Neurobiological mechanisms of social attachment and pair bonding

•Social monogamy has evolved independently in distant species.•Pair bonding has been investigated most rigorously in prairie voles.•Pair bonding is regulated by dopamine, oxytocin, vasopressin, and other neural systems.•A model of the neural pathways of pair bonding has emerged.

Species have evolved diverse social behavior and mating strategies in response to selective forces in their environments. While promiscuity is the predominant mating strategy across most vertebrate taxa, convergent evolution of monogamous mating systems has occurred multiple times across distant lineages. Monogamous behavior is thought to be facilitated by a neurobiological capacity to form and maintain selective social attachments, or pair bonds, with a mating partner. The neural mechanisms of pair bonding behavior have been investigated most rigorously in Microtine rodents, which exhibit diverse social organizations. These studies have highlighted mesolimbic dopamine pathways, social neuropeptides (oxytocin and vasopressin), and other neural systems as integral factors in the formation, maintenance, and expression of pair bonds.