Monday, March 28, 2022

Cognitive ability of indigenous Arctic peoples


In cold environments, human cognitive ability was an adaptation not to resource scarcity, as is often claimed, but to an abundance of resources that could be exploited only through a high level of planning, coordination, and tool development.

Caribou on Thelon River (Wikicommons – Cameron Hayne)



A reader has asked me, via Twitter: “Do you have any articles as to why the IQ of Siberian and Inuit peoples is lower than Northern Europeans despite similarly cold climate?”


Actually, indigenous Arctic peoples seem to be close to the global maximum of cognitive ability. It is also true, however, that the maximum is at more temperate latitudes, specifically within two broad regions:


·         East Asia – this is a “plateau” of populations with consistently high mean IQ, i.e., Chinese, Koreans, and Japanese. For Unz (2013), this plateau arose during the time of recorded history through the upper classes continually replacing the lower classes: “Each generation, the poorest disappeared, the less affluent failed to replenish their numbers, and all those lower rungs on the economic ladder were filled by the downwardly mobile children of the fecund wealthy.” A secondary cause was the imperial examination for civil-service jobs: "in China the proud family traditions would boast generations of top-scoring test-takers, along with the important government positions that they had received as a result."


·         Europe – this second plateau likewise arose during the time of recorded history, at first slowly during antiquity and then more rapidly during the late medieval to early modern period (Clark 2007; Woodley 2017). The latter increase was driven by expansion of the middle class, particularly by craftspeople who participated in the proto-industrial revolution of the 15th to early 19th centuries. There are thus “peaks” in the plateau, notably Ashkenazi Jews and the descendants of cottage-industry communities in Ulster, Lancashire, Yorkshire, Brittany, Flanders, Alsace, Westphalia, Saxony, the Zurich uplands, the Piedmont, and Lombardy (Cochran et al. 2006; Dunkel et al. 2019; Frost 2007; Piffer 2019; Seccombe 1992, pp. 205-217). Those communities contributed disproportionately to European population growth through early marriage and high childbearing, thus changing Europe’s cognitive landscape (Seccombe 1992, pp. 205-217). 

      The fatalism of serfs gave way to the rationalism of craftspeople: "The life-choices that structure family continuity through time had more predictable consequences; critical objectives could be achieved more regularly. Increasingly, the problem of uncontrolled randomness in life's fortunes was addressed through the calculus of probabilities, rather than through ritual, prayer, pleas for divine intercession, and stoicism ..." (Seccombe 1992, p. 212). 

There is another high-IQ peak among the Finns (Piffer 2019), for reasons that remain uncertain (Late transition from hunting to farming? Absence of serfdom?).


If cold climates select for cognitive ability, why do we find maximum cognitive ability at temperate latitudes? This is the apparent contradiction I address in my 2019 paper. In short, I argue that cold climates selected for cognitive ability only when humans were hunter-gatherers. This selection was driven not by resource scarcity, as is often claimed, but rather by an abundance of resources that could be exploited only through a high level of planning, coordination, and tool development (Frost 2019). With the advent of farming, and increasing social complexity, the pressure of selection shifted southward to environments that imposed new cognitive challenges: literacy and numeracy, state formation, laws and law enforcement, social stratification, expansion of the built environment, growth of music, literature, and the fine arts, development of religious beliefs and practices, construction of roads and other infrastructures, and so on.


This cognitive evolution initially went farther in the Middle East. Then, sometime around the 16th century, that region seemed to hit a ceiling as the pace of social complexification slowed down. The slowdown had several causes. First, there was demographic stagnation and loss of food production, due to the cumulative effects of erosion, salinization, and overgrazing. Second, there were ideological constraints. Although Islam was not alone in seeking to limit the free expression of ideas, it was more effective than Christianity in preventing the rise of a secular intellectual class that could spur progress in science and technology. Third, a true market economy failed to develop in the Middle East. The concept of trade was widely understood, but production of goods and services remained mostly within the household, i.e., family members, servants and, more broadly, relatives and in-laws. As a result, the market could not replace kinship as the main organizing principle of society.


Finally, and perhaps most importantly, cognitive evolution continued in Europe and East Asia because their lower classes were continually replaced, demographically, by their middle and upper classes. This process, described by Gregory Clark for England and Ron Unz for China, has three key elements:


1. Social class correlates positively with IQ.


2. Social class correlates positively with reproductive success. Lower classes fail to reproduce themselves, whereas higher classes more than reproduce themselves.


3. There are no barriers to downward social mobility. Lower classes are thus continually replaced by the demographic overflow of higher classes (Clark 2007; Unz 2013).


These three elements are not universal. Hunter-gatherers and simple farming societies have little or no social stratification. Other societies are stratified but have no State that can monopolize the use of violence. There is instead an ongoing free-for-all that selects for ruthlessness, charisma, and the ability to mobilize male violence. Finally, some societies are so stratified that downward mobility is impossible. Social classes are permanent “castes.”


In sum, cognitive evolution was initially driven by cold climate at higher latitudes and later by increasing social complexity at lower latitudes. Some higher-latitude groups then moved south to exploit the opportunities being created by increased social complexity. Those groups were not the ones who initiated the transition to farming, sedentism, and social complexity. Instead, they arrived after the fact, being cognitively pre-adapted for the opportunities that others had created and thus better able to pursue this evolutionary trajectory (Frost 2019).


Studies of cognitive ability in Arctic peoples


To return to the original question, indigenous Arctic peoples seem to be close to the global maximum of cognitive ability, but the evidence is limited and questionable. This situation has three causes:


·         Difficulties in administering IQ tests to people who are unfamiliar not only with modern concepts but also with the modern question-and-answer paradigm. Traditionally, indigenous Arctic people learn not by asking questions but by observing a “master” and then copying whatever he or she does. Asking questions can also be impolite, especially if too many are asked in rapid succession. I should point out that the same difficulties used to exist in Western societies. People in Britain and North America were unfamiliar with standardized written tests until the rise of publicly funded schools and competitive civil-service exams in the late 19th century (Wikipedia 2022). It wasn’t because people got smarter that mean IQ rose during the 20th century. They just got better at taking tests.


·         Ideological constraints. IQ research was discouraged in the Soviet Union, partly because of the dominant belief in environmental determinism and partly because of a desire to avoid stigmatizing certain national groups. A ban on intelligence testing was thus imposed in 1936 and gradually lifted only in the 1960s and early 1970s (Grigoriev and Lynn 2009).


·         Lack of research on alleles associated with educational attainment. This avenue of research offers a better measure of innate cognitive ability but is still in its infancy with respect to Arctic peoples. I know of only one relevant study. Piffer (2013) found that the Met allele at COMT, a gene linked to executive function, working memory, and intelligence, is more frequent in farming societies than in hunter-gatherers, with one interesting exception: "hunter-gatherers living at high latitudes (Inuit) show high frequencies of the Met allele, possibly due to the higher pressure on technological skills and planning abilities posed by the adverse climatic conditions near the North Pole."



Siberia (Evenk, Altai, Yakuts)


In Siberia, IQ tests were conducted in 1929 and later in 2015-17. The first period saw testing among the Evenk of the northeast and the Altai of the south.


When a Binet test was administered to 5 Evenk children 7 to 19 years old, the mean score was 70.16. The study’s author reported that the children had trouble understanding units of measurement and number.


He reported that when Evenk children were questioned about devices for measurement, they did not have the concept of an absolute unit of measurement. They thought that the unit changed with the material measured. Bulanow [the author] reported further that when he asked Evenk adults how many children they had “It was difficult, almost impossible, to get from parents precise information as to how many of their children were alive, how many of their children had died, what was the age of their children, and so on.” (Grigoriev and Lynn 2009, p. 449)


When a Binet test was administered to 52 Altai children 8 to 20 years old, the mean score was 66.9. Again, the subjects had problems with units of measurement: “when they were questioned about the length of a meter, the Altai would often ask: “Which meter?” They thought that the meter in one shop could be longer than in another” (Grigoriev and Lynn 2009, p. 450). Nonetheless, adult Altai showed remarkable aptitudes in other areas of life:


Although adult Altai performed calculations poorly at the time of study, they showed a remarkable ability for visual estimation of large quantities. A herdsman, who could count only to 20–30, noticed very well the absence of one horse, cow or sheep in a herd of many hundreds. He looked at a huge herd and noted that a particular cow was absent. Another example of the great visualization ability of the Altai was that they could remember and showed the way through wild territory, where they had been only once many years previously (Grigoriev and Lynn 2009, p. 450)


In recent years, there has been a renewed effort to study cognitive ability among indigenous Siberian peoples:


·         Shibaev and Lynn (2015) tested 29 Evenk children and found a mean score of 80. Also tested were 13 ethnic Russian children, who had grown up under similar conditions. Their mean score was 85.

·         Shibaev and Lynn (2017) tested 287 Yakut children and 52 ethnic Russian children from eastern Siberia. The mean score was 97.0 for the Yakuts and 97.9 for the ethnic Russians.

·         Shibaev et al. (2020) tested 518 Yakut children and 956 ethnic Russian children. The age range was wider than in previous studies, and the IQ difference between the two groups seemed, in general, to be greater at younger ages than at older ones. At 9 years of age the Russians had a 3 point advantage over the Yakuts, whereas at 17 this advantage was zero. Yakut children may have a slower rate of cognitive maturation. There is also some doubt as to the comparability of the two groups, since the Russians came largely from a city (Tomsk), while the Yakuts came from a city (Yakutsk) and a small town (Vilyuysk).


The authors note that the differences between ethnic Russians and indigenous Siberians can be largely explained by an urban-rural divide:


[…] for both Russians and Yakuts the IQs of the city samples were higher than the IQs of the village samples. For the Russians, there was a difference of 10.5 IQ points between the combined city samples and the village sample, while for the Yakuts the difference was 4.4 points. The higher IQs of the city samples is a common result found in many previous studies reporting that urban populations typically obtain higher IQs than rural populations. (Shibaev and Lynn 2017)


Shibaev and Lynn (2017) attribute this urban-rural divide to differential migration: smarter people move to the city, and dumber people stay home in the village. I would argue that villagers are less familiar with modern concepts and the modern question-and-answer paradigm.


Arctic North America (Inuit)


Like indigenous Siberians, the Inuit (Eskimos) display an unusual ability to find their way across vast expanses of territory, a task that requires remembering huge amounts of visuospatial data. Adults are reported to have an "extraordinary ability to find their way through what appears to be a featureless terrain by remembering visual configurations [...]. According to some reports, such memories persist for long periods of time. Elderly hunters have succeeded in guiding parties through terrain seen only in their youth" (Kleinfeld 1973, p. 344)


Nonetheless, Inuit have done poorly in most IQ studies, especially in older studies of traditional Inuit. Kleinfeld (1973) cites several reasons:


Unfamiliarity with test-taking:

Eskimos' performance on standardized tests may be lowered because of their unfamiliarity with test-taking conventions and because of cultural biases of the tests. Eskimos, for example, may find it difficult to view a trivial, pointless task such as copying a design or running through a finger maze as worthy of serious concentration and maximum effort.


Racial context of test-taking

Eskimos, especially young males, have become increasingly antagonistic to any sort of testing and research, which they view as another form of White exploitation. Co-operation, if given at all, may be perfunctory, resulting in extremely low test scores.


Extreme caution during test-taking

Eskimos, especially males, have been socialized into extreme caution before making a judgment. The hunter is taught never to take risks, never to call out a hasty evaluation because the penalty can be swift death not only for himself but also for others who rely on his decision. […] Especially more traditional Eskimos tend to have a slow, cautious response style which may depress their scores on speeded figural tests.


Slower rate of cognitive maturation

[There is] some evidence that Eskimos' peak performance on figural tests occurs later than that of Western groups. [This] raises the possibility of a slower rate of cognitive maturation among Eskimos which would be consistent with their somewhat slower rate of physical maturation […]. If this is the case, the usual age-matched comparisons between Western and Eskimo children on figural tests may be misleading.


In their reviews of the literature, Kleinfeld (1973) and Taylor and Skanes (1976) note that Inuit generally outperform Whites on visual discrimination and spatial tests. Interestingly, Inuit children do almost as well as non-Inuit children on English spelling tests while doing poorly in other aspects of English, perhaps because they memorize the shapes of words. On the other hand, they underperform White children on verbal-educational and inductive reasoning tests. The latter finding may reflect lack of familiarity with English in earlier studies. When Taylor and Skanes (1976a) tested Inuit and White first graders for vocabulary and arithmetic, using the Wechsler Pre-School and Primary Scale of Intelligence, they found no significant differences between the two groups in spatial, verbal-educational, and inductive reasoning abilities. When the same researchers tested a larger sample of Inuit and White children from different age groups, using a series of digit span tests and Raven’s progressive matrices, they found that the Inuit children caught up with the White children with increasing age on the digit span tests and that the Inuit children outperformed the White children on the Raven’s progressive matrices (Taylor and Skanes 1976b).


Wright et al. (1996) tested the IQ of Inuit children in Arctic Quebec during the first two grades of school, using Coloured Progressive Matrices (CPM). Mean scores were consistently higher than age-appropriate U.S. norms and were comparable with data for White children in southern Quebec. In addition, the scores of children with two Inuit parents did not differ significantly from those of children with mixed Inuit/White heritage. 


Nonetheless, Inuit children do worse at school than other children, having not only lower rates of academic achievement but also higher dropout and suicide rates. For Clifton and Roberts (1988), the reason is inferior self-perception of their ability and less active involvement in the educational process. This mindset may be rooted in the traditional Inuit attitude toward education, where the “student” simply observes and copies the “master.”


In sum, the Inuit seem to have about the same level of cognitive ability as people of European origin, with perhaps some interesting differences: superior visuospatial skills, higher risk aversion, slower cognitive maturation, and a more imitative and less inquisitive approach to learning. It is still unclear whether they have lower verbal-educational and inductive reasoning abilities. In their review, McShane and Berry (1988, p. 392) conclude that indigenous Arctic peoples do well relative to Euroamerican norms, showing “high performance on both piagetian and psychometric tests of visually based spatial, analytic, disembedding, and inductive abilities.” The two researchers attribute reports of lower verbal ability to second-language familiarity with the test language. Clearly, more research is needed, if only to adapt the northern educational system to Inuit needs.


It must be said that the Inuit are ill-suited to the Western model of education and, more broadly, to the Western model of sedentism, individualism, and asociality. Young Inuit feel useless in that kind of society, and all too many end up committing suicide.


Conclusion and discussion


We have only a few studies of cognitive ability among indigenous Arctic peoples. This paucity is due only in part to methodological problems. In the Soviet Union, all IQ research ceased between 1936 and the 1960s. It has recommenced among indigenous Arctic peoples only over the past decade. Meanwhile, similar research in Canada and the U.S. has been nonexistent since the 1990s.


If we look at the existing research, we may doubt whether the subjects were fully familiar with test-taking and the modern question-and-answer paradigm. Another problem is that indigenous Arctic children seem to have a slower rate of cognitive maturation. If Yakut subjects are still catching up to Russian subjects at the age of 17, it might be more appropriate to compare the two groups at an older age. In practice, this would be difficult because young adults start following different life paths after 17. Finally, indigenous Arctic peoples may allocate their mental capacities differently, being better, for instance, at processing visuospatial data than other kinds of information. Since IQ tests have been designed for Western children, the test design may not correspond to the mental tasks that some non-Western groups prioritize.


Yes, dear reader, I hear you. If people do well on one cognitive task, they should do well on all others, shouldn’t they? Isn’t that what the g factor is all about? In other words, people will tap into the same mental capacity for any cognitive task.


The relative strength of the g factor, however, has been calculated from subjects in Western or Westernized societies. Does it have the same strength across different mental domains among people who until recently were nomadic hunters? Anthropologists, like John Berry, have argued that hunters allocate much more of their mental capacity to visuospatial orientation:


Hunters, by this way of thinking, require good visual acuity, keen disembedding skills and a well-developed sense of spatial orientation. To hunt successfully, the hunter must be able to discern the object of the quest (which is often embedded in a complex visual landscape), then disembed the object, and finally return to home base. In contrast, agriculturalists need not develop these particular skills, but rather they need to invest in other areas of development, such as conservation (in both the economic and the Piagetian senses) and close social interactions. (Berry 2008, p. 3)


It would be interesting to find out whether these skills have become hardwired to some degree through gene-culture coevolution. Are hunting peoples inherently better at orienting themselves in space? Did vast expanses of land favor the success of people who could more easily find their way across vast expanses of land? To answer that question, John Berry launched a project in the late 1980s with the geneticist L.L. Cavalli-Sforza. They wished to recruit participants among the Inuit of northern Canada and use aptitude for soapstone carving as a means to measure visuospatial skills:


With most individuals having had a reasonably fair chance and stimulation to become artists, one is in a better condition to study possible genetic factors contributing to artistic talent, if any. Another great advantage of carrying out this study among the Inuit is the frequency with which adoptions (also early ones, at birth) occur in this population. Frequencies of adoptions reported during the meeting varied from 15% to 30%. Adoptions allow one to distinguish cultural from biological inheritance by studying correlations of adopted children with foster relatives on one hand and biological relatives on the other. (Berry and Cavalli-Sforza 1986)


Cavalli-Sforza was thinking, here, along the lines of gene-culture coevolution. He had in fact been one of the founders of that paradigm, although he preferred the term “dual inheritance theory.” Now, he would have a chance to investigate it in the field.


Then, suddenly, he backed out of the project. For “health reasons.” Yet neither his biography nor his autobiography mentions any health problems during that period of his life.





Berry, J.W. (2008). Models of Ecocultural Adaptation and Cultural Transmission: The Example of Inuit Art, paper presented at the conference Adaptation et socialisation des minoritiés culturelles en région, June 3-4, Quebec City.


Berry, J.W., and L.L. Cavalli-Sforza. (1986). Cultural and Genetic Influences on Inuit Art. Report to the Social Sciences and Humanities Research Council of Canada, Ottawa.


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


Clifton, R.A. and L.W. Roberts. (1988). Social psychological dispositions and academic achievement of Inuit and non-Inuit students. Alberta Journal of Educational Research 34(4): 332–343.


Cochran, G., J. Hardy, and H. Harpending. (2006). Natural history of Ashkenazi intelligence. Journal of Biosocial Science 38(5): 659–693.


Dunkel, C.S., M.A. Woodley of Menie, J. Pallesen, and E.O.W. Kirkegaard.  (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.


Frost, P. (2007). Natural selection in proto-industrial Europe. Evo and Proud, November 16  


Frost, P. (2019). The Original Industrial Revolution. Did Cold Winters Select for Cognitive Ability? Psych 1(1): 166-18.  


Grigoriev, A, and R. Lynn. (2009). Studies of socioeconomic and ethnic differences in intelligence in the former Soviet Union in the early twentieth century. Intelligence 37: 447-452,  


Kleinfeld, J.S. (1973). Intellectual Strengths in Culturally Different Groups: An Eskimo Illustration. Review of Educational Research 43(3): 341-359.  


McShane, D., and J.W. Berry. (1988). “Native North Americans: Indian and Inuit Abilities.” In: S.H. Irvine and J.W. Berry (eds.) Human Abilities in Cultural Context (pp. 385-426), Cambridge: Cambridge University Press.


Piffer, D. (2013). Correlation of the COMT Val158Met polymorphism with latitude and a hunter-gather lifestyle suggests culture-gene coevolution and selective pressure on cognition genes due to climate. Anthropological Science 121(3): 161-171.  


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.    


Seccombe, W. (1992). A Millennium of Family Change. Feudalism to Capitalism in Northwestern Europe. London: Verso.


Shibaev, V., A. Grigoriev, E. Valueva, and A. Karlin. (2020). Differential Item Functioning on Raven’s SPM+ Amongst Two Convenience Samples of Yakuts and Russians. Psych 2(1):44-51.


Shibaev, V. and R. Lynn. (2015). The Intelligence of the Evenk/Tungus of the Russian Far East. Mankind Quarterly 56(2): 202-207.  


Shibaev, V. and R. Lynn. (2017). The Intelligence of Yakuts and Ethnic Russians in Yakutia. Mankind Quarterly 57(4): 680-686.  


Taylor, L.J., and G.R. Skanes. (1976a). Cognitive abilities in Inuit and White children from similar environments. Canadian Journal of Behavioural Science 8(1): 1-8.  


Taylor, L.J., and G.R. Skanes. (1976b). Level I and level II intelligence in Inuit and White children from Similar Environments. Journal of Cross-Cultural Psychology 7(2): 157-168.


Unz, R. (2013). How Social Darwinism made modern China, The American Conservative, March/April, 16-27.  


Wikipedia (2022). Test (assessment).  


Woodley, M.A., S. Younuskunju, B. Balan, and D. Piffer. (2017). Holocene selection for variants associated with general cognitive ability: comparing ancient and modern genomes. Twin Research and Human Genetics 20: 271-280.   


Wright, S.C., D.M. Taylor, and K.M. Ruggiero. (1996). Examining the Potential for Academic Achievement among Inuit Children: Comparisons on the Raven Coloured Progressive Matrices. Journal of Cross-Cultural Psychology 27(6): 733-753.  


Santocool said...

I am particularly interested in how cognitive ability varies in these populations. My guess is that it is much lower than in a ''civilized'' society.

Santocool said...

''This cognitive evolution initially went farther in the Middle East. Then, sometime around the 16th century, that region seemed to hit a ceiling as the pace of social complexification slowed down. The slowdown had several causes. First, there was demographic stagnation and loss of food production, due to the cumulative effects of erosion, salinization, and overgrazing. Second, there were ideological constraints. Although Islam was not alone in seeking to limit the free expression of ideas, it was more effective than Christianity in preventing the rise of a secular intellectual class that could spur progress in science and technology. Third, a true market economy failed to develop in the Middle East. The concept of trade was widely understood, but production of goods and services remained mostly within the household, i.e., family members, servants and, more broadly, relatives and in-laws. As a result, the market could not replace kinship as the main organizing principle of society.''

Considered continuing racial mixing in the region as a factor.

Reading his texts, I remember when history was only an explanatory and not a critical discipline...

Santocool said...

''It must be said that the Inuit are ill-suited to the Western model of education and, more broadly, to the Western model of sedentism, individualism, and asociality. Young Inuit feel useless in that kind of society, and all too many end up committing suicide.''


Peter Frost said...


Innate cognitive ability probably varies less, since these societies are not segmented by social class into smaller populations. They're also smaller, so it would be difficult to form endogamous subgroups.

I touched on your second point (sort of). If slaves are continually imported into a society, the upper and middle classes cannot demographically replace the lower class. Instead of being replenished by the demographic surplus of the higher classes, the lower class is demographically replenished from external sources.

Racism is not mentioned by suicidal Inuit as a reason for suicide. The most common reason is a feeling of uselessness that begins at school and continues after school. Young people, especially boys, are immersed in a virtual world (TV, "educational" materials) that seems totally foreign and offers no real role models.

Michel Rouzic said...

Very interesting. I always thought that it was a shame that so much of the current discussion about human intelligence suffers from tunnel vision, all about IQ/g factor, who's smarter than whom, as if intelligence was one simple thing that people have in different quantities, a misconception that both staunch racists (who want to believe that some peoples are simply cognitively superior to others in every way) and anti-racists (who insist that all peoples have the exact same cognitive potential in their DNA) refuse to abandon. It's much more interesting to identify the stark differences in cognitive traits and aptitudes, as this article does. Human cognition is an ensemble of a myriad of different parts working together and it's rather misguided to stubbornly try to reduce it to one number when it tells us so little of value.

It's also crucial for understanding how to deal with non-European populations, mostly when it comes to education and employment. If we (wrongly) assume that all peoples have the same kind of intelligence but in different quantities, then we'll insist on using the same approaches for all peoples. But as this article makes clear, our ways of thinking and learning are far from universal, and imposing a style of education that only works well for us puts other peoples at an unnatural disadvantage due to our domination over them. Just as the Australian government wastes time, money and goodwill on building European-style houses for aboriginals who prefer to sleep under the stars, so do we waste time trying to teach calculus to people for whom abstract mathematics are innately incomprehensible. And in the case of the Inuit the issue of the inadequacy of the way we educate them is compounded by the formerly (presumably) evolutionarily advantageous tendency for suicide ideation from feeling useless.

Anonymous said...

I was just thinking that those who passed the imperial exam were very few, but their families could benefit from a son passing it. If a person's relatives share more genes for intelligence, this would be eugenic fertility.