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naraburns  nihil supernum  1yr ago (text post)   5896 thread views

Small-Scale Question Sunday for January 22, 2023

Do you have a dumb question that you're kind of embarrassed to ask in the main thread? Is there something you're just not sure about?

This is your opportunity to ask questions. No question too simple or too silly.

Culture war topics are accepted, and proposals for a better intro post are appreciated.

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Does anyone know of a good overview of the Race and IQ debate for someone who's completely ducked the topic until now and is basically ignorant?

EDIT: Thanks for the responses everyone!

The facts that need to be explained is a 2012 blog post compiling some of the arguments in favor of gap being at least partially genetic. Of course it is now outdated, I don't follow the subject closely but I know that for instance there are now better admixture studies like this one. But some of the arguments gave me a better sense of why so many researchers in the field consider genetic causes the most parsimonious explanation.

I'm arguably biased but I think debate overviews are unrealistic. This debate is too vast. At this point, collected rebuttals and pointed papers are the best way to appreciate the state of discourse, as if seeing ocean in a drop of water. So, on top of what you've been already given, a few high-profile samples:

Some anti-HBD:

And some responses:

Collections:

Additionally:

Now that I think about it, not much has changed since 1988 and The IQ Controversy, the Media and Public Policy. Well, we've got confirmations of genetic differences, and there's more censorship, and most of the big guys in the debate died. The scientific question received a political answer.

Europeans and recent cognitive evolution + references

I am unconvinced this should be a source. It seems to need more evidence for it's claims.

Until the eleventh century, mean IQ was relatively low throughout Europe, perhaps hovering in the low 90s.

this is a seemingly baseless claim without use of the Flynn effect. And if it is using the Flynn effect it is using it to undermine the authors own argument as he is saying that people in eleventh century western countries had higher IQ's than the 20th century? I would like to know how this number came to be the low 90's as I haven't yet found it in the sources for the article, nor does it seem to be directly sourced. According to the authors own first source (Oesterdiekhoff 2012) used in the authors next paragraph, "In 1900, no pre-modern or early modern population had a mean IQ above 75," (Oesterdiekhoff 2012, Section 2).

Anyway the authors main idea seems to be that the farmers that took roles as artisans, craftsmen, business men etcetera were higher IQ and would have higher fertility rates and thus their higher IQ offspring would have higher IQ's. There kids would be more numerus and thus outbreed all the poor lower IQ people, a neat and tidy theory.

If this was accurate, why would northern Europe have such high IQ's, people who had been near barbarians for several millennia while say Egyptian artisans were being selected for IQ? I would like to know why he only chooses eleventh century Europe as the starting point, as opposed to any other economy in any other region. Did these jobs not exist in the middle east?

That evolution was driven by the high fertility of those people who knew how to exploit the opportunities of an expanding market economy. Their population growth was so great that they overwhelmed the niches available to them. Many had to find niches farther down the social ladder, with the eventual result that their lineages became predominant even within the lower class (Clark 2009a).

The author begins speaking about the eleventh century but cites Clark to make his argument, who only covers between 1600 to 1850 England and makes no mention of IQ but does mention genes. I think using genes is a dubious reason to explain why in a class based society, the rich upper class were able to be better off or more numerous in future generations then the poor generations. While Clarks claim that rich surnames disappeared at a lower rate than poorer surnames, I think it is important to actually add some numbers to that. From 1600 to 1850, the Poorest had 15% of names extinct, the richest had 8% of names extinct. An interesting read, though I do not like that the author does not address other reasons for poorer people not keeping their last names at the same rich people, however I will not get into that here. Clark does make some good argument that England had more social mobility than given credit for but hurts his argument elsewhere and I don't want this to turn into a review of Clark, just the article.

the very next quote is that of (Seccombe 1992, p. 182). The quote is rather unimportant however the source is as it's review seemingly conflicts with the above Clark quote.

The complex text ranges broadly over a vast stretch of historical change from the Middle Ages to the brink of the Industrial Revolution

When speaking about the transition from feudalism to capitalism

Finally, a vital revolution in family size took place, in which the poor came to have larger families than the rich, and in which patterns of intergenerational mobility reversed

so since the industrial revolution ~1750-1840 IQs have been going down? 1600 to 1750 they go up, 1750 to 2000 they go down? So is the message of the article that we are equivalent to our 1600's selves? I get this is a book synopsis so I don't want to be too harsh as perhaps something is missing, but this seems like picking and choosing when to believe an authors claims and forgetting when they would contradict one another.

This is all pretty fair. I've included it on a whim but looking again it's weak, despite citing interesting literature. Retracted, thanks.

We don't have a solid way to talk about anything like Flynn effect in pre-modernity and pre-testing periods; and how 1900's Europeans would've scored on modern tests is not interesting. Personally I'm on the fence regarding the timeline of the current ranking emerging: there probably has «never» been parity between Europeans and Sub-Saharan Africans, but it is plausible that Europeans have been gaining in their advantage in historical time, and so this gap is not explained solely by cold winters or some other factor present for many millenia. On the other hand, cold winters theory seems to explain the pattern of the center of civilization moving up latitudes historically: it's as if building a complex society in the South is playing on easy mode, but then the society hits a limit, and novel technologies flow northward, enabling another round. Today, the most advanced nations in the East and West are indeed populated by people who have passed through the cold winter filter.

My reason for including it was: Breeder's equation, IQ heritability and net fertility differentials allow for meaningful (~0,5 SD) eugenic and dysgenic shifts on the scale of a few centuries, so arguments along the lines of "there wasn't enough time for X" are invalid. It's all speculative until we get good decent IQ PGS for different populations and test that ancient DNA, but I think it's likely that many civilizations have gone through a eugenic phase and subsequent dysgenic collapse, and as you say, Egyptian artisans may have been selected for IQ just like Europeans. This is bog standard cyclical history theory.

I think using genes is a dubious reason to explain why in a class based society, the rich upper class were able to be better off or more numerous in future generations then the poor generations.

Clark, in his oeuvre, demonstrates fertility more directly than by rates of family names going extinct, and his evidence from modern era Japan, China etc. does corroborate that upper classes have innate quality separate from class advantage.

If true this probably imply that concerned ethnic minorities are more likely to responds more potently to nootropics such as e.g. cholinergics. A result I have not yet found through serendipity search, IMO I can't even answer wether women benefit more from nootropics (except for testosterone) but at least it is vastly known people with lower IQ in general, (even more so if specific condition such as fragile X syndrome) and non-young people are much higher responders.

Very interesting list. But isn't it depressing if not much has changed? Shouldn't GWAS studies shown something which can't be handwaved away?

If there's something in the academic debate that can't be handwaved away, that's probably termination of your tenure. I recommend reading this and this.

I apologize for misleading phrasing. People seem to be under the impression that there is some ongoing «debate». No, the debate had been decisively won by the HBD side decades ago, on account of the opposition failing to propose any more parsimonious explanation, even one model of environmental effect that'd be up to snuff and robust to social changes or controls (that wouldn't inherently reduce the genetic component wherever it is present). The best they can do is nitpick here and there and laughably misinterpret some facts, including new facts (my favorite recent example). Admixture studies, GWAS – very cool, but for purposes of the race-IQ controversy, all these fancy new data merely confirm what was known in the 60s.

The political contest has gone the opposite way, however. Now there's an escalating mop-up and gaslighting operation. Scientists know more than ever, but do not care to integrate their knowledge into anything more than affirmation of the prestigious consensus, whereas commoners know less than their grandfathers, and care less about knowing, and flaunt their ignorance and stupidity. In the process of this mental liberation, we are dismantling the vestiges of Enlightenment ideology. Children born today will learn from show trials and grow up to inherit the world where appealing to "facts" or "fairness" or some objective "truth" will be considered inherently cringe, and only the self-affirming tyranny is a legitimate source of knowledge, for it is Based. If you think I'm exaggerating or sound like a crank, you're free to wait and see this hypothesis tested.

People who are see-no-evil-pilled typically need a quick introduction of why anyone would even think races might have varied intelligence. A quick (outdated by now) copypasta that used to get posted:

The average African-American IQ is 85, compared to the average White IQ of 100. (popocateptl note: one more recent large study in the 00s puts it at 90, but this was contested by another study that showed no change. As far as I know, no large scales studies on this have been done since.)

http://www.udel.edu/educ/gottfredson/reprints/1997mainstream.pdf

Human intelligence is highly heritable.

http://www.nature.com/mp/journal/v16/n10/abs/mp201185a.html

Scientific consensus is that IQ tests are not racially biased.

http://www.sciencedirect.com/science/article/pii/S0160289608000305

Very poor Whites are comparably intelligent to very wealthy blacks.

http://www.jbhe.com/features/49_college_admissions-test.html

Privately, intelligence experts hold more hereditarian views than they express in public. (popocateptl note: An anonymous survey from the mid 10s, which I'll see if I can find, polled experts and had on average them privately thinking about 50% of the achievement gap is genetic.)

http://www.udel.edu/educ/gottfredson/reprints/1994egalitarianfiction.pdf

Black children raised in White households have similar IQs to black children in black households.

http://psycnet.apa.org/psycinfo/1977-07996-001

The average African IQ is estimated at 79.

http://www.sciencedirect.com/science/article/pii/S0191886912003741

The white-black gap in SAT scores, a proxy for IQ, is increasing. (popocateptl note: the gap is actually narrowing now, but slowly.)

http://www.jbhe.com/features/49_college_admissions-test.html

Genes for large brains, linked to high IQ, are common everywhere except Africa.

http://www.wsj.com/articles/SB115040765329081636

Intelligence has a 40-50% genetic basis.

http://articles.latimes.com/2011/aug/10/news/la-heb-genetic-study-intelligence-20110809

IQ scores are the best predictor of success in Western society.

http://psychology.uwo.ca/faculty/rushtonpdfs/PPPL1.pdf

IQ is 75% heritable among Whites.

http://psychology.uwo.ca/faculty/rushtonpdfs/PPPL1.pdf

And now for refutations. The most common response to the above syllogism is that whites in America have a shared environment. As such, things like twin studies and adoption studies which purport to show IQ as genetic, actually only show that a smart white child adopted by dumb white parents still benefits from a community and culture that cultivates their intelligence. (Systemic Racism).

For the most interesting refutation of a black-white intelligence gap, read the series of articles Chisala Chanda wrote for the Unz Review. A large part of his argument is that modern transplant populations from Africa to the UK and USA, as opposed to the descendants of slaves, do not show an achievement gap with the native populations.

EDIT: I should clarify that I'm not versed in the latest state of the art in this debate -- I made my conclusions about ten years ago now and don't find the topic that interesting, except as an example of ideological constraints causing otherwise rational societies to act in incredibly stupid ways.

There's an old meme that the best way to get help for Linux is not to ask for help on X, but to publish an overly-confident flawed diatribe about how Linux sucks because it can't do X. I suspect Race IQ debates work the same way.

An anonymous survey from the mid 10s, which I'll see if I can find, polled experts and had on average them privately thinking about 50% of the achievement gap is genetic.

You are thinking of the Rindermann survey from 2014, which was the basis for these publications:

Survey of expert opinion on intelligence: Intelligence research, experts' background, controversial issues, and the media

Survey of Expert Opinion on Intelligence: Causes of International Differences in Cognitive Ability Tests

Prior to that there was the Snyderman survey from 1984:

Survey of Expert Opinion on Intelligence and Aptitude Testing

Thanks! You've found it.

For the most interesting refutation of a black-white intelligence gap, read the series of articles Chisala Chanda wrote for the Unz Review. A large part of his argument is that modern transplant populations from Africa to the UK and USA, as opposed to the descendants of slaves, do not show an achievement gap with the native populations.

The most obvious refutation of that refutation would be that those populations are highly selected for intelligence. I am sure if someone like me who knows next to nothing about the topic can thing of this caveat, Chanda can think of it too. Does he address it?

Yes, he (why did I think Chisala Chanda was a woman?) does. @popocatepetl elaborates further in a sibling comment.

To tldr Chanda's hypothesis: non-African people (especially Europeans and Asians) have a more restricted (canalized) phenotype, as do women. American Blacks are stupider than African Blacks because they have genetic admixture from low-class Whites. The genes that make Seamus a bit stupid and aggressive make Tyrone very stupid and very aggressive, while Shaneequa won't be affected as much, but her sons will.

There are some studies I can think of that should be able to support or weaken this claim, like:

  • middle-class children of ADOS fathers and White mothers should be smarter and less aggressive than middle-class children of White fathers and ADOS mothers

middle-class children of ADOS fathers and White mothers should be smarter and less aggressive than middle-class children of White fathers and ADOS mothers

I don't see how that follows. Shouldn't our prima facie assumption be that the genetic information that contributes to [aggression and stupidity] is passed on patrilineally as well as matrilineally?

Since females are more canalized and we assume that ADOS genomes are saddled with Borderer alleles, an ADOS male of with a substantial IQ is more likely to have fewer of these alleles than an ADOS female with a similar IQ, since her phenotype is more restricted.

Since we are not restricting the selection to specific low-class groups, a White male and a White female with an equally substantial IQ are much less likely to bear a significant load of the alleles we're trying to avoid, so they should be coming from the ADOS parent if they appear in their offspring.

than an ADOS female with a similar IQ

Why are we comparing similar IQs? If the axiom you mention were true, we would expect to see lower IQ in ADOS men on the left tail of the distribution than in ADOS women on the left tail of the distribution, beyond what would be expected from the Greater Male Variability hypothesis. Is this the case?

Because I'm using different sexes having the same IQ as a proxy for having different genetic load: IQ 100 ADOS men probably have "cleaner" genes than IQ 100 ADOS women. If the children of ADOS women slip further left on the tail, then it's probably true. If the children inherit the same IQ, then it's probably false.

Ah, gotcha. Thanks.

It seems like the obvious issue with that is that African Americans mostly have white admixture that comes from the upper classes(mostly the sons of plantation owners), not the lower classes.

The plantation owners in question were presumably violent rapists, which is how much of the admixture happened in the first place.

Having a mistress literally owned by a close relative looks distinctly non consensual today, but that doesn’t mean that’s how it would have been understood as taboo in societies which accepted owning slaves, at least not in a way which was legibly close to rape.

My understanding is that there was a lot of straight-up rape, i.e., the man physically forcing himself on the woman, who of course couldn't resist because of her status. But admittedly I have no idea how much of the admixture is due to violent rape, how much was "borderline" as you described, and how much was consensual.

The best documented example of miscegenation in the antebellum south was plaçage, which featured very little violent rape but lots of elite males, but 1) slavery in French Louisiana was different and 2) that’s just the best documented example, presumably slave owners who raped their slaves didn’t write it down. So it’s up in the air how much white admixture was due to outright coercion and how much of it was the predictable result of high status males and low status females.

It’s also complicated by the fact that very few writers about slavery in the antebellum south were neutral on the practice- they were either abolitionists who generally picked the worst examples to write about, or apologists who were almost certainly lying.

(why did I think Chisala Chanda was a woman?)

Probably because the suffix -a marks something as feminine in romance languages, and, stop me if I'm wrong, russian.

The most obvious refutation of that refutation would be that those populations are highly selected for intelligence. I am sure if someone like me who knows next to nothing about the topic can thing of this caveat, Chanda can think of it too. Does he address it?

I thought the same thing. Half-way through the series, I recall Chisala citing a black refugee population that settled in California (rather than skllled educated immigrants) where their children achieved average results in school. My assumption is that this example was cherry picked from many hundreds of refugee communities that did poorly, but there it is.

Where in California? East LA or the Central Valley, or someplace where average results aren’t ‘shows up about half the time and can spell own name, with assistance’?

Sorry, it was Seattle rather than California. He was writing about refugees from the Horn of Africa (ethiopians, somalians, oromo), whose children performed above the domestic black average test scores depite not speaking English at home. The results weren't collected for intelligence research but as part of the city government's report on refugee education. Here is the exact part

So, how does one of the lowest IQ scoring groups in Africa, emigrating with the lowest evidence of any selection whatsoever (economically or academically), have their children score above black Americans in one of the highest scoring states for native black Americans, (some) even outscoring Hispanics who are assimilated, before they are even assimilated themselves? How do even the Somalian refugees brought in from a total failed state catastrophe outscore black Americans as soon as they just learn to read some English?

It can certainly not be explained by any of the recent HBD answers, individually or in combination

Thank you! I am very happy to finally see someone earnestly attempting to refute HBD arguments. For completeness' sake, here is an archive of the blog post, the source article and the presentation Chisala got his numbers from.

I remain unconvinced. There is no indication that the Somali sample is in any way representative of the source population. Here is Chisala's argument:

Their performance above American blacks (labeled as “English-speaking” blacks) defies the common sociologist explanation that higher achieving black immigrants are simply the most driven members of their source populations (some were just in refugee camps), and it equally defies the modern hereditarian argument that they are just the most self-selected in intelligence relative to their source populations, unless we now start extending this cognitive self-selectivity and “assortative mating” quality to people who run to United Nations refugee camps for protection. (It is not necessarily all who were from these camps, but that doesn’t matter since even those who were from there are performing above native black Americans).

Chisala seems to assume that most of the Somali sample comes from refugee camps. But the source article only mentions that "[The Somali children's] families came to the U.S. to escape their war-torn country, many by way of refugee camps.". Chisala puts this aside by saying that "It is not necessarily all who were from these camps, but that doesn’t matter since even those who were from there are performing above native black Americans". But I didn't get that from a cursory glance of the data, which only seems to report aggregate data. Even so, there are a whole host of different selection effects with those coming from refugee camps. As one commenter puts it:

In a country like Somalia, getting into a refugee camp may be more desirable than not being in one. And from there to be selected for relocation to America may also be more desirable than not.

As with most desirable things in life, those with a higher IQ or socioeconomic status may be better at working the system to their benefit to get them.

Chisala did, as far as I can see, not respond to this concern.

I have not yet looked at the UK data Chisala mentions.

I am skeptical of the race and IQ narrative mostly because Africa has an average IQ so much lower than everyone else. It's fairly easy to come up with just-so stories about Europe and East Asia. But nearly the entire world, including the pure indigenous populations of the Americas, scores notably higher than pure blacks do, on average.

It seems like the answer is as much about "the places where blacks with no European ancestry are to be found are extremely badly run societies with very high rates of child malnutrition and a high parasite load, and this depresses IQ scores. This problem is shared with a few other areas that are not majority black, but purely black populations probably have an average IQ similar to the averages in southeast asia and among native americans, while east asians and most whites underwent selection effects for higher IQ" as it is about genetics. Unless there's some selection effect for all nonafrican populations but not subsaharan africans that I've missed(and before "Ice age", humans were already pretty widely dispersed by then).

To put it another way, it doesn't pass my smell test that every population not considered black scores higher than every population considered black with no white admixture, when neither are monogenetic groups in ways that the entire human race is monogenetic.

Your premise is not sound. Australasian aboriginals are worse off. Poorest Central Asians like the Kyrghizstani are around black level, judging by PISA results. Ditto, it seems, for lower-caste Indians, which is a group bigger than any majority-black nation. Some purely black populations score higher than some non-blacks; Igbos are stereotyped as crafty and big-brained by Africans and they do comprise a big part of those high-performing Nigerians in the Anglosphere. I suspect that Tutsi are smarter than Hutu and indeed pretty smart in general, which is why they eventually suffered a genocide, as it happens. And the lowest results for specific African nations are suspect. Anyway, someone is bound to end up at the bottom of the totem pole.

On the level of rhetoric, it can be said everyone else are overwhelmingly descendants of a single out-of-Africa migration event (hence the popular factoid that there's more "genetic diversity" in Africa than elsewhere). It stands to reason that everyone else might also be close – and different from the left-behind African population – in some important phenotypic traits. Though of course in actuality Africans we talk about are almost 100% Bantu, and thus fairly homogenous.

But yeah, even hardcore hereditarians allow that with continued successes to eliminate causes of deprivation and sickness, along the lines of GiveWell/Gates Foundation, populations that currently report those absurd scores will almost converge with African Americans. E.g. here's Emil Kirkegaard, who himself believes the B-W gap in the US to be 100% genetic, citing the oft-demonized Lynn:

This estimate of the genotypic African IQ as 80 means that the average IQ that Africans would obtain if the environments in which they were raised were the same as those of Europeans would be 80. Throughout sub-Saharan Africa the mean IQ of Africans is approximately 71, so it can be inferred that adverse environmental conditions in sub-Saharan Africa impair the sub-Saharan African IQ by around nine IQ points.

And Emil himself:

As such, we should expect African national IQs to converge to about 80 in the coming decades everything else equal. Ironically, the main factor that could prevent this is the mass emigration of high intelligence Africans into western countries, thus depriving their countries of their elites. This is what we are currently seeing from countries like Nigeria (Igbo elites).

The problem is that the gap may be more than 100% genetic, so to speak. That is, with deliberate interventions to close the gap we can raise individuals from the lower-IQ group above the performance they'd have had, given equal treatment; and on a population level, with humanitarian efforts, we may improve environments of African societies beyond the level they'd be able to sustain on their own, so new South Asian-like averages won't hold if aid program is terminated on account of its success. Still, maintaining optimal African performance would probably be a net moral (and economic) win for humanity.

the popular factoid that there's more "genetic diversity" in Africa than elsewhere

Is that not true?

It's true inasmuch as we literally talk about "genetic diversity" in the context of anthropological research, but implications that people try to smuggle in with these words are false. I'll just quote Cochran again.

On African genetic variation:

Occasionally I hear people talk about Africa’s great genetic variety. It exists: the genetic difference between Bushmen and Bantu is bigger than the difference between Bantu and Finns. A couple of thousand years ago, before the Bantu had arrived in South Africa & mixed with the Bushmen, it was even bigger: looking at ancient DNA from those unmixed Bushmen, looks as if they split off from the rest of the human race at least a quarter of a million years ago. Well before anything that looks like behavioral modernity, by any definition. Half as divergent as Neanderthals.

But the most divergent populations are small. There are fewer than 100,000 Bushmen, on the order of a million Pygmies, around 1000 Hadza. Most people in Africa are Bantu or related populations: next after that are Nilotic peoples.

And the venomously sarcastic Economists and biology:

Naturally, economists know a lot about human biology and evolution, just as civil engineers have to know about the properties of timber, concrete and steel. They have a good grounding in psychometrics, behavioral genetics, and quantitative genetics – how else could they do their job? Populations vary in traits that play key roles in economic activity and growth – in intelligence, asabiya, savings propensity, etc – you have to be aware of that variation, else whole continents would be economic mysteries. In the same way they know that those observed differences are a product of selection – which means economic historians think seriously about psychometric changes over time and their consequences, such as the Industrial Revolution. That kind of analysis helps predict where modern economic institutions can be successfully introduced, and where they cannot. [...]

Deirdre McCloskey has a new book out: Bourgeois Equality: How Ideas, Not Capital or Institutions, Enriched the World. I’m sure that there are many good things in it. But McCloskey makes a significant error in talking about genetics.

“Know also a remarkable likelihood in our future. Begin with the sober scientific fact that sub-Saharan Africa has great genetic diversity, at any rate by the standard of the narrow genetic endowment of the ancestors of the rest of us, the small part of of the race of Homo sapiens that left Mother Africa in dribs and drabs after about 70,000 BCE…. Any gene-influenced activity is therefore going to have more African extremes. The naturally tallest people and the naturally shortest people, for example, are in sub-Saharan Africa. The naturally quickest long-distance runners are in East Africa. The best basketball players descend from West Africans. In other words, below the Sahara the top end of the distribution of human abilities – physical and intellectual and artistic – is unusually thick. …

The upshot? Genetic diversity in a rich Africa will yield a crop of geniuses unprecedented in world history. In a century or so the leading scientists and artists in the world will be black – at any rate if the diversity is as large in gene expression and social relevance as it is in, say, height or running ability. ”

So by this argument that the most cold-tolerant Africans must be more cold-tolerant than Eskimos: but they’re not. The most altitude-tolerant Africans must be more altitude-tolerant than Tibetans – but they’re not. McCloskey is thinking that a turn to free markets will make Africa rich, and that will give educational opportunities to Africans now denied them – but a fair-sized mostly-African population already lives in the United States, a population that is already much more prosperous than sub-Saharan Africans. How are they doing? How many geniuses are they producing?

The whole argument is flawed. Overall genetic variation is mostly in neutral loci. By itself it tells you nothing about any particular trait. Europeans do have less overall genetic variation than sub-Saharan Africans (~20% less), but they show more variation in hair color and eye color than Africans.

Essentially every domesticated species has less genetic variation than its wild progenitor. Dogs have less genetic variation than wolves. So, does this mean that the tallest wolf is taller than any dog? No – the tallest Great Danes are taller than any wolf. The heaviest mastiffs are heavier than any wolf. Chihuahua are the smallest. Greyhounds are faster than wolves (by a little). [...]

What matters is the frequency of alleles that influence a trait, not overall genetic diversity. If, for example, the variants that tend to boost educational achievement (some of which were found in the just-released Nature study) were on average less common in sub-Saharan Africans than in Europeans – says 5% less common – Africans would tend to do less well in school. Like they actually do. Now Africa is a big place, and some groups are genetically quite distinct from others. Bushmen are genetically more distant from the Bantu than the Bantu are from Chinese. Some African populations might have experienced selective pressures that were more (or less) favorable for intelligence than others. Is there evidence, either in test scores or cultural accomplishment (better than any test), that some African populations may have smarts comparable with, or better than, people in Switzerland or Holland or Scotland?

TL;DR: Africans do have greater genetic diversity, but "genetic variation is mostly in neutral loci", i.e., greater genetic diversity does not imply greater phenotypic diversity, and even if there is greater variation in one phenotypic trait (e.g. height), this does not imply that there is greater variation in all traits. Correct?

Pretty much. Actually it's four points.

  1. Most of the asserted "genetic diversity" of Africa as a whole is due to peoples from ancient population clusters, which make up less than 1% of African population and are not associated with colloquial "black people". They are anthropological marvels, but frankly they're not the guys anyone is talking about. Related Razib Khan post.

  2. "Genetic diversity" for a given population is overwhelmingly a measure of ancestral population size and diversity of interchangeable variants that have spread by genetic drift. Out-of-Africa populations have passed through a series of severe bottlenecks, so they've shed some genetic markers we can find in African Bantus. Doesn't have much to do with anything consequential. It's like a JPG that's gone through lossy compression: there are color bands now, and less diversity of color patches or raw pixel values, but it doesn't mean the semantics of the image is altered, or that the range of any color channel is diminished, in fact the opposite can be true.

  3. Local adaptation can very quickly act on non-neutral loci, a few thousand years are more than enough to change a typical polygenic trait by 1 SD. We have no grounds to presume that ancestral (>50KYA) diversity explains modern diversity for groups that have evolved in different environments.

  4. By the same logic, yes, traits are independent products of selection. Just like all Sub-Saharan Africans are pretty dark relative to other races, they can be pretty ... fast runners, putting aside their internal ranking and their variation in toxin resistance or deep-diving talents or cricket skills.

Thank you, that was the TDLR of an effortpost I was looking for.

The Indigenous populations of the Americans came primarily from Asian populations around 18K years ago who underwent one hell of a trek. Funnily enough, 2 day old Navajo and Japanese babies show similar responses on the cloth over nose cognitive test (near complete docility) which would be extremely abnormal in caucasians. The separation between Africans and every other group is over 50K years. Given the standard theory that we all came out of Africa, it makes intuitive sense for the least cognitively capable members of our species to be the ones that didn't make it elsewhere. The Saharan desert is not exactly tolerant of the unintelligent.

Evidence for the horribly run nature of African societies, or malnutritution and parasite load doesn't exactly counter the validity of the genetic hypothesis. All of these are highly indiscriminate, killing the smart at similar rates to the stupid. You need particular conditions for selection pressures to favour intelligence over the simpler traits they might favour (speed, muscle, and high testosterone for example). Note that these are all areas where Africans excel, with African infants showing greater muscle control at birth than caucasians or asians (but not aboriginals).

I think the second half of your first paragraph has a bunch of issues.

I don't think it logically follows that the smartest would be the ones to leave first, especially in the context of simple, pre-agrarian hunter-gatherer societies. It could very easily be that the ones who left first were the least aggressive, and thus least likely to defend their territory. Inuit folklore mention the Dorset and state that their response to outsiders was simply to flee. I don't see why that wouldn't have been the case during the first human migration from Africa. I'd judge the argument that leaving Africa in the first place is a sign of intelligence to be false. Indeed, I think the low aggression hypothesis is actually more likely, given that there are experts who argue that drought in Africa is what first spurred the out-of-Africa migrations. That's a point in favour of aggressiveness/docility being the distinction between stayers and leavers, as conflict over increasingly scarce resources would have been inevitable.

Also, the first migrations out of Africa were fundamentally different than any that came after, as the original out of Africa population was traveling through areas where there were no Sapiens Sapiens, only Denisovans and Neanderthal. Once the first group leaves and is in the way, it becomes significantly less simple to push them out and then migrate, as you have to go through potentially(probably) hostile societies to do so. The first group to leave was incredibly lucky, and if they had been the second group due to minor changes in inter-tribe politics or random chance, they might never have made it out.

Finally, some parts of Africa are close to the Middle East and some are not. Any group that ended up in Southern Africa simply wasn't going to leave, and that is entirely circumstance and has nothing to do with any of their group characteristics. There's no reason the smartest humans 70,000 years ago couldn't have been denied the opportunity to colonize the world due to their location.

The Sahara was unlikely to have been a barrier to the first humans leaving, either. It has cyclical wet/dry periods, and it seems that a wet period ended ~70,000 years ago, which is right in line with the out-of-Africa migration that led humans into Eurasia and beyond. I find it more intuitive, given this fact, to suggest that the drought and desertification of the Sahara region was the impetus, and that it only became a hurdle for migration after the humans had already left Africa. On top of that, the Sans of Southern Africa have been successfully living in the Kalahari desert for 20,000+ years, despite scoring even lower on IQ tests(55 on average!) than other African groups.

With all that in mind, I find it very unlikely(I'd posit 95% confidence that this is the case) that the intellectual differences between Sub-Saharan Africans and non-African populations are the result of genetic differences that existed before humans migrated out of Africa. Any such differences are probably the result of selection pressures after the fact.

That hypothesis, to be clear, was that high malnutrition rates and poor general sanitation leading to high parasite load take IQ points off of Africans. It's a competing explanation for African underperformance relative to other parts of the world which also produce few nobel prize winners. The explanation isn't evidence against competing hypotheses; I don't think that South Sudan with the social conditions of Holland or Japan would have an IQ of 100, I think it would have an IQ similar to blacks in rich countries(which is itself similar to southeast Asian and native American IQ).

The argument is more "there's probably a world baseline somewhere in the 80's, and black countries limbo under it by being in youtube ads asking for money to save the children rather than for genetic reasons". I'm open to the alternative that blacks just have genetically low IQ's, but I want to see the explanation for a common selection pressure on Indonesians and Irishmen but not Bantus.

And I believe the sahara was not a desert when early man crossed it.

Could you rephrase this? It sounds interesting but reads to me like "I'm skeptical of HBD because every single black country has a low IQ, and every black minority population in other countries also has a low IQ." To me this sounds like pretty good first-glance evidence that the HBD story makes sense, even before you look at the genes themselves. Forgive me if I'm tired and completely misreading you.

[The poorly run dysfunction country] problem is shared with a few other areas that are not majority black

Could you give a few examples? I'm under the impression that the IQ in say, Afghanistan, is quite high despite the institutions in those areas being incredibly dysfunctional forever. (EDIT: Woah, dead wrong alert. Afghanistan looks to be in the mid eighties. This table looks to be sourced to Richard Lynn's work.)

But nearly the entire world, including the pure indigenous populations of the Americas, scores notably higher than pure blacks do, on average. [...] Unless there's some selection effect for all nonafrican populations but not subsaharan africans that I've missed(and before "Ice age", humans were already pretty widely dispersed by then).

I left this out because it's pure speculation, but the "Cold Winter" hypothesis is the one you run into the most. Populations incapabale of planning many months into the future died off any time their migration crossed a temperate climate. For example, this also explains why Mesoamerican civilizations which were also tropical or subtropical have such a high IQ and had sophisticated premodern science and maths. (Their ancestors had to pass through Siberia and over the Bering Strait.)

Populations incapabale of planning many months into the future died off any time their migration crossed a temperate climate.

Did the path taken from africa to europe really pass into 'cold winter' areas? Africa -> the Levant -> Turkey -> Greece ends in europe without passing through any places that even really receive snow. Plus there are temperate climates in Africa. Are there really any climates on the way to Europe from Africa that you couldn't find i.e. in the temperate regions of south africa? If so, why aren't i.e. Zulus as high average IQ as white europeans, considering their ancestors would have had to make similar migrations? And furthermore, 'cold winters' aren't the only source of long famines. Couldn't there be plenty of (and different types of) causes of famines in the tropical parts of africa to encourage selection toward individuals capable of long-term planning?

Did the path taken from africa to europe really pass into 'cold winter' areas? Africa -> the Levant -> Turkey -> Greece ends in europe without passing through any places that even really receive snow.

Europe itself was the cold winter area, leading to a population bottleneck. Pop-sci link.

The more dubious and interesting question would the Middle East and India. It's worth noting though that populations do not move in a linear direction, and those regions have at various points gotten heavy admixture and even outright population replacement from the north -- especially after 3500 BC or so.

If so, why aren't i.e. Zulus as high average IQ as white europeans, considering their ancestors would have had to make similar migrations?

I'm completely ignorant of Zulu history, but I'm not really seeing devastating unsurvivable winters anywhere along the migration path. As for the temperature on the highlands and mountains I'm assuming they would descend for winters like foragers, nomadic farmers, and pastoralists have throughout history. Are there any mountain ranges that would take multiple years to cross to South Africa? How was the ice age in middle Africa, I thought pretty mild?

And furthermore, 'cold winters' aren't the only source of long famines. Couldn't there be plenty of (and different types of) causes of famines in the tropical parts of africa to encourage selection toward individuals capable of long-term planning?

Maybe. I'd be interested in seeing if there was a population bottleneck akin to what happened in Europe above.

Nepal, Guatemala, and Nicaragua are the three non-black countries in the bottom ten in the world by IQ score. All three are desperately poor, badly run countries that plausibly have environmental factors causing loss of IQ points in kids that grow up there. And really 7/10 countries being African sounds not too far off from a sample of 3rd world countries.

The main thrust of my argument is that since non-black is not a monogenetic group, and black isn't either, the pattern of every non-black group outperforming every black group demands an explanation. I'm aware of the cold winter hypothesis, and that's why I included southeast asia- why does the dumbest country in SE Asia(Indonesia) have an average IQ roughly on par with the smartest country in subsaharan Africa(Sudan)? Since we know that childhood malnutrition and parasite burden and all sorts of other things black countries usually do badly on lower IQ, it accords with available evidence to suggest that the average IQ of blacks would be in the eighties if they lived in countries that were as nice as Thailand or the Philippines. To my knowledge, it doesn't require a cold winter to reach either of these countries from Africa, and neither of them has undergone some kind of selection effect for high IQ, and if anything biased sampling probably makes Africa look relatively better than more urbanized SE Asian populations rather than explaining the gap.

To my knowledge, it doesn't require a cold winter to reach either of these countries from Africa

All of these countries had quite dark-skinned populations several thousand of years ago. Then, populations originating from territory of modern China came and largely displaced them, sometimes without a trace of preceeding population. A large fraction of area of modern China was permafrost or under glaciers at some point.

Why do you think Indonesians literally living at equator have such light skin?

A diet based almost entirely on rice would tend to lighten the skin over generations, but the Chinese replacement also makes sense.

In general, it almost never occurs that some recent non-African population had its ancestors follow shortest path from Africa.

Goodness. I know you're a regular, but this phrasing reads like stereotypical bait.

Anyway, I don't have a good answer for you. It strikes me as a topic with little debate: two groups of partisans, neither particularly on the fence. There's not really an avenue to a general audience, either, since the mere mention is so radioactive.

Goodness. I know you're a regular, but this phrasing reads like stereotypical bait.

Because it is.

Oh, the original draft was worse :P. I had a bit about looking for something that simultaneously doesn't shy away from uncomfortable facts but also wasn't overreaching the data. Experience online taught me that...that sort of phrasing leads some people to react badly.

I figured themotte could parse "good".

It strikes me as a topic with little debate

There paradoxically seems to be too much debate - i.e. people getting deep in the weeds in niche spaces in a way that is just daunting to enter for all sorts of reasons - but also not enough debate - i.e. enough that some authority has a good, clear overview I can quickly find on popular spaces that broadly covers the state of play without trying to recruit or manage me.

I figured themotte could parse "good".

If there is one word that I would never in a million years trust anyone in (or adjacent to) the rationalist community to parse, it would be "good"

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