Friday, July 29, 2022

Recent evolution in Estonia

 


Estonian women at a song festival (Wikicommons – Anastasia Lakhtikova)

 

Estonian women had more reproductive success during the late 20th century if they possessed a more masculine body build, narrower hips, and shorter legs. Such women married earlier and were less likely to stay on the mate market as long as possible.

 



Human evolution didn’t end in the Pleistocene. In fact, there has been more genetic change within our species over the past 10,000 years than over the previous 100,000, and perhaps more than over the previous million. The growing importance of culture did not slow down the pace of genetic change. In fact, culture became the main driving force of genetic evolution by replacing adaptation to a limited number of natural environments with adaptation to an ever-widening range of cultural environments (Cochran and Harpending 2009; Hawks et al. 2007; Rinaldi 2017).

 

Two years ago, I reviewed a study on recent evolution in the Estonian population (Frost 2020; Hõrak and Valge 2015). Among Estonians born between 1937 and 1962, women with only primary education had 0.5 to 0.75 more children than did women with tertiary education. This difference in reproductive success correlated with difference in cranial volume: children with larger crania were more likely to go on to secondary or tertiary education, independently of sex, socioeconomic position, and rural vs urban origin (Valge et al. 2019). Thus, for Estonian women in the late 20th century, higher education decreased fertility, probably by postponing the age of marriage.

 

That finding was found only for women. Perhaps Estonian men with higher education enjoyed greater reproductive success, in which case selection for less intelligent women may have been cancelled out by selection for more intelligent men.

 

The same research team has now published a new study of the same dataset, this time on both sexes. They confirm the original finding that female fertility correlated negatively with education and cranial volume. As for male fertility, although it correlated positively with education, the most fertile males had only average cranial volume. The authors had no explanation for that finding:

 

Stabilizing selection on the cranial volume of boys was an unexpected result, given that cranial volume in our study population predicts educational attainment independently of sex, socioeconomic background, and height. Since educational attainment was a strong predictor of fatherhood in our study, we would have expected positive directional selection on cranial volume. However, we found only evidence for stabilizing selection (Valge et al. 2022)

 

Perhaps women prefer men who are well-educated but not excessively intelligent. As one goes farther and farther away from the mean IQ of a population, higher intelligence becomes more and more often due to genetic “accidents”—unusual genetic variants or combinations of variants that may adversely affect other aspects of mind and behavior. A very intelligent person may seem autistic or have poor social skills.

 

The new study also shows that women had greater reproductive success if they possessed a more masculine body build, narrower hips, and shorter legs. That finding may seem counterintuitive. Don’t men prefer feminine-looking women? They do. However, as the authors show by citing earlier findings, shorter women are also less selective and likelier to marry earlier:

 

Similar reasoning might also explain why selection favored girls with masculine body build, narrow hips, and absolutely and relatively shorter legs in our study. If choosiness in women increases with desirability, this could lead to women with more feminine phenotypes engaging in a more time-consuming mate selection process, delaying their age of first birth, and thereby negatively affecting reproduction. (Valge et al. 2022)

 

Finally, the new Estonian study shows that heavier and stronger boys had more reproductive success.

 

The results relating to height and strength are consistent with studies of sexual selection showing that men who are taller, stronger, and more physically fit are generally perceived as more physically attractive by women, and therefore, have better opportunities for partnering and becoming a father. For instance, in a sample of Polish men born in the 1930s, childless men appeared significantly shorter than those with at least one child. In West Point graduates, the number of children increased linearly with height because taller men had higher probabilities of marrying more than once. Barclay and Kolk showed in a sample of 405,427 Swedish conscripts born between 1965 and 1972 that men in the lowest deciles of height, and in particular, physical fitness in early adulthood, had the lowest probabilities of transition to parenthood. (Valge et al. 2022)

 


Final thoughts

 

This is a study of Estonians who were born more than a half-century ago, long before the breakup of the Soviet Union. Things may be different now. Estonians have rapidly converged on Western social, behavioral, and ideological norms over the past three decades. Although their country is nominally independent, they are now strongly influenced by the inflow of Western culture via the media, and this new media environment is having a decisive impact on how they think and act (Karlin 2018).

 

Estonia is generally following the lead of the West. With respect to education and fertility, the negative correlation has become stronger throughout the West: “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” (Thomson et al. 2014).

 

This differential is increasing not only between families but also within “families.” Second and third children are born increasingly to women who have divorced and are in relationships with low-quality fathers who often seem to be little more than sperm donors. In Norway, multi-partner fatherhood has become most common among men with the lowest level of education (10 years of schooling, "i.e., compulsory education"):

 

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)

 

This trend may partly explain the slowing down and reversal of the Flynn effect, i.e., the steady rise in mean IQ over the 20th century. There is some debate over whether the Flynn effect was a real increase in intelligence or simply an increase in familiarity with doing tests. In any case, its reversal seems real enough.

 

With respect to Norway, Bratsberg and Rogeberg (2018) have shown that the decline in mean IQ can be explained by “within-family variation.” In other words, mean IQ is declining among people who supposedly share the same genetic background, i.e., siblings. In Norway, however, siblings are increasingly half-siblings. Among Norwegian women with only two children, 13.4% have had them by more than one man. The figure rises to 24.9% among those with three children, 36.2% among those with four children, and 41.2% among those with five children (Thomson et al. 2014). 

 

The family unit is decomposing throughout the West. It is becoming little more than an administrative entity that can be repeatedly dissolved and reconstituted (Frost 2018a; Frost 2018b).

 

 

References

 

Bratsberg, B., and O. Rogeberg. (2018). Flynn effect and its reversal are both environmentally caused. Proceedings of the National Academy of Sciences 115 (26) 6674-6678

https://doi.org/10.1073/pnas.1718793115

 

Cochran, G. and H. Harpending. (2009). The 10,000 Year Explosion: How Civilization Accelerated Human Evolution. Basic Books: New York.

 

Frost, P. (2018a). Why is IQ declining in Norway? Evo and Proud, June 19. https://evoandproud.blogspot.com/2018/06/why-is-iq-declining-in-norway.html

 

Frost, P. (2018b). Yes, the decline is genetic. Evo and Proud, June 26. https://evoandproud.blogspot.com/2018/06/yes-decline-is-genetic.html

 

Frost, P. (2020). Declining intelligence in the 20th century: the case of Estonia. Evo and Proud, August 3. https://evoandproud.blogspot.com/2020/08/declining-intelligence-in-20th-century.html

 

Hawks, J., E.T. Wang, G.M. Cochran, H.C. Harpending, and R.K. Moyzis. (2007). Recent acceleration of human adaptive evolution. Proceedings of the National Academy of Sciences (USA) 104: 20753-20758. https://doi.org/10.1073/pnas.0707650104

 

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 (1): 167–178, https://doi.org/10.1093/emph/eov017

 

Karlin, A. (2018). Gay marriage in Estonia. The Unz Review, October 30. https://unz.com/akarlin/estonian-freezer/

 

Lappegård, T., Rønsen, M., and Skrede, K. (2011). Fatherhood and fertility. Fathering 9: 103-120. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.839.2752&rep=rep1&type=pdf

 

Rinaldi, A. (2017). We're on a road to nowhere. Culture and adaptation to the environment are driving human evolution, but the destination of this journey is unpredictable. EMBO reports 18: 2094-2100. https://doi.org/10.15252/embr.201745399

 

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. https://doi.org/10.1007/s13524-013-0273-6 

 

Valge, M., R. Meitern, and P. Hõrak.  (2022). Sexually antagonistic selection on educational attainment and body size in Estonian children. Annals of the New York Academy of Sciences Early view https://doi.org/10.1111/nyas.14859

14 comments:

Truth Seeker said...

This is what happened in the Netherlands. The Dutch, who are the world's tallest people, weren't always this tall. But researchers found that as recently as the 20th century (they looked at 1935-1967), Dutch women strongly preferred taller men and that led to the much greater reproductive success of tall men with average women. A very clear example of recent evolution in action.
https://www.theguardian.com/world/2015/apr/08/scientists-try-to-answer-why-dutch-people-are-so-tall
https://royalsocietypublishing.org/doi/10.1098/rspb.2015.0211

Santocool said...

"Low quality men"

The alphae ideology.

Brave New World is spot on about human nature and differences. The cleverest are not alphas or betas but that rare mutant breed of Bernard Marx'es, the awake ones.

Leave that mass of dumb people procreating like street cats or pretentious civilized ones, they say.

Little off topic

If firstborns really tend to score higher in cognitive tests and people are having smaller families so it can'may explain partially The Flynn Effect?? More firstborns, proportionally, artificial increase of avg high??

Santocool said...

"They have poor social skills"

Being an asshole and football-obsessed are both social skills??

Maybe smarter people are reprodutively adapted to live in smart societies not in our beautiful idiocracies.

Santocool said...

"Improved" amount of food in the dutch diet throught generations may contribute as well, because dutch people already was COMPARATIVELY taller than other european populations, at least, before the second world war. A massive convergence of similar factors happening in many populations at mostly the same time.

Anonymous said...

yes! on the last point santocool is absolutely right: it is the effect of hormone meat/diary food in the last 30 years, which made/makes people taller - in ALL countries of the west (and increasingly the east, too). dutch people are traditionally eaters of cheese and meat - but now their cows are fed up to the ears with hormone/steroids - and so the consumers of this diet, too :)
...
as with regards to estonia/baltic countries: the big blind spot in this study (as in the others cited some time ago) is the specific situation/role these countries played in the soviet union: the smartest men made up their way to higher ranks/better jobs in moscow (or elsewhere in USSR, not staying in provincial estonia. the more beautiful and smarter women married russian men in moscow/leningrad - mating up as always in human evolution :)
on the other hand, the baltic republics had strong soviet (mainly russian) garrisons and where a welcome and aspired place for retired officers. russian soldiers/officers married estonian women, even if they were less attractive - just to be allowed to stay in estonia (which was better on living standatds than the siberia, e.g.)
any study on the matter MUST include the baltic diaspora then in the inmense gene pool of the entire soviet union - and now in EU and USA - where again the smartest men and most beatiful women have emigrated after the downfall of USSR.

Peter Frost said...

Santocool,

The Flynn effect took place during the 20th century at a time when second and third children were usually full siblings. The slowing down and reversal of the Flynn effect since the 1990s may be related to the decomposition of the "full-sibling family model." That's what the Norwegian data indicate.

Anon and Anonymous,

The Estonian study is based on longitudinal data, i.e., the same person provided data at two points in time. There is a risk of survivorship bias, i.e., the study excluded people who provided data the first time but not the second time. Such people, however, would if anything tend to be less smart. This point was made to my by one of the authors:

"Better-educated people are less likely to drop from the population registry than people with basic education. So if anything, our sample is biased towards over-representation of persons with tertiary education, i.e., the smartest and tallest fraction. As we wrote "when compared to the whole ethnically Estonian population born at 1937–1962, children of urban origin and those with higher levels of educational attainment were somewhat overrepresented in Juhan Aul’s dataset (Table S1 in ESM1)."

Keep in mind that life was actually better in Estonia than in Russia during Soviet times. This point was also made to me by the author:

"Higher ranks/better jobs in Moscow or elsewhere in the USSR were not that attractive for most of people. Yes, several really smart persons got their education/degrees from Moscow University (which was quite good for sciences at that time), but most of them returned afterwards, continuing their scientific career in Estonia (conditions were quite good for this at that time too)."

Santocool said...

''Santocool,

The Flynn effect took place during the 20th century at a time when second and third children were usually full siblings. The slowing down and reversal of the Flynn effect since the 1990s may be related to the decomposition of the "full-sibling family model." That's what the Norwegian data indicate.''

But the infant/juvenil mortality rate was also higher 70,80 years ago.

The drop in fertility in the poorest social strata may also have contributed to the flynn effect, assuming it as something real, and still associated with the increase in the proportion of firstborns.

Anonymous said...

Santo you fool dysgenics is real because despite the childlessness of the poorest people the brightest people and the semi-bright people are experiencing even more childlessness!

how is that hard to understand!

Santocool said...

''Santo you fool dysgenics is real because despite the childlessness of the poorest people the brightest people and the semi-bright people are experiencing even more childlessness!''

Where did I say dysgenia is not happening??

Yes, of course, but the most "smart" are not, on average, the richest.

The biggest problem with dysgenia today is not just that the 1% are not having children above the demographic recomposition threshold, but the 15% are not.

It is not just the high cost of living that causes people to have none or only one child, but also the capitalist ideology of consumerism.

Cliche, but true.

In addition, we also have the problem of the common perception that traditional marriage is for many, if not most, a socially imposed lie.

Santocool said...

My hypothesis for the flynn effect would have a partially compensatory repercussion.

Santocool said...

Human culture/technology-coevolution ressemble a virus evolution in which it looses its sheer complexity and becomes simpler due to increase on its host dependence, in the case of yumans, "our" host is not just the natural environment but the artificial environment "we" created. "We" are progressively transferring ourselves from our own organic domain to artificial ones, loosing our own natural complexity and increasing our dependence on our technological tools. At least we may reduce our parasitical dependence on nature as well.

Santocool said...

Maybe not. I read that the differences are minimal.

Pumpkin Person said...

Human evolution didn’t end in the Pleistocene. In fact, there has been more genetic change within our species over the past 10,000 years than over the previous 100,000, and perhaps more than over the previous million

Then why has brain size hardly changed in the last 10,000 years (yes it temporarily decreased because of malnutrition caused by agriculture but no evidence of genetic change) but changed dramatically int the previous million. Morphological change over the last 10,000 years is tiny compared to the previous million.

Pumpkin Person said...

Human evolution didn’t end in the Pleistocene. In fact, there has been more genetic change within our species over the past 10,000 years than over the previous 100,000, and perhaps more than over the previous million

Then why has brain size hardly changed in the last 10,000 years (yes it temporarily decreased because of malnutrition caused by agriculture but no evidence of genetic change) but changed dramatically int the previous million. Morphological change over the last 10,000 years is tiny compared to the previous million.