In this article, we explained the theory that kissing evolved as a way for women to expose themselves to cytomegalovirus so their future babies wouldn't get hit with a herpesesque disease in the womb. And man, is that the most unromantic explanation for kissing EVER. The good news is that there are other, less awful theories about smooching out there. One is that we've all got a secret sex nerve in our brains that compels us to swap spit.
"My nose is telling me it's time to tongue your face-hole."
But first, some background. Everyone has 12 pairs of nerves jutting out of the brainstem, appropriately named Nerve I through Nerve XII. And most of them are regular sensory nerves, like the olfactory one and the optic one and the one that helps us see the dead. But in 1913, scientists discovered another nerve that everyone had missed before. "Nerve 0" (or, as we like to call it, Nerve Oooooh) sits at the base of our skulls, seemingly useless, like a third testicle on an already sterile old man. So it's not surprising that everyone kind of forgot about it.
Although that doesn't make them shut up about it at parties.
So when scientists finally got around to figuring out what this nerve did, they discovered something funny. Even though it looked like an olfactory nerve, it was present in creatures that had long ago lost their sense of scent. Which means it must have some purpose in humans (and all other animals) besides making public transportation unpleasant. Shortly thereafter, scientists discovered that cutting this nerve caused mice to stop breeding.
It turns out Nerve 0 is directly connected to the regions of the brain associated with sex and gives your nose a direct, private highway to your genitals. Well, that's interesting. What could that be for?
Stop having sex with those flowers and we'll tell you.
Scientists theorize that when you kiss someone, Nerve 0 picks up their pheromones and warns your body to start sending blood and good vibes down to your crotch as quickly as possible. It's important to note that Nerve 0 doesn't travel through your olfactory bulb at all, which means you can't actually smell any of the things your sex nerve is designed to pick up. And since our pheromones don't carry very well, getting close enough to kiss is basically the only way your Boning Nerve can do you any good.
And what kind of things does your brain learn by picking up pheromones this way? For one thing, it allows you to sneak a peek at your lover's immune system. People you're attracted to will tend to have been exposed to very different antibodies over the course of their lifetimes. This ensures that you have a lower chance of miscarriages and a higher chance of birthing superbabies with badass immune systems. It also stops you from finding your relatives sexually viable, so let's give it a round of applause for preventing a lot of awkward family reunions.
Here's a question we bet you never asked yourself: Why do guys prefer big breasts? Don't say it's because it signals that a woman is more capable of nursing -- huge boobs serve no practical purpose for the delivery of milk. Well, according to one theory, it has to do with our ancestors preferring face-to-face sex.
"I call them 'shock absorbers.'"
The humble "missionary position" has the unfair reputation of being the boring option for couples too tired to try anything too crazy. But out in the animal kingdom, that position is crazy -- face-to-face sex is something of a revelation for mammals. Our ape ancestors preferred a much less ... frontal method. But the pair bonding that occurs when couples look each other in the eye while doin' it is beneficial enough to humanity that evolution favored people who had face-first sex.
Also our heads were getting much larger during this time, and that shit gets heavy.
In The Naked Ape, British zoologist and ethologist Desmond Morris proposed that the social benefits to our ancestors who liked missionary-style sex were great enough that evolution favored frontal features that mirrored the backside. Namely, giant breasts that mimic the bulbous buttocks of our great-to-the-power-of-500 grandmas. As Desmond put it:
"The protuberant, hemispherical breasts of the female must surely be copies of the fleshy buttocks, and the sharply defined red lips around the mouth must be copies of the red labia."
The first time he shopped at the greengrocers, he had to lie down in a dark room for three days.
Of course, Desmond, they must be. And that means that big breasts exist purely to compel attention. In other words, evolution masterminded the single most successful advertising campaign in world history.
Robert Evans oversees the image captions at Cracked and has a blog where he writes letters on our messed-up justice system, illegal immigration, oil drilling and drug policy to the conservative parents of the world. If you'd like to hire him, he can be reached at firstname.lastname@example.org.
For more science behind human actions, check out 6 Obnoxious Old People Habits (Explained by Science) and 6 Factors That Secretly Influence Who You Have Sex With.
And stop by LinkSTORM to discover which columnist won't leave people's feet alone.
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