Every once in a while at The Aerie, I’ll come home a little weary and The Beloved will hug me and say, “You don’t smell like you. You’re sick.”, which I usually say is crap, because, well, I never like to admit when I’m sick and human olfaction is pretty crappy – even if you take into account women’s superior sense of smell compared to men’s. Even if I am sick, I can’t smell sick. This usually leads to a happy hour discussion that revolves around the sense of smell in humans – specifically, are there human pheromones that produce biological responses?
What are pheromones? Pheromones are chemicals released from one individual in a species that cause a biological response in others. Some of the common responses are to “sound” an alarm, leave a trail, mark territory, or attract a mate. They are well documented in insects, fish, and mammals. They are not, however, known in humans. In mammals that use pheromones, there’s a mass behind the nose called the vomeronasal organ (VNO) – which specifically receives and transmits pheromone signals.
Lots of animals have this organ – humans do not. Ipso facto, no human pheromone response, right?
Maybe not. Recent research has found a separate pheromone detecting system in mice that bypasses the VNO and directly activates the gonadal axis. Importantly, humans DO have a homologous system. A compound found* to be in high concentration in men’s armpits – androstadienone – has been found to improve the moods and increase sexual arousal of women that smell it compared to other scents (the analogous compound for men seems to be estratetraenol, which is found in women’s urine**). And brain imaging scans of women exposed to androstadienone showed increased activity in the hypothalamus***, an area known to influence mate choice and sexual behavior in animals.
So where does that leave us? Are we at the mercy of compounds that we’re not even aware that we secrete and detect? Or does our “higher” brain circumvent, override and/or justify our attractions and behaviors? Certainly, I think it’s much more the latter, but it is fascinating to know that we’re still learning more about our own biology all the time.
* one of the leaders in this area is a guy with the name of George Petri. Seriously.
** wow, I am not going there.
*** it also lit up homosexual mens' hypothalamus, but not those of heterosexual men.