Tuesday, July 17, 2018

Curly and straight

Portrait of Henriette-Marie de Buade-Frontenac, Claude Mellan (1640). Curly European hair isn’t a holdover from Africa. Europeans initially had the thick, straight, black hair of East Asians. They then evolved thinner hair with curly, wavy, and straight forms, and equally diverse colors.

Today, head hair is straight in ~45% of Europeans, wavy in ~40%, and curly in ~15% (Medland et al. 2009). As with hair and eye color, this is an unusual level of diversity for a population that is, overall, less genetically diverse than humans in general.

Straight hair is produced by different genetic pathways in Europeans and East Asians, being due to a derived EDAR allele in East Asians and to derived TCHH, WNT10A, and FRAS1 alleles in Europeans (Medland et al. 2009; Pospiech et al 2015; Tan et al. 2013). Many other alleles are likely involved (Liu et al. 2018). At first, it was thought that hair became straight in the two groups independently of each other, i.e., through convergent evolution, but ancient DNA now suggests a different scenario:

1. In a population ancestral to Europeans and to East Asians, hair became thick, straight, and long some 30,000 years ago via a derived allele at the EDAR gene (Kamberov et al. 2013).

2. This ancestral Eurasian population differentiated into a western group that would become Europeans and an eastern group that would become East Asians (Rogers 1986).

3. Thick straight hair remained prevalent in the eastern group and gradually disappeared in the western group. Nonetheless, as late as eight thousand years ago it still prevailed in half of Europeans, as shown by ancient DNA retrieved from Motala, Sweden (Mathieson et al. 2015). Today, it has an incidence of 87% in Asians and about 1% in Europeans (McVean et al. 2012; Unterländer et al. 2017).

4. In early Europeans, thick straight hair was apparently replaced by thinner hair with diverse forms ranging from curly to straight. Curly European hair is thus a derived trait, and not a holdover from ancestral Africans.

This diversification must have coincided temporally and geographically with diversification of hair and eye color, and the cause was probably the same: sexual selection of women by men in a mate market with too many unmated women. If the selection pressure is strong enough, preferences for novel visual stimuli become decisive in mate choice (Frost 2006; Frost 2014). This kind of preference was observed in a Viennese study, which found that women tend to change their hair form to less common types (Schweder 1994).

As with hair and eye color, hair form seems to have diversified in response to a stronger selection pressure than the one that caused hair to lengthen at an earlier date in ancestral Eurasians.


Frost, P. (2006). European hair and eye color - A case of frequency-dependent sexual selection? Evolution and Human Behavior 27(2): 85-103.

Frost, P. (2014). The puzzle of European hair, eye, and skin color. Advances in Anthropology 4(2): 78-88. 

Kamberov, Y.G., S. Wang, J. Tan, P. Gerbault, A. Wark, L. Tan, et al. (2013). Modeling Recent Human Evolution in Mice by Expression of a Selected EDAR Variant. Cell 152(4): 691-702.

Liu, F., Y. Chen, G. Zhu, P.G. Hysi, S. Wu, K. Adhikari. (2018). Meta-analysis of genome-wide association studies identifies 8 novel loci involved in shape variation of human head hair. Human Molecular Genetics 27(3): 559-575.

Mathieson, I, I. Lazaridis, N. Rohland, S. Mallick, N. Patterson, S. Alpaslan, et al. (2015). Genome-wide patterns of selection in 230 ancient Eurasians. Nature 528(7583): 499-503

McVean, G.A. et al. (The 1000 Genomes Project Consortium) (2012) An integrated map of genetic variation from 1,092 human genomes. Nature 491: 56-65.

Medland, S.E., D.R. Nyholt, J.N. Painter, B.P. McEvoy, A.F. McRae, G. Zhu, et al. (2009). Common variants in the Trichohyalin gene are associated with straight hair in Europeans. The American Journal of Human Genetics 85(5): 750-755.

Pospiech, E., J. Karlowska-Pik, M. Marcinska, S. Abidi, J. Dyrberg Andersen, M. van den Berge, et al. (2015). Evaluation of the predictive capacity of DNA variants associated with straight hair in Europeans. Forensic Science International: Genetics 19: 280-288.

Rogers, R. A. (1986). Language, human subspeciation, and ice age barriers in Northern Siberia. Canadian Journalof Anthropology 5(1): 11-22.

Schweder, B.I.M. (1994). The impact of the face on long-term human relationships. Homo 45(1): 74-93.

Tan, J., Y. Yang, K. Tang, P.C. Sabeti, L. Jin, and S. Wang. (2013). The adaptive variant EDARV370A is associated with straight hair in East Asians. Human Genetics 132(10): 1187-1191.

Unterländer, M., F. Palstra, I. Lazaridis, A. Pilipenko, Z. Hofmanová, M. Gross, et al. (2017). Ancestry and demography and descendants of Iron Age nomads of the Eurasian Steppe. Nature Communications 8(14615) 

Tuesday, July 10, 2018

It's not self-hate

Long-haired Sango woman, Democratic Republic of the Congo (Friedrich 1913, Fig. 174)

A competitive mate market will reward individuals whose secondary sexual characteristics seem abnormally bigger or flashier. A "supernormal stimulus" has a stronger visual impact than a normal one, and the behavioral response is correspondingly stronger. This effect has been studied in many animal species. When, for instance, a female butterfly passes by a male, the latter is attracted to the flashing wing pattern. The same pattern on a rotating drum exercises the same power of attraction, which increases as the speed of rotation increases—up to almost ten times the speed of a normal wing-beat (Manning 1972, pp. 47-49).  

A human example? Head hair. It has become much longer than hair elsewhere on the body, apparently because it holds some power of attraction. This lengthening has been brought about by several evolutionary changes: faster rate of growth, longer growing phase, higher density, and greater resistance to physical damage (Khumalo 2005; Loussouarn 2001; Loussouarn et al. 2005). These changes have gone farther in some populations than in others. Darwin noted "the extraordinary difference in the length of the hair in the different races; in the negro the hair forms a mere curly mat; with us it is of great length, and with the American natives it not rarely reaches to the ground" (Darwin 1936[1888], p. 906).

Long hair is the "derived" form. It evolved in those modern humans who left Africa for northern Eurasia, including some who later back-migrated to the tropics, such as the Austronesians of Southeast Asia and Oceania and the Amerindians of the tropical New World.

Short, frizzy hair is the ancestral form. Today, it is seen in sub-Saharan Africans and in some remnant groups that remained in the tropical regions of South Asia, Southeast Asia, and parts of Oceania. These groups are the Andamanese of India, the Semang of Malaysia, the Aeta of the Philippines, and the natives of Australia, Papua New Guinea, and Melanesia.

Long head hair, a component of the Kindchenschema

The ancestral hair form is straight and silky in a newborn child: "[...] the majority of African babies are not born with springy tight curls, the African child at birth is either bald or has silky loose curls similar to the Jheri curls" (Ajose 2012). This physical difference was cited by Zambian students when asked to describe how Africans look. Some of the girls "noted that African babies were born with white skin and long hair" (Powdermaker 1956).

Although adults normally have loose, silky hair in most of the world, this was not so in ancestral humans. Such hair was specific to infants and thus formed part of what Konrad Lorenz dubbed the Kindchenschema—a set of visual, auditory, and tactile cues that identifies a human infant to adults, who then feel less aggressive and more willing to provide care and nurturance (Lorenz 1971, pp. 154-164). The infant seems "cute."

This has been no less true in sub-Saharan Africa, and a desire to be similarly cute has led African women to make their own hair longer, looser, and silkier. Some of their techniques predate the colonial era:

Africa as the cradle of mankind is likely to have had hair care since the beginning of human existence. Partly because of the oral tradition of passing down history, it is difficult to corroborate evidence of hair care. But probably the earliest form of hair straightening was the molding of hair into shapes using various clays and mud (e.g., indicating the station of a married woman among the Zulu's). [...] Hair was also lengthened with fibers and grasses, much as is done for braids with synthetic extensions nowadays. Although small decorative comb-like structures have been discovered with archeological finds, it is not clear whether original Africans combed their hair or if these implements were purely decorative. Although not written down, fascinating stories of more recent hair care (and hair disasters) are often told by older women about straightening hair using hot stones even before hot combs became available. (Khumalo 2008: see also Sieber and Herreman 2000)

In 1721, John Atkins provided an early description of women braiding and dressing their hair in Sierra Leone:

[The women] work hard at Tillage, make Palm-Oil or spin Cotton, and when they are free from such work, the idle Husbands put them upon braiding, and fettishing out their woolly hair, (in which Sort of Ornament they are prodigious proud and curious) keeping them every Day, for many Hours together at it. (Sieber and Herreman 2000, p. 67)

West African women still lavish much time on their hair:

"Big hair," "plenty of hair," "much hair"—West African communities, including Mende, admire a fine head of long, thick hair on a woman. Both these elements are crucial: thickness and length. Thickness equals increase in the number of individual strands, and the length is proof of strength. Growing such luxuriant hair requires a Mende woman's patience and care. Because a man's hair is kept shaved or cut close to the scalp, people say that "men don't have hair." Beautiful hair thus is a distinctly female trait; the more of it, the more feminine the woman. (Boone 1986, p. 184)

This hairdressing tradition is ancient enough to have spawned myths, such as this one among the Mende:

It is known among Mende that all the "water people," angels, have marvelous hair. The mermaid Tingoi is known by her long, wavy hair and her glamorous habit of dressing it with a golden comb while seated on a rock. A little girl with especially long hair is feared to be in danger of drowning because she will be very attractive to the "water people," who may think she is one of them and wish her to join them. (Boone 1986, p. 192)

Long-haired women appear in the folklore of other African peoples. Among the Yoruba, a folk-tale explains "why women have long hair." A woman fell into a pit and was pulled out by her hair, which thereby became as long as a man's arm. She initially felt ashamed of her new appearance and hid herself.

But after a while she realized that her long hair was beautiful, and then she felt very proud and scorned all the short-haired women, jeering at them. When they saw this, they were consumed with jealousy, and began to be ashamed of their short hair. "We have men's hair," they said to one another. "How beautiful it would be to have long hair!"

So one by one they jumped into the pit, and their friends pulled them out by the hair.

And in this way they, and all women after them, had long hair. (Ogumefu 1929, chap V)

Another Yoruba folk-tale recounts how a king had a beautiful daughter with hair "so long that it touched the ground when she walked." But she lost her hair and regained it only after a man found a tree that bore human hair. She then became his wife. (Abrahams 1983, pp. 59-63)

Lengthening of women’s hair seems to have been most common in West Africa, but it was also practiced in central and southern Africa during early colonial times. Women of the Manyema (Tanzania) were described as having “an abundance of hair” that would “flow down to the waist in masses of ringlets” (Bettany 1892, p. 661). Among the Sango (DRC), girls old enough for marriage would plait long strands of string into their hair to create long manes (Friedrich 1913, pp. 190-191). Young women of the Mbalantu (Namibia) achieved the same effect by braiding sinew extensions (Sieber and Herreman 2000, p. 65). Nonetheless, such practices seem to have been uncommon in southern Africa. When a black South African woman traveled to the United States in the 1930s, she was struck by the number of African American women who straightened and extended their hair. “What really made me feel strange [was] nearly every girl and woman has long hair and I among them looked like a boy dressed in girl’s clothes” (Thomas 2006, p. 487).

It appears that African American women were already braiding and threading their hair at an early date. Men, however, often shaved their heads—an indication that both sexes viewed long head hair as a female ornament (White and White 1995).

In sum, hair lengthening is an African tradition that precedes colonial contact with Europeans. From the beginning, the aim was to look feminine, and not "white." The motive was not self-hatred but sexual fantasy—a desire for the supernormal, a wish to become a woman with a long mane of hair. This may be an example of humans creating in one part of the world through artificial means what has been created elsewhere through biological evolution. The same desire has been satisfied in different ways.

Evolution of long head hair in Homo sapiens

African hair can revert to the loose, silky form of infancy as a result of some illnesses: AIDS, rheumatoid arthritis, systemic lupus erythematosus, pulmonary tuberculosis with cachexia, and Behçet's disease (Ajose 2012). These illnesses somehow disrupt normal hair growth, and it is plausible that a similar disruption of genetic origin, i.e., a loss-of-function allele, was the first stage in the evolution of long head hair.

Head hair began to lengthen as ancestral humans spread out of Africa and into the temperate and arctic zones. These environments shifted the pressure of sexual selection from men to women. On the one hand, male mortality increased in relation to female mortality because men had to hunt over larger expanses of land. On the other hand, the polygyny rate decreased because it became costlier to provide for a mother and her offspring, particularly during winter. Men were scarcer on the mate market, being fewer in number and less polygynous. (Frost 2006; Frost 2014; Frost 2015).

Women were now in excess supply, and the spotlight of sexual selection was on them. Their physical characteristics became flashier, bigger, or somehow exaggerated. In the case of head hair, the existing practices of artificial lengthening helped show the way for future evolution. The cultural became biological. Over succeeding generations, the infant hair form persisted more and more into adulthood while becoming ever longer and straighter, eventually reaching down to the waist if left uncut. Hair seems to have lengthened within the whole of northern Eurasia, rather than within the smaller zone of steppe-tundra where skin became white and where hair and eyes became brightly and diversely colored. Hair lengthening was thus triggered by a lower intensity of sexual selection.

This selection pressure acted primarily on women and then secondarily spilled over onto men, perhaps because most of the genes in question are weakly sex-linked, as are most genes. Nonetheless, there is some sex linkage. Scalp hairs have a greater mean diameter and hence more volume in women, even in the shorter-haired New Guineans (Walsh and Chapman 1966). Hair growth rate and final length are also somewhat greater in women than in men (Sigler 2011, p. 13). Men furthermore tend to lose their head hair, often as early as their twenties. In general, growth of head hair is under stronger hormonal inhibition in men than in women (Kondo et al. 1990).


Before ancestral humans began to spread out of Africa, women were already pushing the phenotypic envelope by artificially making their hair straighter, longer, and silkier. Later, outside Africa, evolution brought this fantasy to life. As Charles Darwin concluded, such hair serves an ornamental purpose in our species: "for we know that long tresses are now and were formerly much admired, as may be observed in the works of almost every poet; St. Paul says, "if a woman have long hair, it is a glory to her." (Darwin 1936[1888], p. 906).


Abrahams, R.D. (1983). African Folktales. Traditional Stories of the Black World. New York: Pantheon Books.

Ajose, F.O.A. (2012). Diseases that turn African hair silky. International Journal of Dermatology 51 (supp. S1): 12-16.

Bettany, G.T. (1892). The World’s Inhabitants or Mankind, Animals, and Plants. London: Ward, Lock, Bowden and Co. 

Boone, S.A. (1986). Radiance from the Waters: Ideals of Feminine Beauty in Mende Art. New Haven and London.

Darwin, C. (1936 [1888]). The Descent of Man and Selection in relation to Sex. reprint of 2nd ed., The Modern Library, New York: Random House.

Friedrich, A. (1913). From the Congo to the Niger and the Nile. An account of the German Central African Expedition of 1910-1911 by Adolf Friedrich Duke of Mecklenburg, vol. 1. London: Duckworth and Co.

Frost, P. (2006). European hair and eye color - A case of frequency-dependent sexual selection? Evolution and Human Behavior 27(2): 85-103.

Frost, P. (2014). The puzzle of European hair, eye, and skin color. Advances in Anthropology 4(2): 78-88. 

Frost, P. (2015). Evolution of long head hair in humans. Advances in Anthropology 5(4): 78-88.

Khumalo, N.P. (2005). African hair morphology: macrostructure to ultrastructure. International Journal of Dermatology 44(Suppl. 1): 10-12.

Khumalo, N.P. (2008). On the history of African hair care: more treasures await discovery. Letter to the Editor. Journal of Cosmetic Dermatology 7(3): 231.

Kondo, S., Y. Hozumi, and K. Aso. (1990). Organ culture of human scalp hair follicles: effect of testosterone and oestrogen on hair growth. Archives of Dermatological Research 282(7): 442-445.

Lorenz, K. (1971). Studies in Animal and Human Behaviour, vol. 2. London: Methuen & Co.

Loussouarn, G. (2001). African hair growth parameters. British Journal of Dermatology 145(2): 294-297.

Loussouarn, G., C.E. Rawadi, and Genain, G. (2005). Diversity of hair growth profiles. International Journal of Dermatology 44(Suppl. 1): 6-9.

Manning, A. (1972). An Introduction to Animal Behaviour. 2nd edition. London: Edward Arnold.

Ogumefu, M.I. (1929). Yoruba Legends. London: The Sheldon Press. 

Powdermaker, H. (1956). Social change through imagery and values of teen-age Africans in Northern Rhodesia. American Anthropologist 58(5): 783-813.

Sieber, R. and F. Herreman. (2000). Hair in African Art and Culture. African Arts 33(3): 54-96.

Thomas, L.M. (2006). The modern girl and racial respectability in 1930s South Africa. Journal of African History 47(3): 461-490

Walsh, R.J., and R.E. Chapman. (1966). A study of the quantitative measurement of human head hair fibres. Man, new series. 1(2): 226-232.

White, S. and G. White. (1995). Slave Hair and African American Culture in the Eighteenth and Nineteenth Centuries. The Journal of Southern History 61(1): 45-76.

Tuesday, July 3, 2018

South Korea: the ugly side of Westernization

South Korea has one of the highest suicide rates in OECD countries, and the highest rate of elderly suicide in the world

A major challenge for cultural evolution has been the creation of larger and more complex societies that bring together people who are not necessarily close kin or even acquaintances. This challenge has most successfully been met in two culture areas: Europe, especially northwest Europe, and East Asia. 

In both areas there have been certain mental/behavioral adjustments:

- A lower propensity for personal violence: The State has imposed a monopoly on violence, and such behavior is no longer a legitimate way by men to advance their personal interests or to impress other people, especially women.

- A higher capacity for cognitive empathy: people are better able to understand how others feel.

- A higher propensity for rule adherence: people are not only more aware of social rules but also more willing to comply.

- A higher level of cognitive ability: greater ability to think, to store knowledge, and to use  knowledge (Rindermann 2018, p. 43).

Some of these adjustments are relatively recent, whereas others go back to prehistoric times. In the latter case, one can say that these two culture areas were pre-adapted for the transition to larger and more complex societies.

Although Europeans and East Asians have created larger and more complex societies in similar ways, there have also been significant differences. Cultural evolution has thus followed somewhat different paths to achieve a similar result. Among Europeans, it has also relied on:

- A higher capacity for affective empathy: people not only understand how others feel but also transfer those feelings to themselves, i.e., there is a greater tendency to feel the other person's pain. In most humans, affective empathy is largely expressed in relations between a mother and her children. In Europeans, and especially northwest Europeans, this capacity is generalized to all social relations and deactivated only if the other person is perceived as being morally worthless. 

- A higher capacity for guilt proneness: people feel guilty and self-punish if they break a social rule, even if nobody else witnessed the wrongdoing.

- A more independent social orientation: more individualism, weaker kinship ties, stronger motivation toward self-expression, self-esteem, and self-efficacy.

Among East Asians, this cultural evolution has instead relied on:

- Less individualism, rather than more, and even higher capacities for cognitive empathy and rule adherence. 

These two internal tendencies work in conjunction with external means of behavior control (shaming, family discipline, community surveillance, appeals to moral duty). The self therefore has a different relationship with society. Whereas a greater sense of self has helped Europeans to transcend the limitations of kinship and, thus, build larger societies, East Asians have relied on a lesser sense of self to create a web of interdependence that extends beyond close kin. Their relationship between self and society puts more emphasis on social happiness, rather than personal happiness, and less emphasis on self-expression, self-esteem, and self-efficacy (Frost 2015; Frost 2017; Kitayama et al. 2014; Talhelm et al. 2014).

Because East Asian societies rely more on external means of behavior control, they are more vulnerable to the negative effects of Westernization, particularly its emphasis on individualism, maximization of personal autonomy, and personal happiness as a supreme life goal.

Elder abuse and elderly suicide

"Filial piety" is one of the pillars of East Asian cultures. It is the obligation of adult children "to obey, respect, care for, and support their older parents both emotionally and financially" (Yan and Fang 2017, p. 477). Care for elderly parents is thus driven by a different mix of motives in East Asian societies: "While American caregivers cited love and affection more frequently [...], Korean caregivers emphasized that their motivations were primarily based on filial responsibility, strongly influenced by the Confucian sentiment, including three core values: (1) respect for parents, (2) family harmony, and (3) sacrifice for parents" (Chee and Levkoff 2001).

As in Europe, this sort of traditional value has survived better under socialist regimes: "in the PRC, filial piety is still characterized by parental authority and absolute submission. 'Talking back' to parents is viewed as a serious offense" (Yan and Fang 2017, p. 478). In contrast, adult children are less submitted to their parents in Hong Kong and Taiwan: "young people today [...] tend to speak less respectfully to their parents, using language often considered verbal abuse by elders." In Hong Kong and Taiwan, adult children are increasingly following the Western model of putting their elderly parents into retirement homes (Yan and Fang 2017, p. 478).

Westernization is even more advanced in South Korea, and it is in this country that the situation of the elderly has deteriorated the most in relation to other age groups economically, socially, and psychologically. One example of this malaise has been a sharp increase in elderly suicide: "South Korea's elderly suicide rate is not merely the highest among the member nations of the Organization for Economic Cooperation and Development, it is the highest in the world" (Cha and Lee 2017). Elderly suicide largely explains the country's high suicide rate:

In South Korea, the rate of suicide mortality has climbed since 1985, reaching over 30 per 100,000 person-years lived (PYL) in 2010. As a result of these trends, South Korea and Japan now exhibit the two highest rates of suicide mortality among all OECD countries. [...] Previous research has emphasized high suicide rates among the elderly as well as cohort effects as the main reasons for the steep rise in suicide mortality rates in South Korea over the past 20 years. [...] suicide rates appear poised to increase even further in the future without urgent public health action. (Jeon et al. 2016)

Today, half of South Korea's elderly live in poverty. They typically have little contact with their children. With meager financial support from them or the State, they have to work as security guards, cleaners, and trash collectors. A recent report describes an 86-year-old trash collector and the reasons for her poverty:

Mdm Yim worked hard to support five children, even sending one of them to university. But they all moved away to other cities once they got married, and three years ago, her husband died, leaving her once again without real family support.

"When my daughters visit, they come all at once, then they all leave. My grandchildren are afraid to visit me — they complain about the cockroaches in my place. I get so lonely and bored," she said with a humourless laugh.

[...] This self-condemning attitude perhaps also fueled another problem: The erosion of traditional social values in a Korean society built on confucianism and filial piety. (Shushan 2017)


Larger and more complex societies developed in Europe, especially north and west of the Hajnal Line, thanks to a peculiar mix of mental and behavioral traits: stronger individualism, weaker kinship ties, and higher levels of affective empathy and guilt proneness. This mix helped to bring market economies into being, and the success of this form of social and economic organization has, in turn, encouraged Western Europeans to push the envelope of individualism even farther. We're much more individualistic today than we were even a half-century ago. Is this sustainable? Probably not.

But what about non-Western societies that have adopted the Western model? Our hyper-individualism will be even less sustainable for them. This is particularly so for South Korea, which has embraced the Western model not only economically but also socially and culturally—in large part because of its special relationship with the United States. One consequence has been the collapse of filial piety. South Koreans are only now realizing that the Western model of individualism requires a generous system of old-age pensions. In a post-traditional, egocentric society why take care of aging parents?

Modern Western culture has other consequences. It dissolves the traditional supports for family formation and childbearing, as is painfully evident in South Korea. The fertility rate is now 1.2 children per woman, and many of those children are born to migrant mothers from Southeast Asia and elsewhere. The population is thus rapidly aging at a time when its elderly need much more financial support from younger taxpayers:

South Korea faces the problem of a rapidly aging population. In fact, the speed of aging in Korea is unprecedented in human history […] the percentage of elderly aged 65 and above, has sharply risen from 3.3% in 1955 to 10.7% in 2009. The shape of its population has changed from a pyramid in the 1990s, with more young people and fewer old people, to a diamond shape in 2010, with less young people and a large proportion of middle-age individuals. (Wikipedia 2018a)

I suspect that elderly suicide will be legalized in South Korea, just as it has been in many Western countries.

South Korea is also opening up to immigration, ostensibly to counter the problem of low fertility but really to provide employers with low-wage labor, particularly in agriculture. As of 2016, foreign residents made up 3.4% of the total population (Wikipedia 2018b). This figure understates the full extent of ethnic replacement because it excludes undocumented immigrants, foreigners who have become South Korean citizens, and children of "multicultural marriages" (who automatically acquire citizenship). The immigrant population is also much younger.

One curious result of all these changes is that traditional Korean culture is now much more intact on the other side of the DMZ. This is ironic because North Korea, like other socialist regimes, was founded on a project of radical social reform, including abolition of religion and the traditional family. Yet, today, if you wish to see a traditional society, particularly one that has achieved an advanced stage of social development, you're better off going to a former socialist country, or a bitter hold-out like North Korea.

North Korea's fertility rate is 1.98, just below the replacement level. In fifty years the North will still be recognizably Korean. Will the same be true for the South?


Cha, K.S. and H.S. Lee. (2017). The effects of ego-resilience, social support, and depression on suicidal ideation among the elderly in South Korea. Journal of Women & Aging, April 28

Chee, Y.K. and S.E. Levkoff. (2001). Culture and dementia: Accounts by family caregivers and health professionals for dementia-affected elders in South Korea. Journal of Cross-Cultural Gerontology 16(2): 111-125.

Frost, P. (2015). Two paths. The Unz Review, January 14

Frost, P. (2017). The Hajnal line and gene-culture coevolution in northwest Europe. Advances in Anthropology 7: 154-174.

Frost, P. and H. Harpending. (2015). Western Europe, state formation, and genetic pacification, Evolutionary Psychology 13: 230-243.

Jeon, S.Y., E.N. Reither, and R.K. Masters. (2016). A population-based analysis of increasing rates of suicide mortality in Japan and South Korea. BMC Public Health 16: 356.

Kitayama, S., A. King, C. Yoon, S. Tompson, S. Huff, and I. Liberzon. (2014). The Dopamine D4 Receptor Gene (DRD4) Moderates Cultural Difference in Independent Versus Interdependent Social Orientation. Psychological Science 25: 1169-1177. 

Rindermann, H. (2018). Cognitive Capitalism. Human Capital and the Wellbeing of Nations. Cambridge University Press.

Shushan, L. (2017). Poor and on their own, South Korea's elderly who will 'work until they die' Channel NewsAsia, March 19

Talhelm, T., X. Zhang, S. Oishi, C. Shimin, D. Duan, X. Lan, and S. Kitayama. (2014). Large-scale psychological differences within China explained by rice versus wheat agriculture. Science 344: 603-607. 

Wikipedia (2018a). Demographics of South Korea

Wikipedia (2018b). Immigration to South Korea
Yan, E. and G. Fang. (2017). Elder Abuse and Neglect in Asia. In X. Dong (ed.) Elder Abuse: Research, Practice and Policy, pp. 477-493, Springer.

Tuesday, June 26, 2018

Yes, the decline is genetic

Average polygenic score for educational attainment, by year of birth in Iceland. The blue line is a quadratic fit for the full range of birth years. The red line is a linear fit for people born in or after 1940. (Kong et al. 2017)

For most of the 20th century mean IQ went up at the rate of 3 points per decade throughout the Western world. This is the Flynn effect (Rindermann 2018, pp. 85-89). Much of the increase seems to have involved a change in mental priorities rather than a rise in intelligence: a culture of doing as we're told has given way to a culture of having several possible responses and picking the right one. But some of the increase seems real, being perhaps due to better nutrition and a more stimulating learning environment.

The Flynn effect is now running out of steam (Flynn 2007, p. 143). In Scandinavia, mean IQ peaked during the late 1990s and has since declined (Teasdale and Owen 2005). Using the Norwegian population registry, two economists, Bernt Bratsberg and Ole Rogeberg, attribute this decline largely, if not entirely, to "within-family variation." In other words, IQ has been declining even among people of similar genetic background, i.e., siblings. So this decline is not due to the poor outbreeding the rich or immigrants outbreeding natives.

All the same, a genetic cause cannot be excluded. In Norway, siblings are less and less genetically similar; they are increasingly half-siblings. This factor can especially affect the methodology of Bratsberg and Rogeberg (2018) because the IQ decline is most measurable between siblings who are born farther apart. As this birth interval increases, so does the probability that the younger siblings is a half-sibling.

This is not a minor factor. Bratsberg and Rogeberg were looking at pairs of brothers. (The IQ data come from the military conscript register, and only men are subject to conscription). To produce a pair of brothers, a woman has to have three children on average. Among Norwegian women with three children, 36.2% have had them by two or more men (Thomson et al. 2014). Furthermore, because those children tend to be born farther apart than children born to the same father, they contribute more to within-family variation.

If the genetic basis of intelligence has been declining within Norwegian families, specifically between older and younger half-siblings, two things must be happening:

1. The average divorced mother has her second child by a man who belongs to a lower-IQ segment of the Norwegian population.

2. Such men have been contributing more than other men to succeeding generations of Norwegians, at least during the last forty years. This point is important. Even if we look only at first-born sons, mean IQ has steadily declined among Norwegians born since c. 1975 (Bratsberg and Rogeberg 2018).

The first point has been proven by Lappegård et al. 2011) in their study of fatherhood and fertility in Norway. Multi-partner fatherhood is most common among men with the lowest level of education (10 years of schooling, "i.e., compulsory education"). Second place goes to men with college or university education (14 to 17 years of schooling, "tertiary degree"), and third place goes to men with upper secondary (11 to 13 years of schooling). 

At age 45, about 15 percent of all men in the 1960-62 cohort with a compulsory education had had children with more than one woman, compared to about 5 percent among men with a tertiary degree. If looking at fathers only (Figure 6), the pattern becomes even more pronounced. At the lowest educational level, 19.3 percent of those who had become fathers, had children with more than one woman, compared to 6.1 percent of those at the highest educational level. (Lappegård et al. 2011)

As for the second point, Lappegård et al. (2011) found that reproductive success is more variable among men with the lowest level of education. Such men have the highest rate of childlessness of all three groups, while having the highest level of multi-partner fertility. Moreover, multi-partner fertility has increased over time among these men, while childlessness has remained constant. Their overall reproductive success has thus gone up:

Like childlessness, multi-partner fertility has increased across cohorts, but unlike childlessness it has increased more among men with lower education than among those with higher education. From the 1940-44 cohort to the 1960-62 cohort the proportion of fathers who had children with more than one woman more than doubled (from 8.9% to 19.3%) in the compulsory schooling group, while it only rose by about 30% in the highest tertiary group, from 4.7 to 6.1 percent. (Lappegård et al. 2011)

Thomson et al. (2014) made the same observation:

In all countries [Australia, United States, Norway, Sweden], however, education is negatively associated with childbearing across partnerships, and the differentials increased from the 1970s to the 2000s.

Moreover, official statistics do not fully capture multi-partner fatherhood. It can be difficult to identify the paternity of children whose biological father is little more than a sperm donor. Lappegård et al. (2011) allude to this difficulty: "some of these men have never been in a stable relationship with the mother." This is less of a problem in Norway, where "only about 1-1.5 percent of the total number of children has no registered father."  The registered "father" may nonetheless be a cuckolded husband or a boyfriend who has agreed to assume paternity of the unborn child. The second situation is not uncommon if the woman is still young and attractive.

It seems, then, that modern Norwegian culture is facilitating the reproductive success of low IQ men. One such man was Anders Breivik's stepfather:

My stepfather Tore, one of my best friends Marius and my more distant friends Kristoffer, Sturla and Ronny are all living manifestations of the complete breakdown of sexual moral. All five have had more than 300 sexual partners (two of them more than 700) and I know for a fact that three of them have one or more STDs (probably all of them).

[...] My mother was infected by genital herpes by her boyfriend (my stepfather), Tore, when she was 48. Tore, who was a captain in the Norwegian Army, had more than 500 sexual partners and my mother knew this but suffered from lack of good judgement and moral due to several factors (media - glorification of certain stereotypes being one).

[...] Tore, my stepfather, worked as a major in the Norwegian military and is now retired. I still have contact with him although now he spends most his time (retirement) with prostitutes in Thailand. He is a very primitive sexual beast, but at the same time a very likable and good guy. (Breivik 2011)

The evidence from Iceland

Iceland isn't Norway but it is culturally similar. According to a recent study, the genetic basis of intelligence has been declining in that country since the cohort born in 1910. The authors used a "polygenic score," based on alleles associated with high educational attainment, to measure the genetic potential for academic achievement from generation to generation:

Here, we investigate the effect of this genetic component on the reproductive history of 109,120 Icelanders and the consequent impact on the gene pool over time. We show that an educational attainment polygenic score, POLYEDU, constructed from results of a recent study is associated with delayed reproduction (P < 10-100) and fewer children overall. The effect is stronger for women and remains highly significant after adjusting for educational attainment. Based on 129,808 Icelanders born between 1910 and 1990, we find that the average POLYEDU has been declining at a rate of ~0.010 standard units per decade, which is substantial on an evolutionary timescale.

This is the same polygenic score I've discussed in previous posts, such as Frost (2018). Certain genetic variants are associated with high educational attainment and others with low educational attainment. Do these variants determine our capacity for intelligence? For the most part, yes, but I suspect that many of them have a stronger bearing on time preference or willingness to sit still in a classroom. The authors concede this point:

We postulate that, in addition to being correlated with cognitive ability (32, 33), POLYEDU is capturing a portion of the propensity to long-term planning and delayed gratification. (Kong et al. 2017)

These other traits still matter. Together, they form a mental/behavioral package that coevolved with the rising middle class over the last millennium, eventually spreading through all social strata (Clark 2007; Clark 2009a; Clark 2009b). That evolution is now unravelling. Reproductive success is shifting toward individuals with "fast life-history": lower cognitive ability, weaker orientation toward the future, and, for men, a larger number of sexual partners with less investment in the resulting offspring (Frost 2012; but see also JayMan 2012). This shift began seventy years before the decline in IQ scores.

It seems, then, that the Flynn effect has masked a longer-term decline in the genetic basis of intelligence and other mental/behavioral traits. This is in line with other recent findings. Woodley et al. (2013) argue that mean reaction time has increased in Great Britain by 13 points since Victorian times, although this finding may be an artefact of better sampling of the general population over time (hbd* chick, 2013). Another study, however, using Swedish subjects, has confirmed this lengthening of reaction time, particularly in cohorts born since the 1970s (Madison 2014; Madison et al. 2016).


The recent reversal of the Flynn effect seems to result from two trends:

1. a positive trend based on increasing familiarity with tests and test-taking, as well as improvements in nutrition and a more stimulating learning environment;

2. a negative trend due to dysgenic factors.

For most of the 20th century the positive trend overwhelmed the negative trend. In Norway, the negative trend has had the upper hand in post-1975 cohorts, partly because the positive trend has exhausted all room for improvement and partly because the current culture is facilitating the reproductive success of sexy, low-IQ men.

I've long believed that human evolution didn't stop in the Pleistocene. Nor did it slow down. In fact, we've changed much more over the past 10,000 years than over the previous 100,000, and I'm talking here not only about our outward appearance but also about our inward qualities of mind and behavior. But we can quickly lose what we so quickly gained. This reverse evolution is now taking place, and it’s visible even in the relatively closed system of Iceland's gene pool.

I used to be unconcerned about dysgenics. Any negative trends would surely take hundreds of years to produce serious consequences. So we would have plenty of time to get all of the relevant facts, discuss everything thoroughly with everyone, and reach a consensus. Well, I was wrong. Our dystopic future is close at hand.


Bratsberg, B., and O. Rogeberg. (2018). Flynn effect and its reversal are both environmentally caused. Proceedings of the National Academy of Sciences Jun 2018, DOI: 10.1073/pnas.1718793115

Breivik, A. (2011). A European declaration of independence.

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World. Princeton University Press: Princeton and Oxford.

Clark, G. (2009a) The indicted and the wealthy: surnames, reproductive success, genetic selection and social class in pre-industrial England.

Clark, G. (2009b). The domestication of man: The social implications of Darwin. ArtefaCTos 2: 64-80.

Flynn, J.R. (2007). What is Intelligence? Beyond the Flynn Effect. Cambridge University Press.

Frost, P. (2018). A new yardstick. Evo and Proud, May 14

Frost, P. (2012). Are the cads outbreeding the dads? Evo and Proud, November 3

Hbd* chick (2013). a response to a response to two critical commentaries on woodley, te nijenhuis & murphy (2013), hbd* chick, May 27

JayMan (2012). It's not the cads, it's the tramps. JayMan's Blog, December 28

Kong, A., M.L. Frigge, G. Thorleifsson, H. Stefansson, A.I. Young, F. Zink, G.A. Jonsdottir, A. Okbay, P. Sulem, G. Masson, D.F. Gudbjartsson, A. Helgason, G. Bjornsdottir, U. Thorsteinsdottir, and K. Stefansson. (2017). Selection against variants in the genome associated with educational attainment. Proceedings of the National Academy of Sciences 114(5): E727-E732.

Lappegård, T., Rønsen, M., & Skrede, K. (2011). Fatherhood and fertility. Fathering 9: 103-120.

Madison, G. (2014). Increasing simple reaction times demonstrate decreasing genetic intelligence in Scotland and Sweden, London Conference on Intelligence, Psychological comments, April 25
#LCI14 Conference proceedings

Madison, G., M.A. Woodley of Menie, and J. Sänger. (2016). Secular Slowing of Auditory Simple Reaction Time in Sweden (1959-1985). Frontiers in Human Neuroscience, August 18

Teasdale, T.W., and D.R. Owen. (2005). A long-term rise and recent decline in intelligence test performance: The Flynn Effect in reverse. Personality and Individual Differences 39(4): 837-843.

Thomson, E., T. Lappegård, M. Carlson, A. Evans, and E. Gray (2014). Childbearing across partnerships in Australia, the United States, Norway, and Sweden. Demography 51(2): 485-508

Woodley, M.A., J. Nijenhuis, and R. Murphy. (2013). Were the Victorians cleverer than us? The decline in general intelligence estimated from a meta-analysis of the slowing of simple reaction time. Intelligence 41: 843-850.