Saturday, July 20, 2013

Trading in fair-skinned women. Did it happen elsewhere?

Austronesian woman (Roekiah Soeara, 1942, Indonesian actress - source). Austronesian and Papuan peoples intermixed in coastal Papua-New Guinea and on the islands to the east. This intermixture seems to have been mainly due to Austronesian women joining polygynous Papuan households. Did this happen through peaceful exchange (brides for land?) or through raiding and kidnapping? 

In all human populations, the sexes differ somewhat in skin color, women looking paler and men browner and ruddier. This sex difference is mirrored by a cross-cultural tendency to make lighter skin a female norm, which women often accentuate by various means (e.g., staying out of the sun, wearing sun-protective clothing, applying white facial powders or skin-bleaching preparations). Traditionally, this norm was said to be ‘white’ in Europe and East Asia, ‘golden’ in South-East Asia, and ‘red’ in sub-Saharan Africa (van den Berghe and Frost, 1986).

Why are women lighter-colored than men? Some ethologists have argued that light skin is one of several infant traits that the adult female body has adopted to calm aggressive impulses in men and induce caring behavior. This visual stimulus would thus influence male sexual response without being erogenous in and of itself. Whatever the ultimate cause, traditional social environments have tended to make women’s lighter skin a criterion of mate choice, often a leading one (Frost, 2011).

Evidently, skin color varies not only between men and women but also between different human populations. What happens when people become aware of the second kind of skin-color variation? Specifically, what happens to the feelings associated with the first kind? How are they transposed into this new social context?

One result may be a form of trade: women from lighter-skinned populations will become objects of commerce for sale to men in darker-skinned populations. This was the case between the 8th and 19th centuries, when women were exported from Europe to the Muslim world, i.e., Spain, North Africa, the Middle East, and South Asia (see previous post).

Has this kind of trade developed elsewhere? To be economically viable, it should meet certain conditions:

1. The two populations differ enough in skin color to make the trade worthwhile.

2. There is enough supply, i.e., the women are obtained for trade on a large enough scale through local wars or slave raiding.

3. There is enough demand, i.e., the male clients are polygynous enough and wealthy enough.

These conditions came together with the rise of the Muslim world to geopolitical dominance in the 8th century. Elsewhere, and at other times, the conditions were less optimal. People usually had little contact with other people whose skin color substantially differed from their own. In pre-Columbian America, for instance, it’s difficult to see how such trading could have developed, given the slight differences in skin color among different Amerindian groups.

Nonetheless, there are a few intriguing examples, albeit on a small scale:

Sub-Saharan Africa

Skin color does visibly differ among the various peoples of sub-Saharan Africa, to a greater degree in fact than what many non-Africans might think. These differences seem to interact with notions of sexual beauty, as Lugira (1970) writes about pre-colonial Uganda:

The Ganda concept of skin pigmentation considers light coloured complexions to be differing shades of white.  A dark brown skin colour is said to be — eruyeru, that is, somewhat white. A really brown‑reddish‑yellow person is said to be mweru = white, which in comparison would be considered to be blonde; and this in the Ganda aesthetic language is considered as red = myufu, the most perfect skin pigmentation.

As a result, the lighter skin of some groups could become a casus belli:

[…] The Nnyambo people were the handsome looking (brown‑red) inhabitants of the south of Buganda, in the Ziba countries and Kalagwe. The Nnyambo women were one of the reasons that induced Suna II to wage war with Kiziba after which he suffered from small pox and died (Lugira, 1970)

South-East Asia

An incipient trade of this sort existed in 19th- and 20th-century Thailand, where some Chinese merchants would offer their daughters to Thai rulers in exchange for protection and influence:

'Chinese of wealth', wrote the American missionary N. A. McDonald in 1884, 'often become favorites with the rulers and receive titles of nobility, and these noblemen in return present their daughters to Their Majesties.'

[…] William Skinner noted that Chinese women were 'prized for their light skin color'. Here, skin colour was valued as a form of feminine beauty and a sign of 'Chineseness'. (Jiemin, 2003)

This kind of exchange was consistent with indigenous Thai notions of female beauty, as shown by a recent study:

Young women in all four regions of Thailand considered ‘bright face skin’ and ‘white-pink (body) skin’ as the next most important physical appearance characteristics. Women in the North region were most concerned about having bright face skin, perhaps because they already tend to have lighter body skin which is viewed as desirable. Women in South region were most concerned with body skin color, which may be because they tend to have darker skin color. (Rongmuang et al., 2011)

Papua New Guinea / Melanesia

Finally, lighter-skinned women may have been objects of exchange in coastal Papua New Guinea and on the islands to the east (New Britain, New Ireland, the Solomons, Fiji). This area was a zone of intermixture between two streams of settlement: Papuans with dark brown if not black skin and Austronesians with light brown skin. Interestingly, this intermixture mainly took the form of Papuan men pairing with Austronesian women, as shown by comparison of paternally-transmitted Y chromosomes and maternally-transmitted mtDNA:

[…] This genetic admixture was most likely male biased involving mostly Austronesian women and, over time, mostly New Guinean men, resulting in a higher proportion of Melanesian than Asian Y-chromosome together with a higher proportion of Asian than Melanesian mtDNAs as observed in contemporary Polynesians (Mona et al. 2007; see also Kayser et al. 2006)

[…] mtDNA and NRY analyses indicate that this admixture was sex biased (Melton et al. 1995; Kayser et al. 2000; Su et al. 2000; Hurles et al. 2002): about 94% of Polynesian mtDNAs are of Asian ancestry, whereas about 66% of Polynesian Y chromosomes are of Near Oceania ancestry (Kayser et al. 2006). Although the mtDNA support for this sex-biased admixture hypothesis has recently been questioned (Soares et al. 2011), genome-wide SNP data do indicate significantly more Asian versus New Guinea ancestry for the X chromosome of Polynesians than for the autosomes (Wollstein et al. 2010), in agreement with the sex-biased admixture scenario. In addition, Papuan-speaking groups in New Guinea show higher frequencies of Asian mtDNA haplogroups than of Asian NRY haplogroups (Kayser, Choi, et al. 2008).

[…] Overall, the mtDNA haplogroups in the Solomons are predominantly of Asian [i.e., Austronesian] origin, whereas the NRY haplogroups are predominantly of NO [Near Oceania, i.e., Papuan] origin. (Delfin et al, 2012)

Since Papuans are much more polygynous than Austronesians, and in the past more patrilocal, this intermixture was probably due to Austronesian women traveling over some distance and joining polygynous Papuan households.1 How and why is anyone’s guess. Peaceful exchange? “Give us some of your land and we’ll give you some of our women?” Or was it raiding and kidnapping?

In either case, the two groups were probably keenly aware that one of them was lighter-skinned and the other darker-skinned. Even today, after millennia of intermixture, color consciousness remains strong in this contact zone, as noted by a study of the Eastern Solomons:

The Lau were conscious of skin color; some parents, particularly mothers, tried to dissuade their sons from marrying much better-educated girls from the Western Solomons because of their dark skins. Although color consciousness is decreasing, until quite recently clans and persons of higher status have been generally lighter, and marriages have been preferentially within clan or class status levels. (Baldwin and Damon, 1973)

According to an origin myth from New Britain, these differences in skin color arose through the marriage choices of two brothers:

To-Kabinana said to To-Karvuvu, “Do you get two light-coloured coco-nuts. One of them you must hide, then bring the other to me.” To-Karvuvu, however, did not obey, but got one light and one dark nut, and having hidden the latter, he brought the light-coloured one to his brother, who tied it to the stern of his canoe, and seating himself in the bow, paddled out to sea. He paid no attention to the noise that the nut made as it struck against the sides of his canoe nor did he look around. Soon the coco-nut turned into a handsome woman, who sat on the stern of the canoe and steered, while To-Kabinana paddled. When he came back to land, his brother was enamoured of the woman and wished to take her as his wife, but To-Kabinana refused his request and said that they would now make another woman. Accordingly, To-Karvuvu brought the other coco-nut, but when his brother saw that it was dark-coloured, he upbraided To-Karvuvu and said: “You are indeed a stupid fellow. You have brought misery upon our mortal race.  From now on, we shall be divided into two classes, into you and us.” Then they tied the coco-nut to the stern of the canoe, and paddling away as before, the nut turned into a black-skinned woman; but when they had returned to shore, To-Kabinana said: “Alas, you have only ruined our mortal race.  If all of us were only light of skin, we should not die.  Now, however, this dark-skinned woman will produce one group, and the light-skinned woman another, and the light-skinned men shall marry the dark-skinned women, and the dark-skinned men shall marry the light-skinned women.” And so, To-Kabinana divided mankind into two classes. (Gray, 1916, p. 108)


Light-skinned European women became objects of commerce because of an unusual set of circumstances, essentially the relative dominance of the Muslim world and, correspondingly, the relative weakness of the European world.

Circumstances may come and go, but basic notions of human beauty change less quickly. In the near future, a similar situation may develop in response to the impoverishment of common people in Europe and North America and the growing affluence of elites in the Third World, particularly in resource-rich countries.


1. The literature also puts forward the reverse scenario as a possible explanation, i.e., Papuan men marrying into Austronesian communities. In this second scenario, Papuan men would have had to renounce not only patrilocality but also polygyny and low paternal investment. This is a more radical behavioral change than the one associated with Austronesian women marrying into Papuan communities. Elsewhere in the world, we have two other examples of a high-polygyny population coming into contact with a low-polygyny one: Bantu and Khoisans in southern Africa and Bantu and Pygmies in central Africa. In both cases, intermixture has almost wholly involved women moving from the low-polygyny population to the high-polygyny one. There has been little if any movement of men in the other direction.


The Spanish online journal La Tercera Cultura has recently translated and published one of my posts: “Cómo se llegó a pacificar Europa.”


Baldwin, J.C. and A. Damon. (1973). Some genetic traits in Solomon Island populations, American Journal of Physical Anthropology, 39, 195-201.

Delfin, D., S. Myles, Y. Choi, D. Hughes, R. Illek, M. van Oven, B. Pakendorf, M. Kayser, and M. Stoneking. (2012). Bridging Near and Remote Oceania: mtDNA and NRY Variation in the Solomon Islands, Molecular Biology and Evolution, 29(2), 545–564.

Frost, P. (2011). Hue and luminosity of human skin: a visual cue for gender recognition and other mental tasks, Human Ethology Bulletin, 26(2), 25-34.

Frost, P. (2010). Femmes claires, hommes foncés. Les racines oubliées du colorisme, Quebec City : Presses Universitaires de Laval.

Gray, L.H. (1916). The Mythology of All Races, Vol. 9 Oceanic, Boston: Marshall Jones.

Jiemin, B. (2003). The Gendered Biopolitics of Marriage and Immigration: A Study of Pre-1949 Chinese Immigrants in Thailand, Journal of Southeast Asian Studies, 34(1), 127-151.

Kayser M, S. Brauer, R. Cordaux R, et al. (2006). Melanesian and Asian origins of Polynesians: mtDNA and Y chromosome gradients across the Pacific, Molecular Biology and Evolution, 23, 2234-2244.

Lugira, A.M. (1970). Ganda Art, Kampala: Osasa pub.

Mona, S., M. Tommaseo-Ponzetta, S. Brauer, H. Sudoyo, S. Marzuki, and M. Kayser. (2007). Patterns of Y-Chromosome Diversity Intersect with the Trans-New Guinea Hypothesis, Molecular Biology and Evolution, 24 (11), 2546-2555.

Rongmuang, D., B.J. McElmurry, L.L. McCreary, C.G. Park, A. Miller, and C. Corte. (2011). Regional Differences in Physical Appearance Identity among Young Adult Women in Thailand, Western Journal of Nursing Research, 33(1), 106-120.

Van den Berghe, P. L. and P. Frost. (1986). Skin color preference, sexual dimorphism, and sexual selection: A case of gene-culture co-evolution?  Ethnic and Racial Studies, 9, 87-113.


Anonymous said...

"Some ethologists have argued that light skin is one of several infant traits that the adult female body has adopted to calm aggressive impulses in men and induce caring behavior."

This suggests the possibility that it changes over the monthly cycle.

Sean said...

Papuan polygyny would leave some men without wives; they would not have land either (in a female farming system) so they would be disruptive. Papuan society could export the problem by encouraging unmarried males to move into areas inhabited by Austronesian communities to acquire their women and land.

Women with infant traits, like light skin, are supposed to be particularly desirable. Yet these traits are said to be non-erogenous in adult females, to the extent that women apparently choose a tanned appearance as a way of improving their sexual attractiveness. So light skin is sexual, but at the same time it is not.

Infant traits in babies induce maternal feeling (mother love) which is not entirely dissimilar to romantic love. The mental pathway whereby infant traits induce a certain love (the motherly caring type) is already there.

Under selection for eliciting care, provisioning and monogamy infant traits could have been adapted to the telenomic function in adult women of inducing romantic love in men.

There are examples from history of polygynous non-European men buying European girls as sex slaves and then becoming entranced by them to the extent that the slaves were given unprecedented social position.

In the modern WEIRD environment where men are not expected be immediately serious, the romantic love inducing trait of light skin may get in the way of eliciting sufficient male approaches to give females a choice of suitors. Tanning becomes favoured by young women as a superficial cue to men immediately interested in a casual relationship.

Gigerenzer:"Paradoxically, in these situations a more noncompensatory environment may lead to examining cues in increasing order of validity [...] With sexual selection, it could often be that particular traits evolve as signals because of the stage of the assessment process in which they can be examined, rather than that the cue informativeness of preexisting signals has favored an order of inspection".

I think the light skin cue for romantic love and monogamy, having been initially suppressed, would become more important once a stable relationship was established. A prediction would be that women are far less interested in tanning, or even avoid it, in a serious relationship.

Anonymous said...

Women have lighter skin than men for one very obvious reason. Women are responsible for building the baby's bones in the womb. If the mother doesn't get enough Vitamin D through her skin and there's not enough in her diet, there isn't going to be a next generation. Thus women have had greater natural selection for lighter skin. Lighter skinned women were the ones who produced the healthiest offspring.

Sean said...

That's not what Systematic review of first-trimester vitamin D normative levels and outcomes of pregnancy found. Moreover, a large scale association study of the genetic determinants of vitamin D insufficiency in Caucasians found no links to skin pigmentation, See here.

Anonymous said...

Women have lighter skin than men for one very obvious reason. Women are responsible for building the baby's bones in the womb. If the mother doesn't get enough Vitamin D through her skin and there's not enough in her diet, there isn't going to be a next generation. Thus women have had greater natural selection for lighter skin. Lighter skinned women were the ones who produced the healthiest offspring.

One query about this would be whether the same dimorphism is present in chimpanzees, who are mostly covered with hair.

Peter Fros_ said...


It does. I'll discuss this point in my next post.


I agree with part of what you say. Polygyny creates a surplus of young unmated males for whom the only way to get a woman is through raiding of other tribes. I'm skeptical, however, about the idea that these men simply moved into Austronesian communities. Such a move would entail a radical behavioral change, i.e., abandonment of polygyny and increased paternal investment.

The Japanese adopted the female tanning fad from the Western world but then dropped it about thirty years ago. I suspect it has more staying power here because (a) traditional notions of feminity are weaker and (b) many if not most young men and women are locked into a culture of sexual 'churning'.


What if men were the fairer sex? Would you then be arguing that this makes sense because men need more vitamin D to build their denser bone structure?


We see a similar pattern in other primates but it's displayed on the fur and not the skin, i.e., wherever there is a sexual dimorphism in fur color, the females have the lighter color. Moreover, this lighter color seems to mimic the natal coat of the infant.

Blaffer-Hrdy, S. and J. Hartung. 1979. The evolution of sexual dichromatism among primates, American Journal of Physical Anthropology 50:450.

Anonymous said...

The Japanese adopted the female tanning fad from the Western world but then dropped it about thirty years ago. I suspect it has more staying power here because (a) traditional notions of feminity are weaker and (b) many if not most young men and women are locked into a culture of sexual 'churning'.

Japan is also notable for pretty high drops in birthrates and sexual desire among the young.

Sean said...

Japan is notable for an extraordinarily small gap in life expectancy between men and women.
East Asians in general show little sexual dimorphism. I think that is due to the men's lack of prenatal tesosteronisation. That could also explain a lack of interest in the culture of sexual adventure that is dominant in the West.

Do young Western women primarily want sexual adventures nowadays, or are they just in a culture where sex is expected and contraception means there is no longer fear of pregnancy as an excuse?

Anonymous said...

Central Asia seems the exception, with the exception of Kazakhstan, Y haplogroups of Asian origin are lower than non-Asian ones relative to the amount of proportionate ancestry.

Europeans have impregnated women from cultures with polygyny more than their men have European women. This is easy to do if you have colonized the country and have shiploads of horny sailors who will take what they can get.

But wouldn't the Imperial Chinese soldiers or invading Mongols/Turks occupying central Asia leave a bigger mark?