IQ and the Wealth of Nations

by on July 18, 2007 at 5:51 am in Books | Permalink

How many more times will someone suggest this book in the comments section of this blog?  I like this book and I think it offers a real contribution.  Nonetheless I feel no need to suggest it in the comments sections of other peoples’ blogs.

I do not treat this book as foundational because of personal experience.  I’ve spent much time in one rural Mexican village, San Agustin Oapan, and spent much time chatting with the people there.  They are extremely smart, have an excellent sense of humor, and are never boring.  And that’s in their second language, Spanish.

I’m also sure they if you gave them an IQ test, they would do miserably.  In fact I can’t think of any written test — no matter how simple — they could pass.  They simply don’t have experience with that kind of exercise.

When it comes to understanding the properties of different corn varieties, catching fish in the river, mending torn amate paper, sketching a landscape from memory, or gossiping about the neighbors, they are awesome.

Some of us like to think that intelligence is mostly one-dimensional, but at best this is true only within well-defined peer groups of broadly similar people.  If you gave Juan Camilo a test on predicting rainfall he would crush me like a bug.

OK, maybe I hang out with a select group within the village.  But still, there you have it.  Terrible IQ scores (if they could even take the test), real smarts.

So why should I think this book is the key to understanding economic underdevelopment?

Addendum: I am sorry there have been too many nasty comments, so I have taken the comments down.  They aren’t deleted forever, I like to think that I will have time to pick out the bad ones and put the thread back up.  I do understand that most of you (and not just on one side of the debate) are capable of discussing this topic with the appropriate tone.

RRE July 18, 2007 at 6:01 am

Some people do what works. How these individuals stumbled upon their successful rules, I, for one, do not know. One’s Modus Operandi might be more advanced, but carelessly suggesting IQ might be the reason for it surely disproves that thesis.

Harald Korneliussen July 18, 2007 at 6:54 am

I’ve seen some people who treat addiction complain about the official diagnosis criteria. They say that classifying addictions in the same way as diseases tempts people to take what is a description of behavior (something like “has attempted to quit, interferes negatively with social life and work, development of tolerance”) and use it as an explanation of behavior (“He’s that way because he’s addicted”).

Doesn’t IQ tests suffer from the same problem? We know bloody little about what causes what correlations there are, but people go around acting as if IQ is an answer to something.

There is a thread over at crooked timber on it, if anyone really feels like engaging the people who would like to prove their intelligence with a number rather than with achievements…

john Mark van Rozendaal July 18, 2007 at 7:32 am

I would be interested in reading it. I’m pretty sure that I’m intelligent enough to read it, but I can’t afford to buy it.

Perhaps it’s at the public library . . .

Huggy July 18, 2007 at 8:01 am

Poverty and wealth are measured in a way that gives high numbers to the results of massive capital investment. So of course these very smart people would have low IQs. They acquired their skill sets in a low capital environment. IQ measures some of the skill sets that are advantageous for massive capital investment.

Robert Speirs July 18, 2007 at 8:15 am

It is puzzling that anyone should say that IQ can only be measured by written tests. For decades, intelligence tests for illiterates have been used massively, all over the world. I believe that fact is mentioned in the cited book. Also, it is irrational to say that intelligence is a meaningless concept and then to say that some Mexican villagers are as intelligent as anyone else. Is intelligence quantifiable or isn’t it?
Oh, and if they are so “smart”, how come they’re not rich?

Nathan Zook July 18, 2007 at 8:49 am

It’s not just for illiterates… My testing for the gifted program was entirely non-written. This was in 1979. Moreover, the type of testing that was done would have been extremely difficult to do on a written exam.

Whatever it is that IQ measures, a written IQ test would (cheaply) measure something quite different than what I was measured against.

Having said that, there is a well-documented rise in US national IQ over the last hundred years which to my knowlege is yet to be explained, especially since our educational standards have steadily declined over the same period.

michael vassar July 18, 2007 at 8:54 am

Thanks Tyler, personal experience is and should be an important part of our understanding of the world.
It would be nice to hear more about your travel experiences on the blog. “my favorite things” columns only take us so far.

JewishAtheist July 18, 2007 at 9:23 am

If they do argue that people in poor countries are less smart (as distinct from lower IQ measures), how do they explain it? Nutrition? Hopefully not genes.

They do argue that it’s genes:

The significance of the high heritability of intelligence is that it implies that the differences in intelligence between the peoples of different nations are likely to have a genetic basis


Dan chituc July 18, 2007 at 9:52 am

“Or the other way around, of course. An economically well off society increases what the test is measuring.”

That’s always the question in any kind of a statistical study, are we looking at correlation of causation? I haven’t read the book (though it’s certainly on the reading list now), but I’d imagine if the issue isn’t dealt with it’s certainly the next logical step. Simply on the face of things, I’m inclined to think that increasing what’s traditionally called IQ can’t help but drive economic success as people have more opportunities opened to them, but it’s certainly possible it could go the other way.

It’s a real shame to hear they took the genetic route by way of explanation. Besides the wildly inappropriate connotations blaming poverty on inherent inferiority raises, the simple fact is it should be clear to any student of humanity and history that genetic inferiority is patently false. Now an extremely promising work is tainted with the assumed, if not actual, racist overtones.

Scott Miller July 18, 2007 at 10:07 am

Most people from other cultures would not do well on a written IQ test. It reminds me of Stephen Jay Gould’s book The Mismeasure of a Man. Some new European immigrants were IQ tested when they got off the boat on coming to America. Of course, many didn’t speak English. Some who didn’t do well were taken for sterilization. Later it was proved that this process was used to obviously weed out certain groups of immigrants.

Kenji July 18, 2007 at 10:25 am

Bravo on this post—I’ve been waiting for a well-known blogger to make a statement like this (in contrast to say Posner, who seems to put a ridiculous weight on IQ in his various blog posts).

Anderson July 18, 2007 at 11:23 am

What’s remarkable about the stalwart defenders of IQ = intelligence, is how their own arguments seem to cast doubt on their thesis … unless they’re willing to concede that they themselves score poorly.

Any such concessions?

Dennis Mangan July 18, 2007 at 11:29 am

The post shows the massive disconnect between popular ideas on IQ testing and the reality. Ninety percent of academic psychologists think that IQ tests are valid and measure intelligence, while the popular press (and some bloggers) airily dismiss decades of science because it doesn’t fit their prejudices. It’s as if a union member refused to believe in the benefits of free trade.

adrian July 18, 2007 at 11:40 am

Seriously though. Tyler’s remarks on Mexican villagers point to a larger problem among the cognitive elites. They spend so much time with other smart people that, on the rare occasion they do interact with people of average or low intelligence, they are surprised that they can hold a conversation with them. But most people in the world can talk, tell stories etc, this is not a sign of IQ, only of general human-level intelligence.

As JP Rushton has pointed out, this wrongly leads people to not accept the validity of low African IQ’s, because of their ‘winning personality’.

Roy July 18, 2007 at 11:57 am

I’m pretty sure nuclear physicists are capable of running a cach register at Walmart or picking lettuce off the ground and putting it into a cart.

And even if they weren’t, setting a high IQ bar for immigrants won’t leave the US with a population of only physicists. There will still be over 150 million Americans with a 2 digit IQ left to pick lettuce.

Dan Chituc July 18, 2007 at 12:45 pm

I can’t speak for anyone else, but I’d think those mentioning how intelligent people in underdeveloped countries actually are should take this kind of study as a sign for optimism, not as a sign the idea of IQ is inherently useless or racist. The entire reasoning behind the viewpoint everyone is “intelligent” is that all people are basically the same and all equally capable of intellectual success. This study at the very least suggests that all we have to do (or a major part of our strategy going forward) is to help people in underdeveloped countries bridge the gap between a high “intelligence” and a high IQ as measured by the test.

I honestly fail to see how saying “group X that isn’t succeeding is lacking the intellectual skills and training needed” is automatically racist. There’s certainly the possibility that this thinking can lead into an assumption of inferiority or superiority, but the way to fight that is to again look at the facts and discount that possibility, not to try and discredit this entire system for studying reality.

Nathan Park July 18, 2007 at 1:04 pm

Tyler wrote: “So why should I think this book is the key to understanding economic underdevelopment?”

Perhaps because planting corn, catching fish, sketching a landscape or gossiping about neighbors are hardly activities designed to enhance economic development? Subsistence agriculture, no matter how nobly endured, is not a sign of intelligence nor an indicator of success.

noman July 18, 2007 at 1:15 pm

Perhaps instead of shouting down people who present theories people find objectionable we should let peer review determine what’s valid.

“What Dr. Lahn told his audience was that genetic changes over the past several thousand years might be linked to brain size and intelligence. He flashed maps that showed the changes had taken hold and spread widely in Europe, Asia and the Americas, but weren’t common in sub-Saharan Africa.”

We will never know if Dr. Lahn’s research is valid because the thought police have shut him up and he is moving on to other areas of research.

seer July 18, 2007 at 2:29 pm

Tyler, after reading this post and comments, I have a post title request: should you judge a blogger by his commentators?

Looking forward to it.

P.S I’m a loyal MR reader.

Steve Sailer July 18, 2007 at 3:08 pm

If anybody out there actually wants to learn about the book, my 2002 review covers its strength and weaknesses:

In 2004, I put all its natioanl average IQ scores in a convenient table:

Also, see my discussion of the table here:

Lynn has published two follow-up books. Jason Malloy’s massive review on GNXP is here:

And my shorter review, with lots of pretty graphs, showing changes in relative IQ by nation over time, is here:

I’ve also written a couple of article about how to raise IQs in the Third World through adding iodine and iron to staple foods:

Chip Smith July 18, 2007 at 3:36 pm

Not that it matters, but I would be most interested in reading Tyler’s response to Jason Malloy’s comments.

josh July 18, 2007 at 4:05 pm

I don’t know much about this stuff, but Jason Malloy’s comment seems a lot better than Tyler extremely dismissive post. Why do we all have such strong feelings on things we know so little about?

“The problem is that, though Jason Malloy’s point may be true – that IQ test results are correlated with (causes of? who knows?) material wealth – the zealots further extrapolate that a high IQ score is the bar by which we should set immigration (or other social agenda) standards.”

Isn’t this beside the point. Aren’t we discussing whether the hypotheses in the book are true or not? If they are, wouldn’t you at least like to know it so you could base your own arguments in fact?

MIchael Blowhard July 18, 2007 at 4:08 pm

I’m sympathetic with both sides here. On the one hand, IQ seems to be a real measure of something, and that something seems to correlate to other somethings. On the other hand, IQ ain’t everything, smart people can be awfully dumb as well as mess the world up, people who don’t score well on IQ tests can show all kinds of gifts, etc …

So, FWIW, I sort the problem out this way for myself.

Instead of falling into the trap of arguing what’s intelligence and what’s not, I use a meta-category of “talents.”

In other words: there are tons of different kinds of talents, from “character” to “a feel for dogs” to “a nice singing voice” to “intuitiveness” to …. Well, to what I call “IQ-style intelligence.”

In other words, why fight over whether “having an amazing instinctive rapport with dogs” is a form of “intelligence” or not? Seems dumb. Why not say that “having an amazing instinctive rapport with dogs” is one kind of talent, and “having a dazzling IQ-style intelligence” is another one?

That way you get the best of both worlds: people are, yes, multidimensional and do have many differetn attributes and characteristics; and, yes, there is such a thing as IQ-style intelligence and it may even be a pretty important thing.

A and B, not A or B.

Dan Chituc July 18, 2007 at 4:27 pm

@ Attila Smith
As I freely admitted, I haven’t read the book yet (though I absolutely intend to in the near future), but even given the fact I don’t know the entirety of the material in the book I can’t say I agree with the light you’re trying to paint my objections in. It IS irresponsible to attribute lower performance on an IQ test to systematic inferiority of a racial or geographic group unless (and note this unless) there is compelling evidence to suggest that link above other possible explanations. I certainly don’t consider the fact that an underdeveloped country is scoring lower on IQ tests to be evidence that they are genetically less intelligent, and I doubt most people would either.

If the book does provide evidence to back up such a claim, or cites other works that provide that argument, then I’ll be front and center apologizing for having jumped the gun in judging their claim and I’ll be happy to discuss the issue based on the merits of that evidence. I just happen to find it doubtful that a book devoted to the analysis of national IQ tests also happened to find the time and space to build a compelling case for a conclusive genetic inferiority in intelligence among certain racial groups.

I’m not saying that this issue is taboo and can’t be studied, but I am saying given the history of such claims being made without basis and used to extremely distasteful ends, there is a burden on people discussing the issue to be sure of their facts before they make claims. That should be a given in all areas of intellectual discussion, so I don’t think it’s at all an undue burden on research to make sure that’s the case here.

joan July 18, 2007 at 4:40 pm

Civilizations have have been around for over 5000 years and during that time the location of the most prosperous has not been in the countries that are now developed. For the most part there was little movement of population until recent times. Any theory that tries to connect economic success of nations to genetics through IQ testing needs to account for the fact that Northern Europe was a backwater until 500 years ago and during much of human history places that are now third world countries were the centers of civilizations. The correlations between the results of IQ testing and national income need a lot more study to determine which is the cause and which is the effect. From what I know of IQ testing, it represents a composite number measuring many abilities, which is why people with the same IQ excel in different fields. Which of the abilities are most valuable is determined by the nature of the society, for example visual memory is important in learning to read and also in a world without maps so you can find your way home, but maybe maps were invented by people compensating for the lack of this skill.

Tino July 18, 2007 at 4:57 pm

Cowen is mixing (at least) two things.

Do the villagers according to him actually have strong ability for abstract thinking, and are only not well measured by potential IQ tests because of lack of experience? Or o they have lower g, but compensate with a bunch of other soft qualities?

Not clear. If Tyler Cowen honestly believes in the first hypothesis it should be easy to test. There are PLENTY of IQ tests that are not written. IQ tests in third world countries are by the way mostly done by the educated middle class in the cities, not illiterate villagers.

Like many others Cowen confuses a scientific explanation (low average IQ) with a personal attack on his friends in Mexico. He shouldn’t. IQ is not a measure of human worth. Hitler probably had a reasonably high IQ.

However if Cowen indeed admits that a group are good at gossiping and catching fish, but not particularly good at things the market actually values, such as processing abstract information, he has not dispelled the IQ-GDP link.

Lastly Tyler Cowen is making the same feel-good-but-silly mistake Diamond makes in Guns. Fine, you are impressed by how much more than you the natives know about their environment. But the relevant question is how much time Cowen or Diamond would need to match and supersede the natives at “predicting rain†, identifying plants in their surrounding or “mending torn amate paper†.

If you lived there your entire life, or even 6 months in their village, would the average high-IQ individual honestly do worse than Yali and Juan Camilo? Would Juan and other Mexicans do as well as Americans in IQ tests and intellectually demanding (and from the market demanded) tasts if they went to American schools and became familiar with paper and pen tests?

So why aren’t they?

Marc July 18, 2007 at 5:35 pm

As I freely admitted, I haven’t read the book yet (though I absolutely intend to in the near future), but even given the fact I don’t know the entirety of the material in the book I can’t say I agree with the light you’re trying to paint my objections in. It IS irresponsible to attribute lower performance on an IQ test to systematic inferiority of a racial or geographic group unless (and note this unless) there is compelling evidence to suggest that link above other possible explanations. I certainly don’t consider the fact that an underdeveloped country is scoring lower on IQ tests to be evidence that they are genetically less intelligent, and I doubt most people would either.

It’s been a while since I read the book, but if you look into the research on intelligence testing, there is some extremely compelling evidence that the differences in intelligence observed between certain racial groups is substantially genetic.

Take whites and blacks. There is a fifteen point gap in average IQ scores between these two populations that consistently shows up in every developed country where the two groups are tested, from America to Britain to Brazil. In America, a metastudy (google: Minnesota Scarr Adoption Study) found that while black children adopted as infants by middle class white parents scored higher than the black average as young children (though not as high as their white adoptive brothers and sisters), those gains eroded as they grew older, and by adulthood, their IQs had regressed to the black mean.

Why should this be? Studies of twins who have been seperated at birth show that, while the twin raised in the better household often had a higher IQ during childhood, the twins’ respective IQs approached parity as they aged. This suggests that environmental influences on IQ wear off as we get older, and as adults, we are left more or less with whatever IQ is set by our genes. If you look at the Minnesota Scarr Adoption study with this knowledge, it really does seem that black children get a “boost” from being raised by whites, but that the boost is artificial and temporary. As adults, they do no better on intelligence tests, on average, than other blacks.

So if the fifteen point gap between blacks and whites is genetic here in the U.S., we should expect 15 points of whatever gap is present between black nations and white nations to also be genetic, since whites in Europe share the same general gene pool as whites in the States and blacks in West Africa share the same general gene pool as do blacks in the States. If I remember the book’s findings correctly, the gap between Europe and sub-Saharan Africa was more along the lines of 20-25 points. So it stands to reason that 15 points of that difference is genetic, and the other 5-10 points is due to severe rates of malnutrition, vitamin deficiencies, and God knows what else.

In regard to the differences between other racial groups, there hasn’t been as much testing, so it’s more difficult to say. Personally, I suspect that the 5 point difference between East Asians and whites (favoring East Asians) is probably genetic, because in every white country that East Asians move to, from the U.S. to Britain to Italy to Russia, they consistently outperform the natives. But I wouldn’t take a firm stance on that, just because I haven’t seen the same quantity of evidence.

Anyway, the information is out there. You just have to have a strong enough stomach to go through it. Personally, I sympathize with people who are resistant to the idea that these differences exist, because a lot of crap has been done to people in the name of real and perceived racial differences. But if the science says these differences are there, what can you do?

BW July 18, 2007 at 6:23 pm

Professor Cowen & his supporters make a rather curious implicit assumption:

There is no population differences in intelligence.

I cannot take anything you say on the topic seriously until you present a credible evolutionary theory supporting this claim. Can you? If so, please share as I am rather curious and have wondered for years…

Also, recent empirical evidence suggesting substantial recent human evolution, including in neuronal function must be dismissed. I suggest you start with thrashing this rather ‘racist’ pnas article from 2005

Good luck!

RJ July 18, 2007 at 6:25 pm

I would be most interested in reading Tyler’s response to Jason Malloy’s comments.

If past history is any guide, you will be disappointed.

Tino July 18, 2007 at 6:50 pm


A lot of the factors you mention (good governance etc.) are partially or wholly a function of IQ, and should not be controlled for.

Multivariate regressions are not very accurate in my opinion, but since you asked for it: Yes, they do uphold the predictive power of IQ as a determinant of growth.

The history of civilisation is consistent with IQ differences, especially assuming that selection for it took of a few thousand years ago. China, ancient Greece and Rome are all high IQ areas. Mesopotamia, Egypt and Indus might well have been above average 7000 years ago.

Invading more advanced neighbours and claiming their achievements does not count (the so called Muslim civilisation). For all the hype the Americas only managed a stone-age level civilisation, without literacy or advanced tools. Same for Africa and Oceania.

pwyll July 18, 2007 at 6:58 pm

Regarding objections raised that russians or chinese should be just as rich as americans if their IQs are similar, refer to here:

which gets excellent GDP predictability using 3 variables: IQ, economic freedom, and oil wealth. The methodology is overly complicated (the guy should be using log-income instead of income, I think) but the relationship is there.

As an aside, I wonder if Tyler posts these troll-bait entries *expecting* that the well-informed will come in and beat up the facile arguments in them to a pulp. It’s as if he desparately wants the truth to be known, but desparately doesn’t want to be seen as believing it! What other explanation could there be for repeated blog posts, featuring much more simple-minded arguments than the average post quality, with open comments?

Alex July 18, 2007 at 7:25 pm


The claim that economic freedom is caused by high IQ is a highly dubious claim. There are above average IQ people that still believe in socialism and stupid people that oppose it.
Political institutions depend to a high degree on historical contingency, intellectual fashions and the like.

At any rate, even assuming that you’re right, the causal chain of high IQ –> economic freedom –> economic prosperity has quite different policy implications that a more direct high IQ –> economic prosperity.

For instance, it focuses on reforming governmental institutions as a solution to poverty rather that claiming that in order to advance economically you should watch your diet.

Multivariate analysis can have problems, but at least it can be used to make more sensible claims about causation. Given that both IQ and economic freedom have similar correlations with GDP when regressed separately, no conclusion can be drawn about the causal factor without further analysis.

fustercluck July 18, 2007 at 8:42 pm

Let’s just cut the bullshit and move straight to the master race/eugenics part of the discussion, shall we?

It’s the pink elephant in the room at which many of you are winking.

fustercluck July 18, 2007 at 8:46 pm

And now come the myriad protestations…

Dareano July 18, 2007 at 8:57 pm

Sure fustercluck, why not. I mean, it’s not like you can refute comments made from posters like Jason Malloy. Whenever this topic comes up one side presents well thought out arguments backed by a ton of research and the self satisfied and smug commentators simply retort, “bububuracist”.

Also no researach shows that ‘the master race’ has the hishest average IQ. Odd…

Steve Sailer July 18, 2007 at 9:44 pm

The nature vs. nurture arguments about IQ can be a distraction because what we know is that differences in average national IQ are going to be around for a long time. If the gap suddenly disappeared in all the babies being born tomorrow for some magic reason, the gap among the workforce wouldn’t begin to shrink until 2025 and wouldn’t disappear until 2072.

So, the current realities demand far more study than they’ve gotten from the economics profession. I appreciate Prof. Cowen’s complicated method for calling this to the attention of his fellow economists.

fustercluck July 18, 2007 at 9:52 pm

I think you don’t read very well. (Please don’t breed.)

I’m conceding that there might in fact be correlation between wealth building and IQ – I won’t go so far as to admit causation but for argument’s sake, let’s say that’s true.

Now what? Is there something that should be done with that information? Is it outrageous to point out that theories like this have driven nefarious agendas in the past, and suggest that this line of thought would be used for those same purposes now and into the future?

Amazing how much time and energy certain people spend in proving theories only to play the dumb card at the conclusion.

Hopefully Anonymous July 18, 2007 at 10:47 pm

Dareano at Jul 18, 2007 8:45:50 PM, Why talk about white-identified americans and african admixture in terms of the “average white american”, when 30% of white-identified americans have traceable recent african admixture, and 70% of white-identified americans don’t have traceable recent african admixture? Those seem like two discrete populations, and I don’t see the utility of averaging them together if one is trying to determine the relations of populations, actual genetic ancestry, and IQ. It seem to argue to me for moving away from self-reporting of social race and towards genetic ancestry and admixture tests in doing these type studies.

Steve Sailer July 18, 2007 at 11:11 pm


Thomas Sowell pointed out years ago that IQ tests that call for abstract reasoning won’t necessarily do a good job of discerning the full genetic potential of people who grow up in Third World cultures where abstract reasoning is ignored. Sowell cited the example of two 17-year-old African boys who made witty fun of an IQ test question calling for abstract reasoning. They had a real talent for the “vivacious gossip” you value highly.

But, as Sowell went on to point out, the IQ test was also measuring their economic potential correctly. A 17-year-old who despises abstract reasoning has a limited future in a modern technological economy.

And that’s what we see: average national IQ scores have strong predictive power for economics.

Jumpyg July 18, 2007 at 11:26 pm

Dan Chituc said:
I’m not saying that this issue is taboo and can’t be studied, but I am saying given the history of such claims being made without basis and used to extremely distasteful ends, there is a burden on people discussing the issue to be sure of their facts before they make claims. That should be a given in all areas of intellectual discussion, so I don’t think it’s at all an undue burden on research to make sure that’s the case here.
That’s just great. Let’s shut down scientific inquiry and discussion because of fears of the resurrection of Nazi Germany. How about being a grown up and discussing the issues and not trying to shut down debate? The Nazis are long gone, and they’re not coming back. It’s safe to come out from under the bed and discuss this topic.

PhillyGuy July 18, 2007 at 11:39 pm

“Is there any reason not to call IQ-test-taking talent “abstract reasoning power” instead of “intelligence”? ”

Good point Michael. I believe that’s why Herrnstein and Murray chose to use the term “cognitive ability” instead of intelligence in the Bell Curve. Heck, we could even refer to it as developed cognitive ability and remain agnostic the role of genetics with respect to group differences. Unfortunately, whatever their causes, the obsevered differences in “developed cognitive ability” do seem to be real as far as their real world economic effects and, as Steve Sailer noted above, seem to have changed little in relative terms in the last 50 years and there apparent intractibility makes it seem unlikely that they will change in the near future.

aem5 July 19, 2007 at 1:15 am

If IQ is the “key to understanding economic underdevelopment” how did the South Koreans get so much more IQ than the North Koreans?

TGGP July 19, 2007 at 1:30 am

Regarding the question of the importance of IQ for economists, the reason is that they often control for various factors to determine how much of an influence other factors have. You might do some regressions showing education to be very important for growth, and then you would think that in order for a poor country to develop it needs to start educating its people. However, education is often correlated with IQ, and controlling for IQ helps to get a better picture of the gains that can be gotten from education, which for most developing countries would still be significant, but will not turn them into Asian/Celtic “tigers”. Bryan Caplan at first thought that education was the most important thing for “thinking like an economist”, but when he factored in IQ it turned out THAT was the most important. He made the point I just made above here, which I apparently forgot about but remembered part of his argument.

Steve Sailer July 19, 2007 at 2:33 am

Right, Richard Lynn has since adopted my point that the roughly 15 point IQ gap seen between the average African and the average African-American is solid evidence for a sizable non-genetic influence on IQ differences. Black Americans share about 80% of their ancestry with West Africans, but their 15 point advantage in average IQ over Africans is perhaps five times larger than a simple genetic model would account for. So, it appears that the African environment tends to depress IQ below its genetic potential.

Something similar may be true for Tyler’s Mexican village as well.

But, of course, that doesn’t mean that IQ tests are inaccurate at estimating the economic potential of people living in IQ-depressing environments.

According to UNICEF’s Micronutrient Initiative, two proven and cost-effective ways to prevent medical syndromes that lower national average IQ is fortifying staple foods with iodine and iron. We’ve been doing this in the U.S. since the 1930s. Putting iodine in salt has largely eliminated here the disease of cretinism.

Russell Nelson July 19, 2007 at 2:55 am

This discussion would be more interesting if the IQ test was renamed a “Wealth Predictor” test.

adrian July 19, 2007 at 5:17 am

Tyler strikes me as an honest, sunday-school kinda guy, the Ned Flanders of economics, sharing both his naive optimism and faith in the supernatural. He believes what he says.

Kismet July 19, 2007 at 7:39 am

Tyler and Darwin are much more humble and therefore open to the likelihood of competing theories.

Just weird.

josh July 19, 2007 at 8:54 am

As an uninformed observer, I’m glad to see Prof. Cowen responding to comments. Thanks for your time, Tyler.

Petrarca July 19, 2007 at 11:05 am

You’ll have to pardon me leaping in just to go after two posts from yesterday afternoon.

I think that Marc’s comment (5:35) ignores an alternative, and equally compelling explanation about IQ differences: social norms, group behaviour, whatever you care to call it. I’ve heard the same study about cross-race adoption used as an example of American blacks succumbing to pressure about “acting white,” an aregument which would be initially mitigated by growing up in a white household and reinforced by the decrease in scores when American blacks are reminded of racial differences prior to taking cognitive tests.

Tino’s comment at 6:50, though, sounds off-base. There have been no major population movements which would account for the dilution (catastrophic wipe-out sounds more like it) of the above-average populations which catalyzed civilisation in Egypt and Mesopotamia on the scale which IQ&WN demands. Mesopotamia is a weaker argument, since cities were sometimes destroyed en masse and mass migrations occurred (but only constituted a large minority in the best of times, demographically speaking).

Egypt, however, hasn’t had a population shift since the Sea Peoples attacked. Throughout its history, the population of the region has never significantly changed. Unless you argue along the lines that Black Athena is an understatement, that the Book of Exodus represents the literary retelling of utterly massive displacement of the original population, or that the Arab regiments resettled al-Misr completely on their own, there is no basis to suggest that Egypt has a watershed event or tradition of population movement to account for lower IQs today but high scores earlier.

I’m also taken aback by the suggestion that Tino’s blanket descriptor of “the so called Muslim civilization” accomplished nothing. It betrays an incredible historical oversight to suggest that Umayyad Spain or the Abbasid Near East “don’t count” in terms of whatever technological, social, or academic “achievements” define civilisation.

Half Sigma July 19, 2007 at 12:21 pm

Anecdotal stories prove nothing.

Maybe you’re just trying to increase your stockpile of “politically correct” posts in order to preserve your career in academia. Or do you really believe that one person’s impression of a few people is worth more than carefully conducted statistics-based research?

Comments on this entry are closed.

Previous post:

Next post: