Face your heart: resting vagally mediated Heart Rate Variability Shapes Social Attributions from facial appearance

Phylogenetic theories suggest resting vagally mediated heart rate variability (vmHRV) as a biomarker for adaptive behavior in social encounters. Until now, no study has examined whether vmHRV can predict individual differences in inferring personality traits and intentions from facial appearance. To test this hypothesis, resting vmHRV was recorded in 83 healthy individuals before they rated a series of faces based on their first impression of trustworthiness, dominance, typicality, familiarity, caring, and attractiveness. We found an association between individual differences in vmHRV and social attributions from facial appearance. Specifically, higher levels of vmHRV predicted higher scores on ratings of caring and trustworthiness, suggesting that strangers' faces are more likely to be perceived as safer. The present results suggest that higher levels of vmHRV (compared with lower levels of vmHRV) are associated with the tendency to minimize social evaluative threat and maximize affiliative social cues at a first glance of others' faces.