Men and Women react differently to sniffing a social hormone - aggressively versus friendly

Thompson et al have found that a peptide influencing social behaviors in numerous species, Arginine vasopressin (AVP), causes different behaviors in men and women when administered intranasally with an inhaler. In men, AVP stimulates agonistic (i.e. combative) facial motor patterns in response to the faces of unfamiliar men and decreases perceptions of the friendliness of those faces. In contrast, in women, AVP stimulates affiliative facial motor patterns in response to the faces of unfamiliar women and increases perceptions of the friendliness of those faces. AVP also affected autonomic responsiveness to threatening faces and increased anxiety, which may underlie which may underlie the peptide's sex-specific effects on social communication by promoting different social strategies in response to stress in the sexes. The authors note; "Because intranasal AVP administration crosses the blood-brain barrier and, at the dose we used, directly affects central processes, whereas peripheral elevations do not, we argue that the effects we observed were likely centrally mediated, either through CSF-signaling mechanisms or by means of diffusion into discrete brain areas. Thus, our results support the hypothesis that central AVP's ability to influence social communication processes, a conserved trait of AVT and AVP in vertebrates, has been retained in humans."