Reciprocal Altruism and Group Living

Synonyms

Direct reciprocity and group formation; Group living; Reciprocal cooperation; Reciprocity

Definition

Self-costly acts that confer benefits on others are reciprocated by the recipients such that a mutual benefit is gained. This reciprocal favoritism may be a mechanism relevant to the formation and persistence of group living.

Introduction

Group living is an elemental part of human life and is essential for the survival and replication of our species. Thanks to group living we have been more effective in hunting and protecting ourselves from predators through cooperation. One peculiar phenomenon observed in human group living is that individuals provide self-costly and seemingly altruistic benefits to other group members. For instance, someone might save a group member from drowning (benefit to the recipient) and thereby risking his/her own life (cost to the helper). Humans show such kind of behaviors even toward genetically unrelated others, such that inclusive fitness and kin...