Although variation in OXTR in previous studies has been shown to associate with different measures of social behavior (30–46) no one has previously linked it to a phenotype in humans directly corresponding to the species-unspecific and evolutionarily important concept of pair-bonding. Pair-bonding has been studied extensively in voles and shown to be facilitated through the actions of OT in females of this species. The fact that we are able to show an association between OXTR and behaviors reflecting pair-bonding in women but not in men is therefore consistent with previous research in animals. This study adds to previous findings and gives support to the hypothesis that OT in humans, as in other animals, is important for affiliative bonds between individuals of our species (70, 71).
