Individual difference in anticipatory physiological responses to signaled stress: role of locus of control and autonomic balance.

Anticipatory cardiac activity to a signaled stressful event was hypothesized to be related to individual differences in locus of control and to autonomic balance. Subjects experienced 5 trials of a 105-db burst of white noise that was signaled by a milder tone. Significant increases in electrodermal as well as heart-rate responses occurred after the stress tone. While anticipating stress, the 10 subjects designated as having high levels of coherence between heart-rate and respiratory activity (high parasympathetic balance) showed reduced heart-rate and respiratory activity (high parasympathetic balance) showed reduced heart-rate variability over the 10 subjects with low coherence. Locus of control was not related to anticipatory activity. Anticipatory cardiac activity is discussed in light of two current psychophysiological models of attention.