Stress reduction through consolation in chimpanzees

Abstract

Consolation, i.e., postconflict affiliative interaction directed from a third party to the recipient of aggression, is assumed to have a stress-alleviating function. This function, however, has never been demonstrated. This study shows that consolation in chimpanzees reduces behavioral measures of stress in recipients of aggression. Furthermore, consolation was more likely to occur in the absence of reconciliation, i.e., postconflict affiliative interaction between former opponents. Consolation therefore may act as an alternative to reconciliation when the latter does not occur. In the debate about empathy in great apes, evidence for the stress-alleviating function of consolation in chimpanzees provides support for the argument that consolation could be critical behavior. Consistent with the argument that relationship quality affects their empathic responses, we found that consolation was more likely between individuals with more valuable relationships. Chimpanzees may thus respond to distressed valuable partners by consoling them, thereby reducing their stress levels, especially in the absence of reconciliation.

Fig. 1.

Mean self-grooming (A) and self-scratching (B) levels during postconflict periods without reconciliation or consolation, where more than one PC–MC pair was available per individual. For PC data, means for every second minute are used. Means for the whole 10 min are used for MC data, with 95% confidence intervals.

Fig. 2.

Mean (+SE) proportion of 5-sec blocks spent performing self-directed behavior during minutes 2–10 of PCs without consolation or reconciliation and PCs with consolation and during MCs. *, P < 0.05

Fig. 3.

Mean (+SE) proportion of 5-sec blocks spent performing self-directed behavior before consolation and after consolation. *, P < 0.05