On National Kissing Day, celebrate the science and art of kissing — from chemical "sparks" to the thrill of early desire

Kissing helps us weed out incompatible partners, pass on robust immune systems, and test the romantic waters

By Erin Coulehan
July 6, 2016 9:30PM (UTC)
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(Ammit Jack via Shutterstock)

I’ve always looked forward to the same part of every date, movie and romance — the kiss. From first kisses that leave us weak in the knees, sending the body aflutter with a rush of pleasure-inducing chemicals, to those that leave a (literal) bad taste in our mouths, as a culture we’ve mastered the art of the make out. Philematologists — kissing scientists — tend to agree that kissing began as a way for mothers to transfer food to their babies. Like birds, kind of. But the practice evolved to take on a largely romantic connotation to become valued in many cultures throughout the world.

Today marks #NationalKissingDay, one of the more fun pseudo-holidays to celebrate, both in theory and in practice.


According to dating site Zoosk, 47 percent of singles report that it’s acceptable, if not expected, to kiss on a first date. Given the myriad technologies designed to facilitate dating and hookups in the digital age, it’s necessary for lovers to differentiate themselves from all the other options. We crave a connection to something greater than ourselves on a biological level, and our bodies have evolved to help us weed out potential partners via kissing.

The major histocompatibility complex (MHC) is a protein associated with immune system health that helps ensure an organism has a variety of immuno-defenses in order to survive. Levels of MHC have been found to exist in saliva, which has some scientists believing it plays a role in the level of satisfaction we have when kissing certain people.

If two people’s MHC’s are too similar, it means their immune systems are also similar, which could be potentially dangerous for any future offspring. If MHCs are dissimilar, the potential offspring will have the built-in mechanisms to protect them from a multitude of immunological threats — this is what we want. So it might be that the sensation we sometimes feel from kissing a certain person is partially caused by the chemical reaction that occurs when dissimilar MHCs collide — sparks.


How much practice we have at puckering up also says a lot about our romantic behaviors.

The Zoosk survey found that 29 percent of male respondents reported they’ve locked lips too many times with too many partners to count. Interesting enough, 29 percent percent of women say they’ve only kissed between 0-7 people, a low number which might reflect female participants’ desire to minimize their kissing history on a dating survey. Regardless, kissing methods serve different purposes for each gender.

In 2007, psychologist Gordon Gallup Jr. studied kissing perceptions of 1,000 undergraduate students at the State University of New York at Albany, and found the fairer sex placed a higher value on kissing. Female respondents overwhelmingly reported the necessity to kiss before having sex, and were also more likely to encourage kissing during sex. Males, on the other hand, seemed to use kissing as a means to an end to achieve sex, which may explain why so many male respondents reported they were unable to remember how many people they’ve kissed in the Zoosk survey.


When researching this story, I took to Facebook to determine how my friends perceive kissing, and found it’s a topic people tend to be pretty, er, loose-lipped about. Not only did I receive many comments on the actual post, but also texts, phone calls and emails from people wishing to share some of their most memorable kissing experiences.

Some people shared kissing pet peeves that seem to be pretty standard: bad breath, tight lips, too much tongue. Most people I talked to prefer some level of push-and-pull — a lip nibble here and there along with some neck play. The Zoosk study found that 63 percent of people find being kissed on the neck second only to being kissed on the lips.


What touched me the most was how many memorable first kiss stories I heard. One friend was first-kissed in first grade by a foreign exchange student on a slide, while others (myself included) had slightly less romantic experiences.

In high school my best friend and I had crushes on two older boys who happened to invite us to a Fourth of July celebration. We immediately built up the fantasy — being kissed under the fireworks under an expanse of sky in the desert of west Texas — and began planning our outfits and looking up any information we could find. We wanted to have some idea of what we were doing. But as with most romanticized ideas, the fantasy went up in flames. The boys ditched us, and we ended up inadvertently setting a small bush ablaze with our sparklers. Talk about learning a lesson on expectations at a young age.

The weight we put on kisses, especially first ones, reveals a lot about how highly we regard the act. Sure, it’s easy to find a stranger to kiss and never see again, or to dismiss kissing as the first base to round in a more elaborate game, but I think kissing is a fundamental interest and treasured activity for many people. I’m not one for very much sentimentality, but do find #NationalKissingDay as potentially thrilling as it is silly, much like the rush of serotonin and adrenaline we get from a good kiss itself. How wonderful, to be wooed.

Erin Coulehan

Erin Coulehan is a freelance journalist with work in Rolling Stone, Elle, Slate and others. Follow her on Twitter @miss_coulehan

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Dating Kissing Love National Kissing Day Relationships Sex