The mediating effect of empathy in the quadratic relationship between children's resting RSA and sharing behavior.

The present study examined the mediating role of empathy in the quadratic relationship (an inverted U-shaped curve) between resting RSA and sharing behavior in 7- to 8-year-old children. Sharing behavior was measured using children's allocation of resources in the dictator game; the Griffith Empathy Scale-Chinese version was used to assess children's empathy. Resting RSA was calculated by electrocardiogram (ECG) data collected during a resting period in the laboratory. The results demonstrated a significant mediating effect of empathy in the quadratic association between resting RSA and sharing behavior. Specifically, moderate resting RSA was related to greater empathy and then contributed to more sharing behavior, while high and low resting RSA had a negative impact on empathy, which reduced the children's sharing behavior. The present study is the first to investigate the mediating role of empathy in the quadratic relationship between resting RSA and sharing behaviors. Accordingly, this study contributes to a better understanding of the psychological mechanisms that underlie the quadratic vagal tone-prosociality relationship.