Cardiac vagal tone predicts inhibited attention to fearful faces.

The neurovisceral integration model (Thayer, J. F., & Lane, R. D., 2000, A model of neurovisceral integration in emotion regulation and dysregulation. Journal of Affective Disorders, 61, 201-216. doi:10.1016/S0165-0327(00)00338-4) proposes that individual differences in heart rate variability (HRV)-an index of cardiac vagal tone-are associated with attentional and emotional self-regulation. In this article, we demonstrate that individual differences in resting HRV predict the functioning of the inhibition of return (IOR), an inhibitory attentional mechanism highly adaptive to novelty search, in response to affectively significant face cues. As predicted, participants with lower HRV exhibited a smaller IOR effect to fearful versus neutral face cues than participants with higher HRV, which shows a failure to inhibit attention from affectively significant cues and instigate novelty search. In contrast, participants with higher HRV exhibited similar IOR effects to fearful and neutral face cues, which shows an ability to inhibit attention from cues and instigate novelty search. Their ability to inhibit attention was most pronounced to high spatial frequency fearful face cues, suggesting that this effect may be mediated by cortical mechanisms. The current research demonstrates that individual differences in HRV predict attentional inhibition and suggests that successful inhibition and novelty search may be mediated by cortical inhibitory mechanisms among people with high cardiac vagal tone.