A chemical signal in human female tears lowers aggression in males

Rodent tears contain a chemical signal that reduces aggression in conspecifics. This study shows that human tears similarly contain a chemical signal that, although odorless, activates human olfactory receptors in vitro, alters neural activity in an olfaction-aggression brain network, and lowers male aggressive behavior.

Divergence of olfactory receptors associated with the evolution of assortative mating and reproductive isolation in mice