At the end of April, Charles Kenny, a former World Bank economist specializing in international development, published a blistering attack in Foreign Policy entitled “Dumb and Dumber,” with the accusatory subtitle “Are development experts becoming racists?” Kenny charged that a growing number of development economists were turning towards genetic and other intrinsic human traits as a central explanation of national economic progress, often elevating these above the investment and regulatory issues that have long been the focus of international agencies.

Although Kenny suggested that many of his targets had been circumspect in how they raised these highly controversial ideas, he singled out IQ and the Wealth of Nations, published in 2001 by Richard Lynn and Tatu Vanhanen, as a particularly extreme and hateful example of this trend. These authors explicitly argue that IQ scores for different populations are largely fixed and hereditary, and that these—rather than economic or governmental structures—tend to determine the long-term wealth of a given country.

Kenny claimed that such IQ theories were not merely racist and deeply offensive but had also long been debunked by scientific experts—notably the prominent biologist Stephen Jay Gould in his 1980 book The Mismeasure of Man.

As Kenny soon discovered from the responses to his online article, he had seriously erred in quoting the authority of Gould, whose fraud on race and brain-size issues, presumably in service to his self-proclaimed Marxist beliefs, last year received further coverage in the New York Times. Science largely runs on the honor system, and once simple statements of fact—in Gould’s case, the physical volume of human skulls—are found to be false, we cannot trust more complex claims made by the particular scholar.

Despite Kenny’s obvious lack of familiarity with the technical questions he raised, these issues remain important ones to explore, given today’s globalized world. After all, it is generally acknowledged that some people are smarter than other people, and this almost syllogistically raises the possibility that some peoples may be smarter than other peoples.

Most nations prefer material wealth to poverty, and it seems plausible that smarter people might be better at generating the productivity needed to achieve this goal. We should hardly be surprised that this possible factor behind economic advancement has attracted the interest of the development experts criticized by Kenny, and just as he alleges, IQ and the Wealth of Nations ranks as perhaps the most extreme academic example of this analysis.

Although “intelligence” may be difficult to define precisely, most people have accepted that IQ scores seem to constitute a rough and measurable proxy for this trait, so Lynn and Vanhanen have collected a vast number of national IQ scores from the last 50 or 60 years and compared these to income levels and economic growth rates. Since experts have discovered that nominal IQ scores over the last century or so have tended to rise at a seemingly constant rate—the so-called “Flynn Effect”—the authors adjusted their raw scores accordingly. Having done so, they found a strong correlation of around 0.50–0.75 between the Flynn-adjusted IQ of a nation’s population and its real per capita GDP over the last few decades, seemingly indicating that smarter peoples tend to be wealthier and more successful.

From this statistical fact, Lynn and Vanhanen draw the conclusion that intelligence leads to economic success and—since they argue that intelligence itself is largely innate and genetic—that the relative development ranking of the long list of nations they analyze is unlikely to change much over time, nor will the economic standing of the various groups within ethnically mixed countries, including the United States.

Now this hypothesis might indeed be correct, but it is not necessarily warranted by the empirical data that Lynn and Vanhanen have gathered. After all, if high national IQ scores are correlated with economic success, perhaps the high IQs cause the success, but it seems just as possible that the success might be driving the high IQs, or that both might be due to some third factor. Correlation does not imply causality, let alone the particular direction of the causal arrow. A traditional liberal model positing that socio-economic factors strongly influence performance on academic ability tests would predict exactly the same distribution of international results found by Lynn and Vanhanen.

Fortunately, a careful examination of the wealth of empirical data they have gathered provides some important evidence on the relative plausibility of these conflicting hypotheses, allowing us to draw useful conclusions in this extremely taboo subject.

The Distribution of European Intelligence

Critics have often suggested, not without some plausibility, that when Western-designed IQ tests are applied to Third World peoples, the results may be distorted by hidden cultural bias. There is also the possible impact of malnutrition and other forms of extreme deprivation, or even practical difficulties in administering tests in desperately impoverished nations, as Kenny emphasized in his critique.

In order to minimize these extraneous factors, let us restrict our initial examination to the 60-odd IQ datapoints Lynn and Vanhanen obtained from European countries and their overseas offshoots over the last half-century. Obviously, some of these countries have at times been far poorer than others, but almost none have suffered the extreme poverty found in much of the Third World.

What we immediately notice is a long list of enormous variations in the tested IQs of genetically indistinguishable European peoples across temporal, geographical, and political lines, variations so large as to raise severe doubts about the strongly genetic-deterministic model of IQ favored by Lynn and Vanhanen and perhaps also quietly held by many others. (Unless otherwise indicated, all the IQ data that follow are drawn from their work and incorporate their Flynn adjustments.)

Consider, for example, the results from Germany obtained prior to its 1991 reunification. Lynn and Vanhanen present four separate IQ studies from the former West Germany, all quite sizable, which indicate mean IQs in the range 99–107, with the oldest 1970 sample providing the low end of that range. Meanwhile, a 1967 sample of East German children produced a score of just 90, while two later East German studies in 1978 and 1984 came in at 97–99, much closer to the West German numbers.

These results seem anomalous from the perspective of strong genetic determinism for IQ. To a very good approximation, East Germans and West Germans are genetically indistinguishable, and an IQ gap as wide as 17 points between the two groups seems inexplicable, while the recorded rise in East German scores of 7–9 points in just half a generation seems even more difficult to explain.

The dreary communist regime of East Germany was certainly far poorer than its western counterpart and its population may indeed have been “culturally deprived” in some sense, but East Germans hardly suffered from severe dietary deficiencies during the 1960s or late 1950s when the group of especially low-scoring children were born and raised. The huge apparent testing gap between the wealthy West and the dingy East raises serious questions about the strict genetic interpretation favored by Lynn and Vanhanen.

Next, consider Greece. Lynn and Vanhanen report two IQ sample results, a score of 88 in 1961 and a score of 95 in 1979. Obviously, a national rise of 7 full points in the Flynn-adjusted IQ of Greeks over just 18 years is an absurdity from the genetic perspective, especially since the earlier set represented children and the latter adults, so the two groups might even be the same individuals tested at different times. Both sample sizes are in the hundreds, not statistically insignificant, and while it is impossible to rule out other factors behind such a large discrepancy in a single country, it is interesting to note that Greek affluence had grown very rapidly during that same period, with the real per capita GDP rising by 170 percent.

Furthermore, although Greeks and Turks have a bitter history of ethnic and political conflict, modern studies have found them to be genetically almost indistinguishable, and a very large 1992 study of Turkish schoolchildren put their mean IQ at 90, lending plausibility to the low Greek figure. We also discover rather low IQ scores in all the reported samples of Greece’s impoverished Balkan neighbors in the Eastern Bloc taken before the collapse of Communism. Croatians scored 90 in 1952, two separate tests of Bulgarians in 1979–1982 put their IQs at 91–94, and Romanians scored 94 in 1972. While the low scores of the Croatian children might be partly explained by malnutrition and other physical hardships experienced during the difficult years of World War II, such an excuse seems less plausible for other Balkan populations tested decades after the war, all of which seem to score in the same range.

Two samples of Poles from 1979 and 1989 provided widely divergent mean IQs of 106 and 92, with the low Polish figure of 92 coming from a huge sample of over 4000 children tested with “Progressive Matrices,” supposedly one of the most culturally-independent methods. On the other hand, more economically advanced Communist countries in Central Europe often had considerably higher scores, with the Slovaks testing at 96 in 1983, the Czechs scoring 96–98 in 1979–1983, and the Hungarians reaching 99 in 1979.

All of these Southern or Eastern European IQ scores follow the per capita GDP of their countries, a correspondence that supports either the IQ-makes-wealth hypothesis of Lynn and Vanhanen, or the contrary wealth-makes-IQ hypothesis of traditional liberals.

During this same period, the far richer non-Communist nations of Europe—such as Austria, Britain, the Netherlands, Belgium, Norway, and West Germany—all tended to score at or somewhat above 100. The wide IQ gaps between these European peoples and the previous group seem unlikely to have a heavily innate basis, given the considerable genetic and phenotypic similarity across these populations. For example, the borders of Austria and Croatia are just a couple of dozen miles apart, both are Catholic countries that spent centuries as part of the Austro-Hungarian Empire, and it is quite difficult to distinguish Austrians from Croatians either by appearance or by genetic testing. Yet the gap between their reported IQ scores—12 points—is nearly as wide as that separating American blacks and whites.

It seems more plausible that most of the large and consistent IQ gaps between Western Europeans and their Balkan cousins are less a cause than a consequence of differences in development and affluence during the era in which these IQs were tested. For example, Austria had many times Croatia’s per capita GDP during the period in question. One of the few European nations to exhibit a sharp decline in tested IQ, Poland—whose score fell from 106 in 1979 to 92 in 1989—did so amid the economic turmoil of the 1980s, when its per capita GDP also substantially declined according to some measures, even while Western Europe was growing richer.

If these differences of perhaps 10 or even 15 IQ points between impoverished Balkan Europeans and wealthy Western ones reflected deeply hereditary rather than transitory environmental influences, they surely would have maintained themselves when these groups immigrated to the United States. But there is no evidence of this. As it happens, Americans of Greek and South Slav origins are considerably above most other American whites in both family income and educational level. Since the overwhelming majority of the latter trace their ancestry to Britain and other high IQ countries of Western Europe, this would seem a strange result if the Balkan peoples truly did suffer from an innate ability deficit approaching a full standard deviation.

Similar sharp differences occur in the case of Italian populations separated historically and geographically. Today, Italian-Americans are very close to the national white average in income and education, and the limited data we have seem to put their IQ close to this average as well. This would appear consistent with the IQ figures reported for Italy by Lynn and Vanhanen, which are based on large samples and come in at just above 100. However, there is a notoriously wide economic gap between northern Italy and the south, including Sicily. The overwhelming majority of Italian-Americans trace their ancestry to the latter, quite impoverished regions, and in 2010 Lynn reported new research indicating that the present-day IQ of Italians living in those areas was as low as 89, a figure that places them almost a full standard deviation below either their Northern Italian compatriots or their separated American cousins. Although Lynn attributed this large deficit in Southern Italian IQ to substantial North African or Near Eastern genetic admixture, poverty and cultural deprivation seem more likely explanations.

The Lynn/Vanhanen data on Jews also provide some suspicious IQ disparities. American Jews have among the highest tested IQs, with means being usually reported in the 110–115 range. Yet Lynn and Vanhanen report that Israeli Jews have strikingly low IQs by comparison. One large sample from 1989 put the figure at 90, while a far smaller sample from 1975 indicated an IQ of 97, with both results drawn from Israel’s large Jewish majority rather than its small Arab minority. The IQ gaps with American Jews are enormous, perhaps as large as 25 points, and difficult to explain by genetic factors, since a majority of Israel’s Jewish population in that period consisted of ethnic Askhenazi (European) Jews, just like those in America. The huge economic gulf between Israeli Jews, who then had less than half the average American per capita GDP, and American Jews, who were far above average in American income, would seem to be the most plausible explanation.

Similarly, a large 1990 test of South African whites placed their IQ at 94, considerably below that of the Dutch or English peoples from whom they derive, and again this may be connected to their lower level of national income and technological advancement.

Perhaps the strongest evidence supporting this cultural rather than genetic hypothesis comes from the northwestern corner of Europe, namely Celtic Ireland. When the early waves of Catholic Irish immigrants reached America near the middle of the 19th century, they were widely seen as particularly ignorant and uncouth and aroused much hostility from commentators of the era, some of whom suggested that they might be innately deficient in both character and intelligence. But they advanced economically at a reasonable pace, and within less than a century had become wealthier and better educated than the average white American, including those of “old stock” ancestry. The evidence today is that the tested IQ of the typical Irish-American—to the extent it can be distinguished—is somewhat above the national white American average of around 100 and also above that of most German-Americans, who arrived around the same time.

Meanwhile, Ireland itself remained largely rural and economically backward and during the 1970s and 1980s still possessed a real per capita GDP less than half that of the United States. Perhaps we should not be too surprised to discover that Lynn and Vanhanen list the Irish IQ at just 93 based on two samples taken during the 1970s, a figure far below that of their Irish-American cousins.

Even this rather low Irish IQ figure is quite misleading, since it was derived by averaging two separately reported Irish samples. The earlier of these, taken in 1972, involved nearly 3,500 Irish schoolchildren and is one of the largest European samples found anywhere in Lynn/Vanhanen, while the other, taken in 1979, involved just 75 Irish adults and is one of the smallest. The mean IQ of the large group was 87, while that of the tiny group was 98, and the Lynn/Vanhanen figure was obtained by combining these results through straight, unweighted averaging, which seems a doubtful approach. Indeed, a sample of 75 adults is so small it perhaps should simply be excluded on statistical grounds, given the high likelihood that it was drawn from a single location and is therefore unrepresentative of its nation as a whole.

So we are left with strong evidence that in the early 1970s, the Irish IQ averaged 87, the lowest figure anywhere in Europe and a full standard deviation below than that of Irish-Americans, a value which would seem to place a substantial fraction of Ireland’s population on the edge of clinical mental retardation.

Lynn seems to have accepted this conclusion. The current issue of the academic journal Personality and Individual Differences is organized as a tribute to Lynn and contains a lengthy interview in which he describes the turning points of his career, beginning with his appointment as a research professor in Dublin. His official responsibility was to investigate the social and economic problems of Ireland, and he soon concluded that the nation’s backwardness was largely due to the low IQ of its people, with the only obvious solution being a strong eugenics program, presumably including sterilization of a substantial fraction of the population. But given the dominant influence of conservative Catholicism in Ireland, he doubted the government would consider such suggestions, which would probably just get him “accused of being a Nazi,” so he “chickened out” and chose to suppress his findings. A few years later, he relocated to Protestant-run Ulster, where he felt his racial ideas might find a more receptive audience, and he eventually became interested in whether the poverty of other countries might be due to the same low IQ causal factor which he believed explained Ireland’s problems. This led him to the research that culminated in the publication of IQ and the Wealth of Nations.

But Lynn’s late-1960s views regarding the mostly genetic cause of low Irish IQ seem unwarranted. Ireland was then overwhelmingly rural and poor, with a low per capita GDP, while Irish Americans tended to be an urban population and a reasonably affluent one, and this sharp difference in external material conditions seems the most logical explanation for the wide disparity in IQ results. In further support of this environmental hypothesis, we should note that it has been estimated that nearly one-third of Australia’s population is wholly or substantially Irish in ancestry, with the balance mostly British, while the IQ results Lynn and Vanhanen report for Australia are all very close to the British average of 100.

The gathering of social science data, including national IQs, is fraught with difficulty, notably due to sampling problems, and two or three anomalous results might be explained away for those reasons. But the large number of examples cited above in which genetically indistinguishable European-ancestry populations show enormous variations in tested IQ seems to indicate a much broader difficulty. Not only are the results too numerous to be ascribed to chance error, but they follow a consistent pattern of their own, with European-ancestry groups living in affluent, well-developed countries almost invariably having IQ scores of around 100 or above, while their close kinsmen in much poorer regions have far lower scores. Indeed, in several of these cases, the countries and peoples are identical, being merely separated by a generation or less of local economic development.

To a small extent, Lynn and Vanhanen acknowledge the possible importance of non-genetic factors, and they devote a few pages to a discussion of the impact of health, nutrition, and education on IQ scores. But they never provide any clear estimate for the magnitude of these influences and claim that a number of twin or adoption studies have determined that IQ is 80 percent or more heritable. Their text seems to assume that genetics is the overwhelmingly dominant factor behind the national IQ disparities which they catalogue.

Questioning the “Strong IQ Hypothesis”

The central thesis of Lynn and Vanhanen’s work might be called the “Strong IQ Hypothesis,” namely that IQ accurately reflects intelligence, that IQ is overwhelmingly determined by genetics, and that IQ is subject to little or no significant cultural or economic influence after we adjust for the universal Flynn Effect. Since the IQ disparities discussed above seem to provide a powerful challenge to this theory, their validity has sometimes been disputed on the grounds that the populations being compared might actually be more dissimilar than we realize due to the impact of selective migration.

For example, one might speculate that the smarter Irish immigrated to America, while their dimmer relatives remained at home, and the same was also true for the smarter Southern Italians, Greeks, or other Balkan Europeans. Similarly, perhaps the smarter European Jews crossed the oceans to New York Harbor in the years before World War I, while their dimmer relatives stayed behind and later moved to Israel after World War II.

These explanations seem quite unlikely. The intra-ethnic IQ gaps being discussed are absolutely enormous—often approaching a full standard deviation or more—and that would imply a similarly enormous gap between the portions of the population that stayed and those that emigrated, with no contemporaneous source seeming to provide any indication of this. Indeed, during the period when these immigrant flows were occurring, most American observers emphasized the remarkable backwardness of the new arrivals and often speculated that they were intrinsically defective and might constitute a permanent burden to society. If anything, it was sometimes suggested that they were less intelligent than their stay-at-home co-ethnics and had come to America because they were unable to compete at home, hence their description as the so-called “wretched refuse from a teeming shore.”

The limited ethnic IQ data we have from that period support this impression. In his 1978 book American Ethnic Groups, Thomas Sowell included a chapter that summarized the 1920s data on the average IQ scores of various Eastern and Southern European immigrant groups and showed that these were generally quite low, with Slovaks at 85.6, Greeks at 83, Poles at 85, Spaniards at 78, and Italians ranging between 78 and 85 in different studies. A separate analysis of the aptitude scores of World War I draftees published in 1923 came to similar conclusions. These published IQ studies by prominent academics led to widespread belief that the more recent European immigrant groups were much less intelligent than earlier ones and might drag down the national average, a belief that may have contributed to passage of the highly restrictive 1924 Immigration Act.

Even if we ignore all contemporaneous evidence and argue that 19th century European immigrants to America and elsewhere somehow constituted the IQ elite of their originating countries, the theory of selective migration still remains implausible. It has long been established on both theoretical and empirical grounds that IQ scores generally follow a mean-reversion pattern, in which the children of outlying individuals tend to regress toward the typical levels of their larger population or ethnic group. So even if we hypothesize that the Irish, South Italians, Jews, and Greeks who immigrated to America constituted the smartest small slice of their generation—rather than, as seems more likely, often the poorer and most miserable—roughly half their relative IQ advantage would have dissipated after a single generation. Thus, the apparent one standard deviation gap between American Irish and Ireland Irish a few decades ago would have required an initial gap of something closer to two standard deviations at the time the immigration occurred, a difference so large as to be totally implausible.

Furthermore, the most recent 2009 PISA international student academic tests sponsored by the Organisation for Economic Co-operation and Development provide us with results that raise further doubts about the correctness of the Lynn/Vanhanen IQ scores from a wide range of European countries. For example, although Croatia and Austria are geographically quite close, Croatians had IQs 12 points lower when their country was desperately poor just after World War II; yet today their overall PISA scores are not enormously lower, and are actually higher in reading, even though Croatia’s average income is still lower by a factor of two. During the early 1970s, a huge national sample had placed the Ireland IQ at 87, the lowest in all of Europe, but today Ireland’s PISA scores are about average for the continent and roughly the same as those for France and Britain, while Irish per capita incomes have pulled a little ahead.

The subject of race and IQ is an extremely contentious one, and over the years there have sometimes been conflicting accusations that data presented by various academics and other experts were more or less fraudulent, fabricated for ideological reasons. This does appear to be true in the case of Stephen Jay Gould, one of the most widely quoted figures on the subject of IQ. Therefore, if the often anomalous IQ figures discussed above had been provided by any strong critic of IQ as an innate measure of intellectual ability, I would be extremely cautious in accepting them without exhaustive verification of the underlying sources.

But our situation is different. Lynn and Vanhanen rank among the most prominent academic advocates of a strongly genetic basis for IQ scores, and this indeed represents the summary conclusion that they draw from the vast amount of national IQ data they have collected and presented. They are unlikely to have skewed the data against their own ideological beliefs and theoretical hypothesis.

Yet an objective review of the Lynn/Vanhanen data almost completely discredits the Lynn/Vanhanen “Strong IQ Hypothesis.” If so many genetically-indistinguishable European populations—of roughly similar cultural and historical background and without severe nutritional difficulties—can display such huge variances in tested IQ across different decades and locations, we should be extremely cautious about assuming that other ethnic IQ differences are innate rather than environmental, especially since these may involve populations separated by far wider cultural or nutritional gaps.

We cannot rule out the possibility that different European peoples might have relatively small differences in innate intelligence or IQ—after all, these populations often differ in height and numerous other phenotypic traits. But this residual genetic element would explain merely a small fraction of the huge 10–15 point IQ disparities discussed above. Such a view might be characterized as the “Weak IQ Hypothesis”: huge IQ differences between large populations may be overwhelmingly due to cultural or socio-economic factors, but a residual component might indeed be genetic in origin.

We are now faced with a mystery arguably greater than that of IQ itself. Given the powerful ammunition that Lynn and Vanhanen have provided to those opposing their own “Strong IQ Hypothesis,” we must wonder why this has never attracted the attention of either of the warring camps in the endless, bitter IQ dispute, despite their alleged familiarity with the work of these two prominent scholars. In effect, I would suggest that the heralded 300-page work by Lynn and Vanhanen constituted a game-ending own-goal against their IQ-determinist side, but that neither of the competing ideological teams ever noticed.

Presumably, human psychology is the underlying explanation for this mysterious and even amusing silence. Given that Lynn and Vanhanen rank as titans of the racial-difference camp, perhaps their ideological opponents, who often come from less quantitative backgrounds, are reluctant even to open the pages of their books, fearful lest the vast quantity of data within prove that the racialist analysis is factually correct after all. Meanwhile, the pro-racialist elements may simply skim over the hundreds of pages of dry and detailed quantitative evidence and skip to the summary text, which claims that the data demonstrate IQ is genetically fixed and determines which nations will be rich and which will be poor.

Implications for the American Immigration Debate

This lack of attention to the actual data provided by Lynn and Vanhanen has seriously impaired many important public-policy discussions. The widespread belief in the innate mental inferiority of Southern and Eastern European immigrant groups may have played a significant role in the 1920s immigration debate, and it seems plausible that similar perspectives might be at work today. For example, sharp critics of our heavy recent immigration from Mexico sometimes claim—or at least hint—that the intellectual weakness of these millions of newcomers may constitute a disastrous long-term burden to American society. On anonymous Internet forums such voices are often more explicit and directly cite Lynn and Vanhanen in placing the Mexican IQ at just 87, far below the white American average, and a worrisome indicator given that as much as one-quarter of all Americans may be of Mexican ancestry by around the middle of this century.

The IQ figure of 87 that they quote from Lynn/Vanhanen is correct, though admittedly based on a single 1961 study of Mexican schoolchildren in the most impoverished southern part of that country. But such critics always fail to notice that a much larger and more recent study of Irish schoolchildren revealed precisely the same mean IQ of 87. So the most accurate representation of the facts presented in IQ and the Wealth of Nations is that Mexicans and Irish seem to have approximately the same intellectual ability, and since Irish have generally done well in American society, there seems no particular reason to assume that Mexicans will not.

But is this apparent equality of Mexican and Irish IQs several decades ago anything more than a statistical anomaly due to insufficiently thorough testing? Despite its recent economic problems, over the last couple of decades Ireland has become one of the best educated countries in Europe, with solid international PISA scores, and it seems almost certain that Irish IQs have rapidly converged toward the European mean. Indeed, two additional studies provided by Lynn and Vanhanen in their 2006 sequel, IQ and Global Inequality, seem to indicate that by 1993 the average Irish IQ had already risen to 92.

Meanwhile, tens of millions of Mexican-Americans have lived in the United States with its far higher standard of living for decades, and we must wonder whether they have demonstrated any similar rise in IQ. Lynn and Vanhanen provide some early 1970s studies for Mexican-American children living in Texas and California and the IQ scores were generally quite dismal, similar to those from Mexico itself. Surely, if Mexican-Americans had subsequently demonstrated a large rise in tested intelligence, the American media and ethnic-advocacy groups would have widely trumpeted such a fact.

Strangely enough, strong evidence of such an IQ rise does exist, but it has been ignored by our often oblivious national media. Among the most useful sources of detailed quantitative data in America is the General Social Survey (GSS), a huge sociological survey conducted every other year, in which tens of thousands of Americans have been subjected to a wide range of detailed questions and their responses made publicly available over the Internet. One regular item in the survey is the simple “Wordsum” vocabulary identification test, which, although quite crude, turns out to be heavily g-loaded, correlating 0.71 with the results of standard IQ tests. Such a correlation is at least as good as many other measures used to estimate population-wide intelligence, and probably superior to grades or graduation rates, while the vast GSS sample size provides a statistically valid means of discerning American trends and patterns in population segments too narrow for other sources.

Analyzing this GSS data set in a variety of different ways has become a favored activity of a blogger named Ron Guhname, who styles himself “The Inductivist” and every couple of days publishes a new finding on his website. In 2008, he decided to explore the Wordsum-implied IQ of American-born Mexican-Americans and discovered a remarkable result. These IQs were quite low, 84–85, in the 1970s and 1980s, a result consistent with the IQ samples reported by Lynn/Vanhanen for that era. But the Mexican-American IQ then jumped 7 points by the 1990s and an additional 3 points by the 2000s, a rise of 10 full points in just 20 years, while the Wordsum-implied IQ values for white Americans rose merely 2 points during that same period, presumably as an aspect of the regular Flynn Effect.

In actual values, the Mexican-American Wordsum-IQ increased from 84.4 in the 1980s to 95.1 in the 2000s, while the rise for American whites was from 99.2 to 101.3. In addition, the late 1990s IQ of U.S.-born Mexican-Americans has been separately estimated at 92.4 from the large data set contained in the National Longitudinal Survey of Youth (NLSY-97), a figure consistent with these Wordsum-IQ findings.

Thus, almost two-thirds of the IQ gap between American-born Mexican-Americans and whites disappeared in two decades, with these results being based on nationally-representative American samples of statistically significant size. Since Guhname is a right-wing blogger quite hostile to Hispanic immigration, it is to his credit that he published this result without hesitation, and to the embarrassment of America’s vast multicultural academic and media establishment that they had never independently discovered these important findings, nor indeed even noticed them once they appeared. In any event, it appears that Mexican-American IQs in America have been rising about as rapidly as Irish IQs seem to have risen in Europe.

But does this make any sense? During the 25 years between 1982 and 2007 the real per capita Irish GDP more than tripled, passing that of Britain, Germany, and France, while during this same period our national media have tended to emphasize the terrible economic difficulties endured by Mexican-Americans, rarely providing any indications of a major economic boom in that population. If Mexican-Americans—now numbering almost 35 million and well on their way to eventually surpassing Anglo-Saxons in number—had actually experienced rapid economic gains, surely our media would not have ignored such an important story?

I read several major newspapers closely each morning and am particularly interested in immigration-related news items, but on October 1, 2007, I was stunned to read a short New York Timesopinion column by Douglas Besharov, a social scientist at the University of Maryland, which provided exactly such evidence. His U.S. Census-CPS numbers were based on Hispanics as a whole, but Mexicans and closely related Meso-American immigrant groups from Central America account for the vast majority of this population, so his results should mostly be applicable.

Besharov noted that in just the 12 years from 1994 to 2006, the poverty rate among Hispanics had dropped by fully one-third, plummeting from 30.7 percent to 20.6 percent, while the percentage of Hispanics holding skilled blue-collar jobs had more than doubled, rising from 11 percent to 25 percent. Meanwhile, median Hispanic real household income rose by 20 percent and individual real income by 30 percent. Education advancement was also significant, with the percentage of 18- to 24-year-old Hispanics without high-school diplomas or G.E.D.s falling from 44 percent to 34 percent, while college enrollment rose from 19 percent to 25 percent. All these latter numbers are still considerably below those of the comparable white population, but they do indicate remarkable economic and social advancement in just a dozen years.

Furthermore, they certainly understate the real rate of such progress, perhaps by a very substantial factor. The years 1994–2006 represented a period of peak immigration levels from Latin America—with most of this flow being illegal and low-skilled—a wave contributing nearly half the growth of the Hispanic population, which rose from 25 million to almost 45 million. Although the Census data do not allow us to disentangle the economic performance of these new arrivals from the previously established or American-born Hispanic segment, it is certain that the socio-economic advancement figures cited by Besharov would have been enormously better if not for the inclusion of so many additional millions of initially-impoverished newcomers, often with weak language skills and almost always concentrated near the bottom of the labor market. So Besharov’s extremely encouraging picture must underestimate the actual performance of American-born Hispanics.

The severe recession of the last few years has seen the average American family lose 40 percent of its net worth, and Hispanics have similarly lost a portion of their previous economic gains, but meanwhile their rapid educational advances have continued and even accelerated. An indicator of this sense of progress is revealed in an April survey by the Pew Hispanic Center, which found that 75 percent of Hispanics believe that they can get ahead if they work hard, a figure far above the 58 percent average for the general American public.

America’s socio-economic landscape has been reshaped dramatically over the last century or more due to technological and social changes, reducing some opportunities while increasing others, so direct historical comparisons can be misleading. Furthermore, detailed economic stratification data along ethnic lines from a hundred years ago is not easily available. But based on the raw numerical data we do possess, it seems likely that the tens of millions of Hispanics living in America in the early 1990s probably advanced more rapidly in economic and educational terms than had any of America’s large European immigrant groups of the past, such as the Irish, the Italians, the Jews, or the Slavs. Such real-world gains seem quite consistent with the very rapid rise in apparent IQ discussed above, which occurred during this same time period.

Given the existence of large and influential Hispanic-friendly institutions such as the Ford Foundation and the New York Times, it seems almost inexplicable that such dramatically positive developments received virtually no media attention. This silence has surely led much of the national electorate incorrectly to assume that little if any Hispanic progress was occurring, sometimes with unfortunate political consequences.

IQ Puzzles and a Super-Flynn Effect?

This strong empirical evidence of the apparent malleability of IQ scores raises interesting questions about the possible mechanism involved. For example, during the 1960s and 1970s there was a great deal of excitement in elite circles about the role of Head Start-type enrichment programs in dramatically raising the academic performance and the IQ scores of impoverished groups; but the overall evidence seems to be that these failed over the long run, with students regressing to their previous ability levels just a few years after leaving the program.

Similarly, much of the evidence accumulated by the leading advocates of the innateness of IQ, such as the Pioneer Fund, comes from twin adoption studies, which seem to show that individuals’ IQ and personality traits are far closer to those of their fraternal or (especially) identical twins raised apart than to unrelated foster siblings or parents, and this pattern of similarity grows steadily stronger over time. Not unreasonably, many psychometric experts have argued that these results prove that IQ is largely determined by genetic factors and cannot be changed via environmental influences within any normal range. Lynn and Vanhanen cite several of these studies to argue that IQ is at least 80 percent hereditary.

These individual results, usually based on relatively small statistical samples of adopted twins or siblings, seemingly demonstrate the extreme rigidity of IQ—the “Strong IQ Hypothesis”—while we have also seen the numerous examples above of large populations whose IQs have drastically shifted over relatively short periods of time. How can these contradictory findings be squared? I do not have the solution, but it would seem a very worthwhile subject for further research, on both theoretical and practical grounds.

This scientific puzzle probably has a close connection to the well-known Flynn Effect, first widely publicized by Lynn, which describes the consistent, regular rise in nominal IQs for populations almost everywhere in the world: Englishmen or Frenchmen today do far better on IQ tests than did their parents or grandparents, although we have no reason to believe they are much “smarter” in any meaningful sense. There has been considerable speculation that this general rise in IQ-test performance is based on the increasingly complex and technological environment surrounding us, whose intricacies constantly train all of us in the sort of mental abstractions found in most IQ tests, thereby gradually raising our test scores without necessarily raising our intelligence. In effect, life in modern urban societies has become a daily cram-course for IQ tests. Many pre-modern cultures similarly required individuals to undertake considerable feats of memory, so people back then might have excelled on memory-based tests compared to their counterparts today, who do not have the same benefits of daily practice.

If we consider the low scoring Balkan and Eastern European populations listed in the table above, most of them seem to live in countries which were far more rural and agricultural than their higher-scoring counterparts. This was certainly also true of Ireland 40 years ago, when its scores were quite low, and this situation would tend to apply as well to Mexican-Americans, who were a much more heavily rural population prior to the 1970s.

Some support for a significant rural/urban factor behind IQ scores may be seen in the curiously inverted pattern of apparent ethnic success between Europe and America. In the recent past the highest European IQ scores were generally found in northern countries such as Britain, Germany, and the Netherlands, while the lowest ones occurred in Ireland, Greece, Yugoslavia, and Southern Italy, and during the early 20th century this pattern was replicated among those same immigrant ethnic groups in America. Yet strangely enough, if we stratify the recent American GSS results by primary European ethnic origin, we find nearly the opposite result for Wordsum-IQ, years of education, and family income. Among the higher performing white American groups are the Irish, the Greeks, the Yugoslavs, and the Italians, while Americans of Dutch extraction are near the bottom for whites, as are oldstock Americans who no longer identify with any European country but are presumably British in main ancestry. Meanwhile, German-Americans are generally at or slightly below the white American average.

This pattern of apparently inverted white ethnic achievement in Europe and America becomes less mysterious when we discover it tracks quite well with the rural vs. urban divide. Two of the most heavily rural, least urbanized groups are the Dutch-Americans and Old Stock whites, which perform the worst, while the high-performing Italians, Greeks, and Yugoslavs are among the most heavily urbanized. German-Americans are slightly less urbanized than the average white and also tend to perform slightly below average. In fact, across all non-Hispanic American whites, the Wordsum-IQ gap between those who grew up on farms and those who grew up in cities or suburbs is nearly as large as the gap separating American blacks and whites, and even larger with regard to total years of education.

The origin of this inversion of ethnic hierarchies may be quite simple. When desperately poor immigrant groups such as the Irish, Italians, or Greeks arrived on our shores, they were unable to afford farmland, and therefore permanently remained in their East Coast cities of landing, while less-poor Germans might move to the Midwest and become farmers, following the agricultural choice made by many of the earliest frontier settlers derived from the British and the Dutch. So the more rural populations from Europe often became the more urban ones in America, leading to a gradual inversion of their relative IQ rankings.

If we combine this apparent rural/urban achievement pattern with the evidence of the Flynn Effect, we might speculate that scoring well on an IQ test tends to require a certain amount of “mental priming” or complex stimulation while growing up and that in the past such stimulation tended to be lacking in poor rural areas compared with more urban, affluent, or industrial ones. Obviously, working on a farm in a less developed country carries its own complexity, but it could be that the mental skills exercised are far less applicable to the strongly abstract and analytical thinking required on an IQ test.

This might help to explain the enormous variance in test scores recorded in individual European countries better than the chance possibility that large tested samples overwhelmingly consisted of especially bright or especially dim individuals. Based on this data, the hypothesized developmental impact of a lack of sufficient mental stimulation might be to reduce tested IQs by as much as 10–15 points. And once this socio-cultural environment substantially changes—as in the case of the Irish or Mexican-Americans—what might be called a “Super-Flynn Effect” can occur, involving a very rapid rise in nominal IQs. Obviously, all of this is quite speculative and warrants further investigation.

Interestingly enough, these rapid rises in IQ due to changes in the general socio-economic environment appear completely absent when we examine the international or domestic IQ data for East Asian populations, for whom even tenfold differences in real per capita GDP seem to have little or no impact on IQ. Missing this unexpected contrast between the impact of socio-economic factors on Europeans and on East Asians may have been a major reason that Lynn and Vanhanen failed to notice the serious flaws in their “Strong IQ Hypothesis.”

None of these findings would have been possible without the great scholarly effort Richard Lynn and Tatu Vanhanen put into locating and properly presenting an enormous quantity of international IQ data in their books and research papers, as well as their courage in focusing attention on such highly controversial topics. Although I would argue that a close examination of the Lynn/Vanhanen data tend to convincingly refute their own “Strong IQ Hypothesis,” I would be the first to acknowledge my gratitude to the scholars whose efforts made my own analysis possible. Meanwhile, individuals such as Stephen Jay Gould, who commit outright academic fraud in support of their ideological positions, do enormous damage to the credibility of their own camp.