July 1, 2010

Guardian: Lower IQs found in disease-rife countries, scientists claim

From The Guardian:
Lower IQs found in disease-rife countries, scientists claim
Energy can be diverted away from brain development to fight infection, explaining 'lower intelligence in warmer countries'
People who live in countries where disease is rife may have lower IQs because they have to divert energy away from brain development to fight infections, scientists in the US claim.
The controversial idea might help explain why national IQ scores differ around the world, and are lower in some warmer countries where debilitating parasites such as malaria are widespread, they say.

Researchers behind the theory claim the impact of disease on IQ scores has been under-appreciated, and believe it ranks alongside education and wealth as a major factor that influences cognitive ability.

Attempts to measure intelligence around the world are fraught with difficulty and many researchers doubt that IQ tests are a suitable tool for the job. The average intelligence of a nation is likely to be governed by a complex web of interwoven factors.

The latest theory, put forward by Randy Thornhill and others at the University of New Mexico, adds disease to a long list of environmental and other issues that may all play a role in determining intelligence. Thornhill made the news in 2000, when he coauthored a provocative book called A Natural History of Rape in which he argues that sexual coercion emerged as an evolutionary adaptation.

Writing in the journal, Proceedings of the Royal Society, Thornhill and his colleagues explain that children under five devote much of their energy to brain development. When the body has to fight infections, it may have to sacrifice brain development, they say.

In the American South, for example, hookworm, an energy-sapping infection that can cause cognitive impairment, was a giant problem until John D. Rockefeller funded a campaign against it starting in 1909. Poor Southerners seemed to have a lot more pep, physical and mental, once they started wearing shoes and taking other steps to avoid hookworm.

Hookworm is still a big problem in some of the warm-weather parts of the world. I'm sure there are other nasty parasites, and they tend to be more common in the tropics.

As Greg Cochran and Paul Ewald pointed out in the 1990s, there are probably numerous chronic infections that don't attract as much attention as major acute ones, but do often add up to trouble. A lot of things in the modern world, such as clean tap water, probably diminish their impact. Little kids get a lot of antibiotics these days for acute infections like earaches. The antibiotics might be killing off low-level infections at the same time. Who knows?

Likewise, Darwinian selection under conditions of heavy infectious disease burden will tend to be oriented toward improving the immune system more than raising intelligence, which will tend to have long term effects on tropical populations.
To test the idea, Thornhill's group used three published surveys of global IQ scores and compared them with data from the World Health Organisation (WHO) on how badly infectious diseases affect different countries. The list included common infections, such as malaria, tetanus and tuberculosis.

The scientists found that the level of infectious disease in a country was closely linked to the average national IQ. The heavier the burden of disease, the lower the nation's IQ scores. Thornhill believes that nations who have lived with diseases for long periods may have adapted, by developing better immune systems at the expense of brain function.

"The effect of infectious disease on IQ is bigger than any other single factor we looked at," said Chris Eppig, lead author on the paper. "Disease is a major sap on the body's energy, and the brain takes a lot of energy to build. If you don't have enough, you can't do it properly."

"The consequence of this, if we're right, is that the IQ of a nation will be largely unaffected until you can lift the burden of disease," Eppig added.

"It's an interesting and provocative finding," said Geraint Rees, director of the UCL Institute of Cognitive Neuroscience. "It explains about 50 to 60% of the variability in IQ scores and appears to be independent of some other factors such as overall GDP."

"The authors suggest that more infectious disease could lead to lower IQ scores through an impact on brain development. This is an interesting speculation, but the data don't prove it one way or the other," he said. "A bigger problem is that it might be driven by a third factor, that affects both infectious disease prevalence and IQ test scores."

Right. Multicollinearity is always a problem with correlation studies, and this topic especially: are lower IQs in the tropics caused by tropical diseases or by the tropics that cause the tropical diseases themselves?

For example, I've long hypothesized that one general problem that brains need to deal with is shedding heat and that is of course a bigger problem in the tropical than the temperate world. 

How to dissipate heat generated by computer chips is a huge issue in computer design. As I type on my laptop computer, the surface of the machine that is touching my wrists is about 100 degrees F. The bottom of my laptop must be 150 degrees or more. A fan is running full speed to shed heat to keep the CPU chip from melting. My office is heating up from the combination of my PC and myself, both working hard. I have just now opened my window to disperse the heat. It is a cool evening here, so the temperature is palpably dropping by the minute. If I was in a tropical climate, I'd need to turn on the air conditioning or start the fan or whatever.

Intel had driven up the power of CPU chips largely by increasing the clock speed, but when they hit four gigahertz, Intel found that chips were melting down. So, Intel  had to revamp massively and find other way to follow Moore's Law, such as multiple cores.

Similarly, your brain generates more heat when you are thinking hard than when it is idling.

Not surprisingly, skull shapes seem to be somewhat related to heat dissipation problems. Eskimos have round heads to conserve heat, while Kenyan marathoners tend to have narrow heads with a lot of surface area that dissipate heat more easily.
For reasons that are unclear, IQ scores are generally rising around the world. Thornhill suggests monitoring rates of infectious diseases in nations as they develop, to see if they decline and IQ tests scores rise.

Singapore would seem to be an example of a tropical place where public hygiene, antibiotics, air conditioning, education, and so forth combine in a virtuous circle.
Richard Lynn, professor of psychology at Ulster University, and author of the 2002 book, IQ and the Wealth of Nations, said disease and IQ is a two-way relationship, with low national IQs being partly responsible for widespread infectious diseases.

Right, it's hard to get started turning, say, Equatorial Guinea into Singapore without Singaporeans to get you started.

Here's the abstract of Thornhill's paper:
In this study, we hypothesize that the worldwide distribution of cognitive ability is determined in part by variation in the intensity of infectious diseases. From an energetics standpoint, a developing human will have difficulty building a brain and fighting off infectious diseases at the same time, as both are very metabolically costly tasks. Using three measures of average national intelligence quotient (IQ), we found that the zero-order correlation between average IQ and parasite stress ranges from r = −0.76 to r = −0.82 (p < 0.0001). These correlations are robust worldwide, as well as within five of six world regions. Infectious disease remains the most powerful predictor of average national IQ when temperature, distance from Africa, gross domestic product per capita and several measures of education are controlled for. These findings suggest that the Flynn effect may be caused in part by the decrease in the intensity of infectious diseases as nations develop.

Afghanistan would be the leading example of a cold winter place that seems pretty dim, perhaps due to disease burden. It's second in the world in infant mortality. (The rest of the Worst 20 are black African countries, while Afghans are, as Daniel Dravot notes in the Man Who Would Be King, a bunch of more or less white people. But how did that Civilizing Mission thing work out for you, Danny boy?)

James Michener's 1963 novel about Afghanistan, Caravans, has an Afghan leader arguing, with some pride, that while children die like flies in Afghanistan, if they survive past childhood, they grow up to be tough, mean bastards with well-tuned immune systems.

But, it's stupid of Afghans to have so much disease burden. So, I'm not sure that says much about causality. Are they so knuckleheaded because they are sick so much, or are they sick so much because they are so knuckleheaded?

But, even when it proves hard to determine ultimate causation from correlation studies, correlation itself is worth knowing. The general rule is that, as Kingsley Amis said in Lucky Jim: "There was no end to the ways in which nice things are nicer than nasty ones."

63 comments:

Dienekes said...

Singapore is not a very good example, as the majority of its population is of Chinese origin within the last few centuries, and there are tons of other foreigners besides.

Modern Singaporeans and modern Equatorial Guineans may both live close to the equator, but they did not both originate/evolve close to the equator.

Eskimos don't have round heads, they have quite long heads

"Of the yellow races the Eskimo is the most dolichocephalic."

http://www.1911encyclopedia.org/Dolichocephalic

Your claim that: "Likewise, Darwinian selection under conditions of heavy infectious disease burden will tend to be oriented toward improving the immune system more than raising intelligence, which will tend to have long term effects on tropical populations."

makes the presupposition that evolution is an either/or process. For example, Europeans are not less intelligent than native Americans, even though they were adapted to a greater variety of pathogens, which they imported into the New World.

agnostic said...

Heck, I figured all this out two years ago armed with only a laptop, Excel, and the internet. My study is better because it avoids a lot of the multicollinearity problems by looking only at American whites across the various states.

Hotter climates, less civilization

The hotter the state's average annual temperature, the lower the state's average IQ, the lower the rate of earning higher ed degrees, and the higher the imprisonment rate.

Again only whites in America, so a lot of genetic and co-adaptation stuff can be ruled out. It's not the heat per se, as most whites today in hot states enjoy coolness throughout most of the day due to technology. So temperature is just a proxy for disease burden.

l said...

Scientists are dangerously close to reviving phrenology. LOL.

Anonymous said...

"Scientists are dangerously close to reviving phrenology. LOL."

I can't wait for the last stand of the human-bio-conformity (or whatever...) party...

Dienekes said...

You don't understand. Evolution is an either/or process in the sense that it is always working under the constraint of a limited amount of resources.

Yes, but this paper does not propose an evolutionary solution to the problem of global IQ differences, but one based on energetic tradeoffs during ontogeny.

wren said...

Your computer fan may be full of dust.

I blew the dust out of mine and not only did the computer cool way down, the fan almost never has to come on now either.

l said...

As a general rule, more intelligence is needed to survive in harsher climates. Thus it is that Swedes are smarter than Hutus. There are anomalous populations, like the Afghans. But there's a 'hill folk' dynamic operative there -- dumber people within broader racial groups end up stuck with the least desirable land.

Anonymous said...

In New Mexico, the negative consequences of of heat, low Hispanic IQ, and childhood disease (not to mention toddler drug abuse!) must be more obvious to academic researchers than in Minnesota. The fatuous anti-white immigration agenda of both public and private funding agencies demands -- and will pay researchers to develop -- a theory like this one which would seem to suggest that moving to El Norte will lead to lower disease and higher IQ for all brown people. But African people have been living on the South Side of Chicago for generations and subfreezing winters haven't made them any smarter -- or any less likely to contract AIDS, gonorrhea, and syphilis. Actually, in the hard sciences this kind of correlation-implies-causality theory would never make it past peer review because researchers would be forced to explain the existence of low IQ ethnic groups with low disease burdens living in cold climates. Then there are many examples of great European musicians and intellectuals who barely survived their childhood.

Thornhill's theory is thin gruel.

Gaurav Ahuja said...

Mr. Sailer should know Afghans are not White people. There are some White people within the current borders of Afghanistan, but it is obvious that most Afghans are not White people. Afghanistan has been at the intersection of many invasions by people who were partially Black such as Arabs and Mongoloid people. And there has been migration from the Indian subcontinent as well such as Gypsies who went from India to Romania. People sometimes forget that migration has been going on for thousands of years and that all people have been nomadic at some point. Afghanistan has been too tempting to invade for various governments(including an Indian based empire).

Anonymous said...

I would be interested in learning about the IQs of children of recent sub-Saharan African immigrants to America and Europe. I occasionally read that African immigrants do well economically and in terms of educational achievement, but it's always vague, and I'm never sure whether they mean well in absolute terms, or just compared to American blacks. But either way, if there were a big jump in tested IQs compared to their parents that would certainly suggest that something in the African environment was keeping IQ down.

Anonymous said...

>Are they so knuckleheaded because they are sick so much, or are they sick so much because they are so knuckleheaded?<

The $64,000 question.

Many great scientists pulled ahead when sick in youth. Weren't most geniuses sickly kids? Beethoven was ill his whole life. Mencken had malaria as a kid. The examples could be piled up.

Anonymous said...

I've got it. The only rational explanation for the achievement gap in the US then is persistent and pernicious structural racism.

TH said...

It's nice to see that more and more reseachers are using Lynn & Vanhanen's data. IQ is sorely missing from most theories of economic underdevelopment.

Julen Sorel said...

Interesting theory but it would be helpful if they had controlled for race. They include "distance from Africa" among their variables, but that's a pretty blunt instrument! Zero "distance from Africa" is obviously negatively correlated with IQ, but beyond that, it's not helpful. (Europe is much closer to Africa than either the U.S. or Brazil, but so what?)

asdfasdfsdf said...

So, how smart are blacks in cold Detroit?

Anonymous said...

The notion that IQs are depressed in people who live where they have to fight disease is not a theory. It is only an observation of a correlation. It may lead to a theory but as reported here it is requires some sort of hypothesized causal mechanism. The "energy" mentioned here is not a mechanism. It is some form of medieval vitalism.

For example, Linus Pauling observed that dogs and cats don't catch what we call the common cold. He further observed that these animals synthesize Vitamin C internally while humans don't. He then proposed a mechanism that tied these observations together.

Similarly Cochran and Harpending observed that certain Jews seem to be especially smart. They likewise observed that these same Ashkenazi Jews are subject to a number of genetic diseases all of which seem to involve the lipid sheaths of neurons. The Cochran Harpending theory of Ashkenazi intelligence is a theory because it is specific enough to be tested.

Everyone who has read Lynn and Vanhanen already knows that there is a correlation between IQ and latitude, IQ and average temperature (pretty much the same thing) and they already know that tropical diseases are indeed more prevalent in the tropics. This paper's contribution is to propose that the arrow of causation runs from disease to IQ. However that is not enough to consider it a testable hypothesis.

This paper presents a heuristic, a suggestion, an intriguing possibility - not a real hypothesis. The world is littered with notions at this level e.g. half formed. There needs to be at least a sketch of a mechanism - more than just "energy" consumed in fighting diseases taken away from brain building.

Hookworm is a parasite as are many of the tropical diseases. If the claim is that IQ depression is caused by parasite load wouldn't this be obvious to school teachers in the tropics? Those kids who had gotten anti-parasitical drugs should be those who did better in school. If this parasite IQ connection is strong and meaningful why hasn't there been a pattern of sudden school performance boosts in tropical Africa following the introduction of modern medicine? The anecdotal evidence is all the other way. The sub-Saharan Africans seem to remain dullards despite everything that white colonists introduced.

Finally what about Japan? Every parasitologist knows that at the time of Perry's Black Ships the Japanese had among the highest parasite levels anywhere in the world. For example Saigo - "The Last Samurai" - had elephantiasis of the gonads. Unlike in the movie he did no horseback riding.

Albertosuarus

Jamila said...

The disease burden might also have something to do with why blacks in America have lower IQ scores than whites in America. Since black women and men have much higher rates of STD infections, and also many older black people avoided doctors due to fears of becoming victim of another Tuskegee experiment you have many black people grappling with health care issues that have cures but for one reason or another those cures are not being taken advantage of.

Anonymous said...

It would make sense that low level infections would have some impact on intelligence as well as on overall health. Poor nutrition certainly stunted the growth of earlier generations. Stress in the mother can remodel the brains of fetuses and change forever the way they respond to fear or stress themselves. Human potential is not all genes; a lot of it is genes interacting with the environment, often adverse.

Anonymous said...

Could the conquering and virtually wiping out the indigenous people of the Americas be a rebound effect of disease plagued Europe during the 13 and 1400's?

What I mean to say is, did Europeans correlate stupidity with disease and therefore knew they needed to wipe it out?

Justin said...

agnostic said: "The hotter the state's average annual temperature, the lower the state's average IQ, the lower the rate of earning higher ed degrees, and the higher the imprisonment rate."

The problem is, White ethnicity is not evenly distributed across the states. Different states have different ethnic populations of Whites.

You could just be confusing temperature effect with founding population effect.

Makran said...

Agnostic, I did read somewhere that Whites in Rhodesia had a very high average IQ. And Rhodesia is hot.

Simon in UK said...

Disease lowering IQ could explain part of the difference in IQ between blacks in Africa and blacks in white-Western countries, but I suspect it's only significant when combined with malnourishment - with enough to eat the growing child has enough energy for growing brain, growing body and fighting off disease.

Alternatively, one could compare the IQ of young children ca 4-5 in nursery/daycare with those raised at home; control for Socioeconomic status and you should get something meaningful.

Anonymous said...

"Are they so knuckleheaded because they are sick so much, or are they sick so much because they are so knuckleheaded?"


Yes.

The knuckleheaded parents allow the kids to get sick. The sick kids grow up to be knuckleheaded parents and around and around they go.

Anonymous said...

I see Dienekes features this on his site as well:

Dienekes take.

He does not seem to address the reduced pathogen load among African Americans ...

Dienekes said...

African Americans are actually a very good example, as their expected IQ -with a genetic explanation- is 0.8*70+0.2*100 = 76, which is substantially lower than their observed IQ. Clearly, African Americans are a problem for those who think that the African-Eurasian IQ gap is mostly of genetic origins.

sabril said...

"Interesting to hear the idea of a brain at idle. In assessing the IQ of U.S. blacks, how do we rule out the possibility that their brains are almost always at idle? "

One way to do it is to do an experiment involving reaction times. Reaction time is known to have some degree of correllation with IQ.

So you give people a reaction time test which has both a mental and a physical component. For example, the subject has a choice of buttons and has to reach and press one of the buttons based on which light lights up.

Then you measure peoples' reaction times and separate out the mental and physical components, i.e. you measure the time from when the light goes on to when the subject's hand starts moving; and you measure the amount of time the subject's hand is moving.

If black people are stupid because they have "slacker" attitudes, you would expect they would be slower in both the mental processing and physical motion aspect of the experiment. (Indeed, from simple observation one can see that black people tend to move slowly when others are waiting for them. For example, if they are walking across a street and a driver is waiting for the street to be clear.)

On the other hand, if black people are stupid simply because their brains are not as good at processing information, you would expect that only the mental aspect of the reaction time test would be slower and that the physical would be comparable to that of other groups.

As far as I know, this experiment has been done and it supported the latter hypothesis.

Anonymous said...

People who live in countries where disease is rife may have lower IQs because they have to divert energy away from brain development to fight infections, scientists in the US claim.



The other explanation is that disease is rife in these countries because the people there are not intelligent enough to be able to control it. Which comes first, chicken or egg?

The techniques for controlling disease are known now, discovered by Europeans over the past few hundred years. People in the Third World don't even need to re-invent the wheel, but simply apply ideas and techniques already in widespread use.

Anonymous said...

Dienekes refuses to put on his thinking cap when he says:


African Americans are actually a very good example, as their expected IQ -with a genetic explanation- is 0.8*70+0.2*100 = 76, which is substantially lower than their observed IQ. Clearly, African Americans are a problem for those who think that the African-Eurasian IQ gap is mostly of genetic origins.


He forgets about the environmental component, which is not reducing IQs in the US.

I think an improved environmental component gets most of the One STDV difference between Africans and African Americans ...

Anonymous said...

An implication of this might be that Native Americans might be more strongly affected by this phenomenon, as they have pretty low quality immune defenses left over from history (though they've changed a lot since European first contact).

keypusher said...

Dienekes refuses to put on his thinking cap when he says:


African Americans are actually a very good example, as their expected IQ -with a genetic explanation- is 0.8*70+0.2*100 = 76, which is substantially lower than their observed IQ. Clearly, African Americans are a problem for those who think that the African-Eurasian IQ gap is mostly of genetic origins.


He forgets about the environmental component, which is not reducing IQs in the US.

I think an improved environmental component gets most of the One STDV difference between Africans and African Americans ...

Wasn't there a paper not too long ago arguing that African IQ was average 82, rather than 70? Not sure whom that presents problems for, if true.

Anonymous said...

I think an issue might be path dependance. I've been reading 10,000 Year Explosion (great book - if you're at all interested in HBD from a reality based perspective you MUST read this) - if you couldn't tell from the Amerindian low quality immune comment I posted upthread - and the analogy of camels and wheeled vehicles struck me as possibly applying in this case.

It might be the case that if the disease burden is high, investing in brains rather than doing something else might be uneconomical, which might shut you off to a path of advancement in brain power, even if the end point of that path of advancement would be more economical (from a fitness point of view) than the path that you take. That is, high disease burdens might reduce the fitness of investing in brain boosters, just enough to encourage a lower brain power local optimum.

Anonymous said...

Every parasitologist knows that at the time of Perry's Black Ships the Japanese had among the highest parasite levels anywhere in the world.

That's quite interesting. I've heard that parasites have very low vulnerability to boiling relative to other pathogens, which I would guess would explain this (i.e. Europeans and other folks obsessed about finding fresh water sources while the Japanese just boiled bad water, since the Europeans had no knowledge of what boiling did, resulting in the Japanese having water that was well treated for other pathogens but quite brutal in terms of parasite load).

Melykin said...

Is there any evidence that Europeans who colonized Africa got stupider after they settled there? If the theory is true European colonists should have gotten stupider that the native Africans because the native Africans had evolved some protections against local diseases.

The correlation between disease and IQ would be a good example to use in my statistics classes for teaching that that an association is not necessarily a causation, and even if it is a causation it is not necessarily apparent what direction the causation is going in. But of course I will NOT use this example. I wouldn't touch it with a barge pole.

Anonymous said...

makes the presupposition that evolution is an either/or process. For example, Europeans are not less intelligent than native Americans, even though they were adapted to a greater variety of pathogens, which they imported into the New World.

It's a matter of cetaris paribus. I'd assume that selection for disease is not pleiotropic in a way that necessary supports selection for intelligence.

Given this Native Americans probably would have been smarter than Europeans if they didn't have selection for disease but they did otherwise have conditions that selected for intelligence to the same degree as in Europeans. They'd have the advantage of not being pulled in multiple directions.

But they probably didn't have conditions that selected for intelligence to the same degree as in Europeans. Or if they did, they've been so badly affected by the post 1492 world that they haven't anymore.

Whiskey said...

Afghans are resource poor. They spend most of their time trying to get or process food. There is little time for much else, save fighting which gets ... food.

Thus things like keeping animals inside the dwellings, and other stuff, that tends to increase disease (this was a feature in Israel during Jesus's time, and Mediterranean nations up through 1800's) that like Chinese doing the same, creates a vast disease reservoir.

China is the origin of nasty flus and epidemics because of cross-species jumping due to households living with animals.

It was only Europeans (Northern ones) getting wealthy that led to barns and such.

Anonymous said...

Is there any evidence that Europeans who colonized Africa got stupider after they settled there? If the theory is true European colonists should have gotten stupider that the native Africans because the native Africans had evolved some protections against local diseases.

The Europeans may not have if they were starting from a higher baseline. Checkout Razib Khan's graph of US regional wordsums here - http://blogs.discovermagazine.com/gnxp/files/2010/06/wordsumregion1.png. The Whites have a slightly bigger "Southern penalty", but are working from a bigger baseline so are still smarter than Northern Blacks.

On a side note, Gary Brechter (War Nerd) has quite amusingly written about how the Anglo Indians of the Raj and Company (born and raised) were far madder and badder than those from the mother country (I believe in the context of Younghusband's slaughter of the Tibetans and of Kipling's inability to abide England). To me this'd seem to be more likely due to selection for extreme, pioneering personalities (to a far higher degree that any putative such effect in the American colonization) to the extent there's a biological component but there's anecdotal evidence there that pathogenic environments could make you crazy.

Svigor said...

I only skimmed it so forgive me if I missed something.

We know that equatorial climates are easier to survive in, have more diversity, and the resulting abundant species are less robust, right? And colder climates are harder to survive in, have less diversity, and the resulting scarce species are more robust, right?

Would this not apply to germs, too? If so, doesn't this imply that pathogen load (my term, don't know what to call it) is more than just counting species? Just wondering if someone here knows a bit about this.

Svigor said...

Wren's right, my friend acts like her computer's something the Martians sent down. The fan was making lots of noise so I opened the case and cleaned gobs of nasty, greasy dust out of the fan manifold. It runs quietly now, and a lot smoother, too.

Svigor said...

Mr. Sailer should know Afghans are not White people. There are some White people within the current borders of Afghanistan, but it is obvious that most Afghans are not White people. Afghanistan has been at the intersection of many invasions by people who were partially Black such as Arabs and Mongoloid people. And there has been migration from the Indian subcontinent as well such as Gypsies who went from India to Romania. People sometimes forget that migration has been going on for thousands of years and that all people have been nomadic at some point.

Over time I've learned a teeny bit about central Asia. Which means, a teeny bit more than the nothing I learned throughout most of my life. I was surprised to discover how much of central Asia is of Turkic stock. (Turkic is a problematic term for me, because I still haven't figured out the origin of this people; did they evolve in the near east and spread to central Asia, or vice-versa?) As far as I can tell Turkic peoples dominate central Asia. They seem to be the dominant racial type all the way up to Kyrgyzstan. The Uzbek/Kyrgyz thing seemed to me to be at least in part a racial conflict. The Kyrgyz (or whatever TF they're called) seem predominantly Sinoid, the Uzbeks seem predominantly Turkic.

Anyhoo, the region is kind of fascinating to me because it's so "lost" to the history we're taught. Up until the last few years, I think I might've learned more about the region from R.E. Howard than history books.

Svigor said...

I've been wondering, after seeing so many Chinese faces that I thought showed evidence of Caucasoid admixture, and then discovering just how far Turkic peoples actually spread eastward into Asia (basically it seems that Caucasoid blood is a big part of the mix right up to the borders of China, and probably beyond), whether those faces were indeed showing Caucasoid blood. Anybody know any studies? I'm starting to wonder if China might have more Caucasoid blood than Russia has Mongoloid.

Svigor said...

Plus, someone above mentioned mountain peoples; go high enough in the mountains and you can leave the equatorial climate behind without significantly changing latitude. Shouldn't that drop the pathogen load and result in higher IQs if this theory is correct? Shouldn't we at least see some examples of this?

Dutch Boy said...

It was the people of Kafiristan who were white (because of their descent from Alexander the Great's Greco-Macedonian colonists), not the Afghans in general.

Anonymous said...

I'm happy to see this paper, which confirms something I've observed with my own eyes when I lived in a tropical country as a child.

Not only are children in tropical countries exposed to disease, a large proportion of those childhood survivors carry the symptoms of disease in adulthood.

The impact of disease ripples though the generations, as culture, meaning and information can no longer be passed on.

Again, the idea of a genetic base for intelligence doesn't make sense to me and I've never observed it.

Smart people come from everywhere. Unfortunately, disease, hunger, overpopulation and despair are still the norm in most of the world.

-pd in sf

Svigor said...

African Americans are actually a very good example, as their expected IQ -with a genetic explanation- is 0.8*70+0.2*100 = 76, which is substantially lower than their observed IQ. Clearly, African Americans are a problem for those who think that the African-Eurasian IQ gap is mostly of genetic origins.

I think most HBD-ers think the African-American/European gap is mostly genetic, and that Africans could see a significant boost from improved nutrition.

Of course, many of us think IQ's only part of the behavioral genetics story. And nobody came down from Mars and improved Europeans' nutrition, I might add.

Svigor said...

(Indeed, from simple observation one can see that black people tend to move slowly when others are waiting for them. For example, if they are walking across a street and a driver is waiting for the street to be clear.)

This assumes the stimulus is identical for both groups, when it is not; blacks move more slowly when others are waiting because they don't care if others are waiting. This is the sort of thing I lump into behavioral genetics, but am not willing to assume is down to IQ.

Svigor said...

Anonymous makes a lot of assumptions about southern jizz. How do we know it was the slaveowners doing the jizzing? Maybe it was the crackers on horses in the fields? Maybe it was the indentured servants one field over? I see the slaveowners as much more likely to refrain from jizzing in black slaves as a matter of principle than the whip-crackers or the serfs.

I don't know either way, obviously, I just think the common assumption is based on the same old liberal Narrative that's generally a pack of lies and half-truths.

Anonymous said...

Afghanistan has been too tempting to invade for various governments

God alone knows why!

The lesson from history should be that however tempting on the surface, the cost down the line is never going to worth the trouble.

Anonymous said...

"Anybody know any studies? I'm starting to wonder if China might have more Caucasoid blood than Russia has Mongoloid."

In northwestern China and along the old Silk Path, maybe. But there is no appreciable caucasian admixture in the overwhelming majority of the world's Chinese.

http://2.bp.blogspot.com/_Ish7688voT0/TA_8VX3jGkI/AAAAAAAACcM/HVkOLdPm94g/s1600/admixture-global.jpg

Look at the third column. Dark blue represents West Asian/European admixture. It is completely absent in the Han, though present in a very, very small amount among Mongols.

BamaGirl said...

"The hotter the state's average annual temperature, the lower the state's average IQ, the lower the rate of earning higher ed degrees, and the higher the imprisonment rate."

Thats nonsense. Different areas of the US had different founding populations. The southeast has lower stats even for whites (lower but not significantly lower. People love to exaggerate about southerners) because most southern whites are descended at least partially from lower-class British/Irish immigrants and indentured servants. Plus, most southern states are only 60-75 percent white. And your hypothesis falls apart because the whites who score lowest in pretty much all categories are West Virginians. Florida is far more humid and parasite-ridden than semi-cold/ mountainous, West Virginia, but Floridian whites score about average relative to most of the country in IQ/number of higher-ed degrees attained/etc.

Anonymous said...


African Americans are actually a very good example, as their expected IQ -with a genetic explanation- is 0.8*70+0.2*100 = 76, which is substantially lower than their observed IQ. Clearly, African Americans are a problem for those who think that the African-Eurasian IQ gap is mostly of genetic origins.


Starting with an IQ of 70 for African Americans is cheating. They are the recipients of a nutritional improvement.

If we assume a half STDV improvement in IQ due to nutrition, then the numbers come out at around 77*0.8 + 100*0.2 = 81.6, which is closer to the measured average ...

It is disingenuous to provide a calculation using an IQ of 70 for African Americans. It suggests an ideological attachment to a Gouldian viewpoint.

Of course, it would be useful to have a good value for the nutritional boost delivered, and can probably be worked backwards ...

Anonymous said...

Is this paper describing lack of intelligence as merely an acquired characteristic due to the parasite load, or are they going further and saying that those throughout the region's evolutionary history who couldn't sufficiently divert energy from brain-building to the immune system would have perished at a higher rate, therefore leaving their "build a better brain regardless" genes behind, therefore we're still left with a genetic issue?


In other words, have Africans, for example, evolved a more jittery, hair trigger genetic programming that, in effect, says, "Oh shit, that's a virus/bacteria, shift resources, fast and heavily, or you're going to be dead!"

If so we shouldn't be shocked that Africans or their kids who have emigrated to a country with a lower parasite load don't suddenly acquire IQ's of 100.

ATBOTL said...

"The rest of the Worst 20 are black African countries, while Afghans are, as Daniel Dravot notes in the Man Who Would Be King, a bunch of more or less white people."

Nuristan, where that book is set, is probably the whitest looking part of Afghanistan. Most people in Afghanistan would not be considered white in any white country. There are many Afghanis who look Asian. It depends a lot on what ethnic group they are from.

Anonymous said...

People love to exaggerate about southerners) because most southern whites are descended at least partially from lower-class British/Irish immigrants and indentured servants.

If you look at the Razib Khan GNXP @ http://blogs.discovermagazine.com/gnxp/2010/07/region-matters-dont-you-forget-it/, the pattern seems to be evident in zee Germans as well. Are Southern Germans descendants of low class Germans? There has to be some pattern that makes sense as a cross White ethnic phenomenon.

keypusher said...

African Americans are actually a very good example, as their expected IQ -with a genetic explanation- is 0.8*70+0.2*100 = 76, which is substantially lower than their observed IQ.

Unless I am missing something, this is a silly post, no matter what African IQ really is. I don't know anyone who thinks that IQ is entirely controlled by genes. Certainly none of Jensen, Rushton, Herrnstein or Murray do.

catperson said...

But either way, if there were a big jump in tested IQs compared to their parents that would certainly suggest that something in the African environment was keeping IQ down.

Well we already know that "pure"-blooded African Americans have an average IQ around 80, compared to the IQ of 67 in black Africa, thus Lynn concludes that bad nutrition (including disease) supresses the black African IQ by about 13 points. We know from the Flynn Effect that malnutrition (including disease; as as Richard Lynn pointed out decades ago, disease prevents nutrients from being used for growth and development) can supress an entire population's IQ by as much as 20 points and stunt average height by several inches so it would be shocking if the average IQ in Africa was not environmentally stunted. As Steve Sailer once pointed out, black Africans are also shorter than African Americans. This is yet another example of how the gap between American blacks and black Africans mirrors the Flynn Effect.

One technical point. Folks keep stating that the average IQ in Africa is 70 (actually it was found to be 69 but got rounded to 70). This is true if you use American norms, however in the technical literature, Lynn started the trend of using British norms because British norms exclude non-whites and thus produce IQ's that are 2 points lower thus the African IQ is 67. It makes sense to use only white norms because the genetic composition of America is changing so rapidly that using American norms is not a very stable reference point.

catperson said...

African Americans are actually a very good example, as their expected IQ -with a genetic explanation- is 0.8*70+0.2*100 = 76, which is substantially lower than their observed IQ.

Just to play devil's advocate, Rushton & Jensen have speculated that the average African American IQ might actually be 78, not 85 as has been claimed for the past 90 years. The evidence for IQ 78 comes from a massive testing in World war II which supposedly found an average IQ of 78 and this was supposedly the most representative sample of African Americans ever tested. Legend has it that the reason most studies find an average African American IQ of 85 is that the lowest scoring African Americans (those who live in the rural South and the inner-city ghettos where no psycholoist would dare venture) are excluded from the samples and if these massive sub-groups were represented, they would drag the average down to 78. However there is reason to think that black IQ in the rural South is stunted by environment as IQ drops from 85 to 70 as rural Southern black kids go from childhood to adulthood.

Anonymous said...

Plus, someone above mentioned mountain peoples; go high enough in the mountains and you can leave the equatorial climate behind without significantly changing latitude. Shouldn't that drop the pathogen load and result in higher IQs if this theory is correct? Shouldn't we at least see some examples of this?

Armenians, perhaps?

Anonymous said...

You can also drop your pathogen load by living next to salt water. (Being able to swim in it frequently.) And, yes, you do see that civilation has flourished next to the Ocean at all latitudes.

-pd in sf

Anonymous said...

Stupid people do stupid things.

All races in South Africa have adopted the vuvuzela since the start of the world cup (which incidentally is manufactured by a white man), but the poor (largely blacks) seem to be the least likely to use ear protection, and the most likely to blow it in enclosed areas or in the immediate vicinity of other's ears.

So it would not surprise me to discover, a few years down the line, that poor black children in South Africa have had undiagnosed hearing loss, with all the attendant problems. An underclass disadvantaged for another generation by its own foolishness.

rob said...

go high enough in the mountains and you can leave the equatorial climate behind without significantly changing latitude. Shouldn't that drop the pathogen load and result in higher IQs if this theory is correct? Shouldn't we at least see some examples of this?

Svigor, we do, or at least we did a while back. In South America, the Inca pretty much terraformed mountains rather than living in lowlands. In Africa, the Ethiopian highlands held what could reasonably be called an independent African civilization. Hell, the Ethiopes were so advanced for Africans that some anthropologists considered them very dark-skinned Caucasians. IIRC, in his book Race, Richard Bakke takes that position. Or at least he discusses it.

I do wonder why the descendents of the Inca and Abyssinians as so unimpressive. Possibly European disease and Spanish savagery killed basically the entire elite of American Aboriginal civilizations.

The Ethiopians don't have that excuse. OTOH, back then, they were at the height of bronze age civilization, and they still are. They only had a relative, not absolute decline. One possibility might be population size. The relatively small highlands restricted population size, reducing the number of positive alleles to be selected.

Anonymous said...

" blacks move more slowly when others are waiting because they don't care if others are waiting."


Nah, they care. They intentionally delay to inconvenience others. It is a power trip. They can't control themselves or their lives, but they can control you for 5 extra seconds at the intersection. Puerile adolescent thinking, but there it is.

Blumenstein said...

John Ray points out:

"Where it gets amusing is that Eppig et al. did their study in various regions of the world and in 5 out of 6 regions, the correlation held. The exception was South America. The correlation collapsed completely there. Why? Because the South American region included several Caribbean nations almost wholly inhabited by Africans! So why were the results there different from the rest of South America? Could it be a racial difference?

Oh no! Eppig et al say: “It is possible that local parasites … are causing these outliers”. In other words, they abandon the obvious in favour of a totally vague and unfounded speculation!

Two other reasons why the perverse theory of Eppig et al is wrong: They pinpoint nutritional deficit as the mechanism by which parasite load inhibits brain development. But if poor nutition lowers IQ, how do we explain the famous Dutch famine study? In the closing phases of WWII, Nederland experienced a severe famine. So all the Dutch kids born during the famine should be real dummies, right? The reverse happened. They were of higher average IQ than other Dutch cohorts. Only the very healthy survived and, as we have seen, good health and high IQ correlate."

http://www.bloggernews.net/124848

Anonymous said...

An unexpected tale of environmental influence

(Smirk, smirk.)