September 8, 2011

Infectious disease and national IQs

Christopher Eppig is back, this time in Scientific American, with his study showing a high correlation between average national IQs around the world and infectious disease burden. I would hardly be surprised if this were partly true (for example, in some Third World regions, various public health measures undertaken in the U.S. in the 20th Century, like hookworm eradication and iodine and iron staple supplementation, remain low-hanging fruits). But I can't say I've found Eppig's evidence highly persuasive yet that the arrow of causality doesn't mostly run in the opposite direction: e.g.,  that high average IQ Singapore has used its smarts to cut infectious disease more than low average IQ Lagos has managed to do so, despite both being at similar latitudes and altitudes.

Eppig claims that evidence from the U.S. backs up his international correlations:
Despite the strength of our findings, our study was not without its limitations. We did our best to control for the effects of education. But what we really needed was to repeat our analysis across regions within a single nation, preferably one with standardized, compulsory education. The nation we chose was the United States. Average IQ varies in the states. (Massachusetts, New Hampshire, and Vermont are at the high end, for example; California, Louisiana, and Mississippi are near the low end.) Again, infectious disease was an excellent predictor of average state IQ. 

The fever swamps of California? The swarming hordes of malarial mosquitoes in Compton? I don't really get this idea that Californians have their high infectious disease burdens to blame for their stupidity. The climate in California is famously healthy: dry, sunny, few mosquitoes or other insects, and low humidity. Health nuts have been moving to California for 125 years. For example, my grandfather was a health nut and he moved to Altadena in 1929.

A reader points out:
It is hard for me to believe that infectious disease is by far the most important cause of IQ variation.  If this were so, I would expect to see significant numbers of very high IQs even in low-average-IQ regions (asymmetrically long high-end tails of IQ bell curves for these regions), because even in high-infectious-disease areas (I assume) the number of uninfected people is significant.  In reality, the IQ bell curve is shifted to the left for low-IQ regions, but retains its symmetrical shape.  Only if everyone in low-average-IQ regions had been infected with IQ-lowering disease does the infectious disease hypothesis predict that normal distribution curves will be shifted to the left without the shape being affected.

For example, Kenya has high rates of infectious disease, infant mortality, crippling accidents, and so forth. Yet, the Kenyans who avoid all that sometimes do extraordinarily well in Olympic running events.
Also, the hypothesis doesn't square with the fact that people have lower IQs in any region when their family origins and genetic pedigrees originate in low-IQ areas.

56 comments:

last_useful_man said...

Not-too-bad quality discussion over at Reddit:

http://www.reddit.com/r/TrueReddit/comments/k7jwi/why_is_average_iq_higher_in_some_places_a/

(Steve, you should improve your comment system. You can even get + customize Reddit's own software (+ there are others). Feel free to edit this part out. Or the whole thing of course.)

TH said...

The big problem with Eppig's study demonstrating that state IQs (actually, NAEP scores) correlate with infectious disease risk in the United States is that the study doesn't control for race. They note in passing that there's a very high correlation (.9) between their measure of disease risk and the percent of a state's population that is black, but then leave it at that, without analysing if race might be a better predictor of state IQ, even though this would be easy to do with NAEP data (I suspect that they did this analysis, but didn't publish it because it would have undermined their thesis). It's possible that the finding that disease risk correlates with state IQ is entirely an artefact caused by racial differences in IQ and residential patterns.

Anonymous said...

I don't know about this one Steve.
The corellation is more properly with tropical weather and tropical disease which matches with another corellation between weather and IQ.
A case of two rights making a wrong.
Anyway, northern Europe until modern times was rife with infectious disease - think of how many tuberculosis alone killed, not to mention smallpox and a whole host of other nasties, and then you have that great destroyer itself typhus, that thrived in cold countries.
Perhaps malaria is a special case.Being endemic in tropical Africa for millenia, it probably has shaped the evolutionary characteristics of west Africans enormously, and I don't just mean sickle-cell, but reproductive habits amongst other things.
Anyhow, some of the sharpest, savviest and most cunning people in the world (Vietnanmese, southern Chinese etc), seemed to have thrived intellectual in spite of living in steaming parasite loaded tropics.But on the otherhand, I now recall that Mongolians aren't the indigenes of south east Asia, negrito types were.
The theory seems too twee and simplistic.

James B. Shearer said...

A variant of the infectious disease hypothesis is that endemic infectious disease in the past has caused the local human population to acquire more infectious disease resistant genes and fewer IQ enhancing genes. Which would explain your reader's objections.

Anonymous said...

California, Louisiana, and Mississippi are near the low end.

Great company you're keeping, Steve! ;)

Paul Mendez said...

Wouldn't this hypothesis also predict a huge increase in average IQ worldwide over the past century, as modern medicine controlled/eliminated more and more infectious diseases?

Anonymous said...

People like Eppig are not to be taken seriously. This is just a red herring to take our minds off genetic/racial basis of IQ. It's also an excuse for the West to spend more money on Africa.

TGGP said...

As indicated by the last commenter you quote, a history of disease burden in an area likely results in heavy selective pressure for disease resistance, making it harder for selection for IQ to take effect.

TGGP said...

Also, it doesn't sound like Eppig disagrees with you that much on causality. A quote from your last post on him:
"It is lack of development, and the many health problems this brings, which explains the difference in levels of intelligence". Less intelligent places are going to tend to have "less development".

Remnant said...

This is an extremely low joke but ...

Is HIV making Andrew Sullivan dumb?

http://andrewsullivan.thedailybeast.com/2011/09/disease-makes-us-dumb.html

Can't be bothered to read iSteve and be enlightened, I guess.

Kylie said...

From the linked article:
"Average IQ varies in the states. (Massachusetts, New Hampshire, and Vermont are at the high end, for example; California, Louisiana, and Mississippi are near the low end.) Again, infectious disease was an excellent predictor of average state IQ."

"For diversity and humanity!"

Calling Dr. Howard, Dr. Fine, Dr. Howard....

NOTA said...

Isn't the classic version of this hookworm in the South? My understanding is that more or less getting rid of that gave the South a huge economic boost. And today, places where the kids get malaria every year surely are having their average IQs depressed. I doubt this explains much variation within rich societies, but I bet it explains a lot of the variation between rich and poor societies, even though the causality can go both directions.

neil craig said...

I would assume that the correlation is overwhelmingly going to be between long settled populations in these areas since the advantage of low disease incidence (that your kids are likely to grow old enough to be worth educating) is a heritable factor. In which case the populations of Singapore and the non-Amerindian population of the US would not show the effect.

Northern China has historically had a much lower disease incidence than the south. I don't know if the northerners are smarter but most Chinese we know are descende from southernsers and are plenty smart.

Grumpy Old Man said...

It's entirely plausible that infectious diseases, especially in utero or infancy, might reduce IQ, but the label "infectious disease" is much too broad for that.

Infectious disease is likely to be more widespread where there is national poverty, which in turn correlates with low IQ (causal arrow in both directions, methinks). If the hidden agenda is to discount genetic factors, we must say, "Not proven."

Anonymous said...

Prior to antibiotics and such, many Europeans died of infectious diseases too. Inded, large chunks of Africa have more access to modern medicine through international aid(and other means)than much of the West even 100 yrs ago. But for centuries, whites kept making progress. Bubonic plague wiped out 1/3 of Europeans, but that didn't stop whites from making progress.

Anonymous said...

I just made a profound discovery.

I found a correlation between lower IQ test scores and lower IQs. So, lower IQs are produced by people getting lower IQ test scores. Atlanta's teachers may have been onto something.

Anonymous said...

Call this the EPIGG FAIL THEORY.

Anonymous said...

Hey, I found another great correlation. Free peoples with low economic growth have low IQs. So, maybe if we give every South African black $100,000, his IQ will shoot up sky high.

I mean look: Jews have high IQ and have lots of money.
Blacks have less money and low IQ.
How to fix the problem? Give blacks money and IQ will rise.

Anonymous said...

So, how fast are the IQ of Somalis rising in Minneapolis?

Anonymous said...

I don't really care about the bogus infectious disease angle -- the mere fact that Scientific American has published an article (OK, a blog post) acknowledging that:

1) IQ is real (!)

2) IQ varies by country (!!!!!)

is a significant win in and of itself. I'm keeping a link to this article, just in case I ever get into an argument with someone who insists that the idea that IQ might vary by country is ignorant and discredited ranting.

David said...

Just as less incidence of disease is found in certain areas, so certain areas tend to have more domesticable fauna. In relation to a human misery index, does the causal arrow's flight originate in arbitrarily benign/malign environments, or are different peoples having different results in shaping their environments? In other words, which came first: the chickenpox or the egghead?

Steve Sailer said...

Right, the damn yankees of the Rockefeller Foundation did the South a huge favor in the early 20th Century by organizing the virtual elimination of hookworm in the South. I don't know if hookworm affected IQ directly, but these parasites definitely lowered energy, including mental energy. In the third world today, there remain some low-lying fruit, such as fighting hookworm and the like and micronutritional supplementation like iodine and iron in staple foods.

Anonymous said...

"Average IQ varies in the states. (Massachusetts, New Hampshire, and Vermont are at the high end, for example; California, Louisiana, and Mississippi are near the low end.) Again, infectious disease was an excellent predictor of average state IQ."

I looked up the racial breakdown of these states on Wikipedia.

Vermont - 98% white.
New Hampshire - 94% white.
Massachusetts - 76% white.

vs.

California - 40% white.
Louisiana - 62% white.
Mississippi - 60% white.


It's almost as if both average IQ and the infectious disease burden are directly related to the proportion of whites vs non-whites in a population.

Anonymous said...

Blacks have less money and low IQ. How to fix the problem? Give blacks money and IQ will rise.

We all [here at iSteve] know that that point was made tongue-in-cheek, and yet, that bears a truly disturbing resemblance to the actual USA social policy of the last 50 years - in fact, one could plausibly argue that you have just described PRECISELY the dominant* American social policy of the last 50 years.





*Other than SS/Medicare for seniors [obviously].

Camlost said...

Right, the damn yankees of the Rockefeller Foundation did the South a huge favor in the early 20th Century by organizing the virtual elimination of hookworm in the South.

Willis Carrier did quite a bit to instigate migration to the South, also...

Anonymous said...

Hookworms don't make bookworms.

Anonymous said...

One question is how important foresight, low time-preference, etc., are in avoiding disease, for yourself and, more importantly, for your children.

Anonymous said...

This is more of WE MUST DO EVERYTHING FOR AFRICANS(AND AMERICAN BLACKS TOO, THOUGH THEY ARE NOT SUFFERING FROM MALARIA). It's part of WE-OWE-THEM theory.

We live in loopy times. In the past, kids were given piggybanks and taught to save. They were told their main goal should be to make money and save money--not least to buy a home and raise family--, and what was left over should be spend on fun stuff.
Now, kids are raised to spend money borrowed on credit even before they earn real money, and mostly on stupid fun stuff. Borrow and spend before you work and save. And our culture addicts our kids with so many fun stuff that shopping is our religion, economy, politics(where politicians are sold like soap), etc. As for those who cannot borrow and spend(due to horrible credit history), there's entitlement programs so they can have fun stuff too.

Steve Sailer said...

"One question is how important foresight, low time-preference, etc., are in avoiding disease, for yourself and, more importantly, for your children."

My guess would be that until sometime in the 19th Century, it wasn't all that important. Disease hit pretty randomly, so starvation, especially due to winter, tended to dominate selection for foresight. In the tropics, you had dry and wet seasons, so that demanded foresight too, but perhaps less than winter. So, relatively more selection pressure could go toward boosting immune systems against disease.

Anonymous said...

If Africa were disease-free, these leftists would say THAT is reason for lower IQ. Being disease free, even dumb careless blacks survive and have kids.

Anonymous said...

Do infectious diseases lead to lower levels of energy? I suppose so. But blacks are also immune or resistant to many of those diseases. And though we don't see much intellectual output from African blacks, we sure see a lot of singing and dancing, jumping up and down, running around with machetes, howling, and a whole lot of sexual activity. And if white women think having 3 kids is a BIG DEAL, African women seem to have the energy to have 10 kids.
Africa might actually be more pleasant if more people were sapped of energy. But South Africa is the rape capital of the world filled with howling and rampaging blacks. Hutus killed 800,000 Tutsis in 3 months. Congolese managed to kill 3 million in 10 yrs. And we are speaking over vast distances. And what about General Buttnaked of Liberia? Low energy dude? And then there are Somali pirates. Lack of energy, my butt.

And in America, 'youths' are among the most restless in public areas.

The problem is not low levels of energy. It's that blacks prefer to use whatever energy they have to boogie woogie and get down and funky. In fact, people tend to be of lower-energy-level in places like Sweden and Singapore than in places like Lagos where so many people be acting crazy.

Leftists say blacks in America fail in school cuz of lack of self-esteem and low levels of energy, but if that were true, blacks wouldn't be so good at contact sports, high-energy funky music, and street crime(which requires lots of running around). No, blacks are filled with energy but have it more in their butts, fists, legs, and groins in their heads or hearts.

Anonymous said...

Steve, has anyone published the US unemployment rate sorted by IQ?

We all know the overall unemployment rate is 10%, but what is unemployment by IQ cohort?

I would suspect that for workers with IQ 70 to 80 unemployment is 50%,

80 to 90 unemployment is 30%

90 to 100 20%

100 to 110 10%
and over 110 IQ 5%

Of course these are just guesses. But I think a breakdown of this sort is needed in order to prove to the cynics that our modern economy just doesn't produce enough jobs for those people born with below average IQ.

Therefore immigration of people with below average IQs has to be stopped
ie that each below average IQ immigrant takes jobs from below average american citizens.

NOTA said...

If the cause of a lot of low IQ related poverty and societal dysfunction is infectious disease, malnutrition, lack of minimal schooling, etc., then you can get a huge feedback loop toward making a poor country into a wealthy one--as your country gets wealthier, you plow some of that wealth into better sanitation and vaccination and schooling and enriching foods and such, and you get a richer society with a healthier and smarter next generation. I imagine this is behind some of the rocket like rise in wealth you see in some countries--think of S Korea or Taiwan or Singapore, which went from third world to first world in a couple generations. I suspect you can get a very rough stand-in for this effect by watching what happens to average height of successive generations--if the teenage boys are all taller than their dads, you're probably on the sanitation-nutrition-health-IQ feedback loop.

Are there examples where this feedback loop hasn't worked because of limits on the intelligence of the local population? It seems like a first cut would be to look at places that got richer, where there are visible improvements in sanitation and nutrition, and where the kids got taller or fatter than their parents, have better teeth, etc, but where the economy didn't improve much. (Though just better health will help your economy--this is happening to a lot of sub-Saharran Africa in reverse, though. Lots of people get sick from AIDS during what should be their high-productivity working years, dragging already horribly poor places down even further.)

Anonymous said...

From other studies I have read it isn't the direct effect of infectious disease so much as how it effects the evolutionary psychology of mating behavior in that markers of resistance to disease become associated with mate value/attractiveness, specifically testosterone as a marker for resistance to disease ("I have such good disease resistance I can afford all this testosterone!") See: http://www.livescience.com/14713-women-prefer-manly-men-disease-ridden-areas.html
And:
http://deepblue.lib.umich.edu/bitstream/2027.42/30928/1/0000598.pdf

Anonymous said...

From other studies I have read it isn't the direct effect of infectious disease so much as how it effects the evolutionary psychology of mating behavior in that markers of resistance to disease become associated with mate value/attractiveness, specifically testosterone as a marker for resistance to disease ("I have such good disease resistance I can afford all this testosterone!") See: http://www.livescience.com/14713-women-prefer-manly-men-disease-ridden-areas.html
And:
http://deepblue.lib.umich.edu/bitstream/2027.42/30928/1/0000598.pdf

Anonymous said...

Although it is true that the peoples of northern climes were decimated by various nasty diseases, it is also true to say in general that these nasties were largely diseases of civilisation ie the effect of domesticating animals and of humans living too close to one another.
The tropics are a different kettle of fish.In general cold weather such as the really cold winters found in northern Europe and conditions during the ice age is inimical to animal life.Basically, apart from insects that have evolved life strategies to cope with the cold (remember animal bodies are mostly water), the only creatures that can withstand the cold are certain warm blooded mammals and birds - and humans that have mastered the art of survival (entirely dependent on various tehnologies) in these conditions.
It's no accident that all of the world's most noxious insects, protozoa, spiders, reptiles etc are found in the tropics.Basically it's Darwinian, noxiousness is an evolved response to the extreme competition that thrives in environments such as rain forests where life flourishes.
The implication is that although northrn peoples were periodically decimated by disease, the tropical peoples of the world really lived in a constant struggle with life destroying organisms.

Anonymous said...

Anonymous wrote: I don't really care about the bogus infectious disease angle -- the mere fact that Scientific American has published an article (OK, a blog post) acknowledging that:

1) IQ is real (!)

2) IQ varies by country (!!!!!)

is a significant win in and of itself. I'm keeping a link to this article, just in case I ever get into an argument with someone who insists that the idea that IQ might vary by country is ignorant and discredited ranting.


Good point. The IQ taboo is a complex one: Intelligence (IQ for short) only exists when variations in how much people have of it are to be blamed on external forces (e.g., tropical diseases). Whenever IQ would be recognized as a heritable personal characteristic, it does not exist.

Anonymous said...

On the subject of the hookworm, i've been doing research since around 2007 for personal reasons. I eventually stumbled onto the google.com/trends data for hookworms and found it quite interesting.

http://img689.imageshack.us/img689/3936/2004zc.jpg
http://img691.imageshack.us/img691/1636/2005u.jpg
http://img850.imageshack.us/img850/9779/2006e.jpg
http://img593.imageshack.us/img593/6169/2007j.jpg
http://img191.imageshack.us/img191/7414/2008xq.jpg
http://img204.imageshack.us/img204/2101/2009oz.jpg
http://img163.imageshack.us/img163/3663/2010sxb.jpg

Google has since changed the way they handle trends data, and it has had a significant impact on the data shown as a result, but the above is pretty good.

Hal K said...

If we assume that there is at least some truth to this, then it could help explain the Flynn effect.

There is something on this in the Wikipedia article on the Flynn effect

Kiwiguy said...

There was a good debate about this issue at Dienekes blog on the first Eppig paper. princenuadha argues the hereditarian position.

Parasites and Intelligence (Eppig et al. 2010)

Grumpy Old Man said...

Educational level (highest degree attained) is a reasonable surrogate for IQ. I've seen unemployment figures that show the less the highest year/degree of schooling, the higher the unemployment rate.

White (and some black) guys used to be able to get out of HS, get a union job, marry a woman who stayed at home with the kids, work 40 years for the same company, and retire with a decent pension. Not exciting, but decent.

No more. Globalization, rising house prices, women in the workplace, immigration, and the decline of the big unionized factories ended all of that.

Humpty will remain a pile of eggshells, no matter whom we elect.

Anonymous said...

Any research done about hookers with hookworm?

L said...

Didn't DDT get banned back in the early 1970's? I wonder if IQs in the tropics improved during the period of time (about 25 years) that DDT was in use. If so then this would be just one more example of the racism of environmentalists.

Anonymous said...

So... I guess this would mean that the smartest people in the world would be Eskimos, right?

Anonymous said...

To go for the basic statistics argument:

I'm not too sure what the causal model is here. If they could demonstrate that intelligence varies within population by pathogen load, I would be more interested.

I'm not too confident about this matter of computing correlations and then imputing causation without a model.

Anonymous said...

You guys are missing the point about the study. The authors admit that there's a possibility that the body of African people ANTICIPATES (i.e. in an evolutionary fashion) that it WILL be attacked by parasites sooner or later, and therefore INVESTS in the immune system FROM DAY ONE.

That means, even if you eradicate the parasites, their bodies will continue to invest in the immune system instead of intelligence.

So basically, the authors ADMIT that black people are quite likely BORN less intelligent. Of course, MSM has missed this point completely and only focused on the PC part of the study.

jody said...

the german doctor who cured HIV by transferring HIV immune bone marrow from one european to another, i mean that depended on europeans having gone through bubonic plague and 1% of them now being immune to HIV. so 30% of them died about 700 years ago, a FAR higher toll than HIV is taking on africa now, yet they're still at least 30 IQ points smarter than the africans (probably more like 50 points when you compare the english, germans, scots, finns and dutch to the congos, niger, or ethiopia).

africans never went through anything like bubonic plague, and they aren't doing anything on the HIV front. or any other disease front. and they would have the highest motivation. all the work on eradicating disease comes from the europeans.

so it's either a case of this being "another sport africans just don't care about" or the hypothesis here is not so solid. funny how there are so many sports africans don't care about. they don't even care about not dying despite having the greatest motivation out of any group.

Anonymous said...

"So... I guess this would mean that the smartest people in the world would be Eskimos, right?"

Nah, their brains are frozen.

Anonymous said...

I hear having some worms inside you is good for the immune system.

By the way, maybe it can also be promoted as a way to lose weight.

NOTA said...

The effort to find a vaccine or cure for HIV (including the development of antivirals that work in combination therapy for awhile, till the bug evolves around them) is simply not something most people can contribute to. This sucks, but there it is--the average person simply doesn't have the brains for it. The average white person, with an IQ of 100, isn't going to get through medical school or grad school in virology or microbiology or immnology or whatever. The average black person from Africa, with a much lower average IQ (though it's not clear you're measuring quite the same thing with such different cultures and environments), is even less likely to be able to contribute.

This is no more surprising that the small number of people doing useful work on non-CO2 emitting energy sources. Most people arent developing higher efficiency solar panels or working on getting break-even energy from fusion, not because those wouldn't be useful problems to solve, but because those problems are too hard for almost everyone.

NOTA said...

Anonymous:

I think there's a lot of overlap between parasite defenses and both allergies and autoimmune diseases. I've also heard that sometimes, getting intestinal worms can put Crohns into remission, though I gather the effect usuall doesnt last all that long.

jody said...

NOTA, you can't be serious with that reply.

this is the classic "black americans are not good at basketball" argument. the average black american is light years behind the number 12 guy on the LA clippers in hoops ability. some player who scores less than 2 points per game. so the average black american can't even sit on the bench for one of the worst teams in the history of the NBA. because the average black american has a near zero chance of ever playing in the NBA, this conclusively shows that black americans aren't good at basketball.

well, no. but that's definitely the argument used to discredit european ability in almost any field. "The average white guy can't do this, so whites aren't doing this." in fact, discrediting europeans, or blaming them all for something, is now one of the only times we acknowledge that europeans have an identity or are a group. most of the time europeans don't have an identity and are not a group. they are colorless, interchangeable units who have no group interests. they have not made world changing, life improving contributions to any field. and they certainly ARE NOT better at this than any other group.

jody said...

here is the problem with the "NBA versus pathology" comparison. there are 360 player jobs in the NBA and black americans hold most of them. but there are lots of europeans too. in fact a european had the best playoff performance this year and outplayed all the other players.

but if you looked at the most important 360 people in pathology, almost none of them would be african. in fact it's a decent bet that literally none of them would be african. certainly there's a few africans in the field somewhere but not near the top 360 contributors. however, hundreds of those top pathology figures would be europeans, working on diseases which aren't even prevalent where the live.

like this fungus, ug99, which is sweeping east africa. it destroys wheat and is directly threatening to take out of the food supply in kenya, sudan, ethiopia, and so forth. there are about 150 million people in it's path. yet not one of them appears to have been an important laboratory contributor in developing the new breed of wheat that is resistant to the fungus. a new breed of wheat, which was created in the US, where the fungus doesn't even exist.

so either there were zero people out of 150 million with any ability to work on the fungus in the laboratory, or the entire affected population "wasn't interested" in figuring out how to stop the fungus.

thus it is occassionally the case that for a while, the best guy in many disparate fields is some european. but the reverse is never true. and not only is it never true, it's never even close to being true. it's absolutely, positively not true that out of the 1 billion people in africa, a couple african guys in a lab somewhere are "this close" to solving HIV.

NOTA said...

Jody:

The point is, what determines who gets into these fields is overwhelmingly not ethnic genetic interests, nor interests of friends and family of the scientist. Instead, it's mainly about ability and interest. To contribute anything to developing an anti-HIV vaccine, you will need to spend about a decade being trained--BS, MD or PhD, postdoc positions or residency and fellowship. Most people can't do that, and most who can don't want to work that hard for relatively low reward. (You can make good money as a doctor, but you'll do much better as a dermatologist or cardiologist than you will as a MD/PhD working as a researcher.).

Not a lot of blacks are in those fields, though there are some. Very few African blacks are in those fields. This isn't because of lack of interest in making an HIV vaccine, it's because of lack of ability to get through a hard science undergrad degree and have the grades and test scores and desire to get into grad school or med school.

Anonymous said...

To James B. Shearer's comment: I am the reader whose objections Steve quoted in his original post. I said it was hard for me to believe IQ was the most significant determinant of low regional IQ.

The possibility you raise is a smart objection to my objection, but what you suggest would be cold comfort to Eppig, who wants to find hope for afflicted and benighted regions of the world in the possibility that infectious diseases cause low IQ. (Eppig says his findings are "good news for anyone who is interested in reducing global inequality.") Suppose what you posit is right, and infectious diseases operate in populations over an evolutionary time scale (rather than in the lifetimes of individual people) to lower IQ as some kind of tradeoff for boosting immunity. If they remain as homogenous populations, Sub-Saharan Africans and Haitians will have to wait tens of thousands of years before their ancestors start winning international chess tournaments and winning Nobel prizes in the sciences.
--Morgan C

Anonymous said...

"ancestors":
I meant to write "descendants."
--Morgan C