The Chemistry of a Kiss

Yesterday I informed you all about the possible anti-depressive properties of semen; today I will enlighten you regarding the chemistry of your saliva, or to put it more poetically, the science of a kiss.

If you think about it, kissing is a gross behavior - essentially spitting in each others mouth. Because of this, and because we are not the only species to engage in such vile behavior, it is reasonable to believe that there is a reason this behavior has been conserved. So, if you've ever liked someone...that is until you kissed them, there may be more to it than technique (or lack thereof). And furthermore, there may be a reason men are generally considered bad kissers.

The reason may have to do with the fact that, similar to sperm, saliva contains hormones, as explained by Helen Fisher, a biological anthropologist who is a Research Professor and member of the Center for Human Evolution Studies in the Department of Anthropology, Rutgers University and Chief Scientific Advisor to the internet dating site, Chemistry.com:

"There's evidence that saliva has testosterone in it, and there's also evidence that men like sloppier kisses with more open mouth," Fisher said. "That suggests to me that they are unconsciously trying to transfer testosterone to trigger the sex drive in women."
...
And there may be more to this chemical assessment than just kissing, Fisher said. "I think kissing is the tip of the ice berg. I think we'll find that all kinds of other chemical systems are in play that we don't know about."

Fisher says she has found from other scientists' research and from her own analysis of statistics on 40,000 people on the dating Web site Chemistry.com that there are four dimensions of temperaments, or biologically based traits, and each is associated with different chemical systems in the brain: Dopamine is associated with traits like novelty seeking, risk taking, curiosity and creativity; serotonin was linked to calm, caution, cooperation, loyalty, and tradition; testosterone with decisiveness and emotional containment; and estrogen lumped together with oxytocin was linked to nurturing, patience and social skills.

"It now appears that we are drawn to people with particular biological profiles," she said. And the kiss may be how we assess someone's profile."
...
Neuroscientist Wendy Hill thinks it also plays a role in pair bonding. Now doesn't that sound more romantic?

Maybe, but she studied this idea by asking college-aged couples to do the decidedly unromantic act of making out for 15 minutes in a lab room at the campus infirmary. By comparing blood and saliva samples from before and after the kissing sessions, she discovered that cortisol, a hormone involved in stress, went down in both men and women. Interestingly, kissing boosted the mens' level of oxytocin, which has been linked to pair bonding, but the level dropped slightly in women.

Hill suspects that despite the flowers and music she provided, this could be because the college health center is where the students go when they feel sick, not sexy, which may affect women more than men.

I'm not so sure I agree with her assessment of why men like sloppier kisses (and not even sure I agree that we do), but for more, check out the full article at Wired Science. And check out this interview from the Colbert Report with Helen Fisher, talking about the science behind chemistry.com: