.