‘The Bell Curve’: A Book Much Read About, But Rarely Actually Read

The Bell Curve: Intelligence and Class Structure in American Life by Richard Herrnstein and Charles Murray (New York: Free Press, 1994). 

There’s no such thing as bad publicity’ – or so contends a famous adage of the marketing industry. 

The Bell Curve: Intelligence and Class Structure in America’ by Richard Herrnstein and Charles Murray is perhaps a case in point. 

This dry, technical, academic social science treatise, full of statistical analyses, graphs, tables, endnotes and appendices, and totalling almost 900 pages, became an unlikely nonfiction bestseller in the mid-1990s on a wave of almost universally bad publicity in which the work was variously denounced as racist, pseudoscientific, fascist, social Darwinist, eugenicist and sometimes even just plain wrong. 

Readers who hurried to the local bookstore eagerly anticipating an incendiary racialist polemic were, however, in for a disappointment. 

Indeed, one suspects that, along with The Bible and Stephen Hawkins’ A Brief History of Time, ‘The Bell Curve’ became one of those bestsellers that many people bought, but few managed to finish. 

The Bell Curve’ thus became, like another book that I have recently reviewed, a book much read about, but rarely actually read – at least in full. 

As a result, as with that other book, many myths have emerged regarded the content of ‘The Bell Curve’ that are quite contradicted when one actually takes the time and trouble to read it for oneself. 

Subject Matter 

The first myth of ‘The Bell Curve’ is that it was a book about race differences, or, more specifically, about race differences in intelligence. In fact, however, this is not true. 

Thus, ‘The Bell Curve’ is a book so controversial that the controversy begins with the very identification of its subject-matter. 

On the one hand, the book’s critics focused almost exclusively on subject of race. This led to the common perception that ‘The Bell Curve’ was a book about race and race differences in intelligence.[1]

Ironically, many racialists seem to have taken these leftist critics at their word, enthusiastically citing the work as support for their own views regarding race differences in intelligence.  

On the other hand, however, surviving co-author Charles Murray insisted from the outset that the issue of race, and race differences in intelligence, was always peripheral to he and co-author Richard Herrnstein’s primary interest and focus, which was, he claimed, on the supposed emergence of a ‘Cognitive Elite’ in modern America. 

Actually, however, both these views seem to be incorrect. While the first section of the book does indeed focus on the supposed emergence of a ‘Cognitive Elite’ in modern America, the overall theme of the book seems to be rather broader. 

Thus, the second section of the book focuses on the association between intelligence and various perceived social pathologies, such as unemployment, welfare dependency, illegitimacy, crime and single-parenthood. 

To the extent the book has a single overarching theme, one might say that it is a book about the social and economic correlates of intelligence, as measured by IQ tests, in modern America.  

Its overall conclusion is that intelligence is indeed a strong predictor of social and economic outcomes for modern Americans – high intelligence with socially desirable outcomes and low intelligence with socially undesirable ones. 

On the other hand, however, the topic of race is not quite as peripheral to the book’s themes as sometimes implied by Murray and others. 

Thus, it is sometimes claimed only a single chapter dealt with race. Actually, however, two chapters focus on race differences, namely chapters 13 and 14, respectively titled ‘Ethnic Differences in Cognitive Ability’ and ‘Ethnic Inequalities in Relation to IQ’. 

In addition, a further two chapters, namely chapters 19 and 20, entitled respectively ‘Affirmative Action in Higher Education’ and ‘Affirmative Action in the Workplace’, deal with the topic of affirmative action, as does the final appendix, entitled ‘The Evolution of Affirmative Action in the Workplace’ – and, although affirmative action has been employed to favour women as well as racial minorities, it is with racial preferences that Herrnstein and Murray are primarily concerned. 

However, these chapters represent only 142 of the book’s nearly 900 pages. 

Moreover, in much of the remainder of the book, the authors actually explicitly restrict their analysis to white Americans exclusively. They do so precisely because the well documented differences between the races in IQ as well as in many of the social outcomes whose correlation with IQ the book discusses would mean that race would have represented a potential confounding factor that they would otherwise have to take steps to control for. 

Herrnstein and Murray therefore took to decision to extend their analysis to race differences near the end of their book, in order to address the question of the extent to which differences in intelligence, which they have already demonstrated to be an important correlate of social and economic outcomes among whites, are also capable of explaining differences in achievement as between races. 

Without these chapters, the book would have been incomplete, and the authors would have laid themselves open to the charge of political-correctness and of ignoring the elephant in the room

Race and Intelligence 

If the first controversy of ‘The Bell Curve’ concerns whether it is a book primarily about race and race differences in intelligence, the second controversy is over what exactly the authors concluded with respect to this vexed and contentious issue. 

Thus, the same leftist critics who claimed that ‘The Bell Curve’ was primarily a book about race and race differences in intelligence, also accused the authors of concluding that black people are innately less intelligent than whites

Some racists, as I have already noted, evidently took the leftists at their word, and enthusiastically cite the book as support and authority for this view. 

However, in subsequent interviews, Murray always insisted he and Herrnstein had actually remained “resolutely agnostic” on the extent to which genetic factors underlay the IQ gap. 

In the text itself, Herrnstein and Murray do indeed declare themselves “resolutely agnostic” with regard to the extent of the genetic contribution to the test score gap (p311).

However, just couple of sentences before they use this very phrase, they also appear to conclude that genes are indeed at least part of the explanation, writing: 

It seems highly likely to us that both genes and the environment have something to do with racial differences [in IQ]” (p311). 

This paragraph, buried near the end of chapter 13, during an extended discussion of evidence relating to the causes of race differences in intelligence, is the closest the authors come to actually declaring any definitive conclusion regarding the causes of the black-white test score gap.[2]

This conclusion, though phrased in sober and restrained terms, is, of course, itself sufficient to place its authors outside the bounds of acceptable opinion in the early-twenty-first century, or indeed in the late-twentieth century when the book was first published, and is sufficient to explain, and, for some, justify, the opprobrium heaped upon the book’s surviving co-author from that day forth. 

Intelligence and Social Class 

It seems likely that races which evolved on separate continents, in sufficient reproductive isolation from one another to have evolved the obvious (and not so obvious) physiological differences between races that we all observe when we look at the faces, or bodily statures, of people of different races (and that we indirectly observe when we look at the results of different athletic events at the Olympic Games), would also have evolved to differ in psychological traits, including intelligence

Indeed, it is surely unlikely, on a priori grounds alone, that all different human races have evolved, purely by chance, the exact same level of intelligence. 

However, if races differ in intelligence are therefore probable, the case for differences in intelligence as between social classes is positively compelling

Indeed, on a priori grounds alone, it is inevitable that social classes will come to differ in IQ, if one accepts two premises, namely: 

1) Increased intelligence is associated with upward social mobility; and 
2) Intelligence is passed down in families.

In other words, if more intelligent people tend, on average, to get higher-paying jobs than those of lower intelligence, and the intelligence of parents is passed on to their offspring, then it is inevitable that the offspring of people with higher-paying jobs will, on average, themselves be of higher intelligence than are the offspring of people with lower paying jobs.  

This, of course, follows naturally from the infamous syllogism formulated by ‘Bell Curve’ co-author Richard Herrnstein way back in the 1970s (p10; p105). 

Incidentally, this second premise, namely that intelligence is passed down in families, does not depend on the heritability of IQ in the strict biological sense. After all, even if heritability of intelligence were zero, intelligence could still be passed down in families by environmental factors (e.g. the ‘better’ parenting techniques of high IQ parents, or the superior material conditions in wealthy homes). 

The existence of an association between social class and IQ ought, then, to be entirely uncontroversial to anyone who takes any time whatsoever to think about the issue. 

If there remains any room for reasoned disagreement, it is only over the direction of causation – namely the question of whether:  

1) High intelligence causes upward social mobility; or 
2) A privileged upbringing causes higher intelligence.

These two processes are, of course, not mutually exclusive. Indeed, it would seem intuitively probable that both factors would be at work. 

Interestingly, however, evidence demonstrates the occurrence only of the former. 

Thus, even among siblings from the same family, the sibling with the higher childhood IQ will, on average, achieve higher socioeconomic status as an adult. Likewise, the socioeconomic status a person achieves as an adult correlates more strongly with their own IQ score than it does with the socioeconomic status of their parents or of the household they grew up in (see Straight Talk About Mental Tests: p195). 

In contrast, family, twin and adoption studies and of the sort conducted by behavioural geneticists have concurred in suggesting that the so-called shared family environment (i.e. those aspects of the family environment shared by siblings from the same household, including social class) has but little effect on adult IQ. 

In other words, children raised in the same home, whether full- or half-siblings or adoptees, are, by the time they reach adulthood, no more similar to one another in IQ than are children of the same degree of biological relatedness brought up in entirely different family homes (see The Nurture Assumption: reviewed here). 

However, while the direction of causation may still be disputed by intelligent (if uninformed) laypeople, the existence of an association between intelligence and social class ought not, one might think, be in dispute. 

However, in Britain today, in discussions of social mobility, if children from deprived backgrounds are underrepresented, say, at elite universities, then this is almost invariably taken as incontrovertible proof that the system is rigged against them. The fact that children from different socio-economic backgrounds differ in intelligence is almost invariably ignored. 

When mention is made of this incontrovertible fact, leftist hysteria typically ensues. Thus, in 2008, psychiatrist Bruce Charlton rightly observed that, in discussion of social mobility: 

A simple fact has been missed: higher social classes have a significantly higher average IQ than lower social classes (Clark 2008). 

For his trouble, Charlton found himself condemned by the National Union of Students and assorted rent-a-quote academics and professional damned fools, while even the ostensibly ‘right-wing’ Daily Mail newspaper saw fit to publish a headline Higher social classes have significantly HIGHER IQs than working class, claims academic, as if this were in some way a controversial or contentious claim (Clark 2008). 

Meanwhile, when, in the same year, a professor at University College a similar point with regard the admission of working-class students to medical schools, even the then government Health Minister, Ben Bradshaw, saw fit to offer his two cents worth (which were not worth even that), declaring: 

It is extraordinary to equate intellectual ability with social class” (Beckford 2008). 

Actually, however, what is truly extraordinary is that any intelligent person, least of all a government minister, would dispute the existence of such a link. 

Cognitive Stratification 

Herrnstein’s syllogism leads to a related paradox – namely that, as environmental conditions are equalized, heritability increases. 

Thus, as large differences in the sorts of environmental factors known to affect IQ (e.g. malnutrition) are eliminated, so differences in income have come to increasingly reflect differences in innate ability. 

Moreover, the more gifted children from deprived backgrounds who escape their humble origins, then, given the substantial heritability of IQ, the fewer such children will remain among the working-class in subsequent generations. 

The result is what Herrnstein and Murray call the ‘Cognitive Stratification’ of society and the emergence of what they call a ‘Cognitive Elite’. 

Thus, in feudal society, a man’s social status was determined largely by ‘accident of birth’ (i.e. he inherited the social station of his father). 

Women’s status, meanwhile, was determined, in addition, by what we might call ‘accident of marriage’ – and, to a large extent, it still is

However, today, a person’s social status, at least according to Herrnstein and Murray, is determined primarily, and increasingly, by their level of intelligence. 

Of course, people are not allocated to a particular social class by IQ testing itself. Indeed, the use of IQ tests by employers and educators has been largely outlawed on account of its disparate impact (or indirect discrimination’, to use the equivalent British phrase) with regard to race (see below). 

However, the skills and abilities increasingly valued at a premium in western society (and, increasingly, many non-western societies as well), mean that, through the operation of the education system and labour market, individuals are effectively sorted by IQ, even without anyone ever actually sitting an IQ test. 

In other words, society is becoming increasingly meritocratic – and the form of ostensible ‘merit’ upon which attainment is based is intelligence. 

For Herrnstein and Murray, this is a mixed blessing: 

That the brightest are identified has its benefits. That they become so isolated and inbred has its costs” (p25). 

However, the correlation between socioeconomic status and intelligence remains imperfect. 

For one thing, there are still a few highly remunerated, and very high-status, occupations that rely on skills that are not especially, if at all, related to intelligence.  I think here, in particular, of professional sports and the entertainment industry. Thus, leadings actors, pop stars and sports stars are sometimes extremely well-remunerated, and very high-status, but may not be especially intelligent.  

More importantly, while highly intelligent people might be, by very definition, the only ones capable of performing cognitively-demanding, and hence highly remunerated, occupations, this is not to say all highly intelligent people are necessarily employed in such occupations. 

Thus, whereas all people employed in cognitively-demanding occupations are, almost by definition, of high intelligence, people of all intelligence levels are capable of doing cognitively-undemanding jobs.

Thus, a few people of high intellectual ability remain in low-paid work, whether on account of personality factors (e.g. laziness), mental illness, lack of opportunity or sometimes even by choice (which choice is, of course, itself a reflection of personality factors). 

Therefore, the correlation between IQ and occupation is far from perfect. 

Job Performance

The sorting of people with respect to their intelligence begins in the education system. However, it continues in the workplace. 

Thus, general intelligence, as measured by IQ testing, is, the authors claim, the strongest predictor of occupational performance in virtually every occupation. Moreover, in general, the higher paid and higher status the occupation in question, the stronger the correlation between performance and IQ. 

However, Herrnstein and Murray are at pains to emphasize, intelligence is a strong predictor of occupational performance even in apparently cognitively undemanding occupations, and indeed almost always a better predictor of performance than tests of the specific abilities the job involves on a daily basis. 

However, in the USA, employers are barred from using testing to select among candidates for a job or for promotion unless they can show the test has ‘manifest relationship’ to the work, and the burden of proof is on the employer to show such a relationship. Otherwise, given their disparate impact’ with regard to race (i.e. the fact that some groups perform worse), the tests in question are deemed indirectly discriminatory and hence unlawful. 

Therefore, employers are compelled to test, not general ability, but rather the specific skills required in the job in question, where a ‘manifest relationship’ is easier to demonstrate in court. 

However, since even tests of specific abilities almost invariably still tap into the general factor of intelligence, races inevitably score differently even on these tests. 

Indeed, because of the ubiquity and predictive power of the g factor, it is almost impossible to design any type of standardized test, whether of specific or general ability or knowledge, in which different racial groups do not perform differently. 

However, if some groups outperform others, the American legal system presumes a priori that this reflects test bias rather than differences in ability. 

Therefore, although the words all men are created equal are not, contrary to popular opinion, part of the US constitution, the Supreme Court has effectively decided, by legal fiat, to decide cases as if they were. 

However, just as a law passed by Congress cannot repeal the law of gravity, so a legal presumption that groups are equal in ability cannot make it so. 

Thus, the bar on the use of IQ testing by employers has not prevented society in general from being increasingly stratified by intelligence, the precise thing measured by the outlawed tests. 

Nevertheless, Herrnstein and Murray estimate that the effective bar on the use of IQ testing makes this process less efficient, and cost the economy somewhere between 80 billion to 13 billion dollars in 1980 alone (p85). 

Conscientiousness and Career Success 

I am skeptical of Herrnstein and Murray’s conclusion that IQ is the best predictor of academic and career success. I suspect hard work, not to mention a willingness to toady, toe the line, and obey orders, is at least as important in even the most cognitively-demanding careers, as well as in schoolwork and academic advancement. 

Perhaps the reason these factors have not (yet) been found to be as highly correlated with earnings as is IQ is that we have not yet developed a way of measuring these aspects of personality as accurately as we can measure a person’s intelligence through an IQ test. 

For example, the closest psychometricians have come to measuring capacity for hard work is the personality factor known as conscientiousness, one of the Big Five factors of personality revealed by psychometric testing. 

Conscientiousness does indeed correlate with success in education and work (e.g. Barrick & Mount 1991). However, the correlation is weaker than that between IQ and success in education and at work. 

However, this may be because personality is less easily measured by current psychometric methods than is intelligence – not least because personality tests generally rely on self-report, rather than measuring actual behaviour

Thus, to assess conscientiousness, questionnaires ask respondents whether they ‘see themselves as organized’, ‘as able to follow an objective through to completion’, ‘as a reliable worker’, etc. 

This would be the equivalent of an IQ test that, instead of directly testing a person’s ability to recognize patterns or manipulate shapes by having them do just this, simply asked respondents how good they perceived themselves as being at recognizing patterns, or manipulating shapes. 

Obviously, this would be a less accurate measure of intelligence than a normal IQ test. After all, some people lie, some are falsely modest and some are genuinely deluded. 

Indeed, according to the Dunning Kruger effect, it is those most lacking in ability who most overestimate their abilities – precisely because they lack the ability to accurately assess their ability (Kruger & Dunning 1999). 

In an IQ test, on the other hand, one can sometimes pretend to be dumber than one is, by deliberately getting questions wrong that one knows the answer to.[3]

However, it is not usually possible to pretend to be smarter than one is by getting more questions right simply because one would not know what are the right answers. 

Affirmative Action’ and Test Bias 

In chapters nineteen and twenty, respectively entitled ‘Affirmative Action in Higher Education’ and ‘Affirmative Action in the Workplace’, the authors discuss so-called affirmative action, an American euphemism for systematic and overt discrimination against white males. 

It is well-documented that, in the United States, blacks, on average, earn less than white Americans. On the other hand, it is less well-documented that whites, on average, earn less than people of IndianChinese and Jewish ancestry

With the possible exception of Indian-Americans, these differences, of course, broadly mirror those in average IQ scores. 

Indeed, according to Herrnstein and Murray, the difference in earnings between whites and blacks, not only disappears after controlling for differences in IQ, but is actually partially reversed. Thus, blacks are actually somewhat overrepresented in professional and white-collar occupations as compared to whites of equivalent IQ. 

This remarkable finding Herrnstein and Murray attribute to the effects of affirmative action programmes, as black Americans are appointed and promoted beyond what their ability merits because through discrimination. 

Interestingly, however, this contradicts what the authors wrote in an earlier chapter, where they addressed the question of test bias (pp280-286). 

There, they concluded that testing was not biased against African-Americans, because, among other reasons, IQ tests were equally predictive of real-world outcomes (e.g. in education and employment) for both blacks and whites, and blacks do not perform any better in the workplace or in education than their IQ scores predict. 

This is, one might argue, not wholly convincing evidence that IQ tests are not biased against blacks. It might simply suggest that society at large, including the education system and the workplace, is just as biased against blacks as are the hated IQ tests. This is, of course, precisely what we are often told by the television, media and political commentators who insist that America is a racist society, in which such mysterious forces as ‘systemic racism’ and ‘white privilege’ are pervasive. 

In fact, the authors acknowledge this objection, conceding:  

The tests may be biased against disadvantaged groups, but the traces of bias are invisible because the bias permeates all areas of the group’s performance. Accordingly, it would be as useless to look for evidence of test bias as it would be for Einstein’s imaginary person traveling near the speed of light to try to determine whether time has slowed. Einstein’s traveler has no clock that exists independent of his space-time context. In assessing test bias, we would have no test or criterion measure that exists independent of this culture and its history. This form of bias would pervade everything” (p285). 

Herrnstein and Murray ultimately reject this conclusion on the grounds that it is simply implausible to assume that: 

“[So] many of the performance yardsticks in the society at large are not only biased, they are all so similar in the degree to which they distort the truth-in every occupation, every type of educational institution, every achievement measure, every performance measure-that no differential distortion is picked up by the data” (p285). 

In fact, however, Nicholas Mackintosh identifies one area where IQ tests do indeed under-predict black performance, namely with regard to so-called adaptive behaviours – i.e. the ability to cope with day-to-day life (e.g. feed, dress, clean, interact with others in a ‘normal’ manner). 

Blacks with low IQs are generally much more functional in these respects than whites or Asians with equivalent low IQs (see IQ and Human Intelligence: p356-7).[4]

Yet Herrnstein and Murray seem to have inadvertently, and evidently without realizing it, identified yet another sphere where standardized testing does indeed under-predict real-world outcomes for blacks. 

Thus, if indeed, as Herrnstein and Murray claim, blacks are somewhat overrepresented among professional and white-collar occupations relative to their IQs, this suggests that blacks do indeed do better in real-world outcomes than their test results would predict and, while Herrnstein and Murray attribute this to the effect of discrimination against whites, it could instead surely be interpreted as evidence that the tests are biased against blacks. 

Policy Implications? 

What, then, are the policy implications that Herrnstein and Murray draw from the findings that they report? 

In The Blank Slate: The Modern Denial of Human Nature, cognitive science, linguist and popular science writer Steven Pinker popularizes the notion that recognizing the existence of innate differences between individuals and groups in traits such as intelligence does not necessarily lead to ‘right-wing’ political implications. 

Thus, a leftist might accept the existence of innate differences in ability, but conclude that, far from justifying inequality, this is all the more reason to compensate the, if you like, ‘cognitively disadvantaged’ for their innate deficiencies, differences which are, being innate, hardly something for which they can legitimately be blamed. 

Herrnstein and Murray reject this conclusion, but acknowledge it is compatible with their data. Thus, in an afterword to later editions, Murray writes: 

If intelligence plays an important role in determining how well one does in life, and intelligence is conferred on a person through a combination of genetic and environmental factors over which that person has no control, the most obvious political implication is that we need a Rawlsian egalitarian state, compensating the less advantaged for the unfair allocation of intellectual gifts” (p554).[5]

Interestingly, Pinker’s notion of a ‘hereditarian left’, and the related concept of Bell Curve liberals, is not entirely imaginary. On the contrary, it used to be quite mainstream. 

Thus, it was the radical leftist post-war Labour government that imposed the tripartite system on schools in the UK in 1945, which involved allocating pupils to different schools on the basis of their performance in what was then called the 11-plus exam, conducted at with children at age eleven, which tested both ability and acquired knowledge. This was thought by leftists to be a fair system that would enable bright, able youngsters from deprived and disadvantaged working-class backgrounds to achieve their full potential.[6]

Indeed, while contemporary Cultural Marxists emphatically deny the existence of innate differences in ability as between individuals and groups, Marx himself, laboured under no such delusion

On the contrary, in advocating, in his famous (plagiarized) aphorism From each according to his ability; to each according to his need, Marx implicitly recognized that individuals differ in “ability”, and, given that, in the unrealistic communist utopia he envisaged, environmental conditions were ostensibly to be equalized, these differences he presumably conceived of as innate in origin. 

However, a distinction must be made here. While it is possible to justify economic redistributive policies on Rawlsian grounds, it is not possible to justify affirmative action

Thus, one might well reasonably contend that the ‘cognitively disadvantaged’ should be compensated for their innate deficiencies through economic redistribution. Indeed, to some extent, most Western polities already do this, by providing welfare payments and state-funded, or state-subsidized, care to those whose cognitive impairment is such as to qualify as a disability and hence render them incapable of looking after or providing for themselves. 

However, we are unlikely to believe that such persons should be given entry to medical school such that they are one day liable to be responsible for performing heart surgery on us or diagnosing our medical conditions. 

In short, socialist redistribution is defensible – but affirmative action is definitely not! 

Reception and Readability 

The reception accorded ‘The Bell Curve’ in 1994 echoed that accorded another book that I have also recently reviewed, but that was published some two decades earlier, namely Edward O. Wilson’s Sociobiology: The New Synthesis

Both were greeted with similar indignant moralistic outrage by many social scientists, who even employed similar pejorative soundbites (‘genetic determinism’, reductionism, ‘biology as destiny’), in condemning the two books. Moreover, in both cases, the academic uproar even spilled over into a mainstream media moral panic, with pieces appearing the popular press attacking the two books. 

Yet, in both cases, the controversy focused almost exclusively on just a small part of each book – the single chapter in Sociobiology: The New Synthesis focusing on humans and the few chapters in ‘The Bell Curve’ discussing race. 

In truth, however, both books were massive tomes of which these sections represented only a small part. 

Indeed, due to their size, one suspects most critics never actually read the books in full for themselves, including, it seemed, most of those nevertheless taking it upon themselves to write critiques. This is what led to the massive disconnect between what most people thought the books said, and their actual content. 

However, there is a crucial difference. 

Sociobiology: The New Synthesis was a long book of necessity, given the scale of the project Wilson set himself. 

As I have written in my review of that latter work, the scale of Wilson’s ambition can hardly be exaggerated. He sought to provide a new foundation for the whole field of animal behaviour, then, almost as an afterthought, sought to extend this ‘New Synthesis’ to human behaviour as well, which meant providing a new foundation, not for a single subfield within biology, but for several whole disciplines (psychology, sociology, economics and cultural anthropology) that were formerly almost unconnected to biology. Then, in a few provocative sentences, he even sought to provide a new foundation for moral philosophy, and perhaps epistemology too. 

Sociobiology: The New Synthesis was, then, inevitably and of necessity, a long book. Indeed, given that his musings regarding the human species were largely (but not wholly) restricted to a single chapter, one could even make a case that it was too short – and it is no accident that Wilson subsequently extended his writings with regard to the human species to a book length manuscript

Yet, while Sociobiology was of necessity a long book, ‘The Bell Curve: Intelligence and Class Structure in America’ is, for me, unnecessarily overlong. 

After all, Herrnstein and Murray’s thesis was actually quite simple – namely that cognitive ability, as captured by IQ testing, is a major correlate of many important social outcomes in modern America. 

Yet they reiterate this point, for different social outcomes, again and again, chapter after chapter, repeatedly. 

In my view, Herrnstein and Murray’s conclusion would have been more effectively transmitted to the audience they presumably sought to reach had they been more succinct in their writing style and presentation of their data. 

Had that been the case then perhaps rather more of the many people who bought the book, and helped make it into an unlikely nonfiction bestseller in 1994, might actually have managed to read it – and perhaps even been persuaded by its thesis. 

For casual readers interested in this topic, I would recommend instead Intelligence, Race, And Genetics: Conversations With Arthur R. Jensen (which I have reviewed herehere and here). 

Endnotes

[1] For example, Francis Wheen, a professional damned fool and columnist for the Guardian newspaper (which two occupations seem to be largely interchangeable) claimed that: 

The Bell Curve (1994), runs to more than 800 pages but can be summarised in a few sentences. Black people are more stupid than white people: always have been, always will be. This is why they have less economic and social success. Since the fault lies in their genes, they are doomed to be at the bottom of the heap now and forever” (Wheen 2000). 

In making this claim, Wheen clearly demonstrates that he has read few if any of those 800 pages to which he refers.

[2] Although their discussion of the evidence relating to the causes, genetic or environmental, of the black-white test score gap is extensive, it is not exhaustive. For example, Phillipe Rushton, the author of Race Evolution and Behavior (reviewed here and here) argues that, despite the controversy their book provoked, Herrnstein and Murray actually didn’t go far enough on race, omitting, for example, any real discussion, save a passing mention in Appendix 5, of race differences in brain size (Rushton 1997). On the other hand, Herrnstein and Murray also did not mention studies that failed to establish any correlation between IQ and blood groups among African-Americans, studies interpreted as supporting an environmentalist interpretation of race differences in intelligence (Loehlin et al 1973Scarr et al 1977). For readers interested in a more complete discussion of the evidence regarding the relative contributions of environment and heredity to the differences in IQ scores of different races, see my review of Richard Lynn’s Race Differences in Intelligence: An Evolutionary Analysis, available here.

[3] For example, some of those accused of serious crimes have been accused of deliberately getting questions wrong on IQ tests in order to qualify as mentally subnormal when before the courts for sentencing in order to be granted mitigation of sentence on this ground, or, more specifically, in order to evade the death penalty

[4] This may be because whites or Asians with such low IQs are more likely to have such impaired cognitive abilities because of underlying conditions (e.g chromosomal abnormalitiesbrain damage) that handicap them over and above the deficit reflected in IQ score alone. On the other hand, blacks with similarly low IQs are still within the normal range for their own race. Therefore, rather than suffering from, say, a chromosomal abnormality or brain damage, they are relatively more likely to simply be at the tail-end of the normal range of IQs within their group, and hence normal in other respects.

[5] The term Rawlsian is a reference to political theorist John Rawles version of social contract theory, whereby he poses the hypothetical question as to what arrangement of political, social and economic affairs humans would favour if placed in what he called the original position, where they would be unaware of, not only their own race, sex and position in to the socio-economic hierarchy, but also, most important for our purposes, their own level of innate ability. This Rawles referred to as ‘veil of ignorance’.

[6] The tripartite system did indeed enable many working-class children to achieve a much higher economic status than their parents, although this was partly due to the expansion of the middle-class sector of the economy over the same time-period. It was also later Labour administrations who largely abolished the 11-plus system, not least because, unsurprisingly given the heritability of intelligence and personality, children from middle-class backgrounds tended to do better on it than did children from working-class backgrounds.

References 

Barrick & Mount 1991 The big five personality dimensions and job performance: a meta-analysis. Personnel Psychology 44(1):1–26 
Beckford (2008) Working classes ‘lack intelligence to be doctors’, claims academicDaily Telegraph, 04 Jun 2008. 
Clark 2008 Higher social classes have significantly HIGHER IQs than working class, claims academic Daily Mail, 22 May 2008. 
Kruger & Dunning (1999) Unskilled and Unaware of It: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-AssessmentsJournal of Personality and Social Psychology 77(6):1121-34 
Loehlin et al (1973) Blood group genes and negro-white ability differencesBehavior Genetics 3(3): 263-270  
Rushton, J. P. (1997). Why The Bell Curve didn’t go far enough on race. In E. White (Ed.), Intelligence, political inequality, and public policy (pp. 119-140). Westport, CT: Praeger. 
Scarr et al (1977) Absence of a relationship between degree of white ancestry and intellectual skills within a black population. Human Genetics 39(1):69-86 . 
Wheen (2000) The ‘science’ behind racismGuardian, 10 May 2000. 

Judith Harris’s ‘The Nurture Assumption’: By Parent or Peers

Judith Harris, The Nurture Assumption: Why Children Turn Out the Way They Do. Free Press, 1998.

Almost all psychological traits on which individual humans differ, from personality and intelligence to mental illness, are now known to be substantially heritable. In other words, individual differences in these traits are, at least in part, a consequence of genetic differences between individuals. 

This finding is so robust that it has even been termed by Eric Turkenheimer the First Law of Behviour Genetics and, although once anathema to most psychologists save a marginal fringe of behavioural geneticists, it has now, under the sheer weight of evidence produced by the latter, belatedly become the new orthodoxy. 

On reflection, however, this transformation is not entirely a revelation. 

After all, it was only in the mid-twentieth century that the curious notion that individual differences were entirely the product of environmental differences first arose, and, even then, this delusion was largely restricted to psychologists, sociologists, feminists and other such ‘professional damned fools’, along with those among the semi-educated public who seek to cultivate an air of intellectualism by aping the former’s affections. 

Before then, poets, peasants and laypeople alike had long recognized that ability, insanity, temperament and personality all tended to run in families, just as physical traits like stature, complexion, hair and eye colour also do.[1]

However, while the discovery of a heritable component to character and ability merely confirms the conventional wisdom of an earlier age, another behavioural genetic finding, far more surprising and counterintuitive, has passed relatively unreported. 

This is the discovery that the so-called shared family environment (i.e. the environment shared by siblings, or non-siblings, raised in the same family home) actually has next to no effect on adult personality and behaviour. 

This we know from such classic study designs in behavioural genetics as twin studiesadoption studies and family studies.  

In short, individuals of a given degree of relatedness, whether identical twins, fraternal twins, siblings, half-siblings or unrelated adoptees, are, by the time they reach adulthood, no more similar to one another in personality or IQ when they are raised in the same household than when they are raised in entirely different households. 

The Myth of Parental Influence 

Yet parental influence has long loomed large in virtually every psychological theory of child development, from the Freudian Oedipus complex and Bowby’s attachment theory to the whole literary genre of books aimed at instructing anxious parents on how best to raise their children so as to ensure that the latter develop into healthy, functional, successful adults. 

Indeed, not only is the conventional wisdom among psychologists overturned, but so is the conventional wisdom among sociologists – for one aspect of the shared family environment is, of course, household income and social class

Thus, if the family that a person is brought up in has next to no impact on their psychological outcomes as an adult, then this means that the socioeconomic status of the family home in which they are raised also has no effect. 

Poverty, or a deprived upbringing, then, has no effect on IQ, personality or the prevalence of mental illness, at least by the time a person has reached adulthood.[2]

Neither is it only leftist sociologists who have proved mistaken. 

Thus, just as leftists use economic deprivation as an indiscriminate, catch-all excuse for all manner of social pathology (e.g. crime, unemployment, educational underperformance) so conservatives are apt to place the blame on divorcefamily breakdown, having children out of wedlock and the consequential increase in the prevalence of single-parent households

However, all these factors are, once again, part of the shared family environment – and according to the findings of behavioural genetics, they have next to no influence on adult personality or intelligence. 

Of course, chaotic or abusive family environments do indeed tend to produce offspring with negative life outcomes. 

However, none of this proves that it was the chaotic or abusive family environment that caused the negative outcomes. 

Rather, another explanation is at hand – perhaps the offspring simply biologically inherit the personality traits of their parents, the very personality traits that caused their family environment to be so chaotic and abusive in the first place.[3] 

For example, parents who divorce or bear offspring out-of-wedlock likely differ in personality from those who first get married then stick together, perhaps being more impulsive or less self-disciplined and conscientious (e.g. less able refrain from having children from a relationship that was destined to be fleeting, or less able to persevere and make the relationship last). 

Their offspring may, then, simply biologically inherit these undesirable personality attributes, which then themselves lead to the negative social outcomes associated with being raised in single-parent households or broken homes. The association between family breakdown and negative outcomes for offspring might, then, reflect simply the biological inheritance of personality. 

Similarly, as leftists are fond of reminding us, children from economically-deprived backgrounds do indeed have lower recorded IQs and educational attainment than those from more privileged family backgrounds, as well as other negative outcomes as adults (e.g. lower earnings, higher rates of unemployment). 

However, this does not prove that coming from a deprived family background necessarily itself depresses your IQ, educational attainment or future salary. 

Rather, an equally plausible possibility is simply that offspring simply biologically inherit the low intelligence of their parents – the very low intelligence which was likely a factor causing the low socioeconomic status of their parents, since intelligence is known to correlate strongly with educational and occupational advancement.[4]

In short, the problem with all of this body of research which purports to demonstrate the influence of parents and family background on psychology and behavioural outcomes for offspring is that they fail to control for the heritability of personality and intelligence, an obvious confounding factor

The Non-Shared Environment

However, not everything is explained by heredity. As a crude but broadly accurate generalization, only about half the variation for most psychological traits is attributable to genes. This leaves about half of the variation in intelligence, personality and mental illness to be explained environmental factors.  

What are these environmental factors if they are not to be sought in the shared family environment

The obvious answer is, of course, the non-shared family environment – i.e. the ways in which even children brought up in the same family-home nevertheless experience different micro-environments, both within the home and, perhaps more importantly, outside it. 

Thus, even the fairest and most even-handed parents inevitably treat their different offspring differently in some ways.  

Indeed, among the principal reasons that parents treat their different offspring differently is precisely because the different offspring themselves differ in their own behaviour.  

Corporal punishment 

Rather than differences in the behaviour of different children resulting from differences in how their parents treat them, it may be that differences in how parents treat their children may reflect responses to differences in the behaviour of the children themselves. 

In other words, the psychologists have the direction of causation precisely backwards. 

Take, for example, one particularly controversial issue, namely the physical chastisement of children by their parents as a punishment for bad behaviour (e.g. spanking). 

Thus, some psychologists have sometimes argued that physical chastisement actually causes misbehaviour. 

As evidence, they cite the fact that children who are spanked more often by their parents or caregivers on average actually behave worse than those whose caregivers only rarely or never spank the children entrusted to their care.  

This, they claim, is because, in employing spanking as a form of discipline, caregivers are inadvertently imparting the message that violence is a good way of solving your problems. 

Actually, however, I suspect children are more than capable of working out for themselves that violence is often an effective means of getting your way, at least if you have superior physical strength to your adversary. Unfortunately, this is something that, unlike reading, arithmetic and long division, does not require explicit instruction by teachers or parents. 

Instead, a more obvious explanation for the correlation between spanking and misbehaviour in children is not that spanking causes misbehaviour, but rather that misbehaviour causes spanking. 

Indeed, once one thinks about it, this is in fact rather obvious: If a child never seriously misbehaves, then a parent likely never has any reason to spank that child, even if the parent is, in principle, a strict disciplinarian; whereas, on the other hand, a highly disobedient child is likely to try the patience of even the most patient caregiver, whatever his or her moral opposition to physical chastisement in principle. 

In other words, causation runs in exactly the opposite direction to that assumed by the naïve psychologists.[5] 

Another factor may also be at play – namely, offspring biologically inherit from their parents the personality traits that cause both the misbehaviour and the punishment. 

In other words, parents with aggressive personalities may be more likely to lose their temper and physically chastise their children, while children who inherit these aggressive personalities are themselves more likely to misbehave, not least by behaving in an aggressive or violent manner. 

However, even if parents treat their different offspring differently owing to the different behaviour of the offspring themselves, this is not the sort of environmental factor capable of explaining the residual non-shared environmental effects on offspring outcomes. 

After all, this merely begs the question as to what caused these differences in offspring behaviour in the first place? 

If the differences in offspring behaviour exist prior to differences in parental responses to this behaviour, then these differences cannot be explained by the differences in parental responses.  

Peer Groups 

This brings us back to the question of the environmental causes of offspring outcomes – namely, if about half the differences among children’s IQs and personalities are attributable to environmental factors, but these environmental factors are not to be found in the shared family environment (i.e. the environment shared by children raised in the same household), then where are these environmental factors to be sought? 

The search for environmental factors affecting personality and intelligence has, thus far, been largely unsuccessful. Indeed, some behavioural geneticists have almost gone as far as conceding scholarly defeat in identifying correlates for the environmental portion of the variance. 

Thus, leading contemporary behavioural geneticist Robert Plomin in his recent book, Blueprint: How DNA Makes Us Who We Are, concludes that those environmental factors that affect cognitive ability, personality, and the development of mental illness are, as he puts it, ‘unsystematic’ in nature. 

In other words, he seems to be saying that they are mere random noise. This is tantamount to accepting that the null hypothesis is true. 

Judith Harris, however, has a quite different take. According to Harris, environmental causes must be sought, not within the family home, but rather outside it – in a person’s interactions with their peer-group and the wider community.[6]

Environment ≠ Nurture 

Thus, Harris argues that the so-called nature-nurture debate is misnamed, since the word ‘nurture’ usually refers to deliberate care and moulding of a child (or of a plant or animal). But many environmental effects are not deliberate. 

Thus, Harris repeatedly references behaviourist John B. Watson’s infamous boast: 

Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select—doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors.” 

Yet what strikes me as particularly preposterous about Watson’s boast is not its radical environmental determinism, nor even its rather convenient unfalsifiability.[7] 

Rather, what most strikes me as most preposterous about Watson’s claim is its frankly breath-taking arrogance. 

Thus, Watson not only insisted that it was environment alone that entirely determined adult personality. In this same quotation, he also proclaimed that he already fully understood the nature of these environmental effects to such an extent that, given omnipotent powers to match his evidently already omniscient understanding of human development, he could produce any outcome he wished. 

Yet, in reality, environmental effects are anything but clear-cut. Pushing a child in a certain direction, or into a certain career, may sometimes have the desired effect, but other times have the exact opposite effect to that desired, provoking the child to rebel against parental dictates. 

Thus, even to the extent that environment does determine outcomes, the precise nature of the environmental factors implicated, and their interaction with one another, and with the child’s innate genetic endowment, is surely far more complex than the simple mechanisms proposed by behaviourists like Watson (e.g. reinforcement and punishment). 

Language Acquisition 

The most persuasive evidence for Harris’s theory of the importance of peer groups comes from an interesting and widely documented peculiarity of language acquisition

The children of immigrants, whose parents speak a different language inside the family home, and may even themselves be monolingual, nevertheless typically grow up to speak the language of their host culture rather better than they do the language to which they were first exposed in the family home. 

Indeed, while their parents may never achieve fluency in the language of their host culture, having missed out on the Chomskian critical period for language acquisition, their children often actually lose the ability to speak their parent’s language, often much to the consternation of parents and grandparents. 

Yet, from an sociobiological or evolutionary psychological perspective, such an outcome is obviously adaptive. 

If a child is to succeed in wider society, they must master its language, whereas, if their parent’s first language is not spoken anywhere in their host society except in their family, then it is of limited utility, and, once their parents themselves become proficient in the language of the host culture, becomes entirely redundant (see The Ethnic Phenomenon (reviewed herehere and here): p258). 

Code-Switching 

Harris suggests that the same applies to personality. Just as the child of immigrants switches between one language and another at home and school, so they also adopt different personalities. 

Thus, many parents are surprised to be told by their children’s teachers at parents’ evenings that their offspring is quiet and well-behaved at school, since, as they themselves report, he or she isn’t at all like that at home. 

Yet, at home, a child has only, at most, a sibling or two with whom to compete for his parents’ attention. In contrast, at school, he or she has a whole class with whom to compete for their teacher’s attention.

It is therefore unsurprising that most children are less outgoing at school than they are at home with their parents. 

For example, an older sibling might be able push his little brother around at home. But, if he is small for his age, he is unlikely to be able to get away with the same behaviour among his peers at school. 

Children therefore adopt two quite different personalities – one for interactions with family and siblings, and another for among their peers.

This then, for Harris, explains why, perhaps surprisingly, birth-order has generally been found to have little if any effect on personality, at least as personality manifests itself outside the family home. 

An Evolutionary Theory of Socialization? 

Interestingly, even evolutionary psychologists have not been immune from the delusion of parental influence. Thus, in one influential paper, anthropologists Patricia Draper and Henry Harpending argued that offspring calibrate their reproductive strategy by reference to the presence or absence of a father in their household (Draper & Harpending 1982). 

On this view, being raised in a father-absent household is indicative of a social environment where low male parental investment is the norm, and hence offspring adjust their own reproductive strategy accordingly, adopting a promiscuous, low-investment mating strategy characterized by precocious sexual development and an inability to maintain lasting long-term relationships (Draper & Harpending 1982Belsky et al 1991). 

There is indeed, as these authors amply demonstrate, a consistent correlation between father-absence during development and both earlier sexual development and more frequent partner-switching in later life. 

Yet there is also another, arguably more obvious, explanation readily at hand to explain this association. Perhaps offspring simply inherit biologically the personality traits, including sociosexual orientation, of their parents. 

On this view, offspring raised in single-parent households are more likely to adopt a promiscuous, low-investment mating strategy simply because they biologically inherit the promiscuous sociosexual orientation of their parents, the very promiscuous sociosexual orientation that caused the latter to have children out-of-wedlock or from relationships that were destined to break down and hence caused the father-absent childhood of their offspring. 

Moreover, even on a priori theoretical grounds, Draper, Harpending and Belsky’s reasoning is dubious. 

After all, whether you personally were raised in a one- or two-parent family is obviously a very unreliable indicator of the sorts of relationships prevalent in the wider community into which you are born, since it represents a sample size of just one. 

Instead, therefore, it would be far more reliable to calibrate your reproductive strategy in response to the prevalence of one-parent households in the wider community at large, rather than the particular household type into which you happen to have been born.  

This, of course, directly supports Harris’s own theory of ‘peer group socialization’. 

In short, to the extent that children do adapt to the environment and circumstances of their upbringing (and they surely do), they must integrate into, adopt the norms of, and a reproductive strategy to maximize their fitness within, the wider community into which they are born, rather than the possibly quite idiosyncratic circumstances and attitudes of their own family. 

Absent Fathers, from Upper-Class to Under-Class 

Besides language-acquisition among the children of immigrants, another example cited by Harris in support of her theory of ‘peer group socialization’ is the culture, behaviours and upbringing of British upper-class males.

Here, boys were, and, to some extent, still are, reared primarily, not by their parents, but rather by nanniesgovernoresses and, more recently, in exclusive fee-paying all-male boarding schools

Yet, despite having next to no contact with their fathers throughout most of their childhood, these boys nevertheless managed somehow to acquire manners, attitudes and accents similar, if not identical, to those of their upper-class fathers, and not at all those of the middle-class nannies, governoresses and masters with whom they spent most of their childhood being raised. 

Yet this phenomenon is by no means restricted to the British upper-classes. On the contrary, rather than citing the example of the British upper-classes in centuries gone by, Harris might just as well have cited that of contemporary underclass in Britain and elsewhere, since what was once true of the British upper-classes, is now equally true of the underclass

Just as the British upper-classes were once raised by governoresses, nannies and in private schools with next to no contact with their fathers, so contemporary underclass males are similarly raised in single-parent households, often to unwed mothers, and typically have little if any contact with their biological fathers. 

Here, as Warren Farrell observes in his seminal The Myth of Male Power (which I have reviewed here and here), there is a now a “a new nuclear family: woman, government and child”, what Farrell terms “Government as a Substitute Husband”. 

Yet, once again, these underclass males, raised by single parents with the assistance of the state, typically turn out much like their absent fathers with whom they have had little if any contact, often going on to promiscuously father a succession of offspring themselves, with whom they likewise have next to no contact. 

Abuse 

But what of actual abuse? Surely this has a long-term devastating psychological impact on children. This, at any rate, is the conventional wisdom, and questioning this wisdom is tantamount to contemporary heresy, with attendant persecution

Take, for example, what is perhaps the form of child abuse that provokes the most outrage and disgust – namely, sexual abuse. Here, it is frequently asserted that paedophiles were almost invariably themselves abused as children, which creates a so-called ‘cycle of abuse’. 

However, there are at least three problems with this claim. 

First, it cannot explain how the first person in this cycle became a paedophile. 

Second, we might doubt whether it is really true that paedophiles are disproportionately likely to have themselves been abused as children. After all, abuse is something that almost invariably happens surreptitiously ‘behind closed doors’ and is therefore difficult to verify or disprove. 

Thus, even if most paedophiles claim to have been victims of abuse, it is possible that they are simply lying in order to elicit sympathy or excuse or shift culpability for their own offending. 

Finally, even if paedophiles can be shown to be disproportionately likely to have themselves been victimized as children, this by no means proves that their victimization caused their sexual orientation. 

Rather, since most abuse is perpetrated by parents or other close family members, an alternative possibility is that victims simply biologically inherit the sexual orientation of their abuser. After all, if homosexuality is partially heritable, as is now widely accepted, then why not paedophilia as well? 

However, the finding that the shared family environment accounts for hardly any of the variance in outcomes among adults does not preclude the possibility that severe abuse may indeed have an adverse effect on adult outcomes. 

After all, adoption studies can only tell us what percent of the variance is caused by heredity or by shared or unshared environments within a specific population as a whole. 

Perhaps the shared family environment accounts for so little of the variance precisely because the sort of severe abuse that does indeed have a devastating long-term effect on personality and mental health is, thankfully, so very rare in modern societies. 

Indeed, it may be especially rare within the families used in adoption studies precisely because adoptive families are carefully screened for suitability before being allowed to adopt. 

Moreover, Harris emphasizes an important caveat: Even if abuse does not have long-term adverse psychological effects, this does not mean that abuse causes no harm, and nor does it in any way excuse such abuse. 

On the contrary, the primary reason we shouldn’t mistreat children (and should severely punish those who do) is not on account of some putative long-term psychological effect on the adults whom the children subsequently become, but rather because of the very real pain and suffering inflicted on a child at the time the abuse takes place. 

Race Differences in IQ 

Finally, Harris even touches upon that most vexed area of the (so-called) nature-nurture debate – race differences in intelligence

Here, the politically-correct claim that differences in intelligence between racial groups, as recorded in IQ tests, are of purely environmental origin runs into a problem, since the sorts of environmental effects that are usually posited by environmental determinists as accounting for the black-white test score gap in America (e.g. differences in rates of poverty and socioeconomic status) have been shown to be inadequate because, even after controlling for these factors, there remains a still unaccounted for gap in test-scores. 

Thus, as Arthur R. Jensen laments: 

This gives rise to the hypothesizing of still other, more subtle environmental factors that either have not been or cannot be measured—a history of slavery, social oppression, and racial discrimination, white racism, the ‘black experience,’ and minority status consciousness [etc]” (Straight Talk About Mental Tests: p223). 

The problem with these explanations, however, is that none of these factors has yet been demonstrated to have any effect on IQ scores. 

Moreover, some of the factors proposed as explanations are formulated in such a vague form (e.g. “white racism, the ‘black experience’”) that it is difficult to conceive of how they could ever be subjected to controlled testing in the first place.[8] 

Jensen has termed this mysterious factor the ‘X-factor’. 

In coining this term, Jensen was emphasizing its vague, mysterious and unfalsifiable nature. Jensen did not actually believe that this posited ‘X-factor’, whatever it was, really did account for the test-score gap. Rather, he thought heredity explained most, if not all, of the remaining test-score gap. 

However, Harris takes Jensen at his word. Thus, she announces: 

I believe I know what this X factor is… I can describe it quite clearly. Black kids and white kids identify with different groups that have different norms. The differences are exaggerated by group contrast effects and have consequences that compound themselves over the years. That’s the X factor” (p248-9). 

Interestingly, although she does not develop it, Harris’s claim is actually compatible with, and potentially reconciles, the conflicting findings of two of the most widely-cited studies in this vexed area of research and debate. 

First, in the more recent of these two studies, Minnesota Transracial Adoption Study, the same differences in IQ were observed among black, white and mixed-race children adopted into upper-middle class white families as are found among the respective among black, white and mixed-race populations in society at large (Scarr & Weinberg 1976). 

Moreover, although, when tested during childhood, the children’s adoptive households did seem to have had a positive effect on their IQ scores, by the time they reached the cusp of adulthood, the black teenagers who had been adopted into upper-middle-class white homes actually scored no higher in IQ than did blacks in the wider population not raised in upper-middle class white families (Weinberg, Scarr & Waldman 1992). 

This study is often cited by hereditarians as evidence for innate racial differences (e.g. Levin 1994Lynn 1994Whitney 1996). 

However, in the light of the findings of the behavioural genetics studies discussed by Harris in ‘The Nurture Assumption’, the fact that white upper-middle-class adoptive homes had no effect on the adult IQs of the black children adopted into them is, in fact, hardly surprising. 

After all, as we have seen, the shared family environment generally has no effect on IQ, at least by the time the person being tested has reached adulthood. One would therefore not expect adoptive homes, howsoever white and upper-middle-class, to have any effect on adult IQs of the black children adopted into them, or indeed of the white or mixed-race children adopted into them. 

In short, adoptive homes have no effect on adult IQ, whether or not the adoptees, or adoptive families, are black, white, brown, yellow, green or purple! 

But, if race differences in intelligence are indeed entirely environmental in origin, then where are these environmental causes to be found, if not in the family environment? 

Harris has an answer – black culture. 

According to her, the black adoptees, although raised in white adoptive families, nevertheless still come to identify as black, and to identify with the wider black culture and social norms. In addition, they may, on account of their racial identification, come to socialize with other blacks in school and elsewhere. 

As a result of this acculturation to African-American norms and culture, they therefore come to score lower in IQ than their white peers and adoptive siblings. 

But how can we test this theory? Perhaps we could look at the IQ scores of black children raised in white families where there is no wider black culture with which to identify, and few if any black peers with whom to socialize?  

This brings us to the second of the two studies which Harris’s theory potentially reconciles, namely the Eyferth study.  

Here, it was found that the mixed-race children fathered by black American servicemen who had had sexual relationships with German women during the Allied occupation of Germany after World War Two had almost exactly the same average IQ scores as a control group of offspring fathered by white US servicemen during the same time period (Eyferth 1959). 

The crucial difference from the Minnesota study may be that these children, raised in monoracial Germany in the mid-twentieth century, had no wider African-American culture with which to identify or whose norms to adopt, and few if any black or mixed-race peers in their vicinity with whom to socialize. 

This then is perhaps the last lifeline for the radical environmentalist theory of race differences in intelligence – namely the theory that African-American culture somehow depresses intelligence. 

Unfortunately, however, this proposition is likely almost as politically unpalatable to politically-correct liberals as is the notion that race differences in intelligence reflect innate genetic differences.[9] 

Endnotes

[1] Thus, this ancient wisdom is reflected, for example, in many folk sayings, such as the apple does not fall far from the tree, a chip off the old block and like father, like son, many of which long predate either Darwin’s theory of evolution, and Mendel’s work on heredity, let alone the modern work of behavioural geneticists.

[2] It is important to emphasize here that this applies only to psychological outcomes, and not, for example, economic outcomes. For example, a child raised by wealthy parents is indeed likely to be wealthier than one raised in poverty, if only because s/he is likely to inherit (some of) the wealth of his parents. It is also possible that s/he may, on average, obtain a better job as a consequence of the opportunities opened by his privileged upbringing. However, his IQ will be no higher than had s/he been raised in relative poverty, and neither will s/he be any more or less likely to suffer from a mental illness. 

[3] Similarly, it is often claimed that children raised in care homes, or in foster care, tend to have negative life-outcomes. However, again, this by no means proves that it is care homes or foster care that causes these negative life-outcomes. On the contrary, since children who end up in foster care are typically either abandoned by their biological parents, or forcibly taken from their parents by social services on account of the inadequate care provided by the latter, or sometimes outright abuse, it is obvious that their parents represent an unrepresentative sample of society as a whole. An obvious alternative explanation, then, is that the children in question simply inherit the dysfunctional personality attributes of their biological parents, namely the very dysfunctional personality attributes that caused the latter to either abandon their children or have them removed by the social services.

[4] Likewise, the heritability of such personality traits as conscientiousness and self-discipline, in addition to intelligence, likely also partly account for the association between parental income and academic attainment among their offspring, since both academic attainment, and occupational success, require the self-discipline to work hard to achieve success. These factors, again in addition to intelligence, likely also contribute to the association between parental income and the income and socioeconomic status ultimately attained by their offspring.

[5] This possibility could, of course, be ruled out by longitudinal studies, which investigate whether the spanking preceded the misbehaviour, or vice versa. However, this is easier said than done, since, unless relying on the reports by caregivers or children themselves, which depends on both the memory and honesty of the caregivers and children themselves, it would have to involve intensive, long-term, and continued observation in order to establish which came first, namely the pattern of misbehaviour, or the adoption of physical chastisement as a method of discipline. This would, presumably, require continuous observation from birth onwards, so as to ensure that the very first instance of spanking or excessive misbehaviour were recorded. To my knowledge, such a careful and intensive long-term study of this sort has yet to be conducted, if even it is possible.

[6] The fact that the relevant environmental variables must be sought outside the family home is one reason why the terms ‘between-family environment’ and ‘within-family environment’, sometimes used as synonyms or alternatives for ‘shared’ and ‘non-shared family environment’ respectively, are potentially misleading. Thus, the ‘within-family environment’ refers to those aspects of the environment that differ for different siblings even within a single family. However, these factors may differ within a single family precisely because they occur outside, not within, the family itself. The terms ‘shared’ and ‘non-shared family environment’ are therefore to be preferred, so as to avoid any potential confusion these alternative terms could cause.

[7] Both practical and ethical considerations, of course, prevent Watson from actually creating his “own specified world” in which to bring up his “dozen healthy infants”. Therefore, no one is able to put his claim to the test. It is therefore unfalsifiable and Watson is therefore free to make such boasts, safe in the knowledge that there is no danger of his actually being made to make good on his claims or being proven wrong.

[8] Actually, at least some of these theories are indeed testable and potentially falsifiable. With regard to the factors quoted by Jensen (namely, “a history of slavery, social oppression, and racial discrimination, white racism… and minority status consciousness”), one way of testing these theories is to look at test scores in those countries where there is no such history. For example, in sub-Saharan Africa, as well as in Haiti and Jamaica, blacks are not in the majority, and are moreover in control of the government. Yet the IQ scores of the indigenous population of Africa is actually even lower than among blacks in the USA (see Richard Lynn’s Race Differences in Intelligence: reviewed here). True, most such countries still have a history of racial oppression and discrimination, albeit in the form of European colonialism rather than racial slavery or segregation in the American sense. However, the lower scores for black Africans is true even in those few sub-Saharan African countries that were not colonized by western powers, or only briefly colonized (e.g. Ethiopia). Moreover, this merely begs the question as to why Africa was so easily colonized by Europeans. Also, other minority groups ostensibly subject to racial discrimination and oppression (e.g. Jews, Overseas Chinese) actually score very high in IQ, and are economically successful. As for “the ‘black experience’”, this meanly begs the question as to why the ‘black experience’ has been so similar, and resulted in the same low IQs, in so many different parts of the world, something implausible unless unless the ‘black experience’ itself reflects innate aspects of black African psychology. 

[9] Thus, ironically, the recently deceased James Flynn, though always careful, throughout his career, to remain on the politically-correct radical environmentalist side of the debate with regard to the causes of race differences in intelligence, nevertheless recently found himself taken to task by the leftist, politically-correct British Guardian newspaper for a sentence in his recent book, Does Your Family Make You Smarter, where he described American blacks as coming from a “from a cognitively restricted subculture” (Wilby 2016). Thus, whether one attributes lower black IQs to biology or to culture, either answer is certain offend leftists, and the power of political correctness can, it seems, never be appeased.

References 

Belsky, Steinberg & Draper (1991) Childhood Experience, Interpersonal Development, and Reproductive Strategy: An Evolutionary Theory of Socialization Child Development 62(4): 647-670 

Draper & Harpending (1982) Father Absence and Reproductive Strategy: An Evolutionary Perspective Journal of Anthropological Research 38:3: 255-273 

Eyferth (1959) Eine Untersuchung der Neger-Mischlingskinder in WestdeutschlandVita Humana, 2, 102–114 

Levin (1994) Comment on Minnesota Transracial Adoption Study. Intelligence. 19: 13–20 

Lynn, R (1994) Some reinterpretations of the Minnesota Transracial Adoption Study. Intelligence. 19: 21–27 

Scarr & Weinberg (1976) IQ test performance of black children adopted by White familiesAmerican Psychologist 31(10):726–739 

Weinberg, Scarr & Waldman, (1992) The Minnesota Transracial Adoption Study: A follow-up of IQ test performance at adolescence Intelligence 16:117–135 

Whitney (1996) Shockley’s experiment. Mankind Quarterly 37(1): 41-60

Wilby (2006) Beyond the Flynn effect: New myths about race, family and IQ? Guardian, September 27.

Richard Lynn’s ‘Race Differences in Intelligence’: Useful as a Reference Work, But Biased as a Book

[Warning: Vastly overlong book review. Casual reader beware.]

Race Differences in Intelligence: An Evolutionary Analysis, by Richard Lynn (Augusta, GA: Washington Summit, 2006) 

Richard Lynn’s ‘Race Differences in Intelligence’ is structured around his massive database of IQ studies conducted among different populations. This collection seems to be largely recycled from his earlier IQ and the Wealth of Nations, and subsequently expanded, revised and reused again in IQ and Global Inequality, The Global Bell Curve, and The Intelligence of Nations (as well as a newer edition of Race Differences in Intelligence, published in 2015). 

Thus, despite its subtitle, “An Evolutionary Analysis”, the focus is very much on documenting the existence of race differences in intelligence, not explaining how or why they evolved. The “Evolutionary Analysis” promised in the subtitle is actually almost entirely confined to the last three chapters. 

The choice of this as a subtitle is therefore misleading and presumably represents an attempt to cash in on the recent rise in, and popularity of, evolutionary psychology and other sociobiological explanations for human behaviours. 

However, whatever the inadequacies of Lynn’s theory of how and why race differences in intelligence evolved (discussed below), his documentation of the existence of these differences is indeed persuasive. The sheer number of studies and the relative consistency over time and place suggests that the differences are indeed real and there is therefore something to be explained in the first place. 

In this respect, it aims to do something similar to what was achieved by Audrey Shuey’s The Testing of Negro Intelligence, first published in 1958, which brought together a huge number of studies, and a huge amount of data, regarding the black-white test score gap in the US. 

However, whereas Shuey focused almost exclusively on the black-white test score gap in North America, Lynn’s ambition is much broader and more ambitious – namely, to review data relating to the intelligences of all racial groups everywhere across the earth. 

Thus, Lynn declares that: 

The objective of this book [is] to broaden the debate from the local problem of the genetic and environmental contributions to the difference between whites and blacks in the United States to the much larger problem of the determinants of the global differences between the ten races whose IQs are summarised” (p182). 

Therefore, his book purports to be: 

The first fully comprehensive review… of the evidence on race differences in intelligence worldwide” (p2). 

Racial Taxonomy

Consistent with this, Lynn includes in his analysis data for many racial groups that rarely receive much if any coverage in previous works on the topic of race differences in intelligence. 

Relying on both morphological criteria and genetic data gathered by Cavalli-Sforz et al in The History and Geography of Human Genes, Lynn identifies ten separate human races. These are: 

1) “Europeans”; 
2) “Africans”; 
3) “Bushmen and Pygmies”; 
4) “South Asians and North Africans”; 
5) “Southeast Asians”; 
6) “Australian Aborigines”; 
7) “Pacific Islanders”; 
8) “East Asians”; 
9) “Artic Peoples”; and 
10) “Native Americans”.

Each of these racial groups receives a chapter of their own, and, in each of the respective chapters, Lynn reviews published (and occasionally unpublished) studies that provide data on each group’s: 

  1. IQs
  2. Reaction times when performing elementary cognitive tasks; and
  3. Brain size

Average IQs 

The average IQs reported by Lynn are, he informs us, corrected for the Flynn Effect – i.e. the rise in IQs over the last century (p5-6).  

However, the Flynn Effect has occurred at different rates in different regions of the world. Likewise, the various environmental factors that have been proposed as possible explanations for the phenomenon (e.g. improved nutrition and health as well as increases in test familiarity, and exposure to visual media) have varied in the extent to which they are present in different places. Correcting for the Flynn Effect is therefore easier said than done. 

IQs of “Hybrid populations

Lynn also discusses the average IQs of racially-mixed populations, which are, he reports, consistently intermediate between the average IQs of the two (or more) parent populations. 

However, both, on the one hand, hybrid vigour or heterosis and, on the other, hybrid incompatibility or outbreeding depression could potentially complicate the assumption that racial hybrids should have average IQs intermediate between the average IQs of the two (or more) parent populations. 

However, Lynn only alludes to the possible effect of hybrid vigour in relation to biracial people in Hawaii, not in relation to other hybrid populations whose IQs he discusses, and never discusses the possible effect of hybrid incompatibility or outbreeding depression at all. 

Genotypic IQs 

Finally, Lynn also purports to estimate what he calls the “genotypic IQ” of at least some of the races discussed. This is a measure of genetic potential, distinguished from their actual realized phenotypic IQ. 

He defines the “genotypic IQ” of a population as the average score of a population if they were raised in environments identical to those of the group with whom they are being compared. 

Thus, he writes: 

The genotypic African IQ… is the IQ that Africans would have if they were raised in the same environment as Europeans” (p69). 

The fact that lower-IQ groups generally provide their offspring with inferior environmental conditions is therefore irrelevant for determining their “genotypic IQ”. However, as Lynn himself later points out: 

“It is problematical whether the poor nutrition and health that impair the intelligence of many third world peoples should be regarded as a purely environmental effect or as to some degree a genetic effect arising from the low intelligence of the populations that makes them unable to provide good nutrition and health for their children” (p193). 

Also, Lynn does not explain why he uses Europeans as his comparison group – i.e. why the African genotypic IQ is “the IQ that Africans would have if they were raised in the same environment as Europeans”, as opposed to, say, if they were raised in the same environments East Asians, Middle Eastern populations or indeed their own environments. 

Presumably this reflects historical reasons – namely, Europeans were the first racial group to have their IQs systematically measured – the same reason that European IQs are arbitrarily assigned an average score of 100. 

Reaction Times 

Reaction times refer to the time taken to perform so-called elementary cognitive tasks. These are tests where everyone can easily work out the right answer, but where the speed with which different people get there correlates with IQ. 

Arthur Jensen has championed reaction time as a (relatively more) direct measure of one key cognitive process underlying IQ, namely speed of mental processing. 

Yet individuals with quicker reaction times would presumably have an advantage in sports, since reacting to, say, the speed and trajectory of a ball in order to strike or catch it is analogous to an elementary cognitive task. 

However, despite lower IQs, African-Americans, and blacks resident in other western economies, are vastly overrepresented among elite athletes. 
 
To explain this paradox, Lynn distinguishes “reaction time proper” – i.e. when one begins to move one’s hand towards the correct button to press – from “movement time” – how long one’s hand takes to get there. 

Whereas whites generally react faster, Lynn reports that blacks have faster movement times (p58-9).[1] Thus, Lynn concludes: 

The faster movement times of Africans may be a factor in the fast sprinting speed of Africans shown in Olympic records” (p58). 

However, psychologist Richard Nisbett reports that: 

“Across a host of studies, movement times are just as highly correlated with IQ as reaction times” (Intelligence and How to Get It: p222). 

Brain Size

Lynn also reviews data regarding the brain-size of different groups. 

The correlation between brain-size and IQ as between individuals is well-established (Rushton and Ankney 2009). 
 
As between species, brain-size is also thought to correlate with intelligence, at least after controlling for body-size. 

Indeed, since brain tissue is highly metabolically expensive, increases in brain-size would surely never have evolved with conferring some countervailing selective advantage. 

Thus, in the late-1960s, biologist HJ Jerison developed an equation to estimate an animal’s intelligence from its brain- and body-size alone. This is called the animal’s encephalization quotient
 
However, comparing the intelligence of different species poses great difficulties.[2]

In short, if you think a ‘culture fair’ IQ test is an impossibility, then try designing a ‘species fair’ test! 
 
Moreover, dwarves have smaller absolute brain-sizes but usually larger brains relative to body-size, but usually have normal IQs. 

Sex differences in IQ, meanwhile, are smaller than those between races even though differences in brain-size are greater, at least before one introduces controls for body-size. 
 
Also, Neanderthals had larger brains than modern humans, despite a shorter, albeit more robust, stature.

One theory has it that population differences in brain-size reflect a climatic adaptation that evolved in order to regulate temperature, in accordance with Bermann’s Rule. This seems to be the dominant view among contemporary biological anthropologists, at least those who deign (or dare) to even discuss this politically charged topic.[3] 

Thus, in one recent undergraduate textbook in biological anthropology, authors Mielke, Konigsberg and Relethford contend: 

“Larger and relatively broader skulls lose less heat and are adaptive in cold climates; small and relatively narrower skulls lose more heat and are adaptive in hot climates” (Human Biological Variation: p285). 

On this view, head size and shape represents a means of regulating the relative ratio of surface-area-to-volume, since this determines the proportion of a body that is directly exposed to the elements.

Thus, Stephen Molnar, the author of another competing undergraduate textbook in biological anthropology, observes

“The closer a structure approaches a spherical shape, the lower will be the surface-to-volume ratio. The reverse is true as elongation occurs—a greater surface area to volume is formed, which results in more surface to dissipate heat generated within a given volume. Since up to 80 percent of our body heat may be lost through our heads on cold days, one can appreciate the significance of shape” (Human Variation: Races, Types and Ethnic Groups, 5th Ed: p188).

The BermannAllen rules likely also explain at least some of the variation in body-size and stature as between racial groups. 

For example, Eskimos tend to be short and stocky, with short arms and legs and flat faces. This minimizes the ratio of surface-area-to-volume, ensures only a minimal proportion of the body is directly exposed to the elements, and also minimizes the extent of extremities (e.g. arms, legs, noses), which are especially vulnerable to the cold. 

In contrast, populations from tropical climates, such as African blacks and Australian Aboriginals, tend to have relatively long arms and legs as compared to trunk size, a factor which likely contributes towards their success in some athletic events. 

Yet, interestingly, Beals et al report that:

“Braincase volume is more highly correlated with climate than any of the summative measures of body-size” (Beals et al 1984: p305).

Yet, contrary to popular wisdom, humans do not lose an especially high proportion of our body heat through our heads, certainly not “up to 80 percent of our body heat”, as claimed in Stephen Molnar’s anthropology textbook as quoted above, a preposterous figure given that the head comprises only about 10% of the body’s overall surface area.

Indeed, the amount of heat lost through our head is relatively higher than that lost through other parts of the body only because other parts of the body are typically covered by clothes.

At any rate, it is surely implausible that an increase in brain tissue, which is metabolically highly expensive, would have evolved solely for the purpose of regulating temperature, when the same result could surely have been achieved by modifying only the external shape of the skull. 
 
Conversely, even if race differences in brain-size did evolve purely for temperature regulation, differences in intelligence could still have emerged as a by-product of such selection.

In other words, if larger brains did evolve among populations inhabiting colder latitudes solely for the purposes of temperature regulation, the extra brain tissue that resulted may still have resulted in greater levels of cognitive ability among these populations, even if there was no direct selection for increased cognitive ability itself.

Europeans

The first racial group discussed by Lynn are those he terms “Europeans” (i.e. white Caucasians). He reviews data on IQ both in Europe and among diaspora populations elsewhere in the world (e.g. North America, Australia). 

The results are consistent, almost always giving an average IQ of about 100 – though this figure is, of course, arbitrary and reflects the fact that IQ tests were first normed by reference to European populations. This is what James Thompson refers to as the ‘Greenwich mean IQ’ and the IQs of all other populations in Lynn’s book are calculated by reference to this figure. 
 
Southeast Europeans, however, score slightly lower. This, Lynn argues, is because: 

Balkan peoples are a hybrid population or cline, comprising a genetic mix between the Europeans and South Asians in Turkey” (p18). 

Therefore, as a hybrid population, their IQs are intermediate between those of the two parent populations, and, according to Lynn, South Asians score somewhat lower in IQ than do white European populations (see below).[4]

In the newer 2015 edition, Lynn argues that IQs are somewhat lower elsewhere in southern Europe, namely southern Spain and Italy, for much the same reason, namely because: 

“The populations of these regions are a genetic mix of European people with those from the Near East and North Africa, with the result that their IQs are intermediate between the parent populations” (Preface, 2015 Edition).[5]

An alternative explanation is that these regions (e.g. Balkan countries, Southern Italy) have lower living-standards. 

However, instead of viewing differences in living standards as causing differences in recorded IQs as between populations, Lynn argues that differences in innate ability themselves cause differences in living standards, because, according to Lynn, more intelligent populations are better able to achieve high levels of economic development (see IQ and the Wealth of Nations).[6]

Moreover, Lynn observes that in Eastern Europe, living standards are substantially below elsewhere in Europe as a consequence of the legacy of communism. However, populations from Eastern Europe score only slightly below those from elsewhere in Europe, suggesting that even substantial differences in living-standards may have only a minor impact on IQ (p20). 

Portuguese 

The Portuguese also, Lynn claims, score lower than elsewhere in Europe. 

However, he cites just two studies. These give average IQs of 101 and 88 respectively, which Lynn averages to give an average of 94.5 (p19). 

Yet these two results are actually highly divergent, the former being slightly higher than the average for north-west Europe. This suggests an inadequate basis on which to posit a genetic difference in ability. 

However, Lynn provocatively concludes: 

Intelligence in Portugal has been depressed by the admixture of sub-Saharan Africans. Portugal was the only European country to import black slaves from the fifteenth century onwards” (p19). 

This echoes Arthur De Gobineau’s infamous theory that empires decline because, through their empires, they conquer large numbers of inferior peoples, who then inevitably interbreed with their conquerors, which, according to De Gobineau, results in the dilution the very qualities that permitted their imperial glories in the first place. 

In support of Lynn’s theory, mitochondrial DNA studies have indeed found higher frequency of sub-Saharan African Haplogroup L in Portugal than elsewhere in Europe (e.g. Pereira et al 2005). 

Ireland and ‘Selective Migration 

IQs are also, Lynn reports, somewhat lower than elsewhere in Europe in Ireland. 

Lynn cites four studies of Irish IQs which give average scores of 87, 97, 93 and 91 respectively. Again, these are rather divergent but nevertheless consistently below the European average, all but one substantially so. 
 
Of course, in England, in less politically correct times, the supposed stupidity of the Irish was once a staple of popular humour, Irish jokes being the English equivalent of Polish jokes in America.[7]
 
This seems anomalous given the higher average IQs recorded elsewhere in North-West Europe, especially the UK, Ireland’s next-door neighbour, whose populations are closely related to those in Ireland. 
 
Of course, historically Ireland was, until relatively recently, quite poor by European standards. 

It is also sparsely populated and a relatively high proportion of the population live in rural areas, and there is some evidence that people from rural areas have lower average IQs than those from urban areas

However, economic deprivation cannot explain the disparity. Today, despite the 2008 economic crash, and inevitable British bailout, Ireland enjoys, according to the UN, a higher Human Development Index than does the UK, and has done for some time. Indeed, by this measure, Ireland enjoys one of the highest standards of living in the world

Moreover, although formerly Ireland was much poorer, the studies cited by Lynn were published from 1973 to 1993, yet show no obvious increase over time.[8] 
 
Lynn himself attributes the depressed Irish IQ to what he calls ‘selective migration’, claiming: 

There has been some tendency for the more intelligent to migrate, leaving less intelligent behind” (p19). 

Of course, this would suggest, not only that the remaining Irish would have lower average IQs, but also that the descendants of Irish émigrés in Britain, Australia, America and other diaspora communities would have relatively higher IQs than other white people. 

In support of this, Americans reporting Irish ancestry do indeed enjoy higher relative incomes as compared to other white American ethnicities. 

Interestingly, Lynn also invokes “selective migration” to explain the divergences in East Asian IQs. Here, however, it was supposedly the less intelligent who chose to migrate (p136; p138; p169).[9]

Meanwhile, other hereditarians have sought to explain away the impressive academic performance of recent African immigrants to the West, and their offspring, by reference to selective immigration of high IQ Africans, an explanation which is wholly inadequate on mathematical grounds alone (see Chisala 2015b; 2019).

It certainly seems plausible that migrants differ in personality from those who choose to remain at home. It is likely that they are braver, have greater determination, drive and willpower than those who choose to stay behind. They may also perhaps be less ethnocentric, and more tolerant of foreign cultures.[10]

However, I see no obvious reason they would differ in intelligence.

As Chanda Chisala writes:

Realizing that life is better in a very rich country than in your poor country is never exactly the most g-loaded epiphany among Africans” (Chisala 2015b).

Likewise, it likely didn’t take much brain-power for Irish people to realize during the Irish Potato Famine that they were less likely to starve to death if they emigrated abroad.

Of course, wealth is correlated with intelligence and may affect the decision to migrate.

The rich usually have little economic incentive to migrate, while the poor may be unable to afford the often-substantial costs of migration (e.g. transportation).

However, without actual historical data showing certain socioeconomic classes or intellectual ability groups were more likely to migrate than others, Lynn’s claims regarding ‘selective migration’ represent little more than a post-hoc rationalization for IQ differences that are otherwise anomalous and not easily explicable in terms of heredity. 

Ireland, Catholicism and Celibacy

Interestingly, in the 2015 edition of ‘Race Differences in Intelligence’, Lynn also proposes, in addition, a further explanation for the low IQs supposedly found in Ireland, namely the clerical celibacy demanded under Catholicism. Thus, Lynn argues:

“There is a dysgenic effect of Roman Catholicism, in which clerical celibacy has reduced the fertility of some of the most intelligent, who have become priests and nuns” (2015 Edition; see also Lynn 2015). 

Of course, this theory presupposes that it was indeed the most intelligent among the Irish people who became priests. However, this is a questionable assumption, especially given the well-established inverse correlation between intelligence and religiosity (Zuckerman et al 2013).

However, it is perhaps arguable that, in an earlier age, when religious dogmas were relentlessly enforced, religious scholarship may have been the only form of intellectual endeavour that it was safe for intellectually-minded people to engage in.

Anyone investigating more substantial matters, such as whether the earth revolved around the sun or vice versa, was liable to be burnt at the stake if he reached the wrong (i.e. the right) conclusion.

However, such an effect would surely also apply in other historically Catholic countries as well.

Yet there is little if any evidence of depressed IQs in, say, France or Austria, although the populaions of both these countries were, until recently, like that of Ireland, predominantly Catholic.[11]

Africans 

The next chapter is titled “Africans”. However, Lynn uses this term to refer specifically to black Africans – i.e. those formerly termed ‘Negroes’. He therefore excludes from this chapter, not only the predominantly ‘Caucasoid’ populations of North Africa, but also African Pygmies and the Khoisan of southern Africa, who are considered separately in a chapter of their own. 

Lynn’s previous estimate of the average sub-Saharan African IQ as just 70 provoked widespread incredulity and much criticism. However, undeterred, Lynn now goes even further, estimating the average African IQ even lower, at just 67.[12]

Curiously, according to Lynn’s data, populations from the Horn of Africa (e.g. Ethiopia and Somalia) have IQs no higher than populations elsewhere in sub-Saharan Africa.[13]

Yet populations from the Horn of Africa are known to be partly, if not predominantly, Caucasoid in ancestry, having substantial genetic affinities with populations from the Middle East.[14].

Therefore, just as populations from Southern Europe have lower average IQs than other Europeans because, according to Lynn, they are genetically intermediate between Europeans and Middle Eastern populations, so populations from the Horn of Africa should score higher than those from elsewhere in sub-Saharan Africa because of intermixture with Middle Eastern populations.

However, Lynn’s data gives average IQs for Ethiopia and Somalia of just 68 and 69 respectively – no higher than elsewhere in sub-Saharan Africa (The Intelligence of Nations: p87; p141-2).

On the other hand, blacks resident in western economies score rather higher, with average IQs around 85. 

The only exception, strangely, are the Beta Israel, who also hail from the Horn of Africa, but are now mostly resident in Israel, yet who score no higher than those blacks still resident in Africa. From this, Lynn concludes:

“These results suggest that education in western schools does not benefit the African IQ” (p53). 

However, why then do blacks resident in other western economies score higher? Are blacks in Ethiopia somehow treated differently than those resident in the UK, USA or France? 

For his part, Lynn attributes the higher scores of blacks resident in these other Western economies to both superior economic conditions and, more controversially, to racial admixture. 

Thus, African-Americans in particular are known to be a racially-mixed population, with substantial European ancestry (usually estimated at around 20%) in addition to their African ancestry.[15]

Therefore, Lynn argues that the higher IQs of African-Americans reflect, in part, the effect of the European portion of their ancestry. 

However, this explanation is difficult to square with the observation that recent African immigrants to the US, themselves presumably largely of unmixed African descent, actually consistently outperform African-Americans (and sometimes whites as well) both academically and  economically (Chisala 2015a2015cAnderson 2015).[16]

Musical Ability” 

Lynn also reviews the evidence pertaining to one class of specific mental ability not covered in most previous reviews on the subject – namely, race differences in musical ability. 

The accomplishments of African-Americans in twentieth century jazz and popular music are, of course, much celebrated. To Lynn, however, this represents a paradox, since musical abilities are known to correlate with general intelligence and African-Americans generally have low IQs. 
 
In addressing this perceived paradox, Lynn reviews the results of various psychometric measures of musical ability. These tests include: 

  • Recognizing a change in pitch; 
  • Remembering a tune; 
  • Identifying the constituent notes in a chord; and 
  • Recognizing whether different songs have similar rhythm (p55). 

In relation to these sorts of tests, Lynn reports that African-Americans actually score somewhat lower in most elements of musical intelligence than do whites, and their musical ability is indeed generally commensurate with their general low IQs. 

The only exception is for rhythmical ability. 

This is, of course, congruent with the familiar observation that black musical styles place great emphasis on rhythm. 

However, even with respect to rhythmical ability, blacks score no higher than whites. Instead, blacks’ scores on measures of rhythmical ability are exceptional only in that this is the only form of musical ability on which blacks score equal to, but no higher than, whites (p56). 

For Lynn, the low scores of African-Americans in psychometric tests of musical ability are, on further reflection, little surprise. 

“The low musical abilities of Africans… are consistent with their generally poor achievements in classical music. There are no African composers, conductors, or instrumentalists of the first rank and it is rare to see African players in the leading symphony orchestras” (p57). 

However, who qualifies as a composer, conductor or instrumentalist “of the first rank” is, ultimately, unlike the results of psychometric testing, a subjective assessment, as are all artistic judgements. 

Moreover, why is achievement in classical music, an obviously distinctly western genre of music, to be taken as the sole measure of musical accomplishment? 

Even if we concede that the ability required to compose and perform classical music is greater than that required for other genres (e.g. jazz and popular music), musical intelligence surely facilitates composition and performance in other genres too – and, given the financial rewards offered by popular music often dwarf those enjoyed by players and composers of classical music, the more musically-gifted race would have every incentive to dominate this field too. 

Perhaps, then, these psychometric measures fail to capture some key element of musical ability relevant to musical accomplishment, especially in genres other than classical. 

In this context, it is notable that no lesser champion of standardized testing than Arthur Jensen has himself acknowledged that intelligence tests are incapable of measuring creativity (Langan & LoSasso 2002: p24-5). 

In particular, one feature common to many African-American musical styles, from rap freestyling to jazz, is improvisation.  

Thus, Dinesh D’Souza speculates tentatively that: 

Blacks have certain inherited abilities, such as improvisational decision making, that could explain why they predominate in… jazz, rap and basketball” (The End of Racism: p440-1). 

Steve Sailer rather less tentatively expands upon this theme, positing an African advantage in: 

Creative improvisation and on-the-fly interpersonal decision-making” (Sailer 1996). 

On this basis, Sailer concludes that: 

Beyond basketball, these black cerebral superiorities in ‘real time’ responsiveness also contribute to black dominance in jazz, running with the football, rap, dance, trash talking, preaching, and oratory” (Sailer 1996). 

Bushmen and Pygmies” 

Grouped together as the subjects of the next chapter are black Africans’ sub-Saharan African neighbours, namely San Bushmen and Pygmies

Quite why these two populations are grouped together by Lynn in a single chapter is unclear. 

He cites Cavalli-Sforza et al in The History and Geography of Human Genes as providing evidence that: 

“These two peoples have distinctive but closely related genetic characteristics and form two related clusters” (p73). 

However, although both groups are obviously indigenous to sub-Saharan Africa and quite morphologically distinct from the other black African populations who today represent the great majority of the population of sub-Saharan Africa, they share no especial morphological similarity to one another.[17]

Moreover, since Lynn acknowledges that they have “distinctive… genetic characteristics and form two… clusters”, they presumably should each of merited chapters of their own.[18]

One therefore suspects that they are lumped together more for convenience than on legitimate taxonomic grounds. 

In short, both are marginal groups of hunter-gatherers, now few in number, few if any of whom have been exposed to the sort of standardized testing necessary to provide a useful estimate of their average IQs. Therefore, since his data on neither group alone is really sufficient to justify its own chapter, he groups them together in a single chapter.  

However, the lack of data on IQ for either group means that even this combined chapter remains one of the shorter chapters in Lynn’s book, and, as we will see, the paucity of reliable data on the cognitive ability of either group almost leads one to suspect that he might almost have been better omitting both groups from his survey of race differences in cognitive ability altogether. 

San Bushmen 

It may be some meagre consolation to African blacks that, at least in Lynn’s telling, they no longer qualify as the lowest scoring racial group when it comes to IQ. Instead, this dubious honour is now accorded their sub-Saharan African neighbours, San Bushmen
 
In Race: The Reality of Human Differences (which I have reviewed here and here), authors Vincent Sarich and Frank Miele quote anthropologist and geneticist Henry Harpending as observing: 

“All of us have the impression that Bushmen are really quick and clever and are quite different from their [Bantu] neighbors… Bushmen don’t look like their black African neighbors either. I expect that there will soon be real data from the Namibian school system about the relative performance of Bushmen… and Bantu kids – or more likely, they will suppress it” (Race: The Reality of Human Differences (reviewed here): p227). 

Today, however, some fifteen or so years after Sarich and Miele published this quotation, the only such data I am aware of is that reported by Lynn in this book, which suggests, at least according to Lynn, a level of intelligence even lower than that of other sub-Saharan Africans. 

Unfortunately, however, the data in question is very limited and, in my view, inadequate to support Lynn’s controversial conclusions regarding Bushman ability.  

It also consists of just three studies, none of which remotely resemble a full IQ test (p74-5). 

Yet, from this meagre dataset, Lynn does not hesitate to attribute to Bushmen an average IQ of just 52. 

If Lynn’s estimate of the average sub-Saharan African IQ at around 70 provoked widespread incredulity, then his much lower estimate for Bushmen is unlikely to fare better. 

Lynn anticipates such a reaction, and responds by pointing out:  

“An IQ of 54 represents the mental age of the average European 8-year-old, and the average European 8-year-old can read, write, and do arithmetic and would have no difficulty in learning and performing the activities of gathering foods and hunting carried out by the San Bushmen. An average 8-year-old can easily be taught to pick berries put them in a container and carry them home, collect ostrich eggs and use the shells for storing water and learn how to use a bow and arrow” (p76). 

Indeed, Lynn continues, other non-human animals survive in difficult, challenging environments with even lower levels of intelligence:  

“Apes with mental abilities about the same as those of human 4-year olds survive quite well as gatherers and occasional hunters and so also did early hominids with IQs around 40 and brain sizes much smaller than those of modern Bushmen. For these reasons there is nothing puzzling about contemporary Bushmen with average IQs of about 54” (p77). 

Here, Lynn makes an important point. Many non-human animals survive and prosper in ecologically challenging environments with levels of intelligence much lower than that of any hominid, let alone any extant human race. 

On the other hand, however, I suspect Lynn would not last long in Kalahari Desert – the home environment of most contemporary Bushmen.

Pygmies 

Lynn’s data on the IQs of Pygmies is even more inadequate than his data for Bushmen. Indeed, it amounts to just one study, which again fell far short of a full IQ test. 

Moreover, the author of the study, Lynn reports, did not quantify his results, reporting only that Pygmies scored much “much worse” than other populations tested using the same test (p78). 

However, while the other populations tested using the same test and outperforming Pygmies included “Eskimos, Native American and Filipinos”, Lynn conspicuously does not mention that they included other black Africans, or indeed other very low IQ groups such as Australian Aboriginals (p78). 

Thus, Lynn’s assumption that Pygmies are lower in cognitive ability than other black Africans is not supported even by the single study that he cites. 

Lynn also infers a low level of intelligence for Pygmies from their lifestyle and mode of sustenance: 

“Most of them still retain a primitive hunter-gatherer existence while many of the Negroid Africans became farmers over the last few hundred years” (p78). 

Thus, Lynn assumes that whether a population has successfully transitioned to agriculture is largely a product of their intelligence (p191). 

In contrast, most historians and anthropologists would emphasize the importance of environmental factors in explaining whether a group transitions to agriculture.[19]

Finally, Lynn also infers a low IQ from the widespread enslavement of Pygmies by neighbouring Bantus: 

“The enslavement of Pygmies by Negroid Africans is consistent with the general principle that the more intelligent races generally defeat and enslave the less intelligent, just as Europeans and South Asians have frequently enslaved Africans but not vice versa” (p78). 

However, while it may be a “general principle that the more intelligent races typically defeat and enslave the less intelligent” (p78), this is hardly a rigid rule. 

After all, Arabs often enslaved Europeans.[20] Yet, according to Lynn, the Arabs belong to a rather less intelligent race than do the Europeans whom they so often enslaved. 

Interestingly, it is notable that Pygmies are the only racial group whom Lynn includes in his survey for whom he does not provide an actual figure as an estimate their average IQ, which presumably reflects a tacit admission of the inadequacy of the available data.[21] 

Curiously, unlike for all the other racial groups discussed, Lynn also fails to provide any data on Pygmy brain-size. 

Presumably, Pygmies have small brains as compared to other races, if only on account of their smaller body-size – but what about their brain-size relative to body-size? Is there simply no data available?

Australian Aborigines 

Another group who are barely mentioned at all in most previous discussions of the topic of race differences in intelligence are Australian Aborigines. Here, however, unlike for Bushmen and Pygmies, data from Australian schools are actually surprisingly abundant. 

These give, Lynn reports, an average Aboriginal IQ of just 62 (p104). 

Unlike his estimates for Bushmen and Pygmies, this figure seems to be reliable, given the number of studies cited and the consistency of their results. One might say, then, that Australian Aboriginals have the lowest recorded IQs of any human race for whom reliable data is available. 

Interestingly, in addition to his data on IQ, Lynn also reports the results of Piagetian measures of development conducted among Aboriginals. He reports, rather remarkably, that a large minority of Aboriginal adults fail to reach what Piaget called the concrete operational stage of development – or, more specifically, fail to recognize a substance, transferred to a new container, necessarily remains of the same quantity (p105-7). 

Perhaps even more remarkable, however, are reports of Aborigine spatial memory (p107-8). This refers to the ability to remember the location of objects, and their locations relative to one another. 

Thus, he reports, one study found that, despite their low general cognitive ability, Aborigines nevertheless score much higher than Europeans in tests of spatial memory (Kearins 1981).  

Another study found no difference in the performance of whites and Aborigines (Drinkwater 1975). However, since Aborigines have much lower IQs overall, even equal performance on spatial memory as against Europeans is still out of sync with the performance of whites and Aborigines on other types of intelligence test (p108). 

Lynn speculates that Aboriginal spatial memory may represent an adaptation to facilitate navigation in a desert environment with few available landmarks.[22]

The difference, Lynn argues, seems to be innate, since it was found even among Aborigines who had been living in an urban environment (i.e. not a desert) for several generations (p108; but see Kearins 1986). 

Two other studies reported lower scores than for Europeans. However, one was an unpublished dissertation and hence must be treated with caution, while the and the other (Knapp & Seagrim 1981) “did not present his data in such a way that the magnitude of the white advantage can be calculated” (p108). 

Intriguingly, Lynn reports that this ability even appears to be reflected in neuroanatomy. Thus, despite smaller brains overall, Aborigines’ right visual cortex, implicated in spatial ability, is relatively larger than in Europeans (Klekamp et al 1987; p108-9).

New Guineans and Jared Diamond 

In his celebrated Guns, Germs and Steel, Jared Diamond famously claimed: 

“In mental ability New Guineans are probably genetically superior to Westerners, and they surely are superior in escaping the devastating developmental disadvantages under which most children in industrialized societies grow up” (Guns, Germs and Steel: p21). 

Diamond bases this claim on the fact that, in the West, survival, throughout most of our recent history, depended on who was struck down by disease, which was largely random. 

In contrast, in New Guinea, he argues, people had to survive on their wits, with survival depending on one’s ability to procure food and avoid homicide, activities in which intelligence was likely to be at a premium (Guns, Germs and Steel: p20-21). 

He also argues that the intelligence of western children is likely reduced because they spend too much time watching television and movies (Guns, Germs and Steel: p21). 

However, there is no evidence television has a negative impact on children’s cognitive development. Indeed, given the rise in IQs over the twentieth century has been concomitant with increases in television viewing, it has even been speculated that increasingly stimulating visual media may have contributed to rising IQs. 

On the basis of two IQ studies, plus three studies of Piagetian development, Lynn concludes that the average IQ of indigenous New Guineans is just 62 (p112-3). 

This is, of course, exactly the same as his estimate for the average IQ of Australian Aboriginals.  

It is therefore consistent with Lynn’s racial taxonomy, since, citing Cavalli-Sforza et al, he classes New Guineans as in the same genetic cluster, and hence as part of the same race as Australian Aboriginals (p101). 

Pacific Islanders 

Other Pacific Islanders, however, including PolynesiansMicronesiansMelanesians and Hawiians, are grouped separately and hence receive a chapter of their own. 

They also, Lynn reports, score rather higher in IQ, with most such populations having average IQs of about 85 (p117). However, the Māoris of New Zealand score rather higher, with an average IQ of about 90 (p116). 

Hawaiians and Hybrid Vigor 

For the descendants of the inhabitants of one particular Pacific Island, namely Hawaii, Lynn also reports data regarding the IQs of racially-mixed individuals, both those of part-Native-Hawiian and part-East Asian ancestry, and those of part-Native-Hawiian and part-European ancestry. 

These racial hybrids, as expected, score on average between the average scores for the two parent populations. However, Lynn reports: 

“The IQs of the two hybrid groups are slightly higher than the average of the two parent races. The average IQ of the Europeans and Hawaiians is 90.5, while the IQ of the children is 93. Similarly, the average IQ of the Chinese and Hawaiians is 90, while the IQ of the children is 91. The slightly higher than expected IQs of the children of the mixed race parents may be a hybrid vigor or heterosis effect” (p118). 

Actually, the difference between the “expected IQs” and the IQs actually recorded for the hybrid groups is so small (only one point for the Chinese-Hawaiians), that it could easily be dismissed as mere noise, and I doubt it would reach statistical significance. 

Nevertheless, Lynn’s discussion begs the question as to why hybrid vigor has not similarly elevated the IQs of the other hybrid, or racially-mixed, populations discussed in other chapters, and why Lynn has not discussed this issue when reporting the average IQs of other racially-mixed populations in other chapters. 

Of course, while hybrid vigor is a real phenomenon, so is outbreeding depression and hybrid incompatibilities

Presumably, then, which of these countervailing effects outweighs the other for different types of hybrid depends on the degree of genetic distance between the two parent populations. This, of course, varies for different races. 

It is therefore possible that some racial mixes may tend to elevate intelligence, whereas others, especially between more distantly-related populations, may tend, on average, to depress intelligence. 

For what it’s worth, Pacific Islanders, including Hawiians, are thought to be genetically closer to East Asians than to Europeans. 

South Asians and North Africans

Another group rarely treated separately in earlier works are those whom Lynn terms “South Asians and North Africans”, though this group also includes populations from the Middle East. 

Physical anthropologists often lumped these peoples together with Europeans as collectively “Caucasian” or “Caucasoid”. However, while acknowledging that they are “closely related to the Europeans”, Lynn cites Cavalli-Sforza et al as showing they form “a distinctive genetic cluster” (p79). 

He also reports that they score substantially lower in IQ than do Europeans. Their average IQ in their native homelands is just 84 (p80), while South Asians resident in the UK score only slightly higher with an average IQ of just 89 (p82-4). 

This conclusion is surely surprising and should, in my opinion, be treated with caution. 

For one thing, all of the earliest known human civilizations – namely, MesopotamiaEgypt and the Indus Valley civilization – surely emerged among these peoples, or at least in regions today inhabited primarily by people of this race.[23]

Moreover, people of Indian ancestry in particular are today regarded as a model majority in both Britain and America, whose overrepresentation in the professions, especially medicine, is widely commented upon.[24]

Indeed, according to some measures, British-Indians are now the highest earning ethnicity in Britain, or the second-highest earning after the Chinese, and Indians are also the highest earners in the USA.[25]

Interestingly, in this light, one study cited by Lynn showed a massive gain of 14-points for children from India who had been resident in the UK for more than four years as compared to those who had been resident for less than four years, the former scoring almost as high in IQ as the indigenous British, with an average IQ of 97 (p83-4; Mackintosh & Mascie-Taylor 1985).[26]

In the light of this study, it would be interesting to measure the IQs of a sample composed exclusively of people who traced their ancestry to India but who had been resident in the UK for the entirety of their lives (or even whose ancestors had been resident in the UK for several generations), since all of the other studies cited by Lynn of the IQs of Indian children in the UK presumably include both recent arrivals and long-term residents grouped together. 

Interestingly, the high achievement of immigrants, and their descendants, from India is not matched by those from neighbouring countries such as Bangladesh or Pakistan. Indeed, the same data suggesting that Indians are the highest earning ethnicity in Britain also show that British-Pakistanis and Bangladeshis are among the lowest earners

The primary divide between these three countries is, of course, not racial but rather religious. This suggests a religion as a causal factor in the difference.[27]

Thus, one study found that Muslim countries tend to have lower average IQs than do non-Muslim countries (Templer 2010; see also Dutton 2020). 

Perhaps, then, cultural practices in Muslim countries are responsible for reducing IQs. 

For example, the prevalence of consanguineous (i.e. incestuous) marriage, especially cross-cousin marriage may have an effect on intelligence due to inbreeding depression (Woodley 2009). 

Another cultural practice that could affect intelligence in Muslim countries is the practice of even pregnant women fasting during daylight hours during Ramadan (cf. Aziz et al 2004). 

However, Lynn’s own data show little difference between IQs in India and those in Pakistan and Bangladesh, nor indeed between IQs in India and those in Muslim countries in the Middle East or North Africa. Nor, according to Lynn’s data, do people of Indian ancestry resident in the UK score noticeably higher in IQ than do people who trace their ancestry to Bagladeshi, Pakistani or Middle Eastern countries. 

An alternative suggestion is that Middle-Eastern and North African IQs have been depressed as a result of interbreeding with sub-Saharan Africans, perhaps as a result of the Islamic slave trade.[28]

This is possible because, although male slaves in the Islamic world were routinely castrated and hence incapable of procreation, female slaves outnumbered males and were often employed as concubines, a practice which, unlike in puritanical North America, was regarded as perfectly socially acceptable on the part of slave owners. 

This would be consistent with the finding that Arab populations from the Middle East show some evidence of sub-Saharan African ancestry in their mitochondrial DNA, which is passed down the female line, but not in their Y-chromosome ancestry, passed down the male line (Richards et al 2003). 

In contrast, in the United States, the use of female slaves for sexual purposes, although it certainly occurred, was, at least in theory, very much frowned upon. 

In addition, in North America, due to the one-drop rule, all mixed-race descendants of slaves with any detectable degree of black African ancestry were classed as black. Therefore, at least in theory, the white bloodline would have remained ‘pure’, though some mixed-race individuals may have been able to pass

Therefore, sub-Saharan African genes may have entered the Middle Eastern, and North African, gene-pools in a way they were not able to do so among whites in North America. 

This might explain why genotypic intelligence among North African and Middle Eastern populations may have declined in the period since the great civilizations of Mesopotamia and ancient Egypt and even since the Golden Age of Islam, when the intellectual achievements of Middle Eastern and North African peoples seemed so much more impressive.

Jews

Besides Indians, another economically and intellectually overachieving model minority who derive, at least in part, from the race whom Lynn classes as “South Asians and North Africans” are the Jews. 

Lynn has recently written a whole book on the topic of Jewish intelligence and achievement, titled The Chosen People: A Study of Jewish Intelligence and Achievement (review forthcoming). 

However, in ‘Race Differences in Intelligence’, Jews do not even warrant a chapter of their own. Instead, they are discussed only at the end of the chapter on “South Asians and North Africans”, although Ashkenazi Jews also have substantial European ancestry. 

The decision not to devote an entire chapter to the Jewish people is surely correct, because, although even widely disparate groups (e.g. AshkenazimSephardic and Mizrahim, even the Lemba) do indeed share genetic affinities, Jews are not racially distinct (i.e. reliably physically distinguishable on phenotypic criteria) from other peoples. 

However, the decision to include them in the chapter on “South Asians and North Africans” is potentially controversial, since, as Lynn readily acknowledges, the Ashkenazim in particular, who today constitute the majority of world Jewry, have substantial European as well as Middle Eastern ancestry. 

Lynn claims British and US Jews have average IQs of around 108 (p68). His data for Israel are not broken down by ethnicity, but give an average IQ for Israel as a whole of 95, which Lynn, rather conjecturally, infers scores of 103 for Ashkenazi Jews, 91 for Mizrahi Jews and 86 for Palestinian-Arabs (p94). 

Lynn’s explanations for Ashkenazi intelligence, however, are wholly unpersuasive. 

First, he observes that, despite Biblical and Talmudic admonitions against miscegenation with Gentiles, Jews inevitably interbred to some extent with the host populations alongside whom they lived. From this, Lynn infers that: 

“Ashkenazim Jews in Europe will have absorbed a significant proportion of the genes for higher intelligence possessed by… Europeans” (p95). 

It is indeed true that, if, as Lynn claims, Europeans are indeed a more intelligent race than are populations from the Middle East, then interbreeding with Europeans may indeed explain how Ashkenazim came to score higher in IQ than do other populations tracing their ancestry to the Middle East. 

However, interbreeding with Europeans can hardly explain how Ashkenazi Jews came to outscore, and outperform academically and economically, even the very Europeans with whom they are said to have interbred! 

This explanation therefore fails to explain why Ashkenazim have higher IQs than do Europeans. 

Lynn’s second explanation for high Ashkenazi Jewish IQs is equally unpersuasive. He suggests that: 

“The second factor that has probably operated to increase the intelligence of Ashkenazim Jews in Europe and the United States as compared with Oriental Jews is that the Ashkenazim Jews have been more subject to persecution… Oriental Jews experienced some persecution sufficient to raise their IQ of 91, as compared with 84 among other South Asians and North Africans, but not so much as that experienced by Ashkenazim Jews in Europe.” (p95).[29]

On purely theoretical grounds, the idea that persecution selects for intelligence may seem reasonably plausible, if hardly compelling.[30] 

However, there is no evidence that persecution does indeed reduce a population’s level of intelligence. On the contrary, other groups who have been subject to persecution throughout much of their histories – e.g. the Roma (i.e. Gypsies) and African-Americans – are generally found to have relatively low IQs. 

East and South-East Asians 

Excepting Jews, the highest average IQs are found among East Asians, who have, according to Lynn’s data, an average IQ of 105, somewhat higher than that of Europeans (p121-48). 

However, whereas Jews score relatively higher in verbal intelligence than spatio-visual ability, East Asians show the opposite pattern, with relatively higher scores for spatio-visual ability.[31]

However, it is important to emphasize that this relatively high figure applies only to East Asians – i.e. Chinese, Japanese Koreans, Taiwanese etc. 

It does not apply to the related populations of Southeast Asia (i.e. Thais, Filipinos, Vietnamese, Malaysians, Cambodians, Indonesians etc.), who actually score much lower in IQ, with average scores of only around 87 in their indigenous homelands, but rising to 93 among those resident in the US. 

Thus, Lynn distinguishes the East Asians from Southeast Asians as a separate race, on the grounds that the latter, despite “some genetic affinity with East Asians” form a distinct genetic cluster in data gathered and analyzed by Cavalli-Sforza et al, and also have distinct morphological features, with “the flattened nose and epicanthic eye-fold… [being] less prominent” than among East Asians (p97). 

This is an important point, since many previous writers on the topic have implied that the higher average IQs of East Asians applied to all ‘Asians’ or ‘Mongoloids’, which would presumably include South-East Asians.[32]

Yet, in Lynn’s opinion, it is just as misleading to group all these groups together as ‘Mongoloid’ or ‘Asian’ as it was to group “Europeans” and “South Asians and North Africans” together as ‘Caucasian’ or ‘Caucasoid’. 

However, that low scores throughout South-East Asia are entirely genetic in origin is unclear. Thus, Vietnamese resident in the West have sometimes, but not always, scored considerably higher, and Jason Malloy suggests that Lynn exaggerates the overrepresentation of ethnic Chinese among Vietnamese immigrants to the West so as attribute such results to East Asians rather than South-East Asians (Malloy 2014).[33]

Moreover, in relation to Lynn’s ‘Cold Winters Theory’ (discussed below), whereby it is claimed that populations were exposed to colder temperatures during their evolution evolved higher levels of intelligence in order to cope with the adaptive challenges that surviving cold temperatures posed, it is notable that climate varies greatly across China, reflecting the geographic size of the country, with Southern China having a subtropical climate with mild winters.

However, perhaps East Asians, like the Han Chinese, are to be regarded as only relatively recent arrivals in what is now Southern China. This would be consistent with claim of some physical anthropologists that the some aspects of the morphology of East Asians reflects adaptation to the extreme cold of Siberia and the Steppe, and also with the historical expansion of the Han Chinese.

More problematic for ‘Cold Winters Theory’ is the fact that, although Lynn classifies them as East Asian (p121), the higher average IQ scores of East Asians (as compared to whites), does not even extend to the people after whom the Mongoloid race was named – namely the Mongols themselves.

According to Lynn, Mongolians score only around the same as whites, with an average IQ of only 101 (Lynn 2007).

This report is based on just two studies. Moreover, it had not been published at the time the first edition of ‘Race Differences in Intelligence’ came off the presses.

However, Lynn infers a lower IQ for Mongolians from their lower level of cultural, technological and economic development (p240).

Yet, inhabiting the Mongolian-Manchurian grassland Steppe and Gobi Desert, Mongolians were subjected to an environment even colder and more austere than that of other East Asians.

Lynn’s explanation for this anomaly is that the low population-size of the Mongols, and their isolation from other populations, meant that the necessary mutations for higher IQ never arose (p240).[34]

This is the same explanation that Lynn provides for the related anomaly of why Eskimos (“Arctic Peoples”), to whom Mongolians share some genetic affinity, also score low in IQ, an explanation that is discussed in the final part of this review.

Native Americans

Another group sometimes subsumed with Asian populations as “Mongoloids” are the indigenous populations of the American continent, namely “Native Americans”. 

However, on the basis of both genetic data from Cavalli-Sforza et al and morphological differences (“darker and sometimes reddish skin, hooked or straight nose, and lack of the complete East Asian epicanthic fold”), Lynn classifies them as a separate race and hence accords them a chapter of their own. 

His data suggest average IQs of about 86, for both Native Americans resident in Latin America, and also for those resident in North America, despite the substantially higher living standards of the latter (p158; 162-3; p166). 

Mestizo populations, however, have somewhat higher scores, with average IQs intermediate between those of the parent populations (p160).[35]

Like the Asian populations with whom they share their ancestry, Native Americans score rather higher on spatio-visual intelligence than on verbal intelligence (p156). 

In particular, they also have especially high visual memory (p159-60). 

As he did for African-Americans, Lynn also discusses the musical abilities of Native Americans. Interestingly, psychometrical testing shows that their musical ability is rather higher than their general cognitive ability, giving a MQ (Musical Quotient) of approximately 92 (p160). 

They also show the same pattern of musical abilities as do African-Americans, with higher scores for rhythmical ability than for other forms of musical ability (p160). 

However, whereas blacks, as we have seen, only score as high as Europeans for rhythmical ability, but no higher, Native Americans, because of higher IQs (and MQs) overall, actually outscore both Europeans and African-Americans when it comes to rhythmical ability. 

These results are curious. Unlike African-Americans, Native Americans are not, to my knowledge, known for their contribution to any genres of western music, and neither are their indigenous musical traditions especially celebrated. 

Artic Peoples” (i.e. Eskimos) 

Distinguished from other Native Americans are the inhabitants of the far north of the American landmass. These, together with other indigenous populations from the area around the Bering straight, namely those from Greenland, the Aleutian Islands, and the far north-east of Siberia, together form the racial group whom Lynn refers to as “Arctic Peoples”, though the more familiar, if less politically correct, term would be ‘Eskimos’.[36]

As well as forming a distinctive genetic cluster per Cavalli-Sforza et al, they are also morphologically distinct, not least in their extreme adaptation to the cold, with, Lynn reports: 

Shorter legs and arms and a thick trunk to conserve heat, a more pronounced epicanthic eye-fold, and a nose well flattened into the face to reduce the risk of frostbite” (p149). 

As we will see, Lynn is a champion of what is sometimes called Cold Winters Theory – namely the theory that the greater environmental challenges, and hence cognitive demands, associated with living in colder climates selected for increased intelligence among those races inhabiting higher latitudes. 

Therefore, on the basis of this theory, one might imagine that Eskimos, who surely evolved in one of the most difficult, and certainly in the coldest, environment of any human group, would also have the highest IQs. 

This conclusion would also be supported by the observation that, according to the data cited by Lynn himself, Eskimos also have the largest average brain-size of any race (p153). 

Interestingly, some early reports did indeed suggest that Eskimos had high levels of cognitive ability as compared to whites.[37] However, Lynn now reports that Eskimos actually have rather lower IQ scores than do whites and East Asians, with results from 15 different studies giving an average IQ of around 90. 

Actually, however, viewed in global perspective, this average IQ of 90 for Eskimos is not that low. Indeed, of the ten major races surveyed by Lynn, only Europeans and East Asians score higher.[38]

It is an especially high score for a population who, until recently, lived exclusively as hunter-gatherers. Other foraging groups, or descendants of peoples who, until recently, subsisted as foragers, tend, according to Lynn’s data, to have low IQs (e.g. Australian Aboriginals, San Bushmen, Pygmies). 

One obvious explanation for the relatively low IQs of Eskimos as compared to Europeans and East Asians would be their deprived living conditions

However, Lynn is skeptical of the claim that environmental factors are entirely to blame for the difference in IQ between Eskimos and whites, since he observes: 

“The IQ of the Arctic Peoples has not shown any increase relative to that of Europeans since the early 1930s, although their environment has improved in so far as in the second half of the twentieth century they received improved welfare payments and education. If the intelligence of the Arctic Peoples had been impaired by adverse environmental conditions in the 1930s it should have increased by the early 1980s” (p153-4). 

He also notes that all the children tested in the studies he cites were enrolled in schools (since this was where the testing took place), and hence were presumably reasonably familiar with the procedure of test-taking (p154).

Lynn’s explanation for the relatively low scores of Eskimos is discussed below in the final part of this review.

Visual Memory, Spatial Memory and Hunter-Gathering 

Eskimos also score especially high on tests of visual memory, something not usually measured in standard IQ tests (p152-3). 

This is a proficiency they share in common with Native Americans (p159-60), to whom they are obviously closely related. 

However, as we have seen, Australian Aboriginals, who are not closely related to either group, also seem to possess a similar ability, though Lynn refers to this as “spatial Memory” rather than “visual Memory” (p107-8). 

These are, strictly speaking, somewhat different abilities, although they may not be entirely separate either, and may also be difficult to distinguish between in tests. 

If Aboriginals score high on spatial memory, they may then also score high on visual memory, and vice versa for Eskimos and Native Americans. However, since Lynn does not provide comparative data on visual memory among Aboriginals, or on spatial memory among Eskimos or Native Americans, this is not certain. 

Interestingly, one thing all these three groups share in common is a recent history of subsisting, at least in part, as hunter-gatherers.[39]

One is tempted, then, to attribute this ability to the demands of a hunter-gatherer lifestyle, perhaps reflecting the need to remember the location of plant foods which appear only seasonally, or to find one’s way home after a long hunting expedition.[40] 

It would then be interesting to test the visual and spatial memories of other groups who either continue to subsist as hunter-gatherers or only recently transitioned to agriculture or urban life, such as Pygmies and San Bushmen. However, since tests of spatial and visual memory are not included in most IQ tests, the data is probably not yet available.  

For his part, Lynn attributes Eskimo visual memory to the need to “find their way home after going out on long hunting expeditions” (p152-3). 

Thus, just as the desert environment of Australian Aboriginals provides few landmarks, so: 

“The landscape of the frozen tundra [of the Eskimos] provides few distinctive cues, so hunters would need to note and remember such few features as do exist” (p153). 

Proximate Causes: Heredity or Environment?

Chapter fourteen discusses the proximate causes of race differences in intelligence and the extent to which the differences observed can be attributed to either heredity or environmental factor, and, if partly the latter, which environmental factors are most important.  

Lynn declares at the beginning of the chapter that the objective of his book is “to broaden the debate” from an exclusive focus on the black-white test score gap in the US, to instead looking at IQ differences among all ten racial groups across the world for whom data on IQ or intelligence is presented in Lynn’s book (p182). 

Actually, however, in this chapter alone, Lynn does indeed focus primarily on black-white differences, if only because it is in relation to this difference that most research has been conducted, and hence to this difference that most available evidence relates. 

Downplaying the effect of schooling, Lynn identifies malnutrition as the major environmental influence on IQ (p182-7). 

However, he rejects malnutrition as an explanation for the low scores of American blacks, noting there is no evidence of short stature in black Americans and nor have surveys have found a greater prevalence of malnutrition (p185). 

As to global differences, he concludes that: 

“The effect of malnourishment on Africans in sub-Saharan Africa and the Caribbean probably explains about half of the low IQs, leaving the remaining half to genetic factors” (p185). 

However, it is unclear what is meant by “half of the low scores” as he has identified no comparison group.[41] 

He also argues that the study of racially mixed individuals further suggests a genetic component to observed IQ differences. Thus, he claims: 

“There is a statistically significant association between light skin and intelligence” (p190). 

As evidence he cites his own study (Lynn 2002) to claim: 

“When the amount of European ancestry in American blacks is assessed by skin color, dark-skinned blacks have an IQ of 85 and light-skinned blacks have an IQ of 92” (p190). 

However, he fails to explain how he managed to divide American blacks into two discrete groups by reference to a trait that obviously varies continuously. 

More importantly, he neglects to mention altogether two other studies that also investigated the relationship between IQ and degree of racial admixture among African-Americans, but used blood-groups rather than skin tone to assess ancestry (Loehlin et al 1973; Scarr et al 1977). 

This is surely a more reliable measure of ancestry than is skin tone, since the latter is affected by environmental factors (e.g. exposure to the sun darkens the skin), and could conceivably have an indirect psychological effect.[42]

However, both these studies found no association between ancestry and IQ (Loehlin et al 1973; Scarr et al 1977).[43] 

Meanwhile, Lynn mentions the Eyferth study (1961) of the IQs of German children fathered by black and white US servicemen in the period after World War II, only to report, “the IQ of African-Europeans [i.e. those fathered by the black US servicemen] was 94 in relation to 100 for European women” (p63). 

However, he fails to mention that the IQ of those German children fathered by black US servicemen (i.e. those of mixed race) was actually almost identical to that of those fathered by white US servicemen (who, with German mothers, were wholly white). This finding is, of course, evidence against the hereditarian hypothesis with respect to race differences. 

Yet Lynn can hardly claim to be unaware of this finding, or its implications with respect to race differences, since this is actually among the studies most frequently cited by opponents of the hereditarian hypothesis with respect to the black-white test score gap for precisely this reason. 

Lynn’s presentation of the evidence regarding the relative contributions of heredity and environment to race differences in IQ is therefore highly selective and biased. 

An Evolutionary Analysis 

Only in the last three chapters does Lynn provide the belated “Evolutionary Analysis” promised in his subtitle. 

Lynn’s analysis is evolutionary in two senses. 

First, he presents both a functionalist explanation of why race differences in intelligence (supposedly) evolved (Chapter 16). This is the sort of ultimate evolutionary explanation with which evolutionary psychologists are usually concerned. 

However, in addition, Lynn also traces evolution of intelligence over evolutionary history, both in humans of different races (Chapter 17) and among our non-humans and our pre-human ancestors (Chapter 15). 

In other words, he addresses the questions of both adaptation and phylogeny, two of Niko Tinbergen’s famous Four Questions

In discussing the former of these two questions (namely, why race differences in intelligence evolved: Chapter 16), Lynn identifies climate as the ultimate environmental factor responsible for the evolution of race differences in intelligence. 

Thus, he claims that, as humans spread out beyond Africa towards regions further from the equator and hence generally with colder temperatures, especially during winters, the colder climates that these pioneers encountered posed greater challenges for the humans who encountered them in terms of feeding themselves and obtaining shelter etc., and that different human races evolved different levels of intelligence in response to the adaptive challenges posed by such difficulties. 

Hunting vs. Gathering 

The greater problems supposedly posed by colder climates included not just difficulties of keeping warm (i.e. the need for clothing, fires, insulated homes), but also the difficulties of keeping fed. 

Thus, Lynn emphasizes the dietary differences between foragers inhabiting different regions of the world: 

Among contemporary hunter-gatherers the proportions of foods obtained by hunting and gathering varies by hunting and by gathering varies according to latitude. Peoples in tropical and subtropical latitudes are largely gatherers, while peoples in temperate environments rely more on hunting, and peoples in arctic and sub-arctic environments rely almost exclusively on hunting and fishing and have to do so because plant foods are unavailable except for berries and nuts in the summer and autumn” (p227). 

I must confess that I was previously unaware of this dietary difference. However, in my defence, this is perhaps because many anthropologists seem all too ready to overgeneralize from the lifestyles of the most intensively studied tropical groups (e.g. the San of Southern Africa) to imply that what is true of these groups is true of all foragers, and was moreover necessarily also true of all our hunter-gatherer ancestors before they transitioned to agriculture. 

Thus, for example, feminist anthropologists seemingly never tire of claiming that it is female gatherers, not male hunters, who provide most of the caloric demands of foraging peoples. 

Actually, however, this is true only for tropical groups, where plant foods are easily obtainable all year round, not of hunter-gatherers in general (Ember 1978). 

It is certainly not true, for example, of Eskimos, among whom females are almost entirely reliant on male hunters to provision them for most of the year, since plant foods are hardly available at all except for during a few summer months. 

Similarly, radical-leftist anthropologist Marshall Sahlins famously characterized hunter-gatherer peoples as “The Original Affluent Society”, because, according to his data, they do not want for food and actually have more available leisure-time than do most agriculturalists, and even most modern westerners. 

Unfortunately, however, he relied primarily on data from tropical peoples such as the !Kung San to arrive at his estimates, and these findings do not necessarily generalize to other groups such as the Inuit or other Eskimos

The idea that it was our ancestor’s transition to a primarily carnivorous diet that led to increases in hominid brain-size and intelligence was once a popular theory in paleoanthropology. 

However, it has now fallen into disfavour, if only because it put accorded male hunters the starring role in hominid evolution, with female gatherers relegated to a supporting role, and hence offended the sensibilities of feminists, who have become increasingly influential in academia, even in science. 

Nevertheless, it is seems to be true that, across taxa, carnivores tend to have larger brains than herbivores. 

Of course, non-human carnivores did not evolve the exceptional intelligence of humans.  

However, Desmond Morris in The Naked Ape argued that, because our hominid ancestors only adopted a primarily carnivorous diet relatively late in their evolution, they were unable to compete with such specialized hunters as lions and tigers in terms of their fangs and claws. They therefore had to adopt a different approach, using intelligence instead or claws and fangs, hence inventing handheld weapons and cooperative group hunting. 

Lynn’s argument, however, is somewhat different to the traditional version of the Hunting Ape Hypothesis, as championed by popularizers like Desmond Morris and Robert Ardley

Thus, in the traditional version, it is the intelligence of early hominids, the descendants all populations of contemporary humans, that increased as a result of the increasing cognitive demands that hunting placed upon us. 

However, Lynn argues that it is only certain races that were subject to such selection, as their dependence on hunting increased as they populated colder regions of the globe. 

Indeed, Lynn’s arguments actually cast some doubt on the traditional version of the Hunting Ape Theory

After all, anatomically modern humans are thought to have first evolved in Africa. Yet if African foragers actually subsisted primarily on a diet of wild plant foods, and only occasionally hunted or scavenged meat to supplement this primarily herbivorous diet, then the supposed cognitive demands of hunting can hardly be invoked to explain the massive increase in hominid brain-size that occurred during the period before our ancestors left Africa to colonize the remainder of the world.[44]

Indeed, Lynn is seemingly clear that he rejects the ‘Hunting Ape Hypothesis’, writing that the increases in hominid brain-size after our ancestors “entered a new niche of the open savannah in which survival was more cognitively demanding” occurred, not because of the cognitive demands of hunting, but rather that: 

The cognitive demands of the new niche would have consisted principally of finding a variety of different kinds of foods and protecting themselves from predators” (p202)[45]

Cold Winters Theory’ 

There are several problems with so-called ‘Cold Winters Theory’ as an explanation for the race differences in IQ reported by Lynn. 

For one thing, other species have adapted themselves to colder climates without evolving a level of intelligence as high as human population, let alone of Europeans and East Asians. 

Indeed, I am not aware of any studies even suggesting a relationship between brain-size or intelligence and the temperature or latitude of their species-ranges among non-human species. However, one might expect to find an association between temperature and brain-size, if only because of Bergmann’s rule

Similarly, Neanderthals were ultimately displaced and driven to extinction throughout Eurasia by anatomically-modern humans, who, at least according to the conventional account, outcompeted Neanderthals due to their superior intelligence and tool-making ability. 

Yet, whereas anatomically modern humans are thought to have evolved in tropical Africa before spreading outwards to Eurasia, the Neanderthals were a cold-adapted species of hominid who had evolved and thrived in Eurasia during the last Ice age

At any rate, even if the conditions were indeed less demanding in tropical Africa than in temperate or arctic latitudes, then, according to basic Darwinian (and Malthusian) theory, in the absence of some other factor limiting population growth (e.g. warfare, predation, homicide, disease), this would presumably mean that humans would respond to greater resource abundance in the tropics by reproducing until they reached the carrying capacity of the environment.   

By the time the carrying capacity of the environment was reached, however, the environment would no longer be so resource-abundant given the greater number of humans competing for its resources. 

This leads me to believe that the key factors selecting for increases in the intelligence of hominids were not ecological but rather social – i.e. not access to food and shelter etc., but rather competition with other humans. 

Also, I remain unconvinced that the environments inhabited by the two races that have, according to Lynn, the lowest average IQs, namely, San Bushmen and Australian Aborigines, are cognitively undemanding. 

These are, of course, the Kalahari Desert and Australian outback (also composed, in large part, of deserts) respectively, two notoriously barren and arid environments.[46]

Meanwhile, the Eskimos occupy what is certainly the coldest, and also undoubtedly one of the most demanding, environments anywhere in the world, and also have, according to Lynn’s own data, the largest brains. 

However, according to Lynn’s data, their average IQ is only about 90, high for a foraging group, but well below that of Europeans and East Asians.[47] 

For his part, Lynn attempts to explain away this anomaly by arguing that Arctic Populations were precluded from evolving higher IQs by small and dispersed populations, reflecting of the harshness of the environment. This meant the necessary mutations either never arose or never spread through the population (p153; p239-40; p221).[48]
 
On the other hand, he explains their large brains as reflecting visual memory rather than general intelligence, as well as a lack of mutations for neural efficiency (p153; p240) 
 
However, these seem like post-hoc rationalizations 
 
After all, if conditions were harsher in Eurasia than in Africa, then this would presumably also have resulted in smaller and more dispersed populations in Eurasia than in Africa. However, this evidently did not prevent mutations for higher IQ spreading among Eurasians. 

Why then, when the environment becomes even harsher, and the population even more dispersed, would this pattern suddenly reverse itself? 
 
Likewise, if whole-brain-size is related to general intelligence, it is inconsistent to invoke specific abilities to explain Inuit brains. 

Thus, according to Lynn, Australian Aborigines have high spatial memory, which is closely related to visual memory. However, also according to Lynn, only their right visual cortex is enlarged (p108-9) and they have small overall brain-size (p108-9; p210; p212). 

Endnotes

[1] Curiously, Lynn reports, this black advantage for movement-time does not appear in the simplest form of elementary task (simple reaction time), where the subject simply has to press a button on the lighting of a light, rather than hitting a specific button, rather than alternative buttons, on the lighting of a particular light rather than other lights (p58). These latter forms of elementary cognitive test presumably involve some greater degree of cognitive processing. 

[2] First, there are the practical difficulties. Obviously, non-human animals cannot use written tests, or an interview format. Designing a maze for laboratory mice may be relatively straightforward, but building a comparable maze for elephants is rather more challenging. Second, and more important, different species likely have evolved different specialized abilities for dealing with specific adaptive problems. For example, migratory birds may have evolved specific spatio-visual abilities for navigation. However, this is not necessarily reflective of high general intelligence, and to assess their intelligence solely on the basis of their migratory ability, or even their general spatio-visual ability, would likely overestimate their general level of cognitive ability. In other words, it reflects a modulardomain-specific adaptation.

Admittedly, the same is true to some extent for human races. Thus, some races score relatively higher on certain types of intellectual ability. For example, East Asians tend to score higher on spatio-visual ability than on verbal ability; Ashkenazi Jews show the opposite pattern, scoring higher in verbal intelligence than in spatio-visual ability; while American blacks score relatively higher in tests involving rote memory than in those requiring abstract reasoning ability. Similarly, as discussed by Lynn, some races seem to have certain quite specific abilities not commensurate to their general intelligence (e.g. Aborigine visual memory). However, in general, both between and within races, most variation in human intelligence loads onto the ‘g-factor’ of general intelligence.

[3] American anthropologist Carleton Coon is credited as the first to first to propose that population differences in skull size reflect a thermoregulatory adaptation to climatic differences (Coon 1955). An alternative theory, less supported, is that it was differing levels of ambient light that resulted in differences in brain-size as between different populations tracing their ancestry to different parts of the globe (Pearce & Dunbar 2011). On this view, the larger brains of populations who trace their descent to areas of greater latitude presumably reflect only the demands of the visual system, rather than any differences in general intelligence. Yet another theory, less politically-correct than these, is so-called ‘Cold Winters Theory’, which posits that colder climates placed a greater premium on intelligence, which caused populations inhabiting colder regions of the globe to evolve larger brains and higher levels of intelligence. This is, of course, the theory championed by Lynn himself, and I will discuss the problems with this theory below.

[4] Conversely, Lynn also suggests that Turkish people score slightly higher than other Middle-Eastern populations, because they are somewhat intermixed with Europeans (p80).

[5] Lynn has recently published research regarding differences in IQ across different regions of Italy (Lynn 2010).

[6] Actually, Lynn acknowledges causation in both directions, possibly creating a feedback loop. He also acknowledges other factors in contributing to differences in economic development and prosperity, including the effects of the economic system adopted. For example, countries that adopted communism tend to be poorer than comparable countries that have capitalist economies (e.g. Eastern Europe is poorer than Western Europe, and North Korea poorer than South Korea).  

[7] Incidentally, Lynn cites two studies of Polish IQ, whose results are even more divergent than those of Portugal or Ireland, giving average IQs of 106 and 91 respectively. One of these scores is substantially below the European average, while the other the substantially above. 

[8] Essayist Ron Unz has argued that IQs in Ireland have risen in concert with living standards in Ireland (Unz 2012a; Unz 2012b). However, judging from dates when the studies cited by Lynn in ‘Race Differences in Intelligence’ were published, there is no obvious increase over time. True the earliest study, an MA thesis, published in 1973 gives the lowest figure, with an average IQ of just 87 (Gill and Byrt 1973). This rises to 97 in a study published in 1981 that provided little details on its methodology (Buj 1981). However, it declines again for in the latest study cited by Lynn on Irish IQs, which was published in 1993 but gives average IQs of just 93 and 91 for two separate samples (Carr 1993). In the more recent 2015 edition, Lynn cites a few extra studies, eleven in total. Again, however, there is no obvious increase over time, the latest study cited by Lynn, which was published in 2012, giving an average IQ of just 92 (2015 edition).

[9] While this claim is made in reference to immigrants to America and the West, it is perhaps worth noting that East Asians in South-East Asia, namely the Overseas Chinese, largely dominate the economies of South-East Asia, and are therefore on average much wealthier than the average Chinese person still residing in China (see World on Fire by Amy Chua). Given the association of intelligence with wealth, this would suggest that Chinese immigrants to South-East Asia are not substantially less intelligent than those who remained in China. Did the more intelligent Chinese migrate to South-East Asia, while the less intelligent migrated to America? If so, why would this be?

[10] According to Daniel Nettle in Personality: What Makes You the Way You Are, in the framework of the five-factor model of personality, a liking for travel is associated primarily with extraversion. One study found that an intention to migrate was positively associated with both extraversion and openness to experience, but negatively associated with agreeableness, conscientiousness, and neuroticism (Fouarge et al 2019). A study of migration within the United States found a rather more complex set of relationships between migration and each of the big five personality traits (Jokela 2009).

[11] Other Catholic countries, namely those in Southern Europe, such as Italy and Spain, may indeed have slightly lower IQs, at least in the far south of these countries. However, as we have seen, Lynn explains this in terms of racial admixture from Middle-Eastern and North African populations. Therefore, there is no need to invoke priestly celibacy in order to explain it. The crucial test case, then, is Catholic countries other than Ireland from Northern Europe, such as Austria and France.

[12] In the 2015 edition, he returns to a slightly higher figure of 71.

[13] In the 2006 edition, Lynn cites no studies from the Horn of Africa. However, in the 2015 edition, he cites five studies from Ethiopia, and, in The Intelligence of Nations, he and co-author David Becker also cite a study on Somalian IQs.

[14] Indeed, physical anthropologist John Baker, in his excellent Race (which I have reviewed here, here and here) argues that:

“The ‘Aethiopid’ race of Ethiopia and Somaliland are an essentially Europid subrace with some Negrid admixture” (Race: p225).

This may be an exaggeration. However, recent genetic studies indeed show affinities between populations from the Horn of Africa and those from the Middle East (e.g. Ali et al 2020; Khan 2011a; Khan 2011b; Hodgson 2014).

[15] However, it is not at all clear that the same is true for black African minorities resident in other western polities, whose IQs are also, according to Lynn’s data, also considerably above those for indigenous Africans. Here, I suspect black populations are more diverse. For example, in Britain, Afro-Caribbean people, who emigrated to Britain by way of the West Indies, are probably mostly mixed-race, like African-Americans, since both descend from white-owned slave populations. However, Britain also plays host to many immigrants direct from Africa, most of whom are, I suspect, of relatively unmixed sub-Saharan African descent. Yet African immigrants to the UK outperform Afro-Caribbeans in UK schools (Chisala 2015a).

[16] Blogger John ‘Chuck’ Fuerst suggests, the higher scores for Somali immigrants might reflect the fact that the peoples of the Horn of Africa actually, as we have seen, have substantial Caucasoid ancestry, and genetic affinities with North African and Middle Eastern populations (Fuerst 2015). However, the problem with attributing the relatively high scores of Somali refugees and immigrants to Caucasoid-admixture is that, as we have seen, according to the data collected by Lynn, IQs are no higher in the Horn of Africa than elsewhere in sub-Saharan Africa.

[17] If anything, “Bushmen” should presumably be grouped, not with Pygmies, with rather the distinct but related Khoikhoi pastoralists. However, the latter are now all but extinct as an independent people and are not mentioned by Lynn.

[18] For example, Lynn also acknowledges that those whom he terms “South Asians and North Africans” are “closely related to the Europeans” (p79). However, they nevertheless merit a chapter of their own. Likewise, he acknowledges that “South-East Asians” share “some genetic affinity with East Asians with whom they are to some degree interbred” (p97). Nevertheless, he justifies considering these two ostensible races in separate chapters, partly on the basis that “the flattened nose and epicanthic eye-fold are less prominent” among the former (p97). Yet the morphological differences between Pygmies and Khoisan are even greater, but they are lumped together in the same chapter.

[19] There is indeed, as Lynn notes, a correlation between a group’s IQ and their lifestyle (i.e. whether they are foragers or agriculturalists). However, the direction of causation is unclear. Does high intelligence allow a group to transition to agriculture, or does an agriculturalist lifestyle somehow increase a group’s average IQ? And, if the latter, is this a genetic or a purely environmental effect?

[20] Indeed, the very word slave is thought to derive from the ethnonym Slav, because of the frequency with which Slavic peoples were enslaved during the Middle Ages.

[21] Indeed, Lynn could hardly have arrived at an actual figure for the average Pygmy IQ, since, as we have seen, he reports the results of only a single actual study of Pygmy intelligence, the author of which did not present his results in a quantitative format.

[22] Thus, he suggests that the lower performance of the Aboriginals tested by Drinkwater (1975), as compared to those tested by Kearins (1981), may reflect the fact that the latter were the descendants of coastal populations of Aborigines, for whom the need to navigate in deserts without landmarks would have been less important. 

[23] The fact that the earliest civilization emerged among Middle Eastern, North African and South Asian populations is attributed by Lynn to the sort of environmental factors that, elsewhere in his book, he largely discounts. Thus, Lynn writes: 

“[Europeans] were not able to develop early civilizations like those built by the South Asians and North Africans because Europe was still cold, was covered with forest, and had heavy soils that were difficult to plough unlike the light soils on which the early civilizations were built, and there were no river flood plains to provide annual highly fertile alluvial deposits from which agricultural surpluses could be obtained to support an urban civilization and an intellectual class” (p237).

[24] An interesting question is whether there exist differences in IQ as between different caste groups within the Indian subcontinent, since, at least in theory, these represented endogamous breeding populations between whom strict separation was maintained. Thus, it would be interesting to know the average IQ of Brahmins or of the high-achieving Parsi people (though the latter are not strictly a caste, since they are not Hindu).

[25] However, all of these comparisons, in both Britain and America, omit to include Jewish people as a separate ethnicity, instead grouping them with other whites. Jews earn more, on average, than any other religion in Britain and America, including Hindus.

[26] I assume that this is the study that Lynn is citing, since this is the only matching study included in his references. However, curiously, Lynn refers to this study here as “Mackintosh et al 1985” (p83-4), despite their being only two authors listed in his references, such that “Mackintosh & Mascie-Taylor 1985” would be the more usual citation. Indeed, Lynn uses this latter form of citation (i.e. “Mackintosh & Mascie-Taylor 1985”) elsewhere when citing what seems to be the same paper in his earlier chapter on Africans (p47; p49).

[27] In order to determine whether religion or national origin is the key determining factor, it would be interesting to have data on the incomes (and IQs) of Pakistani Hindus, Bangladeshi Hindus and Muslim Indians resident in the West.

[28] An alternative possibility is that it was the spread of Arab genes, as a result of the Arab conquests, and resulting spread of Islam, that depressed IQs in the Middle-East and North Africa, since Arabs were, prior to the rise of Islam, a relatively backward group of desert nomads, whose intellectual achievements were minimal compared to those of many of the groups whom they conquered (e.g. Persians, Mesopotamians, Assyrians, and Egyptians). Indeed, even the achievements of Muslim civilization during the Islamic Golden Age were disproportionately those of the Persians, not the Arabs. 

[29] One might, incidentally, question Lynn’s assumption that Oriental Jews were less subject to persecution than were the Ashkenazim in Europe. This is, of course, the politically correct view, which sees Islamic civilization as, prior to recent times, more tolerant than Christendom. On this view, anti-Jewish sentiment only emerged in the Middle East as a consequence of Zionism and the establishment of the Jewish state in what was formerly Palestine. However, for alternative views, see The Myth of the Andalusian Paradise. See also Robert Spencer’s The Truth About Muhammad (which I have reviewed here), in which he argues that Islam is inherently antisemitic (i.e. anti-Jewish). Interestingly, Kevin Macdonald, in A People That Shall Dwell Alone (which I have reviewed here and here) makes almost the opposite argument to that of Lynn. Thus, he argues that it was precisely because Jews were so discriminated against in the Muslim world that their culture, and ultimately their IQs, were to decline, as they were, according to Macdonald, largely excluded from high-status and cognitively-demanding occupations, which were reserved for Muslims (p301-4). Thus, Macdonald concludes: 

“The pattern of lower verbal intelligence, relatively high fertility, and low-investment parenting among Jews in the Muslim world is linked ultimately to anti-Semitism” (A People That Shall Dwell Alone (reviewed here): p304). 

[30] For example, one might speculate that only the relatively smarter Jews were able to anticipate looming pogroms and hence escape. Alternatively, since wealth is correlated with intelligence, perhaps only the relatively richer, and hence generally smarter, Jews could afford the costs of migration, including bribes to officials, in order to escape pogroms. These are, however, obviously speculative, post-hoc ‘just-so stories’ (in the negative Gouldian sense), and I put little stock in them.

[31] This pattern among East Asians of lower scores on the verbal component of IQ tests was initially attributed to a lack of fluency in the language of the test, since the first East Asians to be tested were among diaspora populations resident in the West. However, the same pattern has now been found even among East Asians tested in their first language, in both the West and East Asia.

[32] For example, Sarich and Miele, in Race: The Reality of Human Differences (which I have reviewed here and here) write that “Asians have a slightly higher IQ than do whites” (Race: The Reality of Human Differences: p196). However, in actuality, this applies only to East Asians, not to South-East Asians (nor to South Asians and West Asians, who are “Asian” in at least the geographical, and the British-English, sense.) Similarly, in his own oversimplified tripartite racial taxonomy in Race, Evolution and Behavior (which I have reviewed here), Philippe Rushton seems to imply that the traits he attributes to Mongoloids, including high IQs and large brain-size, apply to all members of this race, including South-East Asians and even Native Americans.

[33] Ethnic Chinese were overrepresented among Vietnamese boat people, though less so among later waves of immigrants. However, perhaps a greater problem is that they were disproportionately middle-class and drawn from the business elite, and hence unrepresentative of the Vietnamese as a whole, and likely of disproportionately high cognitive ability.

[34] In his paper on Mongolian IQs, Lynn also suggests that Mongolians have lower IQs than other East Asians because they are genetically intermediate between East Asians and Eskimos (“Arctic Peoples”), who themselves have lower IQs (Lynn 2007). However, this merely begs the question as to why Eskimos themselves have lower IQs than East Asians, another anomaly with respect to ‘Cold Winters Theory’, which is discussed in the final part of this review.

[35] With regard to the population of Colombia, Lynn writes: 

“The population of Colombia is 75 percent Native American and Mestizo, 20 percent European, and 5 percent African. It is reasonable to assume that the higher IQ of the Europeans and the lower IQ of the Africans will approximately balance out and that the IQ of 84 represents the intelligence of the Native Americans” (p58). 

However, this assumption that the African and European genetic contributions will balance out seems dubious since, by Lynn’s own reckoning, the European contribution to the Colombian gene-pool is three times greater than that of Africans.

[36] The currently-preferred term Inuit is not sufficiently inclusive, because it applies only to those Eskimos indigenous to the North American continent, not the related but culturally distinct populations inhabiting Siberia or the Aleutian Islands. I continue to use the term Eskimos, because it is more accurate, not obviously pejorative, probably more widely understood, and also because I deplore the euphemism treadmill. Elsewhere, I have generally deferred to Lynn’s own usage, for example mostly using ‘Aborigine’, rather than the now preferred ‘Aboriginal’, a particularly preposterous example of the euphemism treadmill since the terms are so similar, comparable to how, today, it is acceptable to say ‘people of colour’, but not ‘coloured people’.

[37] For example, Hans Eysenck made various references in his writings to the fact that Eskimo children performed as well as European children in IQ tests as evidence for his claim that economic deprivation did not necessarily reduce IQ scores (e.g. The Structure and Measurement of Intelligence: p23). See also discussion in: Jason Malloy, A World of Difference: Richard Lynn Maps World Intelligence (Malloy 2016).

[38] Certain specific subpopulations also score higher (e.g. Ashkenazim and Māoris, though the latter only barely). However, these are subpopulations within the major ten races that Lynn identifies, not races in and of themselves.

[39] Actually, by the time Columbus landed in the Americas, many Native Americans had already partly transitioned to agriculture. However, not least because of a lack of domesticated animals that they could use as a meat source, most supplemented this with hunting and sometimes gathering too.

[40] However, Lynn reports that Japanese also score high on tests of visual memory (p143). However, excepting perhaps the Ainu, the Japanese do not have a recent history of subsisting as foragers. This suggests that foraging is not the only possible cause of high visual memory in a population.

[41] Presumably the comparison group Lynn has in mind are Europeans, since, as we have seen it is European living standards that he takes as his baseline for the purposes of estimating a group’s ”genotypic IQ” (p69), and, in a sense, all the IQ scores that he reports are measured against a European standard in so far as they are calculated by reference to an arbitrarily assigned average of 100 for European populations.

[42] Thus, it is at least theoretically possible that a relatively darker-skinned African-American child might be treated differently than a lighter-skinned child, especially one whose race is relatively indeterminate, by others (e.g. teachers) in a way that could conceivably affect their cognitive development and IQ. In addition, a darker skinned African-American child might, as a consequence of their darker complexion, come to identify as an African American to a greater extent than a lighter skinned child, which might affect who they socialize with, which celebrities they identify with and the extent to which they identify with broader black culture, all of which could conceivably have an effect on IQ. I do not contend that these effects are likely or even plausible, but they are at least theoretically possible. Using blood group to assess ancestry, especially if one actually introduces controls for skin tone (since this may be associated with blood-group, since both are presumed to be markers of degree of African ancestry), obviously eliminates this possibility. Today, this can also be done by looking at subjects’ actual DNA, which obviously has the potential to provide a more accurate measure of ancestry than either skin-tone or blood-group (e.g. Lasker et al 2019).

[43] More recently, a better study has been published regarding the association between European admixture and intelligence among African-Americans, which used genetic data to assess ancestry, and actually sought to control for the possible confounding effect of skin-colour and appearance (Lasker et al 2019). Unlike the blood-group studies, this largely supports the hereditarian hypothesis. However, this was not available at the time Lynn authored his book. Also, it ought to be noted that it was published in a controversial pay-to-publish academic journal, and therefore the quality of peer review to which the paper was subjected may be open to question. No doubt in the future, with the reduced costs of genetic testing, more studies using a similar methodology will be conducted, finally resolving the question of the relative contributions of heredity and environment to the black-white test score gap in America, and perhaps disparities between other ethnic groups too.

[44] It is a fallacy, however, to assume that what is true for those foraging peoples that have managed to survive as foragers in modern times and hence come to be studied by anthropologists was necessarily also true of all foraging groups before the transition to agriculture. On the contrary, those foraging groups that have survived into modern times, tend to have done so only in the ecologically most marginal and barren environments (e.g. the Kalahari Desert occupied by the San), since these areas are of least use to agriculturalists, and therefore represent the only regions where more technologically and socially advanced agriculturalists have yet to displace them (see Ember 1978). However, this would seem to suggest that African hunter-gatherers, prior to the expansion of Bantu agriculturalists, would have occupied more fertile areas, and therefore might have had even less need to rely on hunting than do contemporary hunter-gatherers such as the San, who are today largely restricted to the Kalahari Desert.

[45] Here, interestingly, Lynn departs from the theory of fellow race realist, and fellow exponent of ‘Cold Winters Theory’, Philippe Rushton. The latter, in his book, Race, Evolution and Behavior (which I have reviewed here), argues that: 

“Hunting in the open grasslands of northern Europe was more difficult than hunting in the woodlands of the tropics and subtropics where there is plenty of cover for hunters to hide in” (Race, Evolution and Behavior: p228). 

In contrast, Lynn argues “open grasslands”, albeit on the African Savannah rather than in Northern Europe, actually made things harder, not for predators, but rather for prey – or at least arboreal primate prey. Thus, Lynn writes: 

“The other principle problem of the hominids living in open grasslands would have been to protect themselves against lions, cheetahs and leopards. Apes and monkeys escape from the big cats by climbing into trees and swinging or jumping form one tree to another. For the Autralopithecines and the later hominids in open grasslands this was no longer possible” (p203). 

[46] To clarify, this is not to say that either San Bushmen or Australian Aborigines evolved primarily in these desert environments. On the contrary, many of them formerly occupied more fertile areas, before being displaced by more advanced neighbours, Bantu agriculturalists in the case of Khoisan, and European (more specifically British) colonizers, in the case of Aborigines. However, that they are nevertheless capable of surviving in these demanding desert environments suggests either:

(1) They are more intelligent than Lynn concludes; or
(2) That surviving in challenging environments does not require the level of intelligence that Lynn’s ‘Cold Winters Theory’ supposes.

[47] Besides Eskimos, another potential test case for ‘Cold Winters Theory’ are the Sámi (or Lapps) of Northern Scandinavia. Like Eskimos, they have inhabited an extremely cold, northern environment for many generations and are genetically quite distinct from other populations. Also, again like Eskimos, they maintained a foraging lifestyle until modern times. According to Armstrong et al (2014), the only study of Sámi cognitive ability of which I am aware, the average IQ of the Sámi is almost identical to that of neighbouring populations of Finns (about 101).

[48] Lynn gives the same explanation for the relatively lower recorded IQs of Mongolians, as compared to other East Asians (p240).

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