Development of studies on grooming reciprocity in primates

Abstract

Many researchers have investigated why and how animals benefit from each other in a group. Grooming is considered as prosocial behavior in animal societies; the groomer expends time and energy costs, while the groomee receives hygienic and physiological benefits. Based on the reciprocal altruism hypothesis (Trivers, 1971), many researchers have investigated grooming behaviors in primate species. In primates, individuals exchange grooming for grooming or other social benefits (e.g., tolerance for food, agonistic support, or infant handling). Researchers have also established and modified models of grooming reciprocity. In future researches, it would be valuable to investigate the effects of affiliative relationships, soliciting behaviors, self-rewarding, inequity aversion, and partner choice and partner switching on prosocial behaviors.