Beth Stebner
Updated Aug 21, 2015 @ 10:57 am

It’s inspired centuries worth of poems, the climax to every romantic movie, like, ever, and has probably done wonders for the lip balm and breath mint industries.

But what is the actual science behind kissing? Turns out, it’s a lot more complicated than just locking lips. Here are just a handful of facts we learned about the act of kissing, and now we can never unlearn them. Enjoy.

1. Kissing may or may not be instinctual. Some anthropologists argue that it’s a learned behavior, a relic of early mothers chewing food for their newborns and then using the motion as a form of comfort. Others say it’s pure instinct. Either way, 10 out of 10 scientists agree it’s fun. (OK, we just made that stat up.)

2. There’s that 80 million microbes thing. Locking lips isn’t without an ‘ick’ factor – according to a 2014 study published in Microbiome, more than 80 million microbes are exchanged during the average smooch.

3. But not to worry, kissing isn’t as germ-ridden as you’d think. You’re more likely to get sick from shaking hands than you are from kissing, multiple studies have shown.

4. Our lips love it. There is a significant amount of the cortex region in your brain devoted to possessing sensations from your lips, making them one of the most sensitive and erogenous parts of your body (and, perhaps explaining why kissing just feels good).

5. It’s nature’s chill pill. When you kiss someone levels of the stress hormone cortisol drop, according to a recent Lafayette University study. Basically, kissing is an instant full body relaxer. (Let’s be honest, that’s only if it’s a good.)

6. Dudes feel the bond. In that same study, researchers noticed that men, not women, experienced a rise in Oxytocin, the bonding hormone that makes you feel all mushy and connected, when they kissed. Aw.

7. The kiss is a global phenomenon. According to Sheril Kirshenbaum, author of “The Science of Kissing: What Our Lips Are Telling Us,” more than 90% of cultures kiss. Why, though? She hypothesizes it has to do with bonding and staying together long enough to have kids. But that’s just from an evolutionary standpoint.

8. A kiss is not a contract. In a recent University of Texas study, 66% of women and 59% of men said that they called quits on a new romance because a kiss wasn’t up to snuff.

9. But it can lead us to the right partner. An Oxford University study suggests the act helps us select those partners we want to stick around. One reason may be that it gives us a chance to literally sniff out potential mates.

10. Men like sloppier kisses. Science says so. “There’s evidence that saliva has testosterone in it, and there’s also evidence that men like sloppier kisses with more open mouth,” Helen Fisher, a Biological Anthropologist from Rutgers University said at a press conference about her research on kissing. “That suggests to me that they are unconsciously trying to transfer testosterone to trigger the sex drive in women.” Just wow.

(Image via 20th Century Fox)