Saturday, July 18, 2015

Not everyone does it

Un homme et une femme, 1891, Stephan Sinding (1846-1922). Almost as fun as sex.


All humans love to kiss, so kissing must go back to early hominids and even chimps and bonobos. This is how ethologists and evolutionary psychologists think when they write about the subject.

Just one thing. Even in historic times not all humans loved to kiss. Far from arising millions of years in the past, kissing seems to have arisen no earlier than 40,000 years ago, when modern humans began to enter northern Eurasia.

So concludes a recent cross-cultural study:

We found only 77 out of 168 (46%) cultures in which the romantic-sexual kiss was present. Significantly, no ethnographer working with Sub-Saharan African, New Guinea, or Amazonian foragers or horticulturalists reported having witnessed any occasion in which their study populations engaged in a romantic-sexual kiss. However, kissing appears to be nearly ubiquitous among 9 of the 11 foragers living in Circum-Arctic region (i.e., northern Asia and North America). The concentration of kissing among Circum-Arctic foragers, for which we do not have a satisfactory explanation other than invoking cultural diffusion, stands in stark contrast to its equally striking absence among foragers in other cultural regions. (Jankowiak et al., 2015)

This is not the first study to deny the universality of kissing, although scholars have tended to place its origin in the civilizations of the Mediterranean, the Middle East, and South Asia (Hawley, 2007; Hopkins, 1907). The English sexologist Havelock Ellis argued that kissing began with "civilized man": 

It is only under a comparatively high stage of civilization that the kiss has been emphasized and developed in the art of love. Thus the Arabic author of the Perfumed Garden, a work revealing the existence of a high degree of social refinement, insists on the great importance of the kiss, especially if applied to the inner part of the mouth, and he quotes a proverb that "A moist kiss is better than a hasty coitus." Such kisses, as well as on the face generally, and all over the body, are frequently referred to by Hindu, Latin, and more modern erotic writers as among the most efficacious methods of arousing love. (Ellis,1897-1928)

It may be that kissing originated in prehistory among the hunter-gatherers of northern Eurasia and then spread south, where it reached its full flowering in a milieu that idealized it in prose, poetry, and painting. A kind of positive feedback thus developed between the practice and the ideal.

Then, at a later date, it became less common in northern Europe because of the moral climate that followed the Reformation, having been previously very common. When the Greek scholar Demetrios Chalkokondyles (1423-1511) visited England, he was surprised by its ubiquity:

As for English females and children, their customs are liberal in the extreme. For instance, when a visitor calls at a friend's house, his first act is to kiss his friend's wife; he is then a duly-installed guest. Persons meeting in the street follow the same custom, and no one sees anything improper in the action. (Bombaugh, 1876, p. 33)

Another Greek traveler likewise remarked a century later:

The English manifest much simplicity and lack of jealousy in their customs as regards females; for not only do members of the same family and household kiss them on the lips with complimentary salutations and enfolding of the arms around the waist, but even strangers, when introduced, follow the same mode, and it is one which does not appear to them in any degree unbecoming. (Bombaugh, 1876, p. 33)

Similar comments were made by Erasmus (1467-1536):

If you go to any place, you are received with a kiss by all; if you depart on a journey, you are dismissed with a kiss; if you return, the kisses are exchanged. Do they come to visit you, a kiss is the first thing; do they leave you, you kiss them all around. Do they meet you anywhere, kisses in abundance. In short, wherever you turn, there is nothing but kisses. Ah, Faustus, if you had once tasted the tenderness, the fragrance of these kisses, you would wish to stay in England, not for ten years only, but for life. (Bombaugh, 1876, p. 34)

Kissing then fell into decline among the English; so much so, that frequent public displays became seen as a continental thing. Nonetheless, it remained much more common than in other parts of the world, particularly East Asia and sub-Saharan Africa. This difference amused travelers as late as the 19th century:

An American naval officer, who had spent considerable time in China, narrates an amusing experience of the ignorance of the Chinese maidens of the custom of kissing. Wishing to complete a conquest he had made of a young mei jin (beautiful lady), he invited her—using the English words—to give him a kiss. Finding her incomprehension of his request somewhat obscure, he suited the action to the word and took a delicious kiss. The girl ran away into another room, thoroughly alarmed, exclaiming, "Terrible man-eater, I shall be devoured." (Bombaugh, 1876, p. 80)

For the same time period, Havelock Ellis noted: "Kisses, and embraces are simply unknown in Japan as tokens of affection" with the exception of mothers hugging and kissing their infants. Similarly, "among nearly all of the black races of Africa lovers never kiss nor do mothers usually kiss their babies." He then went on to argue that the romantic kiss evolved out of this maternal kissing, which seems more or less universal.

With the globalization of culture through movies, magazines, and other media, kissing has been spread to the four corners of the earth. Clearly, we can all do it and enjoy doing it to some extent. But I don't think we all share the same urge to do it.

Gene-culture coevolution?

Don't laugh. Even religiosity is partly genetic, so why not the desire to kiss and be kissed? What little we know about the subject comes from studies of compulsive kissing syndrome, where a lesion to the right temporal lobe (associated with epilepsy or glioma) causes an uncontrollable urge to kiss anyone independently of sexual interest (Mendez and Shapira, 2014; Mikata et al., 2005; Ozkara et al., 2004). This compulsion differs from other disorders where increased kissing results from loss of sexual inhibition and is targeted at sexually desirable individuals. The brain may thus have a pre-formed circuit that triggers the desire to kiss. In short, kissing is not solely learned. It has an innate component.

At first, this innate component would have been the same in all humans, back when kissing mainly happened between a mother and her infants. It then became more sexual and more important among the hunter-gatherers of northern Eurasia. Later still, in Europe and the Middle East, it developed into a second channel of sexual arousal almost on a par with the sex act itself.

As Havelock Ellis observed:

[...] there is certainly no such channel for directing nervous force into the sexual sphere as the kiss. This is nowhere so well recognized as in France, where a young girl's lips are religiously kept for her lover, to such an extent, indeed, that young girls sometimes come to believe that the whole physical side of love is comprehended in a kiss on the mouth; so highly intelligent a woman as Madam Adam has described the agony she felt as a girl when kissed on the lips by a man, owing to the conviction that she had thereby lost her virtue.

Sexual kissing initially arose through people pushing the envelope of phenotypic plasticity. This envelope in turn became part of the environment that people had to fit into. Those who couldn't, or wouldn't, were at a disadvantage and were bit by bit pushed out of the gene pool. Those who could, and would, took their place. New genetic variants thus arose and flourished, some to strengthen the new behavior and others to make it more pleasurable.

In this, and in many other ways, Man has created Man. We humans have shaped our environment, which in turn has shaped us, even in our genes. This point becomes clear only if one abandons the assumption, so dear to evolutionary psychology, that we stopped evolving back in the Pleistocene. We didn't. In fact, most of the interesting stuff has come about since then.


Bombaugh, C.C. (1876). The Literature of Kissing, gleaned from history, poetry, fiction, and anecdote, Philadelphia: J.B. Lippincott & Co.  

Ellis, H. (1897-1928). Studies in the Psychology of Sex, vol. IV, Appendix A. The origins of the kiss. 

Hawley, R. (2007). 'Give me a thousand kisses': the kiss, identity, and power in Greek and Roman antiquity, Leeds International Classical Studies, 6.5 

Hopkins, E.W. (1907). The sniff-kiss in ancient India, Journal of the American Oriental Society, 28, 120-134. 

Jankowiak, W.R., S.L. Volsche, J.R. Garcia. (2015). Is the Romantic-Sexual Kiss a Near Human Universal? American Anthropologist, early view 

Mendez, M.F. and J.S. Shapira. (2014). Kissing or "Osculation" in Frontotemporal Dementia, The Journal of Neuropsychiatry & Clinical Neurosciences, 26, 258-261. 

Mikati, M.A., Y.G. Comair, A.N. Shamseddine. (2005). Pattern-induced partial seizures with repetitive affectionate kissing: an unusual manifestation of right temporal lobe epilepsy. Epilepsy & Behavior, 6, 447-451 

Ozkara, C., H. Sarý, L. Hanoglu, et al. (2004). Ictal kissing and religious speech in a patient with right temporal lobe epilepsy, Epileptic Disorders, 6, 241-245


Sean said...

"Even religiosity is partly genetic".
It is easy to see benefits from subscribing to a religious belief such as help from fellow believers, and I think religious people have been found to have good health habits like always brushing their teeth. What would be the advantage of kissing? Off the top of my head I'll suggest that the benefit for reproductive fitness could be that kissing on the mouth makes the relationship more stable. I wonder if women's saliva has something in it ...

Anonymous I said...

Now this was a very interesting post.

Malcolm Smith said...

I noticed the reference to "romantic-sexual kiss". Back in the 1970s, one prominent ethologist - I forget whether it was Irenäus Eibl-Eibesfeldt or Hans Hass - did a similar study, including tribes which had only recently experienced contact with Westerners. The conclusion: kissing of children by adults is universal, but not the romantic-sexual kiss. The latter appears to be another case where a behaviour originating in the parent-child bond migrated to the sexual bond.
Also, some groups regard the romantic-sexual kiss as intensely erotic - something done only in the privacy of one's bedroom. India is like that; the kissing scenes in Western movies are usually censored. It also used to be the case in Japan, and was described in Japanese sex manuals prior to contact with Westerners. That might explain the Japanese maiden's reaction when the America asked her for a kiss.

Santoculto said...

Religiosity is genetic because schizophrenia also is genetic, lol.

as said...

I'm South Indian.

My parents have never kissed each other. My mother told me that kissing on the mouth is dirty and disgusting. People will hug and kiss small children, but after the child reaches a certain age, they stop hugging and kissing. The kissing is only done on the cheek.

One things, in this non-kissing culture, people's lips look pretty bad. Most people have bad teeth. I don't think adults would even want to kiss each other on the mouth. It would be gross.

Peter Frost said...


I agree that a lot of sexual behavior has its origins in the mother-child relationship. I remember visiting a medical facility with a geneticist, and he introduced me to a little girl with Down's syndrome. I said hello and shook her hand. At that point she jumped up and hugged me. Did she learn how to hug? I think hugging, like kissing, is something we do naturally in that kind of context. It can then migrate to a romantic/sexual context if the conditions are right.

Sexual kissing may have increased in importance among arctic hunter-gatherers because of the high dependence of the female on the male. In a tropical environment, a woman can gather food and meet most of her food needs and those of her children. As you go farther north, food gathering declines in importance relative to hunting, with the result that the male-female pair bond becomes more critical to survival for the female and her offspring. Kissing may have correspondingly increased in importance as a means to strengthen this bond.

Anonymous I said...

I agree, but consider also the way clothing covers the body in the arctic, usually leaving only the face exposed for half the year. Flirting is easy when skin is exposed to poking, tickling, pinching, and rubbing; when the body is covered, the kiss becomes virtually the only way of achieving skin to skin contact. The Inuit, of course, found one other way: rubbing their noses together. But when you're both covered from head to toe, even your hands, that's pretty much what there is to do!

Franck Ramus said...

I think that the argument from compulsive kissing syndrome to an "innate component" does not follow.
A brain lesion can selectively affect a behavior that is entirely learnt. A good example is reading. Alexia may occur when a brain region that has been tuned by reading instruction is lesioned. But that brain region was not selected for reading in the first place, it was selected for the vision of things that letters share properties with (cf. Stanislas Dehaene re: neuronal recycling).
Then it turns out, in this example, that reading ability and developmental dyslexia have a genetic component. But this genetic component is understood not to be specific to reading, but to be associated with other cognitive functions (phonology or vision) that are recruited for reading (when taught).
So the argument from brain lesion to a function that may have been selected does not follow. And the gene-culture co-evolution hypothesis is even shakier.

Peter Frost said...

Yes, the ability to read is a good example. The human brain has a specialized region called The Visual Word Form Area (VWFA) which helps us to recognize written words and letters. If it is subjected to a surgical lesion, the patient will suffer a clear impairment to reading ability but not to recognition of objects, names, or faces or to general language abilities. There will be some improvement over the next six months, but reading will still take twice as long as it had before surgery.

Dehaene has argued that the VWFA is not a hardwired mental organ. One of his arguments is that it occupies the same area of the brain because that is where we can most easily recruit neurons when learning to recognize words. But why, then, does this recruitment happen so fast in young children? When kindergarten children were asked to play a grapheme/phoneme correspondence game, their VWFAs preferentially responded to pictures of letter strings after a total of 3.6 hours over an 8-week period. It is worth noting that only a few of these children could actually read, and even then only at a rudimentary level.

Dehaene's other argument is that the ability to read is too recent to have been favored by natural selection. Essentially, it began less than 6,000 years ago. Widespread literacy is even more recent, and there are still many societies where most people cannot read or write. How could an entirely new mental organ have evolved over so short a time?

Fist, the VWFA did not evolve out of nothing. It seems to be a population of neurons that originally served to recognize faces. This sort of recycling is a common pathway for natural selection and explains much of the apparent rapidity of evolution. A complex mental adaptation may take a long time to evolve, but much less time is needed to develop an exaggerated version of it or to alter when and how it becomes activated

Indeed, parallel to the way alphabetical reading ability has spread historically and geographically, there is a similar spread of the latest variant of ASPM, a gene implicated in the regulation of brain growth. In humans, a new variant arose about 6,000 years ago in the Middle East. It eventually became more prevalent in the Middle East (37-52% incidence) and Europe (38-50%) than in East Asia (0-25%).

This is gene-culture coevolution. And it's no hypothesis. It's a reality.

Franck Ramus said...

Let's leave aside that there is currently no evidence for association between ASPM and reading (or any other cognitive ability).
When ASPM arose in the Middle East, what proportion of the Middle East population could read? 1%? What selective advantage did they have over those who were not taught?
If you think of European countries, what proportion of the population could read just 150 years ago? What selective advantage did this give them?
In France, obligatory and free-for-all schooling was voted only in 1882. Before then, not more than 10 or 20% of the French population could read. I doubt that it was much more anywhere else.
So it seems that these are not conditions suitable for the evolution of a new faculty. In 1000 years, perhaps, if the better readers have more offspring (which is probably not the case)...

Peter Frost said...


There currently is evidence of an association between ASPM and reading:

"This is the first study to examine associations of polymorphisms in DRD2, AVPR1A, and ASPM with endophenotypes of communication disorders and SSD and is to our knowledge the most rigorous study of these genes with respect to LD coverage. Previous studies of the association of these genes with speech and language phenotypes generally only focused on one polymorphism per gene. We found that all three genes were associated with measures of vocabulary, phonological memory, and reading, though all three genes were most significantly associated with vocabulary."

Reading ability is a continuum. In premodern European and Middle Eastern societies, most people could read short texts of block letters, e.g., storefront signs, graffiti, etc.

I agree that only a small minority could read lengthy texts in cursive writing. Such people were in high demand and enjoyed not only higher economic status but also superior reproductive success. This is one of the points made by Gregory Clark: middle-class and upper class individuals contributed very disproportionately to succeeding generations. In Western Europe today, most people are descended from lineages that a millennium ago accounted for only tiny fraction of the population.

Evolution can proceed faster than you may think. A lot can happen in only a thousand years. In any case, reading and writing have been around for close to six thousand years.

Rasmus Bååth said...

Inspired by this post I acquired the data from Jankowiak et al. (The authors have been very helpful and I really appreciate their help!). I took that dataset and made it into an interactive "Map of Romantic Kissing" that can be found here:

I think a map really helps visualizing this dataset (and it's puzzling that the original article didn't include a map). Also, I think a map better shows, what I see as, the peculiarities of the dataset, for example, the spotty coverage of Europe.