Emotional closeness as a mediator of the effect of genetic relatedness on altruism

Inclusive fitness theory has been used to explain the overall pattern of al truistic behavior. However, this theory does not address the proximal cause s of altruism. The purpose of the present study was to increase the underst anding of altruism by testing a model that includes both ultimate and proxi mate causes. In particular, emotional closeness was tested as a mediator of the effect of genetic relatedness on altruistic behavior. This was accompl ished by having college students choose which of their family members they would most likely provide with life-saving assistance. As expected, results showed that emotional closeness is an important proximal cause of altruism that partially mediates the effect of genetic relatedness on willingness t o act altruistically.