Eppur si muove

 

General intelligence (g) varies with ethnicity, as do genetic variants associated with educational attainment (Lasker et al. 2019, p. 445)

 

 

Bryan Pesta was fired from a tenured university position for a study he coauthored in a peer-reviewed journal. No one actually disputed his findings. It was simply taken for granted that they could not be true.

 

 

Three years ago I contributed a paper to a special issue of Psych. One of the other contributors, Bryan J. Pesta, coauthored a paper on “Global Ancestry and Cognitive Ability.” It was one of several recent studies that had used genetic data to understand how populations differ on average in their capacity for intelligence.

 

Pesta and his coauthors looked at data from an existing neurodevelopment study of 9,421 participants from Philadelphia. A little over half of them were European American, and a third were African American. They had all been genotyped and had all taken a battery of cognitive tests.

 

The study produced several findings:

 

·         Almost 15 IQ points separated the African American participants from the European American participants. About three quarters of the difference was due to general intelligence (g).

·         Among the African Americans, general intelligence correlated with the degree of European admixture.

·         The correlation was modestly reduced, but not eliminated, when controlled for parental education. Controlling for skin color had no effect. Although skin color does correlate with European admixture, it evidently has a less direct relationship to general intelligence. This finding therefore eliminates “colorism” (discrimination in favor of lighter-skinned African Americans) as a possible cause.

·         As much as 20-25% of the difference in general intelligence between the African Americans and the European Americans was explained by genetic variants associated with educational attainment. By comparison, the same variants explain only 11-13% of the variance in educational attainment among individuals.

·         Although these genetic variants predicted general intelligence in both groups, the predictive power for the African Americans was only 20% of the predictive power for the European Americans. This finding is consistent with a growing consensus that the genetic architecture of intelligence is different in the two groups. Because the genetic variants have been identified in Europeans or European Americans, they may contribute less to the capacity for intelligence in people of African descent. In addition, other variants may be found only in African populations and thus remain to be identified.

 

For the above findings, Bryan Pesta would be fired from his tenured position at Cleveland State University. The whole affair is described in The Chronicle of Higher Education. At no point did anyone actually dispute his findings. It was simply taken for granted that they could not be true. And that’s that.

 

Please don’t argue that Bryan Pesta unconsciously looked for data that would provide the findings he wanted. The data had already been collected by another research team for a completely different purpose. So put aside The Mismeasure of Man and tell Stephen Jay Gould to go back to sleep.

 

This story isn’t over. People are curious, and curiosity ends up finding a way—despite the barriers we erect. Below is a screen shot of the paper’s access statistics (Hint: The Chronicle’s article came out on October 13).

 

 

References

 

Lasker, J., B.J. Pesta, J.G.R. Fuerst, and E.O.W. Kirkegaard. (2019). Global Ancestry and Cognitive Ability. Psych 1(1):431-459. https://doi.org/10.3390/psych1010034  

 

Standifer, C. (2022). Racial Pseudoscience on the Faculty. A professor’s research flew under the radar for years. What finally got him fired? The Chronicle of Higher Education. October 13. https://www.chronicle.com/article/racial-pseudoscience-on-the-faculty?cid2=gen_login_refresh&cid=gen_sign_in

The mental qualities that make a society workable

 

A questionnaire survey found very low levels of altruism in Czechs and very high levels in Moroccans, Egyptians, and Bangladeshis. Do these results show differences in actual behavior or differences in socially desired response? (GPS 2020)

 

Emil Kirkegaard and Anatoly Karlin have written a paper on the relative importance of intelligence versus other mental traits in determining national well-being. Their conclusion? Intelligence contributes a lot more to national well-being than do time preference, reciprocity, altruism, and trust.

 

We find that overall, national IQ is a better predictor of outcomes than (low) time preference as well as the five other non-cognitive traits measured by the Global Preference Survey (risk-taking, positive reciprocity, negative reciprocity, altruism, and trust). We find this result across hundreds of regression models that include variation in the inclusion of controls, different measures of time preference, and different outcomes. Thus, our results appear quite robust. Our results do show some evidence of time preference's positive validity, but it is fairly marginal, sometimes having a small p value in one model but not in the next. (Kirkegaard and Karlin 2020)

 

The two authors especially focus on time preference, i.e., the willingness to defer gratification in exchange for long-term gains. While acknowledging previous studies, which show that time preference has a strong effect on national well-being, they argue that this effect is only apparent. If a society has low time preference (i.e., a strong orientation toward the future), it almost always has a high mean IQ. So the relationship between national well-being and time preference is largely spurious.

 

If true, this is a significant finding. But is it true?

 

I see one big problem: the paper compares datasets with very different levels of error. Intelligence was measured by IQ tests under controlled conditions. On an IQ test you cannot make yourself seem more intelligent than you really are, unless someone has provided you with the right answers.

 

This is not the case with the method for measuring the other mental traits: a questionnaire, on which the "right answer" is whatever the respondent chooses to write down. The difference between the two methods is thus the difference between direct measurement and self-report. The level of error is much higher with the latter, and this difference can explain the findings by Kirkegaard and Karlin, specifically why national well-being correlates more with intelligence than with time preference:

 

The median ß across the indicators was 0.11 for time preference but 0.39 for national IQ. We replicated these results using six economic indicators, again with similar results: median ßs of 0.15 and 0.52 for time preference and national IQ, respectively. Across all our results, we found that national IQ has 2-4 times the predictive validity of time preference.

 

What will happen to the same correlations if intelligence is measured by a questionnaire? Let's survey a thousand people and ask them: "How smart do you think you are?" The result will correlate with their performance on an IQ test, but far from perfectly. So the correlation between self-reported intelligence and national well-being will be lower than the correlation between IQ and national well-being. Instead of getting the correlation of 0.39 that Emil and Anatoly found, we now have something closer to 0.11, i.e., the correlation they found between time preference and national well-being.

 

The problems with questionnaire data are especially apparent if we look at the results of the Global Preference Survey for altruism (see map at the top of this post). We see considerable differences even between neighboring countries that are culturally similar. For some reason, Czechs are at the low end of human variation in altruism, whereas Moroccans, Egyptians, and Bangladeshis are at the high end.

 

What’s going on here? The results are based on the following two questions of the Global Preference Survey:

 

1. (Hypothetical situation:) Imagine the following situation: Today you unexpectedly received 1,000 Euro. How much of this amount would you donate to a good cause? (Values between 0 and 1000 are allowed.)

 

2. (Willingness to act:) How willing are you to give to good causes without expecting anything in return? (Falk et al. 2016, p. 15)

 

The first problem is that the respondents will answer the above questions in a way that is viewed favorably by others and by their own conscience. This is called “social desirability bias,” and it’s stronger in a society with a high level of religious belief, like Morocco, than in one with a low level, like the Czech Republic.

 

Second problem: the term “good cause” has different connotations in different places. In the Western world, it generally refers to a non-religious organization that may endorse controversial views on political or social issues. As a result, many Westerners have mixed feelings about donating to “good” causes. This is not the case in the Muslim world, where “good causes” are explicitly Islamic or at least compliant with Islamic teachings. There is a similar problem with the term “donate.” It usually means the act of giving money to an organization, whereas the corresponding word in another language may simply mean “give.”

 

I wrote to Emil Kirkegaard about my criticisms:

 

In my opinion, you're comparing apples and oranges. Cognitive ability is difficult to fake on an IQ test - unless somebody has provided the participant with the right answers. On a questionnaire, anyone can give the "right" answer. It's entirely self-report. It's like measuring intelligence by asking people how smart they think they are.

 

His reply:

 

Your stance on this seems to imply you are unhappy with any kind of comparison of self-rated data vs. objectively scored cognitive data. One difficulty for you here is that people can also cheat on cognitive tests, namely by scoring low on purpose. Furthermore, while you may disapprove, such comparisons are the norm everywhere. I don't know any other person who refuses to do this comparison. There are also other-rated personality data, and these show even more validity than self-rate ones. https://emilkirkegaard.dk/en/?p=6457  There is a lot of research on faking good on personality tests, generally showing that subjects are not very good at this, presumably owing to lack of understanding of how the tests work.

 

I checked out the link he provided. This is what I found:

 

Self-rating measures of personality suffer from not just regular, random measurement error, but also have systematic measurement error (bias): people are not able to rate their own personality as well as other people who know them can. They introduce self-rating method variance into the data, and this variance is not so heritable. There is a twin study that used other-ratings of personality and when they used them or combined them with self-ratings, the heritabilities went up:

 

So with self-report they found H 42-56%, mean = 51%. Other-report: 57-81, mean = 66%, combined: 66-79, mean = 71%. (I used the AE models' results when possible.) In fact, these analyses did not correct for regular measurement error either, so the heritabilities are higher still according to these data, likely into the 80%s area. This is the same territory as cognitive ability. (Kirkegaard 2017)

 

 

Parting thoughts

 

Emil and Anatoly are right when they argue that intelligence is confounded with other mental traits. If, on average, a human population is high in intelligence, it is almost always low in time preference and high in altruism. This doesn't mean, however, that the latter are secondary expressions of intelligence. Many individuals are high in intelligence but low in altruism, sometimes pathologically low. They're called "sociopaths."

 

Few, if any, populations are both sociopathic and highly intelligent because such a combination can succeed only at the level of individuals, and not at the level of an entire population. The same pressures of selection that increase the mean intelligence of a population will also increase the average level of altruism and the average future time orientation. Consequently, all of these traits correlate with each other at the population level.

 

Will we ever be able to parcel out the relative importance of each mental trait in determining national well-being? In others words, will we ever find out how much of national well-being is due to intelligence, how much to time preference, and how much to altruism?

 

Not for a while. First, because these traits correlate with each other at the population level, it would be difficult to separate them and measure the relative importance of each one. They’re confounded. Second, they probably interact with each other. Altruism, for instance, is not a successful group strategy unless other mental or behavioral mechanisms are in place, in particular mechanisms to exclude non-altruists, i.e., the “free rider problem.” Intelligence, likewise, does not exist in a vacuum.

 

 

References

 

Falk, A., A. Becker, T. Dohmen, B. Enke, D. Huffman, and U. Sunde. (2016). Online Appendix: Global Evidence on Economic Preferences.

https://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/qje/133/4/10.1093_qje_qjy013/5/qjy013_supplemental_file.pdf?Expires=1611916150&Signature=Bc-zlE8jYXQUPteS3fbcNvbEI60jZ0VRXsPC0xkiG3G-5xgW9K2N4hn0LUJ2i-2oxn1BIE9wLMSNdf5-nlMTHf4Hf78TZcsUV-7yGui72UCFz-e7OrcCyiZpzhy-P6LIKXaAqWhIMva5ZKi0Rcf2wuIt195WSSWE7Y2hq9ilWKMuR~xqjHlkMkiq9Exq9D2xS4EIQX3O96IpRm-oMYpEbaCDaehxRA4BinqbuGhWcUcK9i3ocb5kxe2ZjF7OqDDiVZuaRAtDRYezLe8oQciZf4skXuLTfM5aSkNarWkOh617x0kcc1jOBgzrVUZYZ9FeWZY0r9OvHsDQNs6Z2CDp-A__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA

Global Preferences Survey (2020). https://www.briq-institute.org/global-preferences/about  

Kirkegaard, E.O.W. (2017). Getting personality right. Clear Language, Clear Mind.

https://emilkirkegaard.dk/en/2017/02/getting-personality-right/

 

Kirkegaard, E.O.W., and A. Karlin. (2020). National Intelligence Is More Important for Explaining Country Well-Being than Time Preference and Other Measured Non-Cognitive Traits. Mankind Quarterly 61(2): 339-370. http://doi.org/10.46469/mq.2020.61.2.11

https://www.researchgate.net/publication/347563852_National_Intelligence_Is_More_Important_for_Explaining_Country_Well-Being_than_Time_Preference_and_Other_Measured_Non-Cognitive_Traits

 

Declining intelligence in the 20th century: the case of Estonia

Soviet-era stamp. In Estonia, cranial volume shrank between the cohort of girls born in 1937 and those born in 1962, apparently because the intellectually gifted were more likely to pursue higher education and postpone childbearing.

 

Is the genetic basis for intelligence declining from one generation to the next? That’s the conclusion of several recent studies on alleles associated with high educational attainment. By adding up such alleles over the genome, we can get a person's "polygenic score." By calculating the mean polygenic score for each generation, we can then find out whether this genetic basis is declining.

The polygenic score has declined among Icelanders since the cohort born in 1910 and among Euro Americans between the 1931 and 1953 cohorts (Beauchamp 2016; Kong et al. 2017). The Icelandic study is especially interesting because that country took in very few immigrants during the period under study. The decline was thus driven by internal factors. One reason seems to be the tendency of university-educated people to delay reproduction and have fewer children. But that's not the whole story. Even among Icelanders who didn’t pursue higher education, fertility was lower among the intellectually gifted, apparently because their intelligence was associated with a desire to plan for the future and delay gratification.

Before the twentieth century, such forward-looking people were reproductively successful. They were the ones who had enough resources to survive disasters of one sort or another: famine, disease, the Little Ice Age, etc. Today, such disasters are a lot less deadly, and it no longer matters so much whether one is a grasshopper or an ant.

Moreover, because of demographic and cultural changes during the twentieth century, it’s no longer possible to count on the same degree of assistance for child-raising from relatives and grandparents. With childbearing at later ages, grandparents are either dead or too frail to help. With people moving around more, not all relatives live nearby. If you’re the sort of person who plans for the future and delays gratification, you may be a lot more intimidated than your forbears by the costs of raising a family.

Shrinking cranial volume in Estonians

Cranial volume correlates with IQ and with educational attainment, albeit imperfectly (see Frost 2020). Has it been declining in tandem with the decline in alleles for educational attainment?

In Soviet-era Estonia, cranial volume was one of several anthropometric traits that were measured in girls born between 1937 and 1962. Because the measurements were mandatory, there was no volunteer basis; mortality bias was minimal because all the participants were younger than 20. In this respect, the study is better than Western biobank studies. On the other hand, the results may be less applicable to Western populations, given the differences in demographic history. Estonia had no postwar baby boom. Fertility then rose from the late 1960s until the breakup of the Soviet Union. By the late 1980s, fertility was actually higher in Estonia than in any other major region of Europe.

Nonetheless, there were demographic similarities between Soviet Estonia and the West, particularly the rising prevalence of single mothers and the influence of education on fertility:

- Divorce rates began to rise during the interwar years, equalling or exceeding those of Scandinavia from the 1970s onward.

- Throughout the twentieth century, Estonian women with only primary education bore 0.5 to 0.75 more children on average than women with tertiary education. In the population under study, taller children and those with larger crania were more likely to go on to secondary and/or tertiary education, independently of sex, socioeconomic position, and rural vs urban origin (Valge et al. 2019).

The second factor seems to explain why cranial volume declined from the older cohorts to the younger ones:

[...] the majority of selection for smaller cranial volume acted indirectly via educational attainment, whereas the direct path of selection in the SEM model was non-significant (Figs. 2 and 4). In other words, consistent with our prior expectations, girls with larger heads were selected against because they were more likely to obtain higher education than girls with smaller heads. Lower education (Tiit, 2013) and rural origin (Kulu, 2005) have been independently and additively associated with higher fertility in Estonia throughout the past century. The reason for the link between education and fertility is that early reproduction, a major determinant of LRS, is not compatible with schooling for both cultural and genetic reasons. (Valge 2020)

 It is doubtful that this decline is due to ethnic change. All of the girls were from Estonian schools (Russian-speakers had their own schools). Nonetheless some of them were of mixed background. According to a personal communication from the corresponding author, 84% of the fathers and 93% of the mothers were Estonian. Ideally, the study should be redone without individuals of mixed parentage. The problem here is not only that one of the parents was non-Estonian but also that such individuals were disproportionately economic migrants who had trouble finding suitable work elsewhere in the Soviet Union.

Other anthropomorphic changes

Height also declined. Unlike cranial volume, this decline was not wholly explained by educational/socioeconomic differences:

Notably, higher reproductive success of shorter girls in Estonia could not be entirely ascribed to indirect selection via educational attainment, nor via other measured socioeconomic variables such as rural/urban origin, although indirect selection via education did account for a large portion of total selection (Fig. 4). The finding that selection against height remains after controlling for education or income (that favours less-educated individuals who are generally shorter than highly-educated ones) is consistent with findings of studies reviewed by Stulp and Barrett (2016).

 

Female hips and female jaws became narrower even after controlling for educational/socioeconomic differences. There seems to have been selection for rounder female faces, but this selection is significant only if one allows for nonlinear effects. Finally, there was no direct selection on two markers of overall health and nutritional status: handgrip strength and lung capacity.

In general, "direct selection favoured shorter, slimmer and lighter girls with smaller heads, more masculine facial and body shapes and slower rates of sexual maturation."

Conclusion

The genetic basis for intelligence has declined in European populations, apparently since the early twentieth century. This decline is attested by two "hard" measures: 1) alleles associated with educational attainment; and 2) cranial volume. Furthermore, it is attested in two relatively homogenous societies, i.e., Iceland and Estonia.

In Estonia, the decline seems entirely due to the intellectually gifted going to university and postponing family formation. In Iceland, this factor explains only part of the decline: the intellectually gifted chose to postpone family formation even when they didn't go to university. Perhaps the Soviet system was better at steering gifted individuals into higher education.

On a final note, this problem will not go away on its own. If we wish to have large numbers of intellectually gifted people who plan for the future and delay gratification, we will need to reverse certain social and cultural changes of the twentieth century.

Comments by Peeter Horak

In an email, Peeter pointed out that the decrease in height due to natural selection might be offset by an increase in height due to lower pathogen load (as a result of vaccination and antibiotics, see Hõrak and Valge 2015). In addition, we currently don't know the direction of selection on boys. It may entirely cancel out natural selection on girls if men's income and education correlate positively with their reproductive success. In the sample under study, taller boys and those with larger heads went on to obtain more education; if they were reproductively successful, there would be sexually antagonistic selection: selection would favor larger boys and smaller girls at the same time.

References

Beauchamp, J.P. (2016). Genetic evidence for natural selection in humans in the contemporary United States. Proceedings of the National Academy of Sciences 113(28): 7774-7779 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4948342/

Frost, P. (2020). Did women jumpstart recent cognitive evolution? Evo and Proud, July 1 https://evoandproud.blogspot.com/2020/07/did-women-jumpstart-recent-cognitive.html

Hõrak, P., and M. Valge. (2015). Why did children grow so well at hard times? The ultimate importance of pathogen control during puberty, Evolution, Medicine, and Public Health, 2015 (1): 167–178, https://doi.org/10.1093/emph/eov017

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 https://core.ac.uk/download/pdf/154416179.pdf

Valge, M., P. Horak, and J.M. Henshaw. (2020). Natural selection on anthropometric traits of Estonian girls. Evolution and Human Behavior in press. https://doi.org/10.1016/j.evolhumbehav.2020.07.013

Valge, M, R. Meitern, and P. Horak. (2019). Morphometric traits predict educational attainment independently of socioeconomic background. BMC Public Health 19: 1696. https://link.springer.com/article/10.1186/s12889-019-8072-7

Selection for slow life history?

One of several posters to promote family formation in the dwindling Parsi community (Jiyo Parsi)

In India, and overseas, the Parsis are renowned for their achievements, particularly in business but also in science, culture, and philanthropy. 

They are also known for something else: they’re dying out. From 114,000 in 1941, they were down to half that number by 2011. Today, more than 30% of Parsis don't marry, and an equal proportion are over 60 years old. Their fertility rate is 0.8—in other words, the average Parsi woman gives birth to less than one child during her lifetime. This existential crisis is worrying not only the Parsis but also the Indian government. In 2013, a program was set up to subsidize fertility treatments and promote family formation in the community (Dore 2017).

Extinction is irreversible. If the Parsis die out, the loss will be greatest in those things we don’t fully understand: the workings of the human mind. That is precisely where the Parsis have succeeded the most. How much of that success has been due to learning and how much to innate factors?

A few steps toward an answer were taken by Greg Cochran and Henry Harpending in their paper on Ashkenazi intelligence:

Since strong selection for IQ seems to be unusual in humans (few populations have had most members performing high-complexity jobs) and since near-total reproductive isolation is also unusual, the Ashkenazim may be the only extant human population with polymorphic frequencies of IQ-boosting disease mutations, although another place to look for a similar phenomenon is in India. In particular, the Parsi are an endogamous group with high levels of economic achievement, a history of long-distance trading, business and management, and who suffer high prevalences of Parkinson disease, breast cancer and tremor disorders, diseases not present in their neighbours. (Cochran et al. 2006)

Such disorders may be a side-effect of strong selection for intelligence over a short time in a small population. This was historically the case with Ashkenazi Jews. They are unusually prone to four neurological disorders: Tay-Sachs, Gaucher, Niemann-Pick, and mucolipidosis type IV. All four affect the brain by increasing the capacity of lysosomes to store sphingolipid compounds for axonal growth and branching. Furthermore, Tay-Sachs is caused in Ashkenazi Jews by two unrelated mutations and Gaucher disease by five. Random chance simply cannot explain why so many mutations exist in the same metabolic pathway and have reached such high frequencies.

Those mutations apparently spread through heterozygote advantage. Though harmful when two copies are inherited from both parents, they are beneficial when only one copy is inherited, as is more often the case. With a better supply of sphingolipids and no adverse effects, the brain can process information more efficiently.

Jared Diamond (1994) was the first to argue that chance cannot explain the high prevalence of so many lysosome storage disorders in a single population. He suggested the cause was selection for intelligence. His theory was then developed by Cochran et al. (2006). Other researchers have further confirmed Diamond’s theory by showing that Ashkenazim have high frequencies of alleles associated with educational attainment (Dunkel et al. 2019; Piffer 2019).

Frequent neurological/cerebral diseases among the Parsis

We see a similarly high prevalence of neurological or cerebral diseases among the Parsis. Parkinson’s disease is considerably more prevalent among them than among other Indians or even people of developed countries. Strokes are at least twice as common. Essential tremors are exceptionally frequent (Gourie-Devi 2014).

These diseases seem to have a genetic basis among the Parsis. A mitochondrial genome study found 420 unique genetic variants within that community, 178 of which are associated with Parkinson's disease. Others are linked to other neurodegenerative disorders, as well as colon, breast, and prostate cancer. A surprising number of these unique variants, 217, are linked to increased longevity. Finally, and perhaps curiously, some variants are linked to asthenozoospermia, i.e., reduced sperm motility (Patell 2020)

The above results are consistent with the findings of an earlier genetic study of the Parsis, specifically their autosomal, Y chromosome, and mitochondrial DNA. Signals of selection were strongest in SNPs associated with humoral immunity, cerebellar physiology, and neurological disorders like early epilepsy (Lopez et al. 2017).

Conclusion

The evidence is only suggestive, but it looks like the Parsis have undergone strong selection for intelligence over a relatively short time; hence, the high prevalence of neurological disorders.

In addition, this community seems to have adapted to its economic and social niche through a "slow life history" strategy. The Parsis are predisposed to live longer and thus learn more over a longer time. They may also be predisposed to longer birth intervals and higher parental investment in each child (K selection). Such a reproductive strategy is consistent with lower male fertility.

A slower life history, combined with higher intelligence, may have assisted the trading lifestyle of the Parsi community. Trade requires a high level of cognitive ability, particularly for literacy and numeracy, as well as lower time preference and a longer learning period. 

Ironically, low time preference may explain the demographic decline of the Parsis, and other people like them. If you’re future-oriented, you’re also keenly aware of future costs, particularly those of getting married and having a family. So you’ll postpone marriage and family formation until you’re financially ready. Unfortunately, that day may never come. Or it may come too late.

This problem was known to traditional societies, and there used to be social incentives to ensure that young people would marry before they got too old. Unfortunately, those incentives have disappeared in modern societies.

If you wait to check all the boxes, you may check into an old-age home … alone.

References

Cochran, G., J. Hardy, and H. Harpending. (2006). Natural history of Ashkenazi intelligence. Journal of Biosocial Science 38: 659-693

https://pdfs.semanticscholar.org/4440/4954e85b0134c24163ae445e7c591097a2c9.pdf

Diamond, J.M. (1994). Jewish Lysosomes. Nature 368: 291-292.

https://www.nature.com/articles/368291a0

Dore, B. (2017). Glimmer of hope at last for India's vanishing Parsis. BBC News

https://www.bbc.com/news/world-asia-india-40628310#:~:text=More%20than%2030%25%20of%20Parsis,which%20a%20population%20remains%20steady

Dunkel, C.S., Woodley of Menie, M.A., Pallesen, J., and Kirkegaard, E.O.W. (2019). Polygenic scores mediate the Jewish phenotypic advantage in educational attainment and cognitive ability compared with Catholics and Lutherans. Evolutionary Behavioral Sciences 13(4): 366-375.

https://insights.ovid.com/evolutionary-behavioral-sciences/evobs/2019/10/000/polygenic-scores-mediate-jewish-phenotypic/5/01787238

Gourie-Devi M. (2014). Epidemiology of neurological disorders in India: review of background, prevalence and incidence of epilepsy, stroke, Parkinson's disease and tremors. Neurology India 62(6): 588-598. https://doi.org/10.4103/0028-3886.149365  

López, S., Thomas, M. G., van Dorp, L., Ansari-Pour, N., Stewart, S., Jones, A. L., Jelinek, E., Chikhi, L., Parfitt, T., Bradman, N., Weale, M. E., and Hellenthal, G. (2017). The genetic legacy of Zoroastrianism in Iran and India: insights into population structure, gene flow, and selection. American Journal of Human Genetics 101(3): 353-368.

https://www.sciencedirect.com/science/article/pii/S0002929717302914

Patell, V.M., N. Pasha, K. Krishnasamy, B. Mittal, C. Gopalakrishnan, R. Mugasimangalam, N. Sharma, A-K. Gupta, P. Bhote-Patell, S. Rao, R. Jain, and The Avestagenome Project. (2020). The First complete Zoroastrian-Parsi Mitochondria Reference Genome: Implications of 2 mitochondrial signatures in an endogamous, non-smoking population. bioRxiv preprint doi: https://doi.org/10.1101/2020.06.05.124891

Piffer, D. (2019). Evidence for Recent Polygenic Selection on Educational Attainment and Intelligence Inferred from Gwas Hits: A Replication of Previous Findings Using Recent Data. Psych 1(1): 55-75.

https://www.mdpi.com/2624-8611/1/1/5/htm?source=techstories.org

Why is vocabulary shrinking?

Vocabulary decline in adult non-Hispanic White Americans (controlled for years of education completed)



"Are Americans more intelligent than a few decades ago, or less intelligent?" So asks psychologist Jean Twenge in her introduction to a recent paper on vocabulary decline in Americans. The findings are disconcerting, to say the least:

We examined trends over time in vocabulary, a key component of verbal intelligence, in the nationally representative General Social Survey of U.S. adults (n=29,912). Participants answered multiple-choice questions about the definitions of 10 specific words. When controlled for educational attainment, the vocabulary of the average U.S. adult declined between the mid-1970s and the 2010s. Vocabulary declined across all levels of educational attainment (less than high school, high school or 2-year college graduate, bachelor's or graduate degree), with the largest declines among those with a bachelor's or graduate degree. (Twenge et al. 2019)

The last decline was especially large: more than half a standard deviation. In general, vocabulary test scores have fallen by 8.5%. Ethnic change doesn’t seem responsible, since non-Hispanic whites have had almost the same decline: 7.2%.

So what's going on? The authors considered the explanation they first raised: Americans have become less intelligent despite the increase in education.

First, Americans' vocabularies might be shrinking despite the increase in education. This is plausible given the steep decline in the amount of time high school students spend reading [...] and the decline in SAT verbal scores over time [...]. This explanation could account for the narrowing of abilities between those without high school educations and those with college educations. The difference in vocabulary by education was approximately 3.4 correct answers in 1974-79 but dropped to 2.9 correct answers by 2010-16. However, this explanation would not account for the decline in performance in all educational groups. (Twenge et al. 2019)

Uh, why not? The last sentence makes sense if the explanation is simply that postsecondary education has become less effective. But what if vocabulary has declined because the capacity for learning words and retaining them has also declined? The cause may be genetic. Can we at least ask that question?


Lower admission standards? Mismatch between cause and effect

The authors then consider another explanation: because college admission standards have been lowered, people of lower ability have been going on to postsecondary education in larger numbers; those who don't are increasingly the least able.

If education does not improve vocabulary, but educational attainment increases, those with higher ability will be increasingly selected into the higher education groups, leaving those with lower ability in the lowest educational attainment groups. Thus, the no high school degree group will be left with those of lowest ability, and the college graduate group will have absorbed more with only moderate ability. (Twenge et al. 2019)

That explanation is popular, but it doesn’t really match the findings. The vocabulary decline was steepest during the late 1970s and early 1980s. It then levelled off. A second decline may have begun in 2008, but it’s still too early to say (see Figure 1 reproduced above). Most of the decline doesn't correspond to any previous change in college enrollment by recent high school graduates. The enrollment rate rose slowly from 45.7% in 1959 to 49.4% in 1980. It began to grow faster only in the mid-1980s, breaking through the 60% level in 1991 and the 70% level in 2009 (Bureau of Labor Statistics 2010).

So the alleged cause doesn’t match the presumed effect. The steep increase in college enrollment from the mid-1980s onward could not have caused the steep vocabulary decline during the late 1970s and early 1980s. Keep in mind that most of the GSS respondents had completed their education some years earlier, almost ten years earlier on average. So the average respondent in the late 1970s had to meet college admission standards that existed in the late 1960s.


Most of the decline has been among early boomers

Because the GSS was first administered in 1974, we don't know when the steep vocabulary decline began. But we do know when it ended: in the mid-1980s, among respondents who were born on average thirty years earlier. A genetic cause would imply a rapid deterioration in the gene pool from 1945 to 1955 and a slower deterioration thereafter. I have no idea what that cause could be.

If we're looking for a cultural cause, it would have acted most strongly on the same cohort of "early boomers." Perhaps it was their increasing exposure to TV and their decreasing exposure to high literature. Those cultural changes were already a fait accompli for "late boomers," who experienced a more gradual dumbing down of vocabulary on TV and in print. The post-2008 vocabulary decline, if it’s real, might reflect the growing importance of iPhone texting since the late 2000s.

That cultural explanation has some support from the data and is favorably mentioned by the authors. For one thing, comparison with the results of another test (WAIS) suggests that the decline has been mostly in passive vocabulary, i.e., the words we understand but don’t use spontaneously in speech (Twenge et al. 2019). We’re less proficient in "bookish" language:

Perhaps American culture became less intellectual, either because of or in response to a lowering of verbal ability among those who read books. Authors aim to sell more copies of their books, and thus may adjust their vocabulary level to the skills and preferences of a wider slice of the population. Or, perhaps authors lowered the vocabulary level of their books for some other reason such as an interest in getting out a message without linguistic complexity getting in the way. For example, the Bible has been revised repeatedly to make it more accessible with the King James Version, the most complex and lyrical English language version, being succeeded by the simpler New International Version, Living Bible, and New Revised Standard Version. (Twenge et al. 2019)

The last point rings true. When I was studying Shakespeare in high school my mother could explain words I had trouble understanding. She had never gone beyond Grade 10, but she could read the Bible in the King James Version, as well as a lot of high-brow literature. This was true for many ordinary adults in the 1970s. Today, regular reading of the Bible is unusual and almost always confined to modern English versions.


Conclusion

Yes, college has become a less interesting place for learning vocabulary, and for learning in general. Yes, a big reason is the growing number of students who don’t really belong there, and the consequent lowering of standards. Yes, America’s cultural and linguistic mix is changing, and for that reason alone the average American would have a smaller English vocabulary.

Nonetheless, those factors fail to explain why non-Hispanic white Americans know fewer words today than they did a half-century ago, especially in their passive vocabulary. Something else is going on, and it seems to be a shift away from high literature and toward simpler audiovisual media: TV, video, text messaging …


References

Bureau of Labor Statistics. (2010). College enrollment up among 2009 high school grads. TED: The Economics Daily. April 28
https://www.bls.gov/opub/ted/2010/ted_20100428.htm?view_full

Twenge, J.M., W.K. Campbell, and R.A. Sherman. (2019). Declines in vocabulary among American adults within levels of educational attainment, 1974-2016. Intelligence 76: 101377
https://www.gwern.net/docs/iq/2019-twenge.pdf

South Korea's experiment

Mid-term exams at a South Korean middle school (Wikicommons - Samuel Orchard)



South Korea opened up to mail-order brides a quarter of a century ago. Most are from Southeast Asia (Philippines, Vietnam, Cambodia, and Indonesia), although some are ethnic Koreans from northeast China. Men outnumber women in South Korea, as they do elsewhere in East Asia, and the male surplus is even larger in rural areas because of the many women who move to cities for employment (Park 2011). 

As a result, 472,390 "multicultural marriages" were performed between 2000 and 2016 (Lim 2017). In 2005, the peak year, 13% of all marriages involved a foreign-born bride. This way of finding a bride has been especially popular in rural areas, where 40% of all couples are mixed (Park 2011). The offspring of these marriages "are expected to number over 1.6 million by 2020, with a third of all children born that year the offspring of international unions" (Lim 2011). In rural areas, this proportion is expected to be half of all children by 2020 (Park 2011).

Such children will increase both in absolute numbers and proportionately for three reasons. First, they are born mostly in rural areas, where incentives for childbearing are relatively high. Second, their mothers come from cultures where fertility is likewise relatively high. Third, Korean women have a very low fertility rate: only 0.98 children per woman in 2018.

South Korea is thus on track for rapid demographic replacement. This change is interesting not only because of its rapidity but also because it is happening in a country that differs considerably from Western Europe and North America in history and culture. Negative effects cannot be blamed on slavery, colonialism, or other chickens coming home to roost. Until the twentieth century the country kept to itself, to such a point that it was called "The Hermit Kingdom." There then followed Japanese rule, American occupation, and devastating war. Not until the 1980s did South Korea become truly advanced, and affluent.

So can South Korea change its population and remain advanced and affluent? This question is all the more relevant because the country has only one natural advantage in the global marketplace: its human capital.


Academic failure

In general, children of mixed parentage do badly at school: "The drop-out rate among mixed-blood youths is estimated at 9.4% in elementary schools and 17.5% at the secondary level, compared with less than 3% among ordinary Korean youths" (Kang 2010).

This poor performance is usually put down to the mother's poor language skills. "Because their mothers have difficulty in speaking and writing Korean, these children may be making slow progress in language development in comparison to the Korean children" (Kang 2010). If this explanation is correct, such children should do worse in subjects that demand much social interaction and language use. Conversely, they should do better in subjects that require abstract skills, like mathematics, or memorization of names and dates, like social studies. This is, in fact, the pattern we see in children of East Asian immigrants in North America.

But this is not the pattern we see in children born in South Korea to non-Korean mothers: "Their favourite subjects are music/painting/physical education (42.6%), while they dislike math (38.1%), social studies (19.2%) and Korean (12.7%)" (Kang 2010). The learning deficit seems to be strongest in those subjects that require the most abstraction and memorization.

Moreover, a study conducted over several months found that these children do not have language problems that can be traced to deficient learning at home from their mothers: "This study revealed that multicultural children did not exhibit any difficulty in communicating with others in everyday Korean but that they had varying degrees of academic vocabulary mastery" (Shin 2018). So the problem is not with learning of normal spoken language at home but with learning of specialized terminology at school. The study's author concluded: “This finding then raises the questions of why the simplified discourse about multicultural children's deficiency in Korean has been easily accepted as true in society and who benefits from the (re)production of the idea that they need special care, particularly regarding Korean language instruction” (Shin 2018).


Non-compliance with social rules

Koreans are expected to show a high level of compliance with social rules. These rules may apply to everyone (e.g., wearing seatbelts) or only to students (e.g., no smoking, mandatory hand washing). Compliance seems to be weaker in children of foreign-born mothers, as suggested by lower rates of hand washing and wearing of seatbelts and higher rates of smoking (Yi and Kim 2017).


Suicidal ideation and suicidal attempts

Children of mixed parentage are more likely to contemplate and attempt suicide, but this seems to be related more to decreased self-control than to increased depression or stress. Kim et al. (2015) concluded: "There was no significant difference in the levels of depression, self-reported happiness, and self-reported stress between adolescents from multicultural and monocultural families. However, suicidal ideation and suicidal attempt were significantly higher in adolescents from multicultural families."


Violence and hyperactivity

Children of mixed parentage also show higher levels of hostility, fear, anxiety, and anger (Moon and An 2011). Between the ages of 5 and 12 years they are more likely to engage in hyperactive behaviors, as rated by their teachers (Park and Nam 2010). Finally, between the ages of 11 and 13 years they are more prone to delinquency and aggression (Lee et al. 2018).

On the other hand, Yu and Kim (2015) found higher incidences of violence at school and non-compliance with rules (smoking, drug use, alcohol use, sexual activity) only in children of foreign-born fathers and native-born mothers. Children of foreign-born mothers and native-born fathers were behaviorally similar to children of native-born mothers and native-born fathers. It is true that the other studies lump all “multicultural” children together, making no distinction between those with foreign-born mothers and those with foreign-born fathers. However, the second group is much smaller than the first—too small to explain the differing results. This may be seen in the study by Yu and Kim (2015), which had 88 binational children of foreign-born fathers versus 622 of foreign-born mothers.

The findings of Yu and Kim (2015) also run counter to the standard acculturation model. A child normally has a stronger bond with its mother than with its father, so a child should better assimilate Korean behavioral norms if its mother is Korean than if its mother is non-Korean. But here we see the reverse.


Conclusion

The most robust finding is that children of mixed parentage do poorly at school. The reason is commonly said to be poor language skills, yet the pattern of academic failure is actually the opposite of what that explanation would predict. Moreover, these children seem to have no trouble with everyday spoken Korean. Their problem is with specialized vocabulary that is normally learned at school and not at home.

Children of mixed parentage also seem to be less compliant with rules and more prone to violence and hyperactivity. This was the finding of three out of four studies. The underlying cause may be weaker mechanisms for self-control, self-discipline, and internalization of social rules. This factor may also play a role in the higher incidences of suicidal ideation and suicidal attempts.

In the academic literature, these findings are explained in terms of normal versus abnormal development. Children of mixed parentage are said to develop abnormally because they are more interested in music and physical education than in math. Their higher levels of violence and hyperactivity are explained the same way.  But what if they had been assessed in their mothers' home countries? Would they still seem so abnormal? On a global level, few societies expect the degree of academic nerdiness that Koreans expect of themselves. 

Better research is needed. My first suggestion: provide data on ethnicity. It’s not enough to distinguish between "native-born" and "foreign-born." A foreign-born mother could be an ethnic Korean from China who has more in common with a native-born mother. There may also be significant behavioral differences among binational children depending on which Southeast Asian country the mother comes from. The relevant factor is really ethnicity and not place of birth.

This factor may explain why children are less violent when they have foreign mothers and Korean fathers than when they have Korean mothers and foreign fathers. The foreigners are ethnically different in the two cases. In the first case, they are Southeast Asians. In the second case, they are either U.S. servicemen or migrant laborers who come not only from Southeast Asia but also from South Asia, Southwest Asia, and Africa.

My second suggestion: do not frame the issue solely in terms of "acculturation." i.e., insufficient learning by children of Korean culture, particularly the Korean language. This is not to say that acculturation is never a causal factor, but rather that it is assumed to be the only one, even to the point of misrepresenting reality.

Yes, culture does matter, but it interacts with other factors, including genetic ones. Humans everywhere have had to adapt to their cultural environment—more so, in fact, than to their natural environment—and this has been no less true for the Korean people. To survive in a highly complex and demanding culture, they have had to acquire certain mental capabilities:

- high cognitive ability (mean IQ of 106)

- high self-control

- high degree of compliance with social rules

- low time preference and, correspondingly, strong future-oriented thinking

- strong inhibition of violence, which can be released only if permitted by social rules

All of these mental capabilities have moderate to high heritability and are no less real than the more visible aspects of the human body, like gender, skin color, and body height. They exist because they have enabled Koreans to survive and flourish in a specific cultural environment

The Korean people have achieved a high standard of living through their knowledge, foresight, and self-discipline—qualities that are the outcome of a long process of gene-culture coevolution. Generation after generation of their ancestors have had to adapt to the demands of a harsh cultural environment, this adaptation being bought at a high price: the success of some individuals and the failure of many more. This is why Koreans traditionally revere their ancestors.

All of this has been gained through much effort over many generations, but it can all be lost in one or two. To do or to undo—which do you think is easier?   


References

Kang, S.W. (2010). Multicultural education and the rights to education of migrant children in South Korea. Educational Review 62(3): 287-300.
https://books.google.ca/books?hl=fr&lr=&id=sgnKAwAAQBAJ&oi=fnd&pg=PA37&ots=IcekxniSRj&sig=vQ-YWHSlouQuzFor5zP9OOkucsg#v=onepage&q&f=false 

Kim, J-M., B-G. Kong, J-W. Kang, J.-J. Moon, D.-W. Jeon, E.-C. Kang, H.-B. Ju, Y.-H. Lee, and D.-U. Jung. (2015). Comparative Study of Adolescents' Mental Health between Multicultural Family and Monocultural Family in Korea. Journal of the Korean Academy of Child and Adolescent Psychiatry 26(4): 279-287.
https://www.e-sciencecentral.org/articles/SC000022127

Lee, J.S., J.M. Kim, and A.R. Ju. (2018). A structural analysis on the effects of children's parentification in multicultural families on their psychological maladjustment - comparison with children in monocultural families. Journal of the Korea Institute of Youth Facility and Environment 16:117-130.
https://www.earticle.net/Article/A329970 

Lim, T. (2011). Korea's multicultural future? The Diplomat, July 20
https://thediplomat.com/2011/07/south-koreas-multiethnic-future/

Lim, T. (2017). The road to multiculturalism in South Korea. Georgetown Journal of International Affairs, October 10
https://www.georgetownjournalofinternationalaffairs.org/online-edition/2017/10/10/the-road-to-multiculturalism-in-south-korea 

Moon SH, and H.J. An (2011). Anger, anger expression, mental health and psychosomatic symptoms of children in multi-cultural families. Journal of Korean Academy of Psychiatric and Mental Health Nursing 20(4): 325-333.
https://synapse.koreamed.org/DOIx.php?id=10.12934/jkpmhn.2011.20.4.325

Park, S. (2011). Korean Multiculturalism and the Marriage Squeeze. Contexts 10: 64-65.
https://journals.sagepub.com/doi/full/10.1177/1536504211418459 

Park, J.H., and J.S. Nam (2010). The language development and psychosocial adjustment of multicultural children. Studies on Korean Youth. 21:129-152.

Yi, Y., and J-S. Kim. (2017). Korean Adolescents' Health Behavior and Psychological Status according to Their Mother's Nationality. Osong Public Health and Research Perspectives 8(6): 377-383.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5749486/ 

Shin, J. (2018). Minority youth's mastery of academic vocabulary and its implications for their educational achievements: the case of 'multicultural adolescents' in South Korea. Multicultural Education Review 10(1): 35-51,
https://www.tandfonline.com/doi/abs/10.1080/2005615X.2018.1423539 

Yu, J-O, and M. Sung Kim. (2015). A Study on the Health Risk Behaviors of Adolescents from Multicultural Families according to the Parents' Migration Background. Journal of Korean Academy of Community Health Nursing 26(3):190-198
https://synapse.koreamed.org/DOIx.php?id=10.12799/jkachn.2015.26.3.190