Abstract

An increasing number of studies have been conducted to investigate the neurophysiological and psychological processes underlying the construction of biopolitical relationships both within and between groups. This paper will explore the possibility that in animal societies the affiliative bonds, namely the so-called special relationships, may be comparable to human friendship. It has been proposed that special relationships facilitate fundamental tasks, such as parental care, protection, foraging for food, and food sharing. Consistent with this adaptive hypothesis, the neurophysiological correlates of affiliative behaviours are conserved across species. In particular, this paper will focus on the role of oxytocin and vasopressin in social relationships. It will be suggested that specific and ecological constraints may mediate the variety of behavioural outcomes, and that the parochial altruism hypothesis can account for the dual role of oxytocin and vasopressin in social relationships.