Furtive, lascivious, stolen, shy, hungry kisses… We kiss in broad daylight and in the darkest of night. We give ceremonious, affective kisses to the air, death kisses and, at least in stories, pecks that revive princesses. Have you tried to define what a kiss is? Microbiologist Henry Gibbons described it as “ the anatomical juxtaposition of two orbicularis oris muscles in a state of contraction ”. A definition based on that sphincter muscle, which is a kind of ring-shaped ribbon that surrounds the lips, extending to the chin and running between the nose and the upper lip. Thanks to him we can purse our lips and do many interesting things…
Of course, it is a definition light-years from that of Cyrano de Bergerac : “An oath that is made so close / an agreement that seeks ratification / an exact promise / an “o” rose in the word love / a secret spoken in the mouth, not in the ear.” Less poetically, in a survey conducted by Smints candy, North American women and men gave their own definition, ranging from melting butter, to feeling hit by a wave, something akin to vibes at a concert or, more prosaically, a three-pointer that wins the American college basketball tournament. Regardless, for many of us there is little better than a good kiss. You walk closer to your love, close your eyes and … faded to black.
But a kiss is not just that. “Kissing isn’t just lips meeting lips,” says Sarah Woodley, a biologist at Duquesne University in Pittsburgh. The Women’s Christian Temperance Union must have had something like this in mind when it launched a campaign in the US in 1901 to inform people of the dangers of kissing on the lips. Nor is it surprising that such an enthusiastic campaign failed.
Of course, kissing ends up being tiring. In the 1930s, Polish-born makeup expert Max Factor – whose real name was Maximilian Faktorowicz – decided to stop using people to check how long his lipsticks would last. Testers were getting tired and bored so he replaced them with a kissing machine that pressed two rubber lips together over and over again.
By the way, have you ever, in the middle of a kiss, thought why the hell am I doing this? Honestly, it’s a bit gross. We pass several thousand colonies of bacteria with each kiss , plus a generous exchange of saliva, and it’s an excellent way to spread not just the flu, but meningitis, herpes and mononucleosis . What does it do there, in our behavior? Is it something instinctive or learned? Does it provide any evolutionary advantage?
At the beginning of the 20th century, the Danish philologist Kristoffer Nyrop described Finnish tribes whose members bathed together but considered kissing indecent. In 1987 the anthropologist Paul d’Enjoy reported that in certain parts of China it is as horrible to kiss on the mouth as cannibalism is to us . And in Mongolia parents don’t kiss their children, they smack their heads.
According to the pioneer of human ethology Irenäus Eibl-Eibesfeldt, 10% of humanity do not put their heads together to exchange saliva , a fact corroborated by the anthropologist Helen Fisher in 1992. According to her, around 650 million members of the human species have not learned the art of osculation. In fact, and according to cultural anthropologists, they have no idea what the matter is. For the rest, the kiss is an expression of affection in our modern Western culture, but in many others what it represents is respect for the other, without sexual connotation . Thus, it is difficult for a strict Muslim to kiss his wife on the mouth as a sign of affection. A few centuries ago in the Slavic countries the kiss was not seen as something sexual.
To add fuel to the fire there is a wide variety of actions that constitute what we would call a kiss. During the First World War, one of the fathers of modern anthropology, Bronislav Malinowski, visited the Trobriand Islands (today the Kiriwina Islands) off the coast of New Guinea and discovered that a kiss there consisted of both nose and cheek rubbing and a vigorous kissing. slurping from lips or biting them; biting lips, chin and cheek, pulling hair or the even more bizarre action of eating each other’s eyelashes.
However, there are animals that kiss, or so it seems. For some researchers, the intimate kiss could have been inherited from our primate ancestors. Genetically very close to us, bonobos are a particularly passionate bunch. Frans BM Waal, a primatologist at Emory University, recalls one keeper who gladly accepted what he thought was a friendly kiss from one of our cousins, until he felt the primate’s tongue in his mouth .
De Waal acknowledges that the use of reconciliation to repair damaged social relationships is widespread in the animal world. It has been found to exist in many primate species, both in captivity and in the wild. ” Chimpanzees, for example, kiss and hug each other after a fight ,” comments De Waal. Bonobos are especially effusive: “they kiss after fights, to comfort each other, to develop social alliances and sometimes for no apparent reason, like us.” Jane Goodall , during her observations of chimpanzees in Gombe, Nigeria, often saw lower-ranking males bend down submissively and drink some part of the dominant male’s body. And many primatologists have observed how a mother chimpanzee calms her frightened little one: caressing it and kissing it on the head .
The animal kiss has different faces: many mammals lick each other’s faces, elephants put their trunks in each other’s mouths, birds touch their beaks and snails caress each other’s antennae. In some cases the animals groom each other before kissing.
De Boer A., van Buel E. M., and Ter Horst G. J. (2012). Love is more than just a kiss: A neurobiological perspective on love and affection. Neuroscience, 201, 114–124
Kirshenbaum S. (2011) The science of kissing: What our lips are telling us, Grand Central Publishing
Wlodarski, R., & Dunbar, R. I. M. (2014) What’s in a Kiss? The Effect of Romantic Kissing on Mate Desirability, Evolutionary Psychology, 12(1) doi.org/10.1177/147470491401200114