Cardiac cycle modulates social pain.

Social pain is a painful feeling evoked by social rejection, exclusion, or the loss of other important people. Previous research suggests that physical pain is reduced by increased signals from baroreceptors that monitor blood pressure. This pre-registered study investigated whether social pain is attenuated by increased baroafferent signals, as observed in physical pain. Given that baroafferent signals increase during cardiac systole and decrease during diastole, we hypothesized that feelings of pain induced by social rejection would be lower when exclusion events are presented at the cardiac systole than when they are presented at the diastole. Participants completed the cyberball task, a computerized ball-tossing game involving two other players. In the rejection condition, the ball was rarely thrown to the participant, while the other players kept tossing it to each other. Throws between other players were defined as exclusion events and were presented either at the cardiac systole (a systole condition) or at the diastole (a diastole condition). We found that exclusion events evoked significantly less social pain in the systole condition than in the diastole condition. Furthermore, the effects of cardiac cycle were more pronounced in participants with higher heart rate variability than those with lower heart rate variability. Our results suggest that cardiac afferent signals contribute not only to physical pain but also to social pain.