IQ and the Wealth of Nations

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.


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.

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...

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 . . .

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.

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?

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.

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.

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


"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.

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.

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).

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?

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.

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.

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.

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.

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.

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.

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:

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

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?

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.

@ 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.

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.

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?

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?

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!

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.


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.

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?


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.

And now come the myriad protestations...

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...

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.

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.

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.


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.

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.

"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.

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

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.

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.

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

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.

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

Just weird.

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

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.

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?

If this is a charge of racism against Whites then WHY ON EARTH would Ashkenazi Jews and East Asians have the highest IQ scores. If the “master race† (aka evil White men) were intentionally stacking the deck against “minorities† then wouldn’t the master White racist make sure the test didn’t put Jews and East Asians at the top of the IQ pyramid?

The last time I checked the KKK didn’t admit Jews or East Asians into their organization. If this is truly an instance of cultural bias shouldn’t East Asians score worse than American Blacks? If we are to argue that the test is intentionally biased against American Blacks then why wouldn’t the test designer bias it against East Asians and Jews as well?

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?

Yes. I think peoples' policy prescriptions in response may differ, but there are conclusion that can be drawn. If low-average-IQ retards development, we need to find some means either of equalising IQ or of integrating low-average-IQ areas into more developed economic and managerial infrastructures, so they can reap the benefits of economic development despite low-average-IQ that makes it difficult for them to attain that development without substantial outside interference.

So, just as one example, perennial third-world attempts at autarky should be discouraged. High-IQ members of low-average-IQ societies should be strongly encouraged to return home eventually to careers back in their mother countries -- otherwise, those mother countries will be left even worse off, with lower average IQ and so forth. Equalising average IQ's could involve exporting high-IQ individuals to low-IQ areas. And . . . that kind of looks like colonialism (less White administration of colonial areas than Indian or Chinese immigrant control of native enterprises and industry). But that's do-able too. China is doing a little of that kind of thing down in Africa, e.g. in Angola. And we could do a lot more.

Making inferences between national income levels and IQ is laughable. The IQ test was invented a century ago, when these differences were already huge. So of course there'll be a high correlation (as you'd also find between per capita copper consumption and income, but no one would argue that copper caused development).

I'm sure that if you measured IQ in 300 a.C. you'd find that the Maya, a literate and mathematically advanced civilization, would score much higher than your typical Germanic tribe. So why are the Maya today desperately poor and the Germans rich? It ain't IQ.

Tino, I've heard you state before that you are of Iranian Kurd descent, though born in Sweden and currently residing in America. That would suggest to me that you come from a muslim background, but if so you'd be the first to use the phrase "so called muslim civilization". I do agree that the Arabs didn't have much of a civilization, but they conquered others (Egyptians, Persians) who did and rose from that. I think you overlook a case in which islamization did lead to civilizing: the Turks. They were originally Tamerlane-style steppe barbarians, and became the Ottomans.

Hopefully Anonymous, self-reported race isn't that bad. Self reported race matches genetic tests 99.85% of the time.

South Asians are caucasians, though a rather distant branch from europeans. Ethiopians are not. They are Africans with a larger than average (for Africa, not African-Americans) portion of caucasian ancestry, just as nearby Arab and Berber populations have higher African ancestry than other caucasian populations. Checking out Lynn's tables at Sailer's site, I see that average IQ among Ethiopian Falasha (who apparently have been shown by genetic tests to have some jewish ancestry from a long time back) is 63. The average IQ for Indians from Fiji in Australia is 84. The average IQ for Indians in India is usually 81 or 82 with one study showing 78. Keeping in mind that India is a big place with a lot of variation, this gels with the common employment of Indians as "knowledge workers" and the function of some of them as one of Thomas Sowell's "middleman minorities" and Amy Chua's "market-dominant minorities", whereas we do not see the same thing for Ethiopians.

Taeyoung, it isn't just asian culture (although asians do better academically than their IQs predict and blacks underperform for their IQs). Asians adopted by whites score more like asians than whites.

Remember that we should be talking about existing variation in culture rather than imagining a sort of platonic ideal. Do we see any cultures where people descending from sub-Saharan Africa do not exhibit this sort of gap? Flynn (of the Flynn effect fame) claims we do, which he uses as support for a cultural explanation. I advise you to go over the debate between him and Charles Murray, which is both cordial and informative, here. If only discourse both on this issue and numerous others could be so!

TGGP wrote The correlation is pretty strong, especially when you factor in indexes of economic freedom, like the ones the Fraser Institute puts out.

I interpreted the person's point as saying that correlation is not causality. More firetrucks at bigger fires doesn't mean firetrucks cause fires. All I've seen presented are correlations. IQ could be endogeneous to wealth. Wealth and IQ could both be caused by some other unobserved factor. Do the authors of IQ and the Wealth of Nations have a section dealing with problems of endogeneity?

I completely agree with Jason Malloy with enough knowledge of the subject to know that in fact he is right in all he says.

I also agree with Michael Blowhard about there being several different kinds of intelligence, or what he calls “talents† – though I think most of his non IQ talents can be more or less summed up as social intelligence or people smarts. Some people have a real ability to intuit how others feel with fine precision. That usually, though not always is accompanied by greater empathy. Autism, and it’s higher functioning variant Asperger’s Syndrome is the polar opposite of this. Some with Asperger’s have high IQ’s.

Tyler, to answer your lead off question, at least in part, I would once again like to recommend "IQ and the Wealth of Nations" to your readers.

It's very illuminating.

re: TGGP:

Taeyoung, it isn't just asian culture (although asians do better academically than their IQs predict and blacks underperform for their IQs). Asians adopted by whites score more like asians than whites.

Fair enough. Two thousand years of selection pressures in mildly polygamous cultures where status and success are closely linked with education and the ability to take standardised exams are probably not going to be *entirely* without effect.

But if we're talking about "cultural bias" (as in the post I was responding to), and comparing Blacks and Asians, a cultural explanation is more than adequate to explain why Asians would score better than Blacks, even if it is not sufficient to account for all the evidence.


"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?"

Absolutely! If true, this would mean that adding iodine and salt to a malnourished nation's diet might well turn out to be the best developmental policy yet tried, because a lack of those keeps people from reaching their IQ potential, so to speak (see Steve Sailer's post at Jul 18, 2007 3:08:24 PM). This is a rather exciting perspective given that foreign aid so far hasn't exactly been a huge success story.

(Note that this implies that there is definitely a causal arrow from wealth to IQ via nutrition - whether it also runs the other way is the only contentious issue here.)

The Cunha-Heckman paper cited by Tyler is (free) as a IZA working paper (or wait for the American Economic Review...)

To respond to Tyler's latest postings on the wonders of Pre-Columbian civilization, I wrote up a simple genetic model in 2000 to explain this. Over the years, a few dozen Mexicans have emailed me to say it offered the an insight into their country's social structure that they'd been looking in vain for for most of their lives. From my 2000 article:

After almost twenty generations of intermarriage between whites and Indians, Mexico has ended up with an almost wholly white elite, a vast mixed race (mestizo) working class, and at least 10 million extremely impoverished pure Indians who have never assimilated into Hispanic culture. And the ruling class [according to Fox's Foreign Minister Jorge Castaneda] is becoming ever whiter. How did this happen? ...

The first column in this series described the corruption of Mexico's white rulers. The second outlined race in Mexico. This will explain the mechanism through which Latin America's seemingly anti-racist freedom to marry across color lines produces such racially hierarchical societies ...

In Mexico, white conquistadors interbred with Indian women to produce mestizos. Let's assume that in 1519 the Spaniards and the Mexican Indians were equal in IQ and other significantly heritable traits that aid economic success. I'll follow Jared Diamond (Guns, Germs & Steel: The Fates of Human Societies) in stipulating that the conquistadors won solely because by luck they had the guns, germs, and steel on their side, and that the only reason they had superior technology was because Spain was less isolated than Mexico.

Now, imagine a conquistador and his Indian woman have two sons in the 1520s. These two mestizo brothers grow up and go out in the world to seek their fortunes. One is smarter, and he strikes it rich. The other wasn't so lucky in the genetic lottery, and he becomes poor. The rich son has a wide variety of potential wives to choose from. Like most men, and like almost all Mexican men, he is more attracted to blonde women, and thus marries one. (If you aren't familiar with the depths of Mexico's blonde obsession, try watching Spanish-language TV shows. Almost all the women on Mexican TV look like Finns.) His impoverished brother, in contrast, cannot attract a blonde wife. So he marries an Indian girl.

Then, the brothers have children. On average, the smarter, richer brother's kids, who are 3/4 white, are smarter than their underprivileged 1/4 white cousins. They're smarter not because they are whiter, but because their father had more smartness genes than their uncle. This trend continues: in both families, the smartest, most energetic, and most ruthless sons marry the blondest wives, while the blondest daughters marry the husbands with the most Right Stuff. Repeat for another dozen and a half generations. By 2000, this pattern could lead to the most European-looking people being the most naturally formidable, even if they weren't when they arrived in 1519.

Now, in Mexico every century or so, there is a massive upheaval like the Revolution of 1910. The white monopoly is fractured. Up through the cracks come the most talented mestizos and Indians. They start dynasties that persist to this day †¦ but their grandsons and great-grandsons are notably whiter than they were, since the men of the family have been exploiting their social ascendancy to marry white women. (Of course, many rich Mexican men father second families with their lower-ranking mistresses. But these kids seldom get the breaks in life that the legitimate children do.)

To sum up, as can be seen from the comments, the study of IQ offers a sizable and sophisticated body of knowledge of which most economists are strikingly ignorant. The economics profession would be well advised to shed their prejudices against studying the subject of IQ.

Petrarca: 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.

Again, twin studies consistently suggest that environmental influences on IQ wane with age. You seem to be arguing that black adoptees are an exception to this, that blacks actually become more susceptible to environmental influences on IQ as they age. Why should this be? Why should age correlate positively with genetic IQ in non-black adoptees, and negatively with genetic IQ among black adoptees? Why should black test scores depart from their genotypic IQ as they grow older in response to environmental influences, when twin studies suggest that the universal trend is for people's test scores to approach their genotypic IQ as they grow older?

Fustercluck: I find that an odd prescription for an ailment which most of the zealots here are arguing is largely a nature (genetic), not a nurture (health/environmental issue. I'm not against this of course, but it flies in the face of most of the posts in this thread.

Unless I've missed something, no one is arguing that IQ is unaffected by severe nutritional defincies, or that many people in the Third World may not be living up to their genetic potential. People are arguing that environmental influences alone do not explain the significant gaps in intelligence recorded between racial groups. You can think that the fifteen point IQ gap between whites and blacks in America is largely genetic, and also believe that a substantial portion (i.e. 10 points) of the 25 point gap between whites in America and blacks in Africa is environmental, without any logical contradiction.

IQ is not a measure of human worth. Hitler probably had a reasonably high IQ.

It is a measure of human worth. IQ tests have shown that certain populations are lacking in the tools needed to succeed in a modern capitalist society, which implies that these people are inferior since they're unable to compete in our world. It's probably best to deport those who have low IQ, and eliminate the groups with low IQ in the world as they're the source of much worry for guilty Westerners and they prohibit the economic activities of those who can profit greatly from the minerals in resources in places like Africa and Latin America.

Given that these groups are unable to compete and live in misery and will never be able to live comfortably like Westerners do, why don't we just put them out of their misery and kill them off.

Prof. Cowen writes (I paraphrase): "The Aztecs conquered an empire and built a really impressive city. Then the Spanish conquered and [inadvertently, by transmitting disease] wiped out as many as 90% of them and enslaved the rest."

And this proves... what? That the descendants of the survivors of those Aztecs (and their numerous imperial tributaries) must now have high abstract-reasoning abilities? No, the story doesn't prove, or even suggest that. (It may even be the case that cultural factors caused a disproportionate number of higher-IQ Mexicans to perish in the post-Columbian epidemics and conflicts, leaving the survivors and their descendants less bright on average than their pre-Columbian forebears. We just don't know.)

Although it seems to have been lost back about 80 comments plus a shouted response from Prof. Cowen and a second post by Prof. Cowen, the most interesting topic here was that Cowen implied his anecdotal experience with some charming (often drunk? Were you drinking too, Prof?) villagers in Mexico trumped both the science of 'g' (usually discussed as IQ) and sociographic/ economic studies which suggest that broad distribution of abstract reasoning ability ('g') is a key factor in modern industrial economic productivity and growth. Commenters argued otherwise.

Cowen has retreated a little, but into a fogbank. He says that the multidimensionality of cognitive abilities is so confusing that the consistently- reproducible and highly- predictive principal- component result ('g') of factor analysis may be ignored, that sociographic/ economic inferences aren't certain, and anyway (I paraphrase radically) "things besides IQ matter as well, so there!" Cowen cites, e.g., James Heckman's papers to the effect that other traits (say, conscientiousness) also have a strong effect on individual educational and occupational attainment and economic achievement.

Let's look at Heckman again. Sure, individual achievement depends on factors other than IQ. But who ever suggested otherwise? The rest of us were looking at group achievement, and specifically at ability to boost a modern industrial economy, not at getting ahead in one's local social milieu.

Conscientiousness, aggressiveness, etc. affect individual performance in society, and have the same effects on individual outcomes in societies of mean-IQ-85 as in societies of mean-IQ-100. But no matter what non-IQ traits you have, you aren't going to make a good refrigeration mechanic if you can never quite grasp how heating the ammonia boiler with a propane flame can make the heat exchanger in the 'fridge box icy cold.

Really, Heckman's work is inapposite. How can I put this in economists' language? Non-IQ factors are more complements to IQ than substitutes for it. A likable person of modest IQ may rise higher in his society than a high-IQ jerk, he may end up bossing the high-IQ jerk, but only the jerk will be able to design that new motor armature for the pleasant fellow's business.

That is why immigrants from low-IQ countries exhibit lower labor-productivity in America than immigrants from high-IQ countries, even though both trudge through similar impediments to assimilation, and (just a guess) probably both come in a range of personality types.

(People other than Heckman often publish on this subject. They always find the same results: after you control(!) for IQ and its proxies, "social competence" factors predict educational attainment (or whatever).)

I suggest that the next time Prof. Cowen visits San Augustin Oapan, he ask his affable, locally-sophisticated friends to take Raven's Progressive Matrices tests (while everyone's sober, of course). He should use the scores to check whether his subjective perceptions of cleverness correspond to his friends' RPM (~= fluid-'g'/IQ) scores (yes, recognizing that villagers might have scored differently if raised in another culture or homeland). Then (this is key) he should estimate the 'g'-loading of villagers' occupations (just roughly-- farmhand=low, mechanic=high) and compare individuals' RPM scores to their occupations (perhaps with an adjustment for apparent occupational success). He'll want a scatterplot. He should blog about all of this, and note whether the new data prompts any revision of his bottom-line views. I'm not really kidding about this-- careers in ethnography have been built on little more, and the work might support a quirky note in a professional economics journal.

Anyway, if you have a population with a large proportion of dim bulbs, you will have trouble growing a high-tech economy. The not-so-smart folk can't do it by themselves. A few bright people surrounded by dullards will often end up caring for them (as doctors, say), managing their low-skilled labor, or exploiting them. Not many will be free to advance their culture's knowledge and techniques. There's ample evidence of this problem, and you can read Amy Chua for a compelling narrative of the frictions it generates. (And sure, some bright people will become architects so the Emperor can dragoon a hundred thousand subjects into dragging stone for impressive buildings. Blocky pile-of-stone buildings (Amerindians never invented cement, the true arch, or the truss) don't indicate a high-IQ population, just an organized one.)

Shall we let the air out of a few more tires? Prof. Cowen cites "the selective breeding of corn" as "one of mankind's most impressive scientific feats." Nice technical achievement? Yes. Scientific feat? No. There's no evidence that primitive maize-breeders knew or used the scientific method or learnt anything new from their work. Would Cowen not consider the breeding of domestic cattle a greater "scientific feat? " Or do we only laud Amerindians in such terms for sticking with a tedious program of selective breeding enlivened by the occasional discovery of a useful mutant? (Scientific maize breeding was an innovation of the late 19th Century.)

"The Maya, Inca, and Aztec" (I paraphrase again) "did all kinds of cool stuff." So? That isn't even personal anecdote. It's appeal to (irrelevant) history. Centuries ago the academic achievements of some Amerindians were comparable to those of various Europeans and Asians. That proves nothing about the average IQ of modern Mexicans nor about their potential for high achievement in a modern industrial economy.

"Negative supply shocks," put the ancestors of today's Mexicans on the hacienda, demoralized them, and devastated their culture. Also nearly irrelevant. Who cares whether Mexicans' ancestors were peons? What we want to know is, what can they do today? If those folk are malnourished, we can fix that. If they're ill-educated, we can fix that. If they're culturally deprived (by today's standards, not those of AD 1520), we can fix that. And if they're not very bright, gee, uh, well, sorry, we cannot fix that.

So what do we know? We know that bringing many hispanics (Mexicans, chiefly) into the USA, giving their kids plenty of food (enough that many become obese), giving them free educations, and giving them full access to American pop culture, produces a population which fails at triple the rate of white Americans to attain even high-school graduation.[1]

Is the conspicuous Hispanic educational non-achievement in America due to low IQ? Probably in part. Hispanic (Mexican) IQ averages lower than white American IQ and hispanic SAT scores (an IQ proxy) predict hispanic college success (low) quite well. But black Americans with even lower average IQ are more likely to complete high school--so probably some non-IQ factors are also to blame for poor hispanic educational attainment. The data supports both Cowen's hypothesis that non-IQ factors matter, and the hypothesis that low-skilled hispanics (again, many from Mexico) fall short (on average) on non-IQ factors which promote success for themselves and their descendants in a modern industrialized economy. (Although IQ may be the one ring to rule them all. High IQ does not predict high SES all that strongly, but low IQ predicts low SES quite reliably.)

So finally, what about that Flynn effect? Well, Flynn and his collaborator Dickens believe along with all other informed individuals that IQ is an important predictor of educational and occupational attainment. Dickens and Flynn think the American black/ white mean IQ gap has narrowed a bit recently, but chiefly for young people-- the adult gap has remained nearly the same. The change is trans-generational only and slow, so people who have low IQ's today will have low IQ's for the rest of their lives (unless medical science amazes us). Dickens and Flynn agree with everyone else that it is difficult to change individual or group IQ's on purpose-- no one has identified any simple or distinct interventions to do either. They don't even know if black and hispanic IQ's will respond to the same influences.[2]

So if Prof. Cowen's Mexican friends have low IQ's, they probably won't be very productive in an industrialized society, and we don't know any way to fix that. Furthermore, their offspring will likely exhibit similar IQ's, similar educational attainment and similar industrial productivity. We don't know how to fix that either.

What if those Mexicans have high IQ's (seeing as how they function so well in their environment)? That would be nice. I think it's possible, but Prof. Cowen's unstructured observations don't provide strong evidence of it. I'm not trying to insult Prof. Cowen--I've never heard of anyone who could judge IQ's by casual observation. To estimate IQ accurately and reliably you need some kind of test (and it must measure cognitive function, not amiability--look up Williams Syndrome).

I really hope Prof. Cowen can share some useful evidence with us next time. That would advance this discussion more than additional statistical citations or economists' speculations.

[1] Note that the downward trend in dropout rates over time likely reflects lowering of educational standards and shrinking job prospects for dropouts more than any improvements in student performance.

[2] For example, the late increase in average American black teenage IQ may be due to improved nutrition. We don't know whether there's any room for a comparable improvement in hispanic nutrition, nor whether such an improvement would boost IQ even for teenagers.

It may even be the case that cultural factors caused a disproportionate number of higher-IQ Mexicans to perish in the post-Columbian epidemics and conflicts, leaving the survivors and their descendants less bright on average than their pre-Columbian forebears.

This actually makes sense. If the middle-class tradesmen, who would have higher IQs, lived in cities, where people were more likely to catch disease, then they would be more likely to die. The dumber Aztecs living outside the cities would be more likely to survive.

Good examples of how communism can produce drastically different results for basically the same people are East vs West Germany, North vs South Korea and Hong Kong vs Mao's China.

This is what I don't get. Given the extreme outcomes in these cases, of which a huge percentage could certainly be attributed to the political system (which in turn is hugely attributable to culture, at least pre-information age), how can any study of "average" IQs purport to make any conclusions? How do you control for Mao and Kim Il Sung vs. what's-his-name in Singapore or, for that matter, the House of Saud?

This is a real question, not an argument in disguise.

Mr. Seecof: interesting post. Do you blog somewhere regularly?

iam writes:
"Bill Gates is no Einstein, etc."

Warren Buffet explains why he never invested in Microsoft:
"Bill Gates is a good friend and I think he may be the smartest guy I ever met. But I don't know what these little things (computers) do."

The smartest person Warren Buffet ever met sounds like a strong endorsement to me.

I interpreted the person's point as saying that correlation is not causality. More firetrucks at bigger fires doesn't mean firetrucks cause fires. All I've seen presented are correlations. IQ could be endogeneous to wealth. Wealth and IQ could both be caused by some other unobserved factor. Do the authors of IQ and the Wealth of Nations have a section dealing with problems of endogeneity?
Quit being stupid. Causality does not work backward, and that is how you avoid confusing correlation with causation. East Asia has many countries that had high IQs even while they were poor. After a change in policies, they rocketed ahead. As already mentioned before, there are numerous middle eastern states with lots of money from oil, but it hasn't done much for IQ. Latin America is all upset about the failed promises of neo-liberalism because the only countries that really saw significant gains were ones with most european populations, and at the same time there is no African "tiger" and people of African descent in countries with good policies underperform. High IQ in a child from a poor family predicts that he/she will likely improve their situation later in life. Twin adoption studies bear this out.

But if we're talking about "cultural bias" (as in the post I was responding to), and comparing Blacks and Asians, a cultural explanation is more than adequate to explain why Asians would score better than Blacks, even if it is not sufficient to account for all the evidence.
Given a set of asian children and black children with the same IQs, the former tend to outperform the latter. However, considering that asians have two standard deviations over blacks, the largest factor is the IQ gap.

I find that an odd prescription for an ailment which most of the zealots here are arguing is largely a nature (genetic), not a nurture (health/environmental issue. I'm not against this of course, but it flies in the face of most of the posts in this thread.
Note that earlier in this thread I pointed out that it is not credible to claim the worldwide black-white IQ gap to be entirely genetic. I posted the link to Gene Expression, but the summary is that the gap between African Americans and Africans is way too large for the small group differences in genetics. Africans are some of the poorest and most malnourished (and tropical disease ridden) people around. There is much low-hanging fruit to be had that can and should be use to improve their situation, and the sooner the importance of IQ is recognized the sooner we'll programs to ensure such nutrients as are necessary will be given. Remember though, that it logically follows that when environmental variation is decreased, genetic variation must form a larger part of the remaining variation, so there are diminishing returns. The Flynn effect appears to be reaching its end among first world populations, but Africa is a ways from reaching that point. For singulitarian techno-optimists out there, don't despair of the end of environmental improvement as gene therapy for this and other attributes may become within reach.

This is what I don't get. Given the extreme outcomes in these cases, of which a huge percentage could certainly be attributed to the political system (which in turn is hugely attributable to culture, at least pre-information age), how can any study of "average" IQs purport to make any conclusions? How do you control for Mao and Kim Il Sung vs. what's-his-name in Singapore or, for that matter, the House of Saud?
There are indices of economic freedom. Heritage and the WSJ put out one, I much prefer that from Fraser and Cato. Take countries with similar freedom scores and the one with more IQ will likely grow faster. Sometimes smart countries will outperform less smart ones with more freedom.

So, what we can see from this debate is that while IQ hardly explains everything in this extremely complicated world, it does explain more than economists have traditionally given it credit for (which is virtually nothing). In other words, IQ is an underexploited resource in the field of economics. It's a $20 bill that's been lying on the sidewalk while the entire U. of Chicago faculty walks by.

"East Asia has many countries that had high IQs even while they were poor."

Do you have any evidence?

Well the anti-IQ brigade has been roundly crushed, most have given up it seems. Why? 2 possible reasons. 1. As somebody already mentioned, there is a positive correlation between the amount one reads about IQ and the importance one places on it, so maybe some have been converted by this enormous fact-filled thread. Or 2. They just stopped reading because they didn't like all the facts, and the best way to maintain pc lies in the modern world is to actually believe them yourself. Facts about IQ hurt the PC head, so they close their eyes to them.

It's relatively easy to make such arguments when you're white or Asian and nobody has said to you "your people are too stupid to live in Western culture". The bulk of IQ research only proves the rants and ravings of racists, and as a young Hispanic male, it leads one to believe that there are some closet racists here cheering at the fact that Hispanics and Blacks rank poorly in terms of IQ.

These tests per the interpretation of the information given seems to prove that blacks and Hispanics are unable to cope and live with the reality of the Western capitalist civilization. Thus, the results of the studies prove that blacks and Hispanics are inferior to whites and Asians, and that we as a group are some type of sub-human. Given the links of low IQ to low educational attainment, low employment opportunities, and high rates of criminality and other bad habits, we've effectively discovered the source of the world's problems. In short, blacks and Hispanics will NEVER catch up and will always be the world's retards and intellectual midgets.

Now reading the above posts if you're black or Hispanic, and intelligent. You end up going from feeling intelligent to feeling as if one is a fluke and some aberration. It's highly depressing and there's an obvious reason as to why some of us would prefer that this information be suppressed, lest this become public knowledge and be used as a tool to encourage poor treatment and general harassment of blacks and Hispanics regardless of citizenship status.

Of course, this leads one to wonder, what do the people here, the intellectual giants that seem to crowd this blog's comments area plan to do about the pool of low IQ in the world and specifically in America. There's a whole pool of blacks and Hispanics who have citizenship and even if you were to magically end immigration by these groups, you'd still have to deal with the effects of both groups living in the country. There appears to be no real solutions to the problem and I don't think Americans will take kindly to having poor people around in their country who simply cannot function.

Beta Academic snivels:

"some of us would prefer that this information be suppressed"

Cowardly pussies can't take the truth. The Noble Lie is an invention by cowardly, dungeons and dragons playing neocon girly-men.

A mistake many people (also in this thread) make, is to confuse 'genetically determined' with 'inheritable'. The first means that a certain fenotypical trait is largely determined by an individuals genes, while the other means that the fenotypical trait is correlated to THE PARENTS' fenotype.

The .7 correlation in IQ between identical twins raised in different families suggest a high genetic component to IQ, and probably to most other measures of intelligence. But that doesn't necesarily mean that the children of intelligent people will be intelligent. In fact, the observed correlation between the IQs of non-identical siblings in different families is much lower, in the order of .1-.15 (siblings have basicaly the same genetical relation as parents vs children). So, on average the children of 2 highly intelligent people will be above average intelligent, but much less so than their parents, while the grandchildren of 4 highly intelligent people will very much resemble a cross-section of the population.

This result isn't too surprising. Whatever the genes may be that are related to intelligence, they wll be many, and their interdepence will be complicated. So, if a given constellation of genes lead to high intelligence, that doesn't mean that 50% of them mixed with 50% of some other 'intelligent constellation' will lead to intelligence. ( by the way, the results are similar for under-average inteligent people and their children, but in reverse).

What does this mean? Basically, these results suggest that 'evolutionary stories' about for example intelligent mexicans picking out white wifes, making the average white more intelligent, have absolutely no basis. Current scientific knowledge suggests ( and of course no more than suggests) that if you were to pick the 50% most intelligent people of a population and put them on an island, and the 50% least intelligent on another the intelligence of the great-grandchildren of both populations would be close to the average of the original population.

Of course, this still allows for differences in 'base average' between continuous populations. But the way these differences might have developed and have been propagated will have little to do with the slight actually measured correlations in IQ between siblings, and nothing with the high correaltion between identical twins

Marius at Jul 20, 2007 7:42:09 AM, Why don't humans regress to the mean intelligence of primates? It would seem to be according to your theory humans are endogamous (due to gamete incompatibility with other primates) as a species, and as a species we're keyed to a particular IQ. That's why the IQ's of the low IQ people would rise over generations and the high IQ people's IQ would fall over generations, until they reached the current average, according to your theory, right?

But according to your theory, I don't see why the high IQ isolated population and the low IQ isolated population would approach the exact same keyed IQ, because whatever heritable component their is to genetic IQ (and you seem to acknowledge the heritable component is more than zero) the high IQ isolated population seems likely to have more of it.

So, I think there'd be more likely to be a regression to the mean that controls for nonheritable genetic components to IQ (such as from random mutations and how two high iq parents contributed alleles happen to interact in their offspring) and the non-genetic environmental components to IQ that high IQ people can't currently control in their offspring, due to lack of current knowledge about them or ability to control them. I'd expect the high IQ parents' offspring would get less of the good luck and the low IQ parents' offspring would get less of the bad luck.

But after all that, the high IQ parents' offspring would still seem to me to have the advantage of whatever heritable component to genetic intelligence there is, and after the regressions functionally ended in a generation or more, the island population with high IQ progenitors would be keyed to a higher IQ than the island population with the low IQ progenitors, even if the initial differences were greater.

However, let's say after 1000 very good boats were invented and people from the two islands could now visit each other. The people from the somewhat higher IQ island happen to be natural blue-eyed blondes, and the people from the somewhat lower IQ island happen to not be. If the entire population has a strong built in preference for blondes, but blondes are a minority population and only the higher IQ members of the non-blonde population succeed in procreating with blondes (and the same applies to their children), then it becomes viable as a theory that both regression to the mean and blondes having the highest IQ in a population can occur.

Basically I think the theory is that phenotypical blondes happen to be keyed to a somewhat higher IQ than non-blondes, that that blondes tend to be non-endogamous when it presents an IQ advantage over remaining endogamous.

I have no idea if the theory is true or not, but I don't think your post introduces evidence counter to it Marius.

In particular, I don't think your post demonstrates that two islands, one starting with a low IQ population and one starting with a high IQ population will end up with about equal IQ populations, instead of ending up with a maintained IQ differential that may be somewhat smaller than before.

"Caucasian economic superiority is almost certainly a accident of history and geography that will soon be rectified by the dominance of high IQ groups like Asians"

It's notable that northern Europeans were not regarded as a particularly smart group until quite recently - around 1700 AD I'd say. Furthermore, northern European IQ scores seem notably higher than you'd expect by measures such as brain size; they ought to be closer to the world average, a bit over 90. While they're not the smartest population, they're only around 5 points behind north-east-Asians, not the ca 10 points other factors would predict. The question is whether this is due to environment, to culture, or some kind of genetic reason?


"I find that an odd prescription for an ailment which most of the zealots here are arguing is largely a nature (genetic), not a nurture (health/environmental issue."

IQ is like many other personality variables: Genes and environment interact to produce a certain result. It is pretty much a settled issue that IQ is not 100% genetic, and I don't think anyone here argued this.

Then again, it has been 150+ posts...

Now reading the above posts if you're black or Hispanic, and intelligent. You end up going from feeling intelligent to feeling as if one is a fluke and some aberration. It's highly depressing and there's an obvious reason as to why some of us would prefer that this information be suppressed....

Well, I guess you're realizing that life isn't fair. It's really too bad that this isn't taught to kids anymore. Every kid is taught that they are special--everyone is above average.

I'd really prefer to let the science play out than to hide it so that you aren't depressed. The church elders were no doubt highly depressed when Copernicus developed his model of the sun being the center of the universe. Nevertheless, humans are no doubt better off for knowing the truth, don't you think? Suppression of science for such reasons is infantile and ultimately futile.

The correlation between IQ and economic development is pretty obvious. As for Russia & chess, Russia also has vodka. Compared to NFL & beer, vodka destroys the brain. And IQ is a product of genes & nurture, although high IQ & bad nurture can produce a brilliant criminal.

Thousands of studies & everyday experience show the correlation, but some people just don't trust their lyin' eyes.

1. Tyler Cowen is losing ground (no pun intended) by the minute. Instead of actual arguments he want to impress us because Heckman’s models are “well specified†?

First as a matter of principle, if one scholar explains a great deal about reality with a very simple model, and another is only able to explains as much (in fact much less) only by using an extremely complicated model, which one do we normally think has the better theory?!?!

Second it is a joke to use Heckman as an argument against IQ and genetics. Ignore the politically correct abstract and conclusions, and just look at the actual findings from these “well structured† models.

This are some of what Heckman is writing in the papers linked:

†¢ Completely concedes that IQ is nonmalleable above age 10, and strongly determines life outcome.

†¢ Heckman thinks IQ can be raised substantially before the age of 10, but offer no evidence. In his “well specified† model this is simply assumed. He offers no explanation to why children adopted into upper-middle class households at a early age resemble their biological parents, not their adopted parents.

†¢ Heckman is using the same data and (albeit more complicated) the same methods Murray used, to reach largely the same results. He is using the AFQT that he so harshly criticized Murray and Herrnstein for. Deeds speak more than abstracts.

†¢ Estimate of the effect of IQ on Income almost exactly the same as in Bell curve, if you don’t control for education (which you shouldn’t).

†¢ Access to higher education is same for all or almost all Americans. Success is a function of cognitive skills.

†¢ One year of schooling at the margin raises measured IQ 1-2 points. This ‘proves Murray wrong’, because the Bell Curve suggested 1 point per year(!). Again, how laud someone yells does not say much about what they are actually finding in this taboo-ridden debate.

†¢ Heckman still has the arrogance to write “Achievement test scores, sometimes confused with IQ scores (e.g., Herrnstein and Murray, 1994),†. Keep in mind that Herrnstein was a world renowned researcher on IQ and the g factor, that Heckman is himself using the AFQT now, and that the authors have already explained that an achievement test can be used as an excellent proxy for g if applied to a group with similar prior exposure to knowledge.

†¢ Their careful studies find that various early start, Perry etc. school programs had *no effect* on young children IQ. They increase life outcome through “preference formation†.

Note that this is what Murray predicted Heckman and others would find, in 1995! (Response in Commentary). Do not expect Heckman to admit anything, just silent surrender. After 12 years of “well structured† models we are back where Murray left of: the IQ gap is real and probably impossible to remove, so we should focus on raising conscientiousness, work ethic and other non-cognitive skills among the poor.

2. “In fact, the observed correlation between the IQs of non-identical siblings in different families is much lower, in the order of .1-.15†

What are you talking about? The standard weighted correlation of IQ from meta studies between non-twin siblings reared apart is 0,24, whereas “normal† siblings reared together get 0,46.

Since siblings on average only share 50% of genes, this gives roughly the same heritability. But hey, don’t let facts get in your way of pulling things out of thin air.

3. “It's notable that northern Europeans were not regarded as a particularly smart group until quite recently - around 1700 AD I'd say.†

Regarded by whom? Do you have any references to back this claim up? Why were the northern Europeans, such as the Dutch, Flemish and English some of the richest and (in competition with high IQ Chinese and north Italians) most advanced nations on earth already in the 1400s?

Please google Occam, Roger Bacon, Gutenberg, Copernicus and Galilei and and repeat your point about Northern Europeans being considered stupid until 1700 AD. I guess the history textbooks you read contained more about Pocahontas and the largely miss or unspecified but great marvels of Arab civilization than anything Europeans ever did. But that doesn’t prove anything.

By the way, there is no real difference between north and south Europe in IQ. I guess the only reason you people insist on referring to "north europeans" is to infer nazism? Or to ignore Ancient Greece, Rome and Byzantium in your historical discussions?

4. This is also the problem with this goodfacts vs. truefacts. Again, if it makes people feel better I personally do not mind publicly pretending that a “Great Zimbabwe† (the size of any small roman military outpost) is as impressive as classical Athens.

But it becomes ridiculous when people believe these myths, and use them as arguments. You are the ones that force us to point out that the Mayans didn’t manage to advance beyond stone age technology, didn’t invent the wheel, internally collapsed hundreds of years before Europeans arrived, that their great achievement in the Chichen Itza pyramids is a fraction of the size of the pyramids Egyptians built 4000 years earlier. The historical significance of the Mayans is really part of the point: they are famous because they were the ONLY American civilization that developed literacy!
By any objective measure the intellectual contributions of Europeans and south East Asians have dwarf everyone else for at least the last 3000 years. They invented almost every aspect of modern society. I would be happy not to remind the world of this, if only you at least had the common sense not to bring attention to the issue.

5. “northern European IQ scores seem notably higher than you'd expect by measures such as brain size†

When there is selection of intelligence there is also selection for economizing on brain size. Do you have any indication whatsoever that European measured IQ overestimaes their cognetive achievements?

It's really annoying that TypePad allows comments with unclosed italics tags.

Anyone seriously interested in the relationship between economic development and IQ should read this analysis which shows an amazingly high correlation between, not just IQ, but verbal IQ and economic development:

Idiots like the host of this blog are doing a horrendous disservice to those he feels he is defending. First, because "economic development" is not the be all and end all of human existence and, second, because to the extent that economic development is the Darwinian struggle for existence within globalism, he is not allowing those people to understand the real sources of their competitive weakness and take the proper corrective action.

Economists have long know that market economies (with or without extensive regulations) allow by far the best long term sustainable economic growth.

What's been a mystery is why some underdeveloped societies which adopt market economic stategies with or without government guidance grow towards wealth so quickly (e.g. Japan, S.Korea, Taiwan, Singapore and now China), while others move forward more slowly (e.g. the Philippines, Malyasia, S.America), and others seem to hardly move forward at all (e.g. almost all of sub Saharan Africa with it 's still substantial white and Asian minorities). Now check the IQ averages for these clusters of societies.

“northern European IQ scores seem notably higher than you'd expect by measures such as brain size†

"When there is selection of intelligence there is also selection for economizing on brain size. Do you have any indication whatsoever that European measured IQ overestimaes their cognetive achievements? "

No - my point was that, going by the data in Lynn's 'Race & Intelligence', it looks like there is a clear positive correlation between brain size and measured IQ, but Europeans have somewhat smaller brains than you'd expect from their measured IQ, or higher IQ than their brain size would predict. It's also notable that other Caucasian populations that are genetically very similar have lower IQ, often markedly lower (eg north African & Arabian populations) - Lynn rather obscures this by lumping all the non-European Caucasian populations into a different race than Europeans. It seemed to me from the data that the 'natural' IQ for Europeans would be more like 90-92 rather than 100. The question why this is, is interesting to me - perhaps because most researchers are themselves European it rarely seems to occur to them.

Forehead sizes have been increasing in northern europe over the past few hundred years. A brief glance at various races as you wander down the street will show marked differences in skull size, east asians with the largest, widest skulls, then whites with narrower faces but higher foreheads, then hispanics, then the more sloped foreheads of blacks etc. Skull size is correlated with IQ. It's depressing, but true.

Adrian, I am a Somali, and one characteristic of Somalis is a large forhead. According to the data by L&V, my country has a collective IQ in the 60s.

My people have large skulls.

Yet, apparently, low IQs.

Bark up another tree.

"Sure England wasn't leading the world, but it had built the Tower of London, Windsor Castle and Old St. Paul's Cathedral by then. And Chaucer had written the Canterbury Tales"

Tower of London & Windsor Castle are pretty crude lumps of rock IMO; Old St Paul's burned down of course but to my knowledge it didn't compare to middle-eastern, south Asian or far eastern architecture of the period.

Ibrahim Nur:
"Really, the link between skull size and IQ is ridiculous, because many ethiopians and somalis have gigantic forheads. What gives?"

This seems like a non-sequitur to me - the stated correlation is between brain volume & intelligence, not forehead size & intelligence. At the macro scale this isn't controversial anyway - certainly nonhuman animals' intelligence correlates with brain size, and humans have the largest brains relative to body size of any animal. But it's not a perfect correlation - other factors like heat insulation are important, neanderthals apparently had larger brains than modern humans but seem to have had lower intelligence.

Simon, it was Adrian who brought up forheads and suggested a correlation along race. Specifically, he referenced the "more sloped forheads of blacks" and the bigger forheads of Asians and whites. I suspected this observation was based on ignorance of what East Africans--Ethiopians, Eritreans and Somalis look like.

1. “In any case, England (where I live) in 1400 AD certainly was not a particularly advanced or cultured society.†

Compared to what? 1400 is a useless starting base, given the fact that you had the plague hit them in 1350 or so. More general England in the late medieval period was one of the economically, politically and socially most developed nations on the earth.

It is really bizarre when people think it is normal to raise the stone age Mayans to the heaves, but diminish a country that had founded both Oxford and Cambridge and was a few generations from Shakespeare and Newton as “not a particularly advanced or cultured society†.

2. “Recent examination of medieval English medieval skeletons indicates significantly smaller brain size than the modern English†

Again, not the relevant comparison group. What was the skull size compared to other groups?

3. “Caucasian populations that are genetically very similar have lower IQ, often markedly lower (eg north African & Arabian populations)†

Since when are arabs and north Africans genetically “very similar† to Europeans? Ignoring the Vandals and similar mixture (the vandals were maximum 80.000 people anyway) arabs and north Africans are genetically far from Europeans.

Anyway you did ignore my point. Brain size is not a good measure of IQ, certainly not likely to be a linear one (as I said because there will be selection for size efficiency when you have selection for processing power).

4. “perhaps because most researchers are themselves European†

I guess you are including Americans and Jews as “European†. Well, in that case you might have noticed that almost all social scientist on the planet are “European†. Does that tell you anything?

5. “the levels of African Americans. (median household income for whom is $31K year!)†

To be fair here that is to a large extent because they live among high productive populations. This pushes up demand for low skill labour (unless you have open borders†¦), creates a marvellous institutional environment that minorities and Democrats are constantly trying to break down, and not the least gives hundreds of billions in public transfers to low income groups.

6. “being, for example, an extremely intelligent black person would be not much better than an average
black person†

Wrong. You get massive amounts of rents from being a smart member of a underachieving group.

7. “I'm wondering why it must necessarily be IQ that accounts for economic development. Why not culture?†

Why not both? Anyway culture is to some extent a function of culture.

If we can increase average african IQ from 70 (the current value) to 85 (the value for african-americans) than their average incomes can be expected to rise from current subsistance levels (like Nigeria at $1200 a year) to the levels of African Americans. (median household income for whom is $31K year!)

That is a completely absurd statement.

"Since when are arabs and north Africans genetically “very similar† to Europeans? Ignoring the Vandals and similar mixture (the vandals were maximum 80.000 people anyway) arabs and north Africans are genetically far from Europeans. "

On any gene-mapping, some north African groups like Berbers are practically indistinguishable from Europeans. Kurds, Turks, Iranians, high-caste Indians are extremely close; Arabs and most other Indians are still very close - far closer than east-Asians and Amerindians, with sub-Saharan Africans being further away. I believe Cafalli-Sforza is a good reference on this.

Of course genes are not the same as culture - I'm happy to accept there are large cultural differences, but in terms of the major races/population groups, Europeans fit with the other Caucasians in the Caucasian population group.

pwyll:"But if it's a completely absurd statement, tell me, how would *you* go about enabling Africans to raise their median household income to $31k?"

Move to Sweden ? >:)

Seriously, it's clear that there are simple steps to removing the major depressants on African median IQ, like Iodine in salt. These probably won't raise the median African IQ to that of African-Americans, but should greatly lessen the gap. They certainly won't raise African household income to that of African-Americans, but an Africa with median IQ 80 might well achieve similar household income to other IQ 80 nations, and a virtuous circle might take effect with further increases in both wealth & IQ over time.

For the foreseeable future there will be distinct populations with different measurable IQs, and countries with different levels of wealth. I don't see that as a big problem if every country is doing reasonably well, without endemic starvation, disease and war. And that, while not an egalitarian utopia, ought to be achievable.

To David Alexander:

I remember reading somewhere that quite often help is resented greatly by the person being helped because if you are helped than it must imply that the person helping you is superior. So, better to stay unhelped, and suffer, than be helped and thus implicitly admit that there are some who are in a position to do you a favor.

It definitely seems that you feel this way about the idea of giving low-IQ races an IQ boost. You also seem quite pessimistic about the status quo being changable, yet you're simultaneously very bitter about the status quo.

Do you have a solution in mind that you would prefer? Do you prefer the status quo? And, since you say you're a higher-IQ member of a race/group with a lower average IQ, do you think your opinion is representative of other higher-IQ members of your race/group? I'm curious.


Advice for the high-IQ member of a lower-average-IQ group who wants smart kids:

* Marry the smartest (and otherwise satisfactorily attractive) mate you can woo from some other (preferably high-IQ) group. By this approach, you will select for IQ, and also you may offset regression toward the IQ mean with general hybrid vigor.

* Try really hard to ensure that your kids are nourished on mother's milk for the first year of their lives. Buy a quality (e.g., Medela Pump-In-Style) breastpump to help with that. Get a chest freezer and store extra mother's milk in it at -15 degrees F.

* Stay married and spend a lot of time talking with your kids and helping them do things with you (even though it would be easier to get things done if you parked the kids in front of the TV). Whatever maximum IQ potential your kids' genes may code for will best develop in a secure and stimulating environment.

* Feed your kids well. In particular, don't give them skim milk, margarine, or adult dietetic foods, nor ask them to live on junk food or packaged prepared foods for adults. If no one in your household has much time to cook, get some microwave and pressure-cooker cookbooks and buy semi-prepped quality ingredients like frozen vegetables. Give your kids vitamin supplements (don't go crazy, just feed them a standard vitamin pill two or three times a week). If your kids don't spend much time in the sun, give them extra Vitamin D (recent science shows that the old RDA is too small)--say, 1000IU daily less the amount you estimate they get by drinking cow's milk.

* If you need daycare for your kids when they're very small, try to put them with a relative, even a somewhat distant one (spouse's cousin, whatever). Contrary to all the well-funded propaganda you may encounter, "home based" care is generally better for infants and toddlers (of course there are exceptions, but they're all obvious ones like incompetence/ neglect/ abuse or overcrowding).

* Send your kids to school with other bright kids. If you can't afford a house in an upscale neighborhood (and believe me, I know how that feels!), then be clever. Send your kids to a preschool in a nice neighborhood (the fees are generally about the same!)--you can drive a little farther to drop off and pick up. When it's time for K-6 check out private schools, or rent an apartment in a nice public-school district or go through the hassle (a hassle, you will note, which serves mainly to filter out lower-IQ parents) to get your kids into a public magnet school. (For school admissions it is an advantage to belong to a preferred-minority group. In America, the one drop rule will make your kids preferred too!)

* Play cards and tabletop games (Scrabble, Monopoly, Risk) with your kids, at least until they're old enough to play with their peers.

* Limit your children's TV time. Do not place a TV in a child's bedroom. Don't play the TV during meals or study time. In modern society most people watch some TV every day, but ever-droning TV is for morons. It's probably best to have only one TV in your home so that when a child complains that s/he doesn't like the show other people are watching, you can say "go read your book" with some chance of being obeyed!

* Personally teach your kids to read properly. Even supposedly "top-rated" schools very often do not teach reading by effective methods (because they figure smart parents will all teach their kids at home anyway. You must play along). Order a copy of Phyllis Schlafly's Turbo Reader (no, I'm not kidding. Yes, it's from that Schlafly. It's not political). Start each of your kids through it at the earliest age they seem to "get it" (generally 4-5). You'll spend as much time on this as your child; allocate 20-30 minutes per day. Avoid distractions during lessons-- put your other kids in front of the TV while you teach one to read. Then, and this is key, start your kids reading series books ("Magic Treehouse" is the current rage). Once a child learns to read for pleasure, success in school reading is almost assured.

* Take your kids places. Travel really does broaden the mind. Small children find museums boring, so take them for a short tour then let them play around the institutional lawn.

* Teach your children to write in the first few years. This is another area where even "good" schools don't deliver. To save themselves work, many schoolteachers will not correct their pupils' writing. You should, though. Demand to see all homework assignments. Discuss corrections with your child then force her to make them before she turns her work in. Ask your children to write letters and such. You can teach a bright child to write a good "five paragraph essay" by the 4th grade-- and even if you quit then, your 5th-grader will be better prepared for college than 90% of 12th graders.

* Personally coach your kids in any subject which gives them trouble in grade school. Virtually every kid can master all grade-school subjects, so if your child is struggling with one, it is probably his teacher's fault. Do not waste your time berating the teacher--do the job yourself, or ask the principal to move your child to another classroom.

* Encourage your kids' musical interests. Take them to some free park concerts and so-forth. If they show any aptitude, encourage them to learn to play an instrument. Prod them into school musical, choral, or dramatic groups (but permit them to withdraw if things really don't work out).

* Try to figure out how to keep your kids interested in learning through high-school. Simple advice is impossible here because individual kids will have different personalities. At least, whenever one of your kids shows a talent for something, try to give him/her a chance to develop it.

Thanks, Victor. I hope people will read your whole post. There is some great advice in there (I know, I have two little ones). You can teach your kids more in 5 minutes than they'll pick up in an hour of watching TV.

It's fascinating to see how much hatred for scientific inquiry and knowledge is nakedly displayed here in the comments by the politically correct anti-IQ dogmatists.

Personally, I think the truth is better for humanity than ignorance, lies, or wishful thinking, but, clearly, others disagree.

I am damned if I can come up with a single reason why it should be publicly supported with university research dollars

Because human intelligence is incredibly important. Brains make us human. We cannot understand vision, or mental retardation, or Alzheimer's, or memory, or a thousand other topics in neuroscience without constantly bumping into the issue of human cognitive ability...and of inherent *differences* in cognitive ability.

Imagine an anatomy class which stipulated that no one could study or acknowledge differences between bodies. Imagine surgery with just one set of knives, or pharmacology under the assumption that everyone had a weight of 170 pounds and a height of 70 inches.

Incoherent, right? You can't study human similarities without studying human differences. And intelligence research ultimately relates to anatomy as well.For example, differences in brain morphology (e.g. as measured by MRI) are already known to predict intelligence differences; for example:

Neurobiological determinants of intelligence as measured by IQ:

1. Posterior lesions often cause substantial decreases in IQ. Duncan and colleagues suggested that the frontal lobes are involved more in Gf and goal-directed behaviour than in Gc (Fig. 2). In addition, Gf is compromised more by damage to the frontal lobes than to posterior lobe...
2. MRI-based studies estimate a moderate correlation between brain size and intelligence of 0.40 to 0.51
3. g was significantly linked to differences in the volume of frontal grey matter, which were determined primarily by genetic factors... the volume of frontal grey matter had additional predictive validity for g even after the predictive effect of total brain volume was factored out
4. Only one region is consistently activated during three different intelligence tasks when compared to control tasks...The surface features of the tasks differed (spatial, verbal, circles) but all were moderately strong predictors of g (g LOADING; range of r, 0.55–0.67), whereas control tasks were weaker predictors of g (range of r, 0.37–0.41). Neural activity in several areas, measured by a positron emission tomography (PET) scan, was greater during high-g than low-g tasks.
5. Speed and reliability of neural transmission are related to higher intelligence (reviewed in Refs 15,20). Early neuroimaging studies using PET found that intelligence correlated negatively with cerebral glucose metabolism during mental activity54 (for a review, see Ref. 55), leading to the formulation of a 'neural efficiency' hypothesis...
6. Gf is mediated by neural mechanisms that support the executive control of attention during working memory...greater event-related neural activity in many regions, including the frontal, parietal and temporal lobes, dorsal anterior cingulate and lateral cerebellum. Crucially, these patterns were most distinct during high-interference trials, even after controlling for behavioural performance and for activity on low-interference trials within the same regions
7. RAPM scores obtained outside the scanner predicted brain activity in a single left parietal/temporal region, and not in the frontal lobes.
8. An exploratory fMRI study60 (n = 7) indicated that parietal areas are involved in inspection time tasks, specifically Brodmann area (BA) 40 and the ventrolateral prefrontal cortex (BA47) but not the dorsolateral prefrontal cortex

Behavioral Genetics of IQ:

1. Monozygotic twins raised separately following adoption show a correlation of 0.72 for intelligence
2. For 48 identical twin pairs separated in early infancy and reared apart, Bouchard et al.83 found remarkably high between-twin correlations for verbal scores on the WAIS (0.64) and for the first principal component of special mental abilities (0.78)
3. Psychometric g has been shown to be highly heritable in many studies, even more so than specific cognitive abilities (h2 = 0.62, Ref. 87 compare with Ref. 88; h2 = 0.48, Ref. 89; h2 = 0.6–0.8, Refs 90,91)...
4. Intriguingly, the influence of shared family environments on IQ dissipates once children leave home — between adult adoptive relatives, there is a correlation of IQ of -0.01

Molecular Genetics of IQ:

1. Chorney et al.104 discovered an allelic variation in a gene on chromosome 6, which codes for an insulin-like growth factor-2 receptor (IGF2R), that was linked with high intelligence...
2. Later studies identified a second IQ-related polymorphism in the IGF2R gene, and others in the cathepsin D (CTSD) gene, in the gene for an acetylcholine receptor (CHRM2)106, and in a HOMEOBOX GENE (MSX1) that is important in brain development107, 108.
3. Influence of each polymorphism was minimal — variants of CHRM2 accounted for a range of only 3–4 IQ points, whereas different forms of CTSD accounted for about 3% of the variation between people...None of these associations has yet been replicated by other research groups
4. Some patients with microcephaly also possess the ASPM mutation, indicating that a shortened version of the gene might lead to the development of fewer cerebral neurons and a smaller head.
5. Polymorphism in the human brain-derived neurotrophic factor (BDNF) gene is associated with impaired performance on memory tests
6. Catechol-O-methyltransferase (COMT) gene influences the activation of working memory circuits. COMT polymorphisms seem to be highly specific to some prefrontal cortex-dependent tasks in children.
7. Dopamine receptor (DRD4) and monoamine oxidase A (MAOA) polymorphisms are associated with differences in performance and brain activity during tasks that involve executive attention

There are many, many more reviews and papers in this area coming down the pipe. "God [=PC] is dead", so to speak, among the people in the IQ field and has been dead for a while. The public hasn't yet been apprised of this fact, but read Nick Wade's articles in the NYT (f'rinstance) and you'll see where things are going.

To stop this, you would literally have to murder thousands of top scientists in neuroscience. Moreover, you'd need to bring modern genetics research to a screeching halt, as it increasingly focuses on population (aka racial) differences (google "Hapmap" or "copy number variation").

That's not unprecedented. Lysenko did it in the USSR. Jail enough scientists, ruin enough careers with accusations of counterrevolutionary (="racist") activity, and you can slow things down (at least in the West -- the East doesn't care so much about our taboos).

But that's what I mean about the noble lie. It starts to get a lot less noble when you start persecuting truth tellers. Short of measures like that, it's important to start coming to terms with what is going to be a huge intellectual shift over the next few decades.

Thanks for the review of literature and recent work in this area. Did you assemble it yourself or is there a website where we can find all this?

I'm glad to see that the population geneticists, etc. are moving in a big way into the field of traits like intelligence and heritability. I agree with you on the practical importance of studying these topics (with good science). In particular it sounds like there is a move away from self-reported race to actual genetic admixture and ancestry tests, which I also think is a good sign. That should help to add a lot more results like the discoveries about specific genes mentioned in your earlier post.

As one might expect, Thomas Sowell has an observation that renders Tyler’s observations about the villagers moot. From “Race and Culture†

“For many practical purposes, however, it makes no real difference whether poor performances in abstract thinking are due to neglect or to lack of capacity. In either case it has serious ramifications in a scientific and technological society.†

Honest talk about IQ would expose some deeply personal inconsistencies among our most influential thinkers. Although the typical white intellectual claims he wants to censor discussion of IQ to shield black self-esteem, his sometimes berserk reactions reveal that he finds it a peril to his own. The typical white intellectual considers himself superior to ordinary white people for two contradictory reasons: a] he constantly proclaims belief in human equality, but they don't; b] he has a high IQ, but they don't.

"Individuals may vary, but as a group, belief in the intellectual superiority of one's group has been inevitably led to a belief in one's moral superiority. There simply aren't any counterexamples (that I know of)."

The Nazis did not kill Jews because they thought they were so stupid - the stereotype was that they were sly and cunning. The Khmer Rouge killed everyone they perceived to be an intellectual - you could get murdered for wearing glasses.

Those of you claiming respect for science: look at those in science who have actually influenced how other people think, and adopt their tone and manner of writing.

On subatance, the Flynn Effect shows that IQ is endogenous to environment. Heckman's work shows that IQ is endogenous to conditions during the first ten years of life.

Some of you are dealing with this context, but many of you are not.

"Heckman's work shows that IQ is endogenous to conditions during the first ten years of life."

Jesus Chrust. He does no such thing. Here is what Heckman writes in a June 2007 paper:

"IQ scores become stable by age 10 or so, suggesting a sensitive period for their formation below age 10. (See Kenneth Hopkins and Glenn Brecht, 1975.) There is evidence that adolescent interventions can affect non cognitive skills."

Causally referring to a 30 year paper does not constitute 'showing' anything. (The paper he refers to is by the way about contrasting one IQ-test that shows high stabillity below age 10 to another IQ test that shows less stability below age 10. Really strong stuff...). In another paper, Heckman puts a footnote making the same claim, and refers to Jensen(!).

For future reference, the "stability" of IQ is *not* the inverse of malleability. It just means the noise in testing is much higher in lower age groups, for example because different people mature at different paces. To make a claim about high malleability of IQ below any age you have to show some SYSTEMATIC bias, not just noise (what they find is essentially that tests of a 5 year old is less correlated to a test of that child at 6, that tests comparing children between say age 12 to 13).

From Heckman papers: "The success of these [early] interventions is not attributable to IQ improvements of children, but rather to their success in boosting non cognitive skills"

..."The program did not boost IQ (see Figure 1)"

How about Heckmans strongest argument, the famed Abecedarian Project? Surely this intensive program, starting at close to the youngest age possible permanently boosted IQ?

Well, as usual it did innitially, but faded quickly by age, with the participants converging to the genetic average. At age 21 the IQ off the Full Scale and Verbal IQ of program participants was only 89,1 compared to 85 for the treatment group. So much for that.

As I already pointed out, Heckman has long retreated from his 1995 claims, and is now only emphasizing the mealibillity of NON-cognetive skills. Let me reapeat: N O N - C O G N E T I V E.

What is Heckmans own countribtuion to this literature? The guy is good at what he does. When he analyzed the Perry pre-School program, starting at age 4, he found NO PERMANENT EFFECT by age 10.

I urge Tyler Cowen and everyone else to go to figure 14A in Cunha, Heckman et al 2006 "Interpreting the Evidence on Life Cycle Skill Formation.". Look at the IQ converging almost as if by magic to 85 by age 10.

Obviously malleability exist in extreme form (malnutrition), and probably to some degree intellectual climate. But the natural experiments (adoption and twin studies) demonstrate the oposite. Heckman can assume whatever he wants in a model, but he has not in any way demonstrated malleability of IQ among the young, and not from lack of trying. That is why the commentators that actually know about the science don't pay much attention to Tyler Cowens safety blanket in James Heckman.


The Flynn effect is less weak, but it would have been more interesting here if it had actually reduced the group IQ-gap, which it conspicuously didn't. The Flynn effect also seems to have stopped almost two decades ago in the west.

Early Childhood Education: Young Adult Outcomes From the Abecedarian Project
Frances A. Campbell et al, Applied Developmental Science, 2002.

It didn't take Jews long to set things up (albeit unintentionally) in Europe so that their IQs increased by 15 points relative to their white neighbors.

I'm still trying to figure out how that process developed when the other Semetic groups and Sephardic Jews have lower IQs. Was it their isolation from other European groups that allowed them to develop? If that's true, why didn't this happen to blacks given legally enforced segregation in the US?

Good luck... A lot of people are still trying to figure out how the process developed! Charles Murray and Gregory Cochran have given the idea a great deal of thought and come up with some very good theories. I know Murray had a long, long piece in Commentary magazine detailing his thoughts on the subject, and Cochran included a theory in his recent study on Ashkenzai intelligence.

Here's Murray's article:

Here's the response to the article, which includes a letter from Cochran on his own theory:

I'm not going to be able to do either of these gentlemen's theories justice, so you really need to read the article, but, just to whet your appetite... If I recall correctly, the difference between the Jewish and black experience that's important in terms of evolution of IQ, at least according to Murray and Cochran, is that, while they were both segregated into ghettos, Jews were pushed into banking - a trade that demanded a very high intelligence for success - because of laws and/or customs prohibiting Christians entering the field. Also, the Jewish faith from the beginning focused on memorization of complex texts. Jews that couldn't make the cut, either as bankers or "good Jews," had good motivation to forego Judaism and blend in with the larger society. So, among Jews, you had factors encouraging the highly intelligent to remain Jews and breed litle Jewish babies on the one hand, and for the less intelligent to assimilate into the larger society on the other. Over generations, this elevated Jewish IQ.

As for blacks in America, yeah they were segregated, but they weren't forced to feed their children by working in jobs requiring relatively high levels of intelligence for success. So there wasn't this universal pressure within the community leading the very intelligent to produce significantly more offspring. Nor was there pressure for less intelligent blacks to marry and reproduce with whites.

Anyway, read the article. My summation of Murray's and Cochran's theories is clumsy at best. Still, I think it's important to read because it suggests that even if the differences in IQ between the races are genetic as opposed to environmental, change remains possible, it would just require significantly more time.

Thank you for putting the comments back up

One article of many citing that 30% of white-identified Americans have recent, traceable (through genetic admixture tests) African/black ancestry, constituting more than 50 million Americans. It's interesting because this is a significantly larger population than actually self-identifies as black in America.


You make some very good points regarding the dangers of this type of research - or rather, the dangers of making certain findings, should they come about, accepted wisdom. As someone who is supportive of this research, I'm reluctant to dwell on your concerns just because, well, who wants to think that something he supports will lead to Jim Crow or genocide? I'd much rather that people responded to the idea of genetically based racial differences in intelligence with ideas on how to ameliorate them, or at least, how to improve the overall standard of living for those groups on the lower end of the spectrum. But maybe they won't. They certainly haven't in the past.

Anyway, since you expressed your fears, let me be entirely honest and express mine. You say to Steve Sailer:

Can you give me *any* example of a society where group intellectual differences are widely socially accepted that you'd want to be a part of? Then why so quick to destroy the society that we have which, at its core, is based on the assumption of equality?

My fear is that this society you want to preserve - one which assumes absolute racial equality - may contain the seeds of its own destruction IF it is the case that there are genetic differences in intelligence between the races.

Look at our immigration policy, which is turning us into a majority-minority nation. And the minority that is filling the country up (Mestizos) is not one that performs very well. I would like it very much if Mestizos assimilated to the white norm. But the evidence suggests they are currently doing otherwise. If this is because of culture, we can work to change that. But what if it's not because of culture? What if it is related to genetics? What will happen to our country then? What kind of country will our grandchildren inherit?

I mean, if the difference measured between the races in intelligence is caused largely by genetics, then is it not the cold, hard truth that our current colorblind immigration policy is going to be bad for the future of this country, given that the people immigrating are not from high-IQ groups? Personally, I would love to switch to an immigration policy like they have in other countries that allow only the highly skilled to come in; that would permit us to retain a colorblind immigration policy while selecting for intelligence using skills and education as proxies. But our country is so dedicated to the idea of equality that such a policy is deeply offensive and seen as unAmerican. We just can't believe that people have different potentials. Therefore, we can't bring ourselves to discriminate in any way.

Your fears concern me, but this concerns me, too. I don't know. On the one hand, we risk reverting to the days of Jim Crow (or worse). On the other hand, we risk losing our status as a first world country.

Maybe they will show that it is environment, not genes, that cause these differences in intelligence, in which case both our worries are moot. I don't see that happening, though.

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