Open-mouthed, passionate kisses are central to our popular culture. In countless movies from Casablanca to Pretty Woman to Star Wars, kisses define characters and change the narrative direction. Reality television salivates over a couple’s kiss like the starving beast that it is. The power of the kiss, though, is not a figment of our entertainment imagination and neither is it new.
Romantic poet John Keats fully bought into the power of the kiss writing, “Now a soft kiss — Aye, by that kiss, I vow an endless bliss.” Two centuries later, just remember this, a kiss still does promise bliss, and as an average Australian you will spend around 20,000 minutes of your life engaged in kissing.
The kiss is powerful: when couples first kiss they are cementing mutual attraction, and continued kissing maintains and expresses close bonds. Kissing also enables and paves the way for sex. The entire experience of living in countries like Australia and New Zealand makes it easy to think that the open-mouthed “French” kiss is a natural, universal part of the human experience, but the truth about kissing is far more complex, more fascinating and a little unnerving.
Not the norm
Some of the most graphic evidence that passionate kissing is not a universal human behaviour was given in William Winwoode Reade’s 1864 book Savage Africa. In the book Reade described falling in love with the daughter of an African king. Eventually he decided to express his emotions with an open-mouthed kiss, but unfortunately the regal daughter screamed and ran away in tears. Apparently, Reade later discovered, she interpreted his kiss as an intention to eat her. It’s easy to see how some overzealous kisses could be interpreted this way, but the story points to a cultural divide that we may easily overlook.
The varying cultural attitudes to a kiss were the focus of a 2015 study published in the journal American Anthropologist. The researchers studied 168 cultures over the course of a year and found evidence of open-mouthed romantic kissing in just 46 per cent of those cultures. In the Middle East, the researchers found that 100 per cent of cultures partake in romantic kissing, in Asia 73 per cent and in Europe 70 per cent. Meanwhile, in Central America no cultures were disposed to a smooch. Kissing also had no place in the cultures of Sub-Saharan Africa or New Guinea, or among Amazonian hunter-gatherers. The conclusion of these authors was that there is ”No evidence that the romantic–sexual kiss is a human universal or even near universal.”
The Ma-ori of New Zealand and the Inuits of Canada, for instance, employ a nuzzling bonding behaviour. There are many other expressions of sensual intimacy, such as patting, licking, rubbing, sucking or blowing on your partner’s face prior to sex. One of the more striking intimate behaviours has been described by Bronisław Malinowski, who reported that Trobriand Islanders would bite each other’s eyelashes off during intimacy and at orgasm. To us it might seem a risky pursuit, and to beauticians a devastating loss of trade, but is it any stranger than locking your mouth onto your partner and engaging in a spirited bout of Greco-Roman tongue wrestling? Of course, it is not. Kissing is, objectively, a bizarre thing to do.
If we want to understand this thing we call a kiss and why we adopt kissing so enthusiastically, it will help to consider what happens when you kiss.
What’s in a kiss?
Applying science to what we like to think of as the romantic art of kissing might seem like attempting to describe the sky with a screwdriver, but there are some definite, quantifiable qualities to a kiss that have been measured. In a paper published in the American Journal of Medicine, Joseph Alpert MD sought to outline the verifiable “anatomic, neurophysiologic, epidemiologic, and clinical information” that exists on kissing.
After reviewing the medical literature on the subject, Alpert reported that a simple peck on the lips may use as few as two muscles and burn only 8 to 12 kilojoules.
A passionate kiss, however, involves 23 to 34 facial muscles and 112 postural muscles, and burns between 20 and 108 kilojoules per minute. Of course, it’s not just a workout that you get when you decide to play tonsil hockey. When passionately kissing couples exchange around 9mL of water, 0.7mg of protein, 0.7mg of fats and 0.45mg of salt. If that has you furrowing your brow then cover your eyes, because in a typical kiss tens of millions of bacteria (probably around 80 million) will be exchanged, representing more than 270 different species. Most of these bacteria are either harmless or beneficial, but you can also swap pathogenic bugs like herpes, streptococci, syphilitic spirochetes and Mycobacterium tuberculosis.
Given that kissing, particularly kissing a stranger, is objectively at best risky and at worst revolting, the burning question is why we Westerners have embraced it so wholeheartedly.
A brief kisstory
Sheril Kirshenbaum is the author of The Science of Kissing and she says, “I’m a firm believer that we are more creatures of historical forces than we are biological.” Historically, there is evidence of kissing existing as far back as 1500 BCE in the Indian Vedic texts. These texts have no corresponding word for “kiss”, but they do talk about lovers “setting mouth to mouth” and a man “drinking the moisture of the lips” of a slave woman. Passionate kissing is certainly advocated in the Kama Sutra around 400 BCE. Social kisses are mentioned in the works of the Greek poet Homer and the historian Herodotus, but it is thought that the idea of passionate kissing may have been brought to the Greeks by Alexander the Great after his invasion of India in 326 BCE. The Roman civilisation certainly embraced romantic kissing and differentiated the social kiss of the hand or cheek (osculum) from kissing the lips (basium) and a deep passionate kiss (savolium). At what point, though, did kissing become imbued with the meaning we attach to it today?
One origin story for the power of the kiss might lie in a tradition known as the osculum pacis. According to Marcel Danesi, author of A History of the Kiss!, the osculum pacis (literally the “kiss of peace”) was a European marriage ritual dating back to the sixth or seventh century CE, in which the couple would exchange breath. They would place their lips close to each other and breathe into their partner’s mouth, symbolically exchanging souls. Some Oceanic cultures have a similar practice today. It is not difficult to imagine bringing the lips a little closer and pretty soon spirituality transforms into sensuality. If the osculum pacis was not the root of the meaning associated with romantic kissing, then customs like it certainly were, but such customs took root because there was some fertile biological soil there to nourish them.
Lips and noses
Kissing is not a widespread practice in the animal world. Aside from humans only chimpanzees and bonobos do it, and the latter two do it for reasons that are more social than romantic. One reason why humans might link kissing with pleasure and intimacy lies in our lips.
Unlike other animals, human lips are everted: they purse outwards. They are also packed with nerve endings so that just a brush of your lips sends a tidal surge of information to your brain. The neural impulse that travels from your lips leads to the release of hormones and neurotransmitters including oxytocin, dopamine, serotonin and adrenaline. This is a cocktail that leaves you feeling very good, much better than anything you could order in a glass, and it promotes bonding as well. The other organ that helps explain the biological power of the passionate kiss is your nose.
In the scheme of things the human nose is a little lacklustre, especially when it comes to reproduction and mate selection. Wild boars and hamsters, for instance, can detect pheromones in the urine of prospective mates that gets them very excited without being anywhere near each other. It’s not just animals either; a male black widow spider can smell if a female is hungry by how she smells from a distance, and he won’t try to mate with her if she is. For humans to smell each other, though, with our paltry proboscis, we need to get up close, and kissing helps with this. Research by biologist Claus Wedekind has shown that women prefer the smell of men who are genetically different from them, especially in a region of DNA that codes for the immune system. Pairing with a partner who has a different set of genes for immunity makes sense because it will lead
to children with more genetic diversity and a greater likelihood of survival. It might not fit the romantic ideal, but in a very practical way passionate kissing gets you close enough to another person to pick up subconscious cues to their genetic suitability as a partner.
Simply irresistible
Put everything we have said about kissing together and it quickly becomes apparent why, in our society, it is such a powerful phenomenon. On a biological level it does admittedly involve swapping millions of bacteria, but you can’t feel bacteria. What you can feel is a massive euphoria at the same time as being able to assess your kissing partner without even thinking about it. Lade the kiss with a millennium or so of cultural meaning and a rabid adoption by popular culture and the kiss is an intoxicating blend. Perspective, however, is an invaluable tool, and it is important to remember that according to the research, more than half of all human cultures use intimate contact methods other than the kiss. Among Western societies, however, the kiss remains the preferred method to express and seal a romantic bond. With the impetus of modern entertainment behind it, the romantic kiss also seems to be infiltrating younger generations in cultures where it was previously taboo. For the moment, at least, the kiss seems simply irresistible.
