The g Factor   General Intelligence and its Implications   Christopher BRAND
PreviousContentsPrefaceIntroductionChap. IChap. IIChap. IIIChap. IVEpilogueNext



IV - Intelligence in Society - the practical importance of g differences


  • Is realism avoidable?
  • Believing in g and that it can be raised: Jensen and Head Start.
  • Disputing the importance of g:
    • Ceci - savants, gamblers, school causes;
    • Flynn - the worldwide rise in IQ test scores, & race;
    • Howe - IQ only a number.
  • Merits of streaming according to mental age.
  • Embracing realism: pupil empowerment (track choice).


Today's evidence is that there exists a strong general, apprehensional and genetic factor that yields much of the variance between people in mental abilities. The evidence is far superior to was available to Binet, Spearman or Burt. But what if there are also racial differences in g? What if massive public expenditures have yielded no sign as yet that children's IQ's can be lastingly raised by conventional state endeavours? What if, despite great hopes, people can still not improve their own intelligence by vitamins or mental gymnastics? When pessimism seems to beckon, to dispute that g is important becomes an attractive option. At least for the purposes of conversation in polite or multicultural society, perhaps the topic of g can just be avoided? The present Chapter thus considers four modern attempts to play down the importance of g - and especially the major critical campaign mounted by James Flynn.

Whatever may be the importance of g as a causal variable influencing life-chances, there is a further, more particular question about the relevance of g differences to education. Have educators understood how to respond to g differences? In the second half of this Chapter, it is argued that both children's educational attainments and their happiness at school depend on achieving the right combination of intelligence and teaching; and that, even without any re-introduction of IQ testing, selective schools or compulsory streaming, new and far-reaching educational breakthroughs for children can be achieved today by taking the g factor seriously.

As new psychogenetic work came on stream around 1990, the Burt Affair and the anti-realism that it had encouraged were becoming ancient history. Genetic causation and possible feats of genetic engineering were increasingly acknowledged as the key realities of modern agriculture, medicine and psychiatry. Thomas Kuhn's anxious relativism and philosophical idealism had been answered by a triumphantly accelerated advance of science and technology (Hobsbawm, 1994) - as if a deeply structured 'real world' did indeed exist and scientists could reveal, measure and harness its secrets quite successfully. In psychology itself, the main alternative to admitting the role of genetic factors had failed to deliver: the latter-day behaviourist attempt to understand people in terms of their 'situations' could not survive psychologists' growing appreciation that 'situations' usually reflect personal choices made according to deeper-seated proclivities. Social environmentalism had long dominated expert discussions of welfare and educational policy in Britain and North America, and the Burt Affair helped keep it alive; but g had not been broken up into numerous 'differential aptitudes' or 'cognitive components' or been shown to be a mere verbal label. Instead, IQ's generality and fairness (Chapter I), its link with speed of apprehension (Chapter II), and its primary basis in genetic differences (Chapter III) had all been re-affirmed.

Nevertheless, g might still require no more attention from politicians or educators than do human differences in, say, handedness, musical preferences or table manners. Especially when compared to variables in medicine and social science like health, fertility, religion or wealth, g might simply not matter very much. Even to educators, mass compulsory secondary education may seem to require no hard choices about what can be taught to whom, or how. Children may differ intellectually in measurable ways, and perhaps because of genetic factors; but such differences can be officially ignored. All children can be supplied with simple curricula which they can all manage - even if success at what will often be undemanding lessons equips even the most able of them only for entry to more of the same slow-paced education. Such a long race of low hurdles can even be claimed to cater for individual differences: after all, some students can simply drop out earlier than others. And dropout can hardly be blamed on the educators: all children have being given 'the same chances' - even if these are not in fact the best chances for most of the children. Ordinary citizens themselves can think of occasions where it is tactless to mention intellectual differences without hedging as to their importance, fixity, deep-seatedness or generality: rather than acknowledge the main facts of educational achievement, it is easier to pretend that any poor student can catch up by hard work. To talk of 'mere academic intelligence' as 'irrelevant' has often seemed the easiest of these options to modern educationalists: it licenses arranging education without any regard to g .

The importance of differences in general intelligence, especially to human achievements, was first urged by Galton (see Chapter I). From historical records of national biography, he had shown that eminent men in Britain came from a relatively small number of families. Such inheritance was especially notable for musical, literary and scientific achievement; and Galton himself was well pleased that he and his second cousin, Charles Darwin, could trace their own ancestry back to Charlemagne. However, although his ambitions, energy and clarity of vision assured him a lasting reputation, Galton had little luck in his own researches on virtually any aspect of intelligence. He failed to come up with a direct measure of intelligence: without that, even his promising tests of tone thresholds and short-term memory on his 9,000 fee-paying testees could hardly clarify its essential psychological nature. Though he was the first to suggest twin studies into mental abilities, his own work was inconclusive; his Victorian presuppositions as to the intellectual inferiority of women and Jews were soon disproved by his descendants in differential psychology;(1) and the inheritance of genius that he had discovered may have been as much social as genetic - Galton himself believed that it was a mother's stress on telling the truth that would lead her children into the paths of science.

Nevertheless, Galton's stress on the importance of intelligence was popular in his own day and for the next half-century. It could have remained popular: the taking of IQ's would have seemed mere 'common sense' if only educationists had been required to demonstrate the success of their teaching. For example, it is expected that education should benefit both boys and girls, and not just one of the two sexes; and modern educators reliably profess distress if, say, boys do better than girls in mathematics. Just so, twentieth-century schools might have been expected to enhance children's knowledge, performance and employability at all levels of intelligence. Unfortunately, after 1945, as white-collar employment expanded, no very demanding standards were set for the educational and occupational achievements of high-IQ children. So long as such children moved into 'better' jobs than had their parents, most were satisfied, even though such upward mobility was bound to occur, regardless of educators' real achievements, as Western economies expanded (in response to re-building, American Marshall Aid and the new investments of the Cold War). Increasingly, syllabuses were adapted to include little more than what brighter children normally picked up from their parents and media exposure: e.g. the 'new maths' dispensed with rote learning and skill rehearsal and 'taught' only those principles that are grasped without any teaching at all by children of higher MA's.

Since the schools' apparent successes were not largely a matter of education, their remaining problem was not one of education either. Simply, the problem that remained was whether the IQ's of duller children could be boosted so as to give them, too, a chance in what was increasingly recognized as a competition for well-paid, congenial and secure employment - often in the public sector. IQ was thus thought important of itself, rather than in- its conjunction with relevant education; and much of the new education came to seem pointless unless g itself could somehow be raised. There was an important implication for psychology: IQ itself would continue to interest educators only if it could be changed.

By the 1960's, there was awareness in the USA of the general success story of the scores of millions of 'starving and huddled' immigrants that had accepted (very generously, if with a little discretion - see Chapter 1) over a century. Yet there was awareness too of the failure of American blacks to catch up with whites economically since the century-old abolition of slavery - or since the fifty-year-old USArmy data had first suggested that blacks might have a special IQ-type problem.(2) Under the Democratic Presidents, Kennedy and Johnson, the USA was ready to embark on the biggest educational project of all time. 'Operation Head Start', the modernized and transatlantic version of kindergarten, aimed to improve the abilities and skills of pre-school children of low IQ so that they would not start school with a handicap. Over the next thirty years, thousand-billion-dollar sums would be poured into employing graduates to coach at-risk children from US inner city (i.e. predominantly black) areas in reasoning, comprehension and puzzle-solving tasks of the IQ type.

The early Head Start programmes produced only modest gains of 10-IQ-points - little more than is expected from the practice effect conferred by a first occasion of being tested; and even these gains were lost within two years. So g seemed to require closer study. Attracted to Head Start work was the idealistic psychologist from San Diego who was soon to become the leading expert on the validation of IQ tests (especially on the question of their possible biases), on their links to reaction times and on psychogenetic methods (see Chapters I, II and III). Arthur Jensen's reading and researches soon suggested that lower-IQ children would benefit only from teaching techniques that did not assume the possession of high levels of g . For duller children, Jensen recommended the use of highly structured, rote, visually aided, humour-assisted learning in which an instructor could be imitated and role models were conspicuously rewarded with applause. These were the very techniques that would soon be used with success by the popular TV programmes for pre-schoolers, Sesame Street and The Electric Company. Yet all this was at first rather shocking to liberal educators: they were unhappy with anything which involved pointing out, let alone criticising, failures (whether of children or TV characters), and also with the 'mindless' procedures of learning-by-heart. Invited by the Harvard Education Review to explain his positon, Jensen (1969) added fuel to the fire: he thought that the most likely (though unproven) cause of the increasingly familiar difficulties of black children under normal instruction methods would be a genetically low level of g . In particular, he was unimpressed by the likelihood that parental social class (SES) was a major cause of black children's problems: for example, Mexican children from poorer backgrounds did better than black children at Figure Copying (an excellent index of g in children - see Chapter 1, Figure I,1) (see Figure IV, 1).

Jensen's classic, 100-page article would trigger a twenty-year crusade against him and his London School supporter, Hans Eysenck (see Chapter II). (Unlike most behaviourists, Eysenck accepted both the 'reality' of intelligence differences and their mainly biological origins; and he had already upset social scientists in Britain by claiming that Nationalists and Communists might have underlying psychological traits of illiberalism, insensitivity and spitefulness genetically in common.) Jensen and Eysenck's critics were further inflamed by the suggestion of the Nobel-prizewinner who invented the transistor that extra welfare payments might be awarded to lower-IQ women who had been sterilized (Shockley, 1975(3)) and that sex differences, like IQ differences, had biological bases (see Wilson, 1993).

Most educational experts agreed with Jensen and Eysenck that black IQ levels were low (for whatever reason) and that this deficiency helped to explain poor educational records and later lifestyles of crime and promiscuity. To recognize this deficiency (if not to publicize it) had remained tolerable while the racial difference in IQ seemed changeable - by the state providing black children with stimulation and experiences of the type standardly enjoyed by white children. Ready improvability of IQ was what Jensen doubted. His challenge was thus to the American dream. Up till then, those who wished to realize or bring about more equality could believe that 'compensatory' assistance to black people and their children would soon do the trick: this was the belief that Jensen implicitly contested. The USA's Declaration of Independence claimed that "all men are created equal"; but, for Jensen, doing the best for low-IQ children would require educators to work with, not to cut across the grain of unequal nature. The rage of frustrated idealists was soon to be witnessed worldwide: Jensen and Eysenck were treated as pariahs on the campuses of American, Australian and British universities. Jensen himself had supported the desegregation of American schools, and urged that children should be educated according to their individual IQ's - and not according to their race. Nevertheless, he was condemned by supposedly liberal-left students and the media as a 'racist' and subjected to hate mail and physical intimidation. While lecturing in the University of London, Eysenck was assaulted by young 'socialist workers' who had bussed to London especially for that purpose; and for many years both Jensen and Eysenck required police bodyguards. (For a full history of 'the Jensenist heresy' and the attempts to purge it from the universities of the West, see Pearson, 1996.)

However non-improvable intelligence itself may be, the faith of the behaviourist that practice makes perfect continued to find a little support from scores on IQ tests. Gains continued to be reported on g tests, Piagetian conservation tests and allied cognitive-processing puzzles to which low-IQ pre-schoolers were repeatedly exposed in media-acclaimed efforts to boost intelligence. While Jensen and Eysenck were being pilloried for 'racism' and 'pseudo-science' (e.g. Hirsch, 1975), one project caused particular jubilation. Often called 'The Miracle in Milwaukee', its leaders were cock-a'-hoop by 1975: for the twenty black inner-city pre-schoolers exposed to the efforts of the team for five days a week for two years were showing gains of between 20 and 30 IQ points. George Albee's (1976) view was typical of enlightened educators: "I think the Milwaukee Project is very exciting. It challenges the notion that IQ is fixed. It has been criticized by the group around Jensen and Eysenck because it represents a threat to their position."

Yet do the improved scores of disadvantaged four-year-olds at IQ-type exercises lead to genuine improvements in the classroom? If self-confidence and expectations are important, wider gains should follow; and they should also follow in so far as IQ gains reflect increased 'knowledge' - often a help at even the most enlightened school. However, like a thermometer, an IQ test can be made to give a reading that no longer reflects what it is intended to measure; and Head Start programmes are like the cup of hot chocolate into which the hopeful truant slips his mother's health-checker. IQ scores can increase under unusual procedures; but wider and lasting educational gains can hardly be expected if no real and lasting gain has occurred in underlying mental ability - in the g factor. It was just such gains that eluded Head Start programmers. Even in the thorough and well-documented Abecedarian Project, gains on particular tests - whether the gains were great, or, more usually, small - were not reflected in IQ assessments on different tests at later ages, or in school skills. Such learning as the children had shown was 'shallow' and did not transfer (Reynolds, 1987). Most of the apparent improvements were the result of 'teaching the test' - of teaching the kinds of things required on IQ tests for children of a child's own CA.(4) The problem of was specially notable in children's reading ages: these usually correlate very strongly (at about .70) with MA's and IQ's, but they showed no substantial improvement from IQ-score-boosting. The exciting claims from Milwaukee remained unpublished in academic journals; and two of the Milwaukee team leaders were jailed and a third put on probation for fraudulent misuse of the research funds which their own extravagant promises had made it easy to attract. (Pine-log ranches in the forest were a special favourite with the researchers.) Nor had public expense been spared: the Milwaukee Project cost $14 million over fifteen years; and, counting all the professional and administrative personnel involved, the cost of such Head Start gains as were claimed was $23,000 per IQ-point gained per child (Spitz, 1986). Although the twenty-one experimental children had been reported as much as 32 IQ points ahead of controls when the intensive 51/2-year intervention stopped at age six, only a 10 point advantage remained by age fourteen (see Garber, 1988).

Twenty years after the beginning of the crusade against 'the Jensenist heresy', the game was up. Using data from the US Department of Health and Human Services on the seventy-two major programmes to have been researched, two British researchers who had themselves been instrumental in exposing Burt's roguery accepted that the 9-10 IQ-point gains typically washed out within one year and that "by the end of the second year, there are no educationally meaningful differences on any of the measures" (Clarke & Clarke 1986, 1989) The Clarkes concluded that "....preschool intervention programmes cannot by themselves be expected to have long-term dramatic effects...." Nor had imitators been more successful. In the British Isles, none of the three substantial Head Start researches had delivered worthwhile gains. For example, following an intensive two-year programme and annual testing for three-year-olds in a deprived Dublin suburb (and involving children's parents), experimental children, by age eight, were merely seven IQ points higher than untreated control children and showed no distinctive educational gains (Kellaghan, 1977).

More spectacularly, in Israel, the grandfatherly, cherubic Reuven Feuerstein continued to attribute minority children's educational problems to a lack of "mediated learning experiences." Feuerstein supposed that minority parents defer unduly to the "dominant culture" and thus refrain from transmitting what they know best - the culture in which they themselves grew up. According to this account, many ordinary remedial efforts by white psychologists and teachers would be of little help to black children - as indeed had happened in Head Start.

However, Feuerstein's ingenious proposal, his outright belief that "the human organism is modifiable at all ages and stages of intellectual development", and his therapy of "instrumental enrichment" (Feuerstein, 1980) are still of uncertain relevance to raising g itself. His own enthusiasm and sensitivity certainly helped non-Ashkenaze Jewish children with little educational background to adapt to Israel. Yet no other minorities have the15 IQ-point disadvantage in g of black people in America; low scoring by other American minorities such as Indians, Hispanics and the deaf is mainly on tests of the verbal, crystallized type - reflecting a language handicap more than a problem with fluid intelligence; Feuerstein, too, engages in 'teaching the test' (Reynolds, 1987); and Feuerstein's own treatment results have not replicated (Frisby & Braden, 1992; Braden, 1994). The Local Education Authority of the English county of Somerset was keen enough to involve thirty teachers in trying out instrumental enrichment on a thousand low-achieving pupils over three years; but researchers found little evidence of any positive effect on intelligence and no gains at all on reading, mathematics or study skills (Blagg, 1991). Twenty years on, and after vast expenditures of public monies, Jensen had been vindicated: just as he had written a quarter-of-a-century earlier (Jensen, 1969, p.2), "Compensatory education has been tried and apparently it has failed... In other fields, when bridges do not stand, when aircraft do not begins to question the basic assumptions, principles, theories and hypotheses that guide one's efforts." Head Start had proved to have a modestly improving effect on the delinquency rates of children who had received this preschool exposure to kindly middle class adults (Zigler et al., 1992); but its impact on intelligence and educational achievements had proved vanishingly slight. Only the sheer scale of the public funding of Head Start had fulfilled the wildest dreams of its supporters.

As they gradually came to realize the limitations of Head Start, crusaders against the 'Jensenist heresy' found that three lines of dignified retreat had been blocked.

  1. IQ tests were just as fair and valid for use with black children and adults as with anyone else (see Chapter I). In particular, the tests were markedly fairer than life itself (Jensen, 1980; Blinkhorn, 1985): if the tests erred, it was in predicting slightly more achievement and productivity than was actually forthcoming when black workers of particular IQ levels were selected and hired.

  2. In the 1980's, it had emerged that low IQ's were not generally characteristic of racial and ethnic groups that had been surrendered by their native communities to hard labour and serious discrimination in far-off lands. Jewish migrants from anti-Semitic Europe and the Chinese and Japanese brought as indentured labour to North America in the nineteenth century are examples of groups whose children enjoyed normal or above-average IQ's despite growing up as readily identifiable minorities amidst blatant ethnic prejudice - and, for American Japanese, outright wartime dispossession for which compensation was not awarded till 1990 (Vernon, 1982; Lynn, 1992b). Likewise in Britain, although Pakistani immigrants suffer prejudice and maintain a language, religion and moral code that distance them from their British hosts, their children have always tested as being of normal intelligence once they have learned English, and they slightly out-perform English children educationally by mid-adolescence (see Mackintosh and Mascie-Taylor, 1985; Brand, 1987c). 3. Almost the full Afro-American deficit, of some 15 IQ points, could be detected in children as young as three years, born to black mothers who were themselves college-educated, married and had no pregnancy complications or health problems (Montie & Fagan, 1988). Medically and socially matched, these young black children had a mean IQ of 91 and the white children tested at 104. The matching ruled out explanations of the black deficit in terms of rearing by single-parent mothers in the squalid conditions of welfare-dependency, criminality, male intimidation and drug abuse that are certainly all too often the lot of black children. At the same time, what Jensen had long taken to be the best-established IQ-boosting exercise of all had been tried without achieving any special purchase on the black deficit: adoption of black infants into white middle class homes had yielded its usual 8-point IQ gain plus some narrowing of the gap between black and white adoptees at age 7; but, by 17, the black youngsters lagged the white by the usual 12-15 IQ points (Weinberg et al., 1992; Lynn, 1994).

Altogether, Operation Head Start was over (except as an expensive way of producing minor improvements in delinquency rates). Black children's lower IQ's persisted even when black homes were matched to those of whites in terms of income, years of education, marital stability and health, or when children grew up in professionally selected white homes; blacks did not perform conspicuously better in any of the countries or North American cities run by blacks themselves - indeed, they usually performed much worse, though testing was patchy and subject to the interpretative problems that arise when comparing people having different countries and languages; and there was mounting evidence that the Japanese children, whether growing up in their war-torn and subjugated homeland or in North America had IQ levels that actually exceeded those of whites (Lynn, 1982; Vernon, 1982; Herrnstein & Murray, 1994; Burnham, 1994). The American dream of human improvability was now becoming a nightmare, for the only way to equalize black people in outcomes (and not just in opportunities) was to compel 'affirmative action' by colleges and employers. To legislate and enforce reverse racism would necessarily create bitterness - especially amongst Asians(5) and whites of mediocre abilities who were thus deprived altogether of college places and middle-class career opportunities by still less qualified black candidates. This resentment would be translated into political action if ever the US economy faltered. Inevitably, there developed gun-toting and bomb-making militias that exhibited a paranoid hostility to all Federal government and sought the freedom to deal with crime (50% of it being by blacks in the USA) in terms of local rather than nationwide conventions. Nowhere else in the West were modern liberal and welfare-state values so starkly dependent for their recognition on the local success of capitalism. However, a powerful narcotic was on its way.

By the 1980's, the sheer weight of evidence was beginning to tell on the opponents of g . Especially, it was noticeable that the main scholarly efforts to rid the world of talk of heritable g now came from non-psychologists (notably Stephen J. Gould (1981) at Harvard, Steve Rose (Rose et al., 1984) at Britain's Open University and Maurice Schiff in Paris (Schiff & Lewontin, 1986)).

Yet some were braver. Apparently g itself would not break up into multiple, uncorrelated components; perhaps it had correlates in mental intake speed; clearly it was mainly genetic in origin, and its average measured level seemed bound to remain low in one of the major racial groups despite unprecedented public expenditures. But there was another line of argument that could be tried - a finger that could be put in the dike. Perhaps g could at least be pronounced somehow 'irrelevant' to real-life achievements or at least enjoyments? If the enlightened would only step back from what might, after all, be a twentieth century obsession with mass-literacy and numeracy, perhaps g could be seen as actually of no greater general importance than are ability differences in boxing, rowing or table-tennis? If so, educational problems could still be left to liberal educators to handle in line with modern conventions: they would simply treat all children alike, encourage them for all their attainments and efforts, and simply steer clear of the understanding of g that has accumulated through the twentieth century. There was once a time when egalitarians argued for environmental causation of IQ and troubled to investigate by experiment whether it could be raised: egalitarians had not invariably taken the position of asserting that there simply must be many different types of intelligence and complex interaction effects that defy any simple view. Yet there was an alternative. It had once been a criticism of g that it might be a concept too closely related to the requirements of the military-industrial complex and the capitalist system. Yet perhaps the very opposite might be true? At least, it might be easier on the nerves to believe. At least, face might be save by behaving publicly as if g itself were simply of little general consequence. By 1990, four versions of this thesis were on offer from modern academia, querying g 's relevance along the following lines.

  1. (i) The possible irrelevance of g to explaining the skills of savants. The first way of disputing g 's psychotelic importance has been to talk up the achievements of those children and adults once called idiot savants, but today often diagnosed as suffering from the reality-curtailing disorder of autism which especially impairs social intelligence.(6) Autistic people test at around IQ 55 (though with an unusually wide range of scores) and are quite incapable of earning a living; but some, the savants, have remarkable gifts for music, drawing, calendrical calculation, finding prime numbers and learning bus timetables. (Such knowledge of timetables is admittedly purely numerical and without spatial reference. - It would be of little assistance to helping anyone trying to plan how to travel from one location to another.) So there are some unusual abilities that do not depend on g . However, other special human features like language, bipedalism (enabling long-distance carrying of heavy weights) and a marked sex role division of labour equally distinguish homo sapiens without depending on g .(7) (See Anderson (1992) for major ability 'modules', like the sense of balance; and see Cosmides & Tooby (1992) for more specific abilities like that of detecting whether a sexual partner is cheating.) The existence of autists having special, non-g-dependent 'gifts' makes no new point of wider significance: there are many special abilities that have rather little relation to g or indeed to anything else - as Spearman had first noted of the ability to draw. Perhaps such abilities develop more easily when they are not in competition with other abilities for access to processing resources; but however they arise, savant gifts are uncommon, often highly practised and have so far thrown no light on how normal people calculate or play music. Lastly, autists gifts have no functional significance when unassisted by g . - The world's most remarkable known mnemonist, for example, combines her gift with an IQ that puts her in the top 0.1% of autists in terms of g (see Jensen, 1993). Autists' own major problem - of having no 'theory of mind', i.e. of finding it hard to recognize that they live in a world that is composed partly of people who have feelings, beliefs and intentions - is itself an interesting specific disturbance, presumably in an innate mechanism. Even so, the extent of autists' social difficulties is well predicted (r = .50) quite simply by the degree to which they fall below average in plain IQ (Eisenmater & Prior, 1991); and autistic symptoms are seen in 80% of children in the IQ range 0-19 (Frith, 1993). So g is a major predictor of both the skills and the handicaps of autism.

  2. (ii) The possible irrelevance of g to understanding learned skills. Some critics of g 's importance have impressed each other by claiming to find skills that are unrelated to intelligence levels in normal people. Thus Ceci & Liker (1986) claimed that regular gamblers' skills at estimating the odds that bookmakers will set on race-horses are not predictable from gamblers' IQ's. Yet this research involved comparison of gamblers who seemed to use a mathematically sophisticated model with track-knowledgeable but mathematically unsophisticated subjects, and re-analysis found different effects in the two groups: the brighter unsophisticates tended to do poorly (perhaps reflecting lack of interest in the experimental task), whereas, among the sophisticates, there was actually a true correlation of +.59 between success at odds-estimation and IQ (Detterman & Spry, 1988). Anyway, apart from the methodological limitations of this study, to appeal to the skills of inveterate gamblers is strange: these 'skills' require half a lifetime of practice and still make gamblers no reliable profit. Stephen Ceci (1991) has further claimed that mental abilities are only collections of skills that can be taught, and that IQ differences are simply caused by differences in time spent at school. However, this testimony to John Watson's inspiration has not been accompanied by any general evidence of restricted IQ ranges in children who have similar lengths of exposure to education. Probably the lower-IQ children of 1930's North America in studies reviewed by Ceci took more time off school because they were needed on their fathers' farms or did not like repeatedly failing at school in competition with higher-IQ classmates. - The early non-environmentalist theory of Yerkes et al. (1921) (Chapter 1) would seem more likely in view of Ceci's failure to deliver the required demonstration from half a century of data. Krechevsky and Gardner (1994, p.287) may claim that IQ's non-academic correlates are "unimpressive"; but they fail to consider the unreliability of many of the laboratory, school and workplace performances that IQ does predict at a level that far exceeds the correlations achieved elsewhere in the social sciences.

  3. (iii) The possible irrelevance of g in view of generational changes. - Are there sudden, "massive" yet remarkably inconsequential secular changes in "mere problem-solving ability"? A third line of attack on g 's importance has focussed more closely on the best established racial difference in g - that black people score markedly lower than whites, who in turn, despite their numerous economic advantages after 1945, score somewhat lower than Asians. In the 1980's a New Zealand athlete and political scientist, James Flynn (who had been radicalized when seeing police shoot students during rioting in 1968 at Kent state University, USA) became Jensen's sternest yet most scholarly critic. At first, Flynn (1980) granted the case for g 's existence and heritability, admitted that the 'Factor X' causing the 15-point black-white difference in g had still to be found, and only stopped short of saying that no environmental explanation for the racial difference would ever be found. However, Flynn's continued involvement with IQ test data soon yielded him a firmer environmentalism: apparently, group differences in g might be affected by previously unidentified factors that had been at work through the middle of the twentieth century. Flynn (1987) published IQ test results from batches of military conscripts who had been tested over the years in seventeen economically advanced countries. Levels of tested IQ-type intelligence had been rising "massively", said Flynn, by some 6 IQ points per decade since at least 1950. In fact, rises in IQ-type intelligence had first been noticed in America and Britain of the 1940's (e.g. Cattell, 1949), and then in other countries by the late 1960's (Koppen-Thulesius & Teichmann, 1972). However, Flynn's observations seemed to him of special interest in establishing two points. (1) g could show "massive" changes without anyone noticing very much - and even while creativity was actually falling by some criteria. In particular, Flynn observed that, despite a big IQ rise among Dutch conscripts, fewer patents for new inventions were being taken out in Holland in 1980 than in 1950; that US students' Scholastic Aptitude Test (SAT) scores had been falling since the mid-1960s; and that modern art continued its sad decline into meaninglessness. Possibly g did not really matter after all. (2) Peoples like the Dutch and the French had changed their g levels quickly, so US Afro-Americans might one day do the same.

    There are SEVEN PROBLEMS [a - g, below] for Flynn's important thesis regarding the IQ-type rise and its interpretation. (For the arguments between Brand and Flynn, see Brand (1995a) and Flynn (1995).)

    1. (a) Gains from reduced reluctance to guess. Flynn's evidence is drawn largely from short, timed, multiple-choice, group-administered tests of IQ on which there is no correction for guessing. Scores on such tests may have improved since 1945 not just because of rising g levels but because of modern educators' encouragements to children to avoid 'obsessional' accuracy and 'pedantic' attention to detail. Being composed of different sections, each requiring use of different principles (e.g. series completion, analogies, oddity), most group tests effectively penalize testees who strive for accuracy. Such testees spend valuable time trying to be quite sure they are giving correct answers - rather than making use of guesswork (see Figure IV,2).

      Time spent labouring on harder questions at the end of the earlier sections of multiple choice tests would often be better spent on the much easier, but equally weighted questions that lie ahead at the beginning of new sections. The correct strategy for testees is: 'When in doubt, guess'. By contrast with such 'group' tests, full, individually administered Wechsler testing (where questions increase steadily in difficulty and where there is no trade-off between time available for the different subtests) shows much less inter-generational change in intelligence levels. For example, the Wechsler scores of Scottish primary school children showed an increase of only 2 IQ-points from 1964 to 1983 - even though, in accordance with the big cultural changes over the period, the 1983 children were significantly less likely to know what 'a belfry' was and more likely to be able to define 'alcohol' (Brand et al., 1989). The mid-twentieth-century intelligence rise is certainly less than Flynn has sometimes suggested; and(8) he himself has settled for Wechsler gains of 3 IQ points per decade. However, the gains on Verbal tests, of around 2 points per decade, are considerably less than the gains of 7 points on Performance tests (all of which involve score credits for speedier solutions) (Lynn & Pagliari, 1994): so even the Wechsler gains are not due wholly to a rise in levels of g .

    2. (b) Gains not unimportant, just obscured. Flynn is quite right that university professors have not been seen 'dancing in the streets' at their students' new-found comprehension and creativity. However, the enormous post-War expansion of university intakes (Hobsbawm, 1994) would have been likely to reduce the average intelligence of students from around IQ 145 in 1950 to a modest rise-corrected IQ of perhaps 115 today - lower than used to obtain in the average British grammar school of the past. The population IQ rise and greater selectivity by IQ-type criteria (rather than by the advanced learning once fostered in private and grammar schools) merely served to keep student IQ levels at around the pre-rise level of 125 that used to obtain in good universities of the 1960's. For example, scores on Raven's Advanced Progressive Matrices by students at the University of Adelaide showed no change from 1967 to 1992 (Con Stough, personal communication).

    3. (c) No true decline in patenting. The decline in patenting (suggesting the uselessness of the supposed g gains and thus of g itself) is not in fact general. Flynn's observation was drawn from the Dutch Patent Office in Amsterdam and he neglected that, from 1960, inventors in all European countries were increasingly using the Europe-wide patenting facilities available in Munich.

    4. (d) A real 'dumbing down' of education. The US decline in the high-level scholastic attainments and aptitudes measured by SAT will equally reflect the lowering of educational standards, despite rising student abilities. Herrnstein & Murray (1994) document the case for this in the USA, as do Green & Steedman (1993) for Britain (see below). (In Britain , state scholarship examinations, Oxbridge entrance exams and Oxbridge scholarship exams were all abolished between 1960 and 1995 - thus decreasing the motivation of secondary schools to teach pupils to a high academic level and to employ suitably educated staff.)

    5. (e) Why expect further Afro-American gains? The secular g rise - or part of it - was presumably due to the massive twentieth-century improvements in affluence, in diet, in health and hygiene, and in obstetric and gynaecological practice. Yet, if such improvement-led g rises have occurred in the past, black people in the USA - the world's best-fed country - will already have enjoyed the g boost along with whites. Big nutritional improvements will be more readily achieved in people who, because of poverty or ignorance of proper nutrition have especially poor diets in the first place; so any black 'catching up' that was possible should have been accomplished already in the USA. Some highly publicized experiments have claimed IQ-boosting by vitamin and mineral supplements in schoolchildren on normal diets. However, these gains have occurred only on some tests rather than others; the particular tests showing gains were not especially the tests of fluid intelligence on which researchers had expected gains (Blinkhorn, 1991); and the gains were mainly slight and bore no relation to dosage (see Peritz, 1994(9)). Furthermore, wide uptake of even the most obviously improving advices about nutrition cannot be guaranteed - as with advice that mothers should not smoke or take other drugs. The first good evidence from controlled experiment is now available that breast milk is causal to the higher IQ' s of breast-fed babies (Lucas et al., 1992; Lanting et al., 1994): premature babies in Cambridge and Sheffield, supplied with their mother's milk by tube feeding, had IQ's at 8 years that were 10 points higher than those of babies whose mothers had intended to breast feed but could not do so; and breast-fed babies had only half the rate of neurological abnormalities by age 9 in a Dutch sample where the breast-feeding mothers were only a little higher in the frequency of being 'middle class' (97% vs 81%) and of having completed secondary education (94% vs 87%).(10) However, beyond the world of research, mothers of lower educational level and socio-economic status are will not normally breast-feed despite campaigns by health and welfare staff to shift their preferences; and whether breast-feeding could be markedly increased among black women is unknown. There are some frankly irresponsible claims that nicotine improves concentration and intelligence test performance (O'Hare, 1995); however, the benefits of nicotine have been reported only in smokers - so it probably serves only to reduce the familiar withdrawal symptoms of addiction, and not to boost IQ in non-addicts. Overall, Flynn's argument makes the mistake of which hereditarians are often accused: Flynn assumes that heritability implies non-plasticity, and he therefore concludes that generational plasticity limits heritability estimates and implicates environmental factors in accounting for low black IQ. However, an environmental cause for a between-generation change may be entirely compatible with within-generation differences being largely genetic - as Lionel Penrose first pointed out in 1946 (Evans & Waites, 1981, p.71). Mean levels of features that are heritable within one generation can change by the occurrence of environmental values that were not in operation previously; and heritability itself may be lowered if these environmental changes occur for some individuals but not for others. Conversely, an environmental change can affect all individuals yet leave heritabilities and group differences intact - until the next novel environmental shift. Such between-generation environmental change is what seems to have happened in the case of the secular rises in height and in g levels. There is no clear implication for whether black IQ levels might be especially boosted in future. It is hard to imagine that average dietary standards could again be improved as much as happened in the century from 1870: to that extent further IQ-type gains would seem unlikely. Finally, for any treatment to arrive that boosted black IQ without boosting white IQ would reveal a more remarkable racial difference than anything that has so far been suspected.

    6. (f) Within generations, IQ's importance is readily demonstrable. Flynn's claim that IQ tests measure "mere problem solving ability", is strange IN FIVE WAYS. (Emphasizing the distinction that he wishes to draw between 'mere problem solving ability' and 'intelligence', Flynn (1987) maintains that IQ is only "a correlate with weak causal links to intelligence." However, Flynn does not spell out what the other ingredients of intelligence itself might be.)

      1. (1) Many people would take pride in being thought to have good 'general problem solving ability'; and many IQ testers would be perfectly content if problem-solving were indeed what their tests had been deemed to measure.

      2. (2) IQ is just as important and predictive for children as their early attainments (as assessed by teachers or in exams). This was first established in work undertaken for the Scottish Council for Research in Education (McClelland, 1942); and "IQ rises in predictive value relative to other measures as years go on" (p.77). In a long-term follow-up of a random sample of state-school five-year-olds on the Isle of Wight, IQ correlated strongly (at .50) with children's later educational attainments, when they were fifteen. Such prediction for individuals across ten supposedly formative years is unparalleled in social science. Notions of IQ's 'unimportance' in education (e.g. Eckberg, 1981) typically derive from studies in which IQ range is severely restricted: for example a correlation of .50 in the general population will be only .35 in either the top or the bottom half of the population (Detterman, 1993). IQ has seldom correlated better than .30 with college grades; but this is because of the relatively strict admission criteria for university students of the past, and because students self-select themselves by ability level for particular colleges and courses and thus restrict IQ ranges in the present. Anyhow, college exams are often incapable of correlating with anything very much because the correlations between their own components (i.e. their own internal reliabilities) are not checked by college authorities (for fear of what will be revealed about the validity of modern assessment procedures) and are often low.(11)

      3. (3)There is nothing 'mere' about the correlates of IQ today. IQ is substantially related to: athletic ability, choice of marital partner, dietary preferences, liberalism and anti-authoritarianism of social attitudes, achieved socio-economic status (by age 40), law-abidingness, middle class values, marksmanship (especially with a tank gun), altruism, good health, likely psychiatric illnesses and a better sense of humour (Gordon, 1986; Brand, 1987d; Egan, 1989; Seligman, 1992; Herrnstein & Murray, 1994).

        Using a representative sample of 11, 878 young Americans studied from adolescence to age 30, the late Harvard professor of psychology, Richard Herrnstein, and the economist, Charles Murray, found strong effects in the bottom 10% of the IQ distribution. At around IQ 75, young Americans (regardless of race or class-of-origin) are much more likely to be unemployed, to be receiving welfare, to be living in a correctional facility (males) or living as a single parent (females). Among single-parent mothers, the low IQ were far more likely to be rearing their children in poverty than were the high-IQ (70% vs 10%). Quite generally, the effect of low IQ on lifestyles is much greater than that of similarly low levels(12) of parental socio-economic status or of young adults' own current incomes. Herrnstein and Murray further believe that the USA is becoming increasingly 'stratified' according to IQ - with a high IQ being increasingly in demand for top jobs and increasingly an objective of middle-class socialization procedures. (Genetic-environmental covariation could have increased if higher-IQ parents now provide especially IQ-enriching early environments for children whose genes already predispose them to an above-average IQ - see Chapter III.)(13) The importance of perceived intelligence in important personal life choices accords with the above: across thirty-seven cultures, people show a strong preference for intelligence in their potential spouse (Buss, 1989).

      4. (4) Occupational psychologists have lately received a definite answer to their own long-standing question of how to predict occupational productivity in adulthood. In a review of work involving thousands of jobs and professions in the USA, and hundreds of testing procedures, it was the mental tests which correlated best amongst themselves (i.e. indexing g) that turned out to be the main predictors of occupational success and income (Hunter & Hunter, 1984; Schmidt et al., 1992). Even quite everyday skills require g: for example, Jensen found US Army data showing that, though anyone with a little training can make a 'jelly roll' (jam sandwich) to US Army specifications, it is higher-g cooks who make the better scrambled eggs. Just about the only white-collar occupation for which g is not in demand is that of being a salesman: evidently there are some 'social skills' that are not g-related, even if they may not be admired by all. Beyond what g supplies, it is usually only a few specific packages of skills - e.g. typing speed and accuracy - that are relevant to job success. Upward 'intergenerational mobility' (advancing beyond the socio-economic position of one's own father) in the USA is strongly predicted only by IQ (Waller, 1971(14); Touhey, 1972; Herrnstein & Murray, 1994). In the UK, literally no large scale work involving IQ is undertaken in the countless 'surveys' by social scientists. Still, such modern work as has been conducted shows children's intelligence (and other 'personal' factors) to provide some forecast of occupational status even by the early age of 23; by contrast the father's job, social status and type of home provided today predict little (Cassidy & Lynn, 1991). (Even such modest predictions as might be made from parental SES will themselves reflect g differences transmitted to children - Brand, 1987c; Bouchard, 1995 .

      5. (5) If IQ is dismissed as an unimportant variable, how can Flynn explain the educational progress of American Orientals (e.g. Humphreys, 1988) and their massive over-representation in the better universities and in the professions? Flynn answers that Oriental success is due to achievement motivation and hard work.(15) This view would be quite unacceptable to the West's educationists, but that alone should not commend it. In fact, the more adequate modern samples of Asian people in North America and Japan indicate they score on conventional group-administered IQ tests at around 105, but higher on non-verbal tests (Lynn, 1993; and see Figure IV, 1). Moreover, since Orientals are introverted and conscientious, they are actually somewhat handicapped on the many group tests of IQ that require speed of answering rather than accuracy. Probably Oriental IQ is around 110 (though still higher in childhood, at the period when the complexities of Asian languages need to be learned - in several different forms - by growing children). In any case, by most accounts Japanese university students and businessmen do not work particularly hard. They put in long hours, but appearing deferential and being a team player are primary concerns - as they doubtless were when Britain was a great manufacturing nation. Flynn's own effort to play down the importance of g to Oriental success is nothing more than a quaint diversion: it has never yet been shown that hard work is a major cause of economic success, and the case of the Japanese does not change matters.

    7. (g) Flynn's arguments range from the self-contradictory to the unparsimonious. Flynn's two points regarding IQ's unimportance and the hoped-for impermanence of the black-white difference do not sit comfortably together. If IQ were "mere problem solving ability", there would presumably be little educational or economic gain from Afro-Americans coming to experience the inter-generational IQ rise (assuming they have not experienced it in full already). Moreover, what could be the explanation of continued Afro-American educational or economic lags if the black-white IQ difference has dematerialized into 'mere problem solving ability'? Is Flynn suggesting that black workers are lazy? It is unparsimonious to hold that low black IQ and low black achievements require two separate explanations. (Likewise, it is unparsimonious to suppose that low IQ in black people has different causes from low IQ in whites. Once again, this would make blacks still more of a special race: they would be more dissimilar from other 'disadvantaged' minorities than London School theorists have ever entertained when attributing black difficulties simply to g .) Although Flynn has the distinction of being the only political scientist since Adam Smith to make a contribution to psychology, many of his ingenious arguments now serve only to draw a veil over his never having found the environmental 'Factor X' for which he started looking twenty years ago.

  4. (iv) The supposed irrelevance of g to explaining anything at all in psychology? A putatively philosophical approach is adopted by some critics of g 's importance. Are IQ's after all not 'mere numbers'? Surely such IQ numbers cannot themselves explain anything or be of any importance except indirectly as a crude reflection of countless more subtle processes that have yet to be understood? The criticism that IQ's can be dismissed as mere numbers that are of no causal or real significance in their own right was advanced by Professor M.J.A.Howe (of the University of Exeter) and found favour with the editors of the prestigious medical journal, The Lancet (see Brand et al. ,1991). Incisive as Howe's criticism may seem, however, a version of it has always been intrinsic to the conceptions of the London School. Tested IQ itself has never been viewed by the followers of Spearman as more than a surface phenomenon: they have always presumed that IQ test scores themselves are only more-or-less faithful reflections of deeper, underlying processes and realities. Figure IV,3 represents the classical London School position: psychometric g (gpm) is just one surface outcrop of a causal play of several distinguishable influences. From the material forces that set up nervous-system differences in what might be called 'physiological g ' (gph), gf differences emerge that express themselves, eventually, in gc, educational interests, attainments of all kinds and also in performance on IQ and other cognitive tests (gpm).

The theoretical approach developed by the London School - now including outposts in the universities of Auckland, Adelaide, Berkeley, Brisbane, Edinburgh and Perth (Western Australia) - posits precisely a real, underlying, essential variable of g . Especially in its fluid form, g plays out (sometimes in interaction and covariance with other life features) into numerous human differences and test scores: it is envisaged as central to many effects that may seem superficially environmental. No-one but a surviving devotee of 'labelling theory' (see Chapter 1) would suppose that an IQ score is of itself an important cause of anything. To issue the causal inefficacy of IQ scores in criticism of the London School shows an unwillingness to read what Jensen and Eysenck have actually written.

Is there possibly some hidden strength to Howe's argument? A modification of it would be to assert that g itself cannot be causal since, except in so far as it is a number, no-one knows what it really is. However, this would merely be to revive the arguments addressed in Chapter I. The critic who cannot accept the case for g 's existence offered in Chapters I and II should consider whether any conceivable evidence could attest g 's reality. - If not, the philosophical problems belong to the critic rather than to g . Still, perhaps g is just a vague concept that it is up to professionals, and not the critic, to define? Perhaps the critic can hide behind the coat-tails of the layman who merely requires the experts to do their own proper job? Yet 'electricity' and 'gravity' are precisely like g as far as lay users are concerned. Like these concepts, g has a clear definition within its own field, psychometric psychology, as 'that which most mental tests measure'. The layman's inability to say much about electricity and gravity may express many attitudes to science - ranging from boundless indifference to perfect confidence; but it does not constitute a challenge to the causal force of these variables. To withhold causal status from g because it is 'undefined' is not to do battle but only to opt out of the argument: it shows a head well and truly in the sand - probably insisting also that g can only be a mathematical abstraction just because it is measurable (unlike several of the personality influences that Howe has mooted as explaining the IT/IQ correlations of Chapter III).

Such are the ways of continuing to pretend that people are essentially equal - and not just morally equally in their entitlement to opportunities. Radical inequalities in g are persistent and important to human social hierarchy and division of labour - and thus to society itself in its dynamic interplay of mutual need and mutual regard. Nor, apparently, could equalization be achieved by a sacrifice of liberty - and fraternity would be a further casualty of such a swap. To deny the importance of intelligence might ease the pain of the failures of Head Start programmes, but reality will keep on breaking through. The decade in which James Flynn provided the major talking point for utopian hopefuls was one in which Herrnstein and Murray (1994) reported the first mass-scale, representative study in which IQ and SES were tested against each other for their ability to predict important lifestyle outcomes in adulthood: the thorough testing of adolescents that was enabled by cash payments to testees from the US Army demonstrated the full extent of the explanatory power of IQ differences. Leon Kamin (1995) has tried to explain why Herrnstein and Murray found little effect of SES on its own: Kamin's idea is that no environmentalist would expect SES to operate other than via IQ. This is itself a startling concession by a devotee of SES to the centrality of IQ in human affairs. Yet Kamin is still leaving most of the causal story untold. For the fact is that IQ still generates big differences even amongst young adults from identical SES backgrounds: as Kamin suggests, SES may indeed be uninfluential apart from IQ; yet IQ demonstrably important even without any involvement of SES (especially across the lower part of the IQ range, from 75 to 100). Figures IV, 4, 5 and 6 illustrate the loci and strengths of effect for IQ's influence that were found by Herrnstein &Murray.

Indeed, matching for social class of origin leads to an underestimate of IQ's full potency because such matching sets aside the influence of any genetic differences between the classes - Bouchard, 1995). Once upon a time, IQ may have correlated so well with parental affluence as to yield a correlation of +.63 between British soldiers' IQ's and the number of teeth in their heads (Eysenck, 1973, p.78); but today such correlations and the causation from SES that they betokened have been washed away by half a century of welfare capitalism. In today's conditions, at least, a Marxist tracing of adult outcomes to class origins is hopeless and IQ emerges as the major social variable - especially affecting outcomes across the bottom half of the IQ range.

Furthermore, Herrnstein & Murray's national longitudinal study of individual differences has been followed by Philip Rushton's (1995) compilation of evidence about group differences in outcomes such as early-and-often childbirth, promiscuity, rates of heterosexually transmitted AIDS and failure to provide for children. Other personality variables are certainly involved here: for example, East Asians' crime rates are even lower than would be expected from their 5-10 IQ point advantage. Yet IQ is still near the centre of the story of worldwide black-white-Asian cultural and economic differences, just as it is probably the key to major differences between young adults in the West in social and sexual behaviour (see Brand, 1995/6b). Even the worrying problem of aggression in children has turned out to be more a question of intelligence than of anything else: in 256 Dutch boys studied over three years, IQ was quite the strongest correlate (-.45) of their aggressiveness as rated by other children - quite dwarfing variables like social class, parental behaviour and the boys' own viewing of televised violence (Wiegman et al., 1992).(16) Instead of running from the realities of IQ, utopians will have to face the music. Do they want a society that idly tolerates its own undermining by the problems so often associated with low IQ? Or will they begin to address the question of what can be done to ensure freedom, welfare, and the maximum productivity and happiness for people and their children at all levels of intelligence?

Fortunately for those who seek amelioration of the human condition, the above four arguments about g 's importance do not exhaust the questions that can be raised about the practical relevance of g differences today. Higher general intelligence on its own is plainly a key to high attainments in many fields; but some crucial outcomes depend on other personal and environmental features and on how any particular g level is combined with them. For example, it is well known that people commonly prefer as friends and colleagues not especially the high-IQ (who might inspire them) or the low-IQ (who might defer to them) but those who are similar to themselves in intelligence. It is as if people function best and most happily in social micro-environments where similarity of intelligence assists mutual understanding. These social niches will often be selected and created by people themselves. People might be said to have marked preferences for the intellectual difficulty level of their immediate micro-environments (with whatever associates and tasks may be involved): they are affected by the intelligence of the environment, and their preferences reflect their own IQs. Thus strangers who meet in the psychology laboratory are more likely to report each other to have 'a good sense of humour' when their IQ's are similar (Nias, 1981); children's search for like-minded companionship begins at an early age (Janos & Robinson, 1985);(17) and gifted children, if they have any choice, make friends who are several years older yet similar to them in intellectual and emotional development (Gross, 1992; Silverman, 1993). As Gross (1994) has observed, the tendency to choose intellectually similar spouses and friends "may not be 'politically correct', but it is human nature."

Might individual choice of preferred micro-environment bring any benefits in education? It may seem unnecessary to ask such a question when people whom we know put so much effort into finding and persisting with courses of study, jobs and hobbies that 'suit them' - as being at least not too hard and not too easy. Likewise, it may seem strange to ask whether children of different abilities need different types and levels of teaching. There are in particular six pointers to what could be a wide agreement on providing individuation in education, as follows.

  1. (1) Ancient. The original proponent of individualization of education was probably Quintillian. He observed in 70A.D.: "It is generally and rightly considered a virtue in a teacher to observe accurately the differences in ability among his pupils, and to discover the direction in which the nature of each particular pupil inclines him. There is an incredible amount of variability in talent, and the forms of minds are no less varied than the forms of bodies." The need to distinguish between children was subsequently recognized by such respected masters of pedagogy as Comenius (1592-1670), Locke (1632-1704), and Rousseau (1712-1778).(18)

  2. (2) Pre-modern. Itard (c.1755-1838) was the French physician of empiricist persuasion who tried to educate 'the wild boy of Aveyron' (Itard, 1801 & 1806) and became the accepted pioneer of modern education. He expressly condemned "the defective management of education, whose principal fault is that it is essentially the same for all children and never adapted to the innumerable variations in the intellectual make-up of the individual"; and he even held this "principal fault" to cause and perpetuate "intellectual dullness" (quoted by Spitz, 1986).(19)

  3. (3) Modern. Psychological research in education repeatedly shows that "qualitatively different alternative treatments are needed to adapt instruction to intellectual differences" (Snow & Yalow, 1982). Plainly, "if the students within [a] group are highly heterogeneous in preparation for learning....both the highly prepared and the poorly prepared are disadvantaged" (Humphreys, 1994). Jensen (1969, p.117) had made this point in his original critique of Head Start: "If diversity of mental a basic fact of human nature....and if the idea of universal education is to be successfully pursued, it seems a reasonable conclusion that schools and society must provide a range and diversity of educational methods, programs, goals and educational opportunities, just as wide as the range of human abilities." (Jensen, 1969, p.117) By contrast, the demonstrable neglect of the educational needs of many children in modern schools is startling: 45% of Montreal fifth-grade children know 60% of their school curriculum (in French and maths) before the year's work begins (see Gagné, 1986). In a study of 160 gifted English children (IQ's 123-212), 60% of them were found to be doing classwork at a level more than four years below their actual attainments (Painter, 1976).

  4. (4) Psychometric. The top 10% of 71/2-year-olds are higher in g than are children in the bottom 10% of 151/2-year-olds (Raven, 1989 - reporting new data on 3,250 British schoolchildren). These bright 71/2-year-olds thus have more objective psychological similarity with the 151/2-year-olds than with their chronological age-peers.

  5. (5) British. In some areas of study, even the generally egalitarian educational system of modern Britain admits the need for distinctions: Britain provides specialized state schools where places are free-of-charge for children having special gifts and enthusiasm for ballet and music.

  6. (6) Socialist. In the past, selection for grammar school according to IQ proved especially helpful in giving chances to working class children (whose primary school records were poorer than those of middle class children) (Floud & Halsey, 1957). Today, socialist spokespersons on education usually say that they favour courses being adapted to all children's "widely different aptitudes and abilities"; and they may even say that this was one of the original reasons for the replacement of Britain's grammar schools with comprehensives (Straw, 1992).(20)

Nevertheless, if it is 'common sense' to treat children according to their own particular abilities, talents, inclinations and even personalities (Sybil Eysenck, 1993),(21) why are children of the same chronological age so seldom taught according to their different general capacities to take things in - i.e. according to their levels of g? If the slightest importance were attached to providing such differential instruction at all economically, would not the children be taught in 'streams', 'groups', 'bands', 'tracks' or 'sets' (or whatever may be the educators' latest titles for the arrangement of treating like with like)? (Doubtless versions of streaming still exist in places, even within British state comprehensive schools: even comprehensive educators may admit the need for there to be 'sets' according to ability in the most academically demanding subjects. However, a British Professor of Education has insisted that, in his experience, British comprehensive schools generally try to maintain "broad banding" as far as possible - i.e. that they largely resist pressures for streaming. (22))

In fact, it is well understood why streaming is seldom practised today in the state schools of the English-speaking world. It is impolitic to say that some children are duller than others, especially while little can be done about dullness. It is simply easier for educators to strip out recognition of difference than to build in the adaptation to g-levels that children require. Yet the rationale of current educational practice is incoherent, as follows.


Generally speaking, modern liberal democracies do not pursue any objectives that interfere with equality of treatment - unless unequal treatments themselves serve to reduce prior inequalities that were still more conspicuous. For example, most state health expenditure is unequally targeted on people who are near death. In this case, what is achieved if things go well is preservation of life, thus postponing the most glaring inequality of all. This is not as inspiring a prospect as restoring younger patients to many years of health, but it is still an understandable ambition. In particular, it is egalitarian not just in the short term but also in the long term: whatever our youthful intentions, any of us may eventually wish the state provide for us, without charge, expensive but life-preserving medical treatments in the few months or years before we finally die.

In education likewise, equality of treatment means that no child is conspicuously favoured with an especially 'good' education unless other children also benefit. (Some children are withdrawn from the state scheme but their parents' tax contributions to the state scheme continue to assist other children.) The only exceptional state outlays not officially available to all are on children with 'special needs' and 'learning difficulties' - i.e. on children who usually have IQ's of less than 85. Thus the egalitarian principle is broadly maintained: the system may have its inequalities but they certainly do not operate simply to help anybody get ahead of anyone else.

However, in another way there is a stark contrast with state provision of medicine. In all this equality and provision for educational needs, where is the ingredient of 'life-saving' that provides the justification of the majority of expenditure on welfare state medicine? Where is the positive merit or virtue of state-educational arrangements? Or are they only justified negatively, by the singular merit of not transgressing the egalitarian imperative? Drug companies and brain surgeons have to produce positive evidence that their products and procedures work and that they do so without unacceptable side effects. In particular, it has to be shown that 'treatments' do better than 'placebos' - where no active or expensive intervention is involved. Thus psychoanalysis is not usually available from the British National Health Service (or from medical insurance schemes in the USA): although it may benefit some individual patients, it is not the treatment of choice for the symptoms of any common diagnostic category. Yet, even though 'experimental' and 'control' groups should be much easier to arrange in education, where life is not at stake, there is no such equivalent positive evidence required in the world of education. (state education is possibly assumed to be a common-sense continuation of what parents mean by education, and thus to require no research into its efficacy. This would explain the sense of shock experienced by parents when they see how little is achieved for their children by the modern state school.)

Alternatively, it might be that nothing but a positive respect for 'equal rights' provides the sine qua non of state education. Perhaps comprehensive education is essentially an ongoing celebration of the wished-for community of equals? As such, its function might be essentially religious - providing through childhood an experience of apparent equality to make up for the loss of that equality of everyone before the Almighty that religion traditionally asserted in the past. However, if it is chiefly rights that are being acknowledged, what respect is accorded to that right of a child to be treated as an individual - without which treatment counting as 'education' can begin? Since low-IQ children can obtain special education according to their own 'needs', should not ability differences be admitted generally as primary creators of different educational 'needs'? Certain central concepts and values require assertion against both liberal and authoritarian educationists. According to the Oxford educator and moral philosopher, John Wilson (1994), one such concept is "that pupils may differ, and differ non-negotiably, from each other in respect of their abilities, aptitudes and attainments, as well as in their psychological needs and attitudes, and that these differences must be taken into account in the structure and organisation of their learning." Another is "that justice entails treating like cases alike, but unlike cases differently." Other educationists (Fiedler et al., 1993) quote Thomas Jefferson's 'Nothing is so unequal as the equal treatment of unequal people'.

Unlike hospitals, modern schools and educational authorities pursue their largely egalitarian ways without proving that they work and without any attention to a feature like intelligence that is a key aspect of human individuality. All told, it is hard to find the positive rationale for current educational practices; and, in so far as they are justified negatively as inoffensive to liberalism, special provision for the low-IQ would seem logically to require corresponding special provision for children of other IQ levels.

The inadequacies of modern state-educational philosophy cannot on their own constitute a conclusive argument for streaming. Practical objections are often raised against a thoroughgoing shift towards responding to children's IQ differences, so these too need consideration. What are the excuses that lead to the denial of g 's importance for how individual children should be educated? Four main arguments are commonly heard, as follows - though each has serious problems.


  1. (1) Modern teaching methods allow all children, of whatever levels of ability, social advantage or deprivation, to work at their own pace within the mixed-ability class. This assurance is hollow. What happens in reality is that higher-IQ children spend their time either teaching their duller classmates or completing entirely non-essential 'projects' single-handedly or with the help of their parents and of equipment found at home. In either case, these children are simply being denied their right to an effective education. For example, why should they not learn the two or three languages and area-histories that are taught from an early age to the brighter children of other countries? (Or, if they are not considered to need more than English, what are they taught instead of the languages on which children in non-English-speaking countries have to spend so much time?). According to Scotland's Quality in Education Centre at Strathclyde University, "a 'fairly large' group of Scottish youngsters say they are not being challenged by their classwork" and a similar number report that their work is too difficult (McBain, 1996). Mixed-ability teaching may work in Japan: but there, classroom discipline and achievement motivation are high, and slower pupils attend out-of-hours classes to help them keep up. Notoriously, observers note the relative disorderliness and purposelessness of British school classes as compared to Japan (discipline) and France and Germany (streaming) (White, 1987). Strangely, it is almost as if the British educational experts who arrange all this reckon that intelligence is indeed all that matters: apparently they see little need for intelligence to be expressed and channelled, with the help of education, into as many high-level attainments as possible.

  2. (2) True mixed ability teaching would be much easier if only the Government spent more on education to reduce class sizes. Yet class sizes in Britain are now typically a third of what they were before 1939. Meanwhile Britain's position in most international educational league tables has sunk from third to twenty-third: in mathematics, at age 13, British children now lag German children by 1 year and Japanese children by two years; and a MORI poll of British adolescents found that a third of them could not calculate a weekly wage from an hourly rate, and a quarter could not identify which direction on a map was north (Green & Steedman, 1993, pp.9, 31). Anyhow, research repeatedly finds children's educational outcomes quite unrelated to class size - as the Educational Secretary for England and Wales must repeatedly to explain to teachers who understandably find mixed-ability teaching a strain (see Eysenck, 1973/1975, p.134; Walsh, 1995): even a class size of six will be difficult for a teacher if children span the normal range of IQ. Small classes do not in fact lead to teachers adopting the acclaimed 'interactive' teaching methods;(23) and class sizes in Japan average over 40 while those of around 55 in communist China apparently work well (Walsh, 1995). For England and Wales, Her Majesty's Inspectors of Schools reported their conclusion by 1977 that mixed-ability teaching (at least for mathematics) primarily required "exceptional" teachers. Parents often seem to favour the small class sizes maintained by private schools; but such schools are streams in their own right - usually having no pupils of below-average intelligence.

  3. (3) It would be uneconomic to teach a class of, say, eight-year-olds in three different ability groups. This objection presumes the creation of new classes. But what if the brighter eight-year-olds were simply placed with the nine-year-olds and the slower eight-year-olds with the seven-year-olds, and so on? Indeed, if economy were required, assignment-on-the-cheap could accord simply to a child's current school attainment and not to tested IQ - though selection by IQ would be fairer to disadvantaged and minority children than procedures involving teacher nomination (Baldwin, 1985). 'Mastery learning' (as it is called in the USA) ensures that learning has taken place before a child moves up the age range towards senior classes. Mastery was the main determinant of a child's school class until school numbers expanded in the 1920's (Gross, 1994). The practice of 'grade repeating' is widespread Japan, France and Germany (where ten per cent of children will repeat a year at some stage through their schooling). The glaring 'diseconomy' that requires attention is rather in modern teaching methods in the USA and Britain. These keep children together who in their free time choose very different paths of development. Why are children's own preferences thus disregarded?

  4. (4) Mixing chronological ages is insensitive to children who have to 'stay down' and deprives them of the valuable models that brighter peers provide; and the brighter and younger children who were moved up a year are put at risk of sexual abuse and bullying. Such anxiety is baseless for four reasons, as follows.

    1. (i) Models. Discipline problems are the hallmark of the modern school, not of the pre-1960s school where children stayed down a year if they could not keep up. Children's troublesomeness and unhappiness are especially associated with feeling a failure at school and are reduced for low- and average-ability children when bright and gifted children are withdrawn from the classroom: lower-ability children then have a chance to excel (Kennedy, 1989). Fiedler et al. (1993, p.7) record a primary school pupil's comment: "When Bill [a gifted pupil] was in class, it was like the sun was shining on a bright, clear day. But when he went out to work with the other gifted kids, it was like when the sun goes over the horizon. The rest of us were like the moon and stars: that's when we finally got a chance to shine." Nor are average children 'deprived of role models': for they seldom identify with high-ability children, and usually take more interest in other children of similar ability who have succeeded in what they are trying to do (Schunk, 1987).

    2. (ii) Well-being. Psychologically, from all that is known of g 's influence on friendship formation, children will be happier mixing predominantly with others of a similar intellectual level. Reviewing the literature, Southern et al. (1989) observe:
      "Both early admission [to school] and later acceleration have been extensively studied.... Considering that the body of literature spans five decades and has consistently associated the acceleration of precocious young children with positive changes in their academic achievement and a lack of negative effects on social or emotional growth, one might conclude that the questions regarding the advisability of acceleration have been conclusively resolved.... [Studies finding the contrary are] at worst fraught with severe methodological deficiencies and, at best, misapplied [e.g. examining young-in-grade children selected on the basis of chronological age alone, or because their parents were low-SES parents (of the 1950's) who wanted early school admission for the children chiefly because they were both working]."
      The worry that grade-advanced children will not be of sufficient 'maturity', 'emotional age', 'emotional quotient' or 'moral development' to be able to cope is groundless: whatever educators mean by these terms is actually predicted better by tested Mental Age than by Chronological Age (see Boehm, 1962; Kohlberg, 1964; Hallahan & Kaufman, 1982; Tannenbaum, 1983; Janos & Robinson, 1985). The 'balance', 'social skills' and 'sense of responsibility' that teachers like to see are closely (though doubtless not exclusively) linked to g level: for example, on eleven of twelve measures of social and emotional adjustment, gifted children in Grade 3 were found to be more advanced than average children in Grade 6 (Lehman & Erdwins, 1981). There is simply no sound research basis for supposing that grade advancement will yield either social or emotional maladjustment (see Silverman, 1989, and Feldhusen, 1991). Research in France shows no harmful effect of redoublement on pupils' self-esteem, and even better subsequent progress for a proportion of grade repeaters (Robinson et al., 1992). Anyhow, since intellectual and emotional maturity are substantially correlated, conventional grouping by chronological age is no more justified by the emotional than by intellectual similarity of children so grouped.

    3. (iii) Generation-mixing. The chronological-age divisions of schools should in any case be broken up. That each school 'year' lives in virtual ignorance of the others makes it hard for traditions and information to be passed down from one year to another. This too prevents children forming intelligent opinions that might lead to intelligent choice. - Divide and rule is, sadly, the slogan of the egalitarian educator.

    4. (iv) Why compulsion? Why need there be compulsion at all? The most extraordinary feature of modern 'education' is children's lack of choice. So long as parents can provide a little daily guidance, most bright children are well served by the modern home with its illustrated encyclopaedia, radio, TV, video and personal computer. There is no reason at all to continue with the legalized compulsion of most current primary and secondary education.

Instead of the present coercion, schools should let all children try out classes in other years, if they and their parents desire; and provide all children with a continuing choice of difficulty levels in the subjects which they are taught. Allowing self-streaming by parents and children would doubtless threaten the authority of teachers. However, teachers today seldom claim to want to wield authority; so it would presumably suit them to function in an advisory capacity - free of the burden of mixed ability teaching and able to maintain their own specialist qualifications. The advisory system is what obtains in modern Germany. Here the traditional academic distinctions between schools and school classes are maintained on a voluntaristic basis. In most areas, parents have the legal right to send their children, however limited or lazy, to the 'grammar school' (Gymnasium) if they insist; but, when necessary, parents are cautioned that school standards will be fully maintained and that their child might have been happier and benefited more from the less academic, or more practically oriented curricula of a technical Realschule or vocationally oriented Hauptschule. (This tripartite division of secondary schooling was what Burt had planned for Britain in the mid-1940's; but few local educational authorities took the trouble to steer the brighter but less verbal children in the technical direction.)

Although children and their parents might welcome democratic self-streaming as best for their own children, would they actually be correct to do so? By 1982, researchers at the University of Michigan had conducted a 'meta-analysis' of the fifty-two high-quality studies of streaming to have appeared in the academic literature of modern education. They concluded that streamed pupils of all levels of ability did indeed show significant educational gains. The Michigan researchers also addressed anxieties about what happens to lower-streamed children. They wrote:

"[Some articles by other educationists] tended to emphasize the negative effects of grouping on the attitudes and self-concepts of low-ability students. Such conclusions, however, were based primarily on anecdotal and uncontrolled studies. The controlled studies that we examined gave a very different picture of the effects of grouping on student attitudes. Students seemed to like their school subjects more when they studied them with peers of similar ability, and some students in grouped classes even developed more positive attitudes about themselves and about school."(24)

Subsequent researches by the Michigan team allowed an update confirming the original review; and other researchers also report favourably on streaming, grade advancement and differentiation of schoolchildren by ability (Nemko,1988; George, 1990; Quah, 1990; Jensen, 1991; Southern, 1993). Lately, in New South Wales, systematic efforts have been made to accelerate bright youngsters to into university - apparently with success (Croker, 1995).(25) Surveying forty years of studies for the American Research Center on the Gifted and Talented, Kulik (1991) concluded that "bright, average and slow youngsters profit from grouping programs that adjust the curriculum to the aptitude levels of the groups." Across five meta-analyses of gifted and talented learners, Rogers (1991) found that "full-time ability grouping (tracking) produced substantial academic gains." Coleman et al.(1993) reported that "the one common element" in successful education of gifted children was "that students were grouped by ability and/or performance for language, arts and mathematics instruction." Dooley (1993) found that "appropriate differentiated reading programmes are essential for the academic growth of gifted readers"; Maker (1993) includes several chapters which similarly favour tailoring of instruction within regular classes; and Fowler (1993) and Stanley (1993) both find gifted adolescents to make rapid progress when offered summer programmes of accelerated coaching. Even US law courts have come round to upholding practices of grouping because of evidence of beneficial outcomes to lower-track students (see Reschly et al., 1988). The value at all ages of 'matching' schoolchildren to tasks that are not too hard and not too easy for them has been repeatedly confirmed (St-J Brooks, 1989).(26)


Feldhusen et al.(1986) reference studies going back to 1959 and observe that few teachers can sufficiently individualize instruction within normal classes. Van Tassel-Baska (1992) likewise reviews the academic literature about acceleration (on which "perhaps more has been written....than about any other single educational intervention with any population"). She concludes that, while educational authorities shun the results of research, grouping by ability (accompanied by appropriately tailored curricula) enhances gifted children's achievements and "produces a positive attitude toward subject matter for all groups of learners". It has also become clear that the efficacy of educational procedures generally is more dependent on g-level than on any other variable. According to John Carroll (1993, pp.675-6), the effect of any given education will depend on the children's g levels - excepting only when the sheer power of g itself determines outcomes on its own, quite regardless of education. (The eminent psychologists, Lee Cronbach and John Snow once examined whether performance depended on particular mixtures of both aptitude levels and the teaching supplied. Carroll records their conclusion: "the pervasive correlations of general ability with learning rate or outcomes in education limits the power of Aptitude-Treatment Interaction findings to reduce individual differences.")

Such research developments and increased awareness of children's differences in educational research have occurred against a most unpropitious background. There have been little streaming and IQ-testing to study, and little encouragement for researchers. Streaming itself is the cardinal heresy of the modern English-speaking educator, as Jensen had found. Nevertheless, available results would seem to explain the long-term success of streaming arrangements in Germany and Russia, the continuing acceptability and success of binary education in Northern Ireland, the success of the few surviving English grammar schools (even after allowing for children's IQ's and socio-economic backgrounds), the maintenance of special lycées in Turkey and Azerbaijan for gifted children from disadvantaged backgrounds, the permission of 'grade skipping' in the state schools of France, Switzerland and New South Wales, and the recent shift in Denmark away from pursuit of educational 'equality' and towards children's 'optimal development' (e.g. Swing, 1994).(27) Even the 70% black Paideia schools of Chattanooga that pride themselves on democracy and egalitarian 'single-tracking' nevertheless maintain "leveled" sections for children's education in algebra (Wheelock, 1994). In contrast, the twenty-five year experiment with comprehensive schools in Britain has not even helped those who are so often put forward as the prime concern of the modern educator: children of working class origins now provide a lower percentage of university students than they did in 1970. Without the special provision for the bright that streaming makes, secondary school performance becomes mainly a matter of persistence with babyish exercises that are only tolerable to middle class students who have extremely middle class aspirations.

Behaviourism's inventor, John Watson, wasted very little of his own time on his bizarre idea that any child could be trained to do anything and that children's training would not require careful attention to their own individual natures and mental abilities. Indeed, on leaving academic psychology he went on to succeed in the very different world of advertising: this area of endeavour typically requires shrewd assessment of what might serve as inducements for a small number of already product-prone consumers - that is, it requires close attention to enduring human differences. Even Watson's best-known behaviourist descendant, B.F.Skinner (1904-1990) declared, after years of behaviourist indifference to naturally occurring individuality :

"The phalanx was a great military invention, but it has long been out of date, and it should be out of date in American schools.... We would double the efficiency of education with one change alone - by letting each student move at his or her own pace." (Skinner, 1984).

- That each individual will have 'his or her own pace' (and other general, enduring and unlearned distinctions of personality) had long been acknowledged by Eysenck, but not by most behaviourists.

Today it is clear what should be done about the ideological extravaganza of the last generation of educators and their psychological advisers. Those appointed educational experts who have declined to attend to the phenomenon of intelligence differences will need to be granted early retirement; and children and parents will need an immediate offer of choice. To continue to be state-funded, schools should be required to demonstrate that, for the majority of the hours of the school day, most pupils have a choice as to which lessons to attend; and that the choice that is offered to them (and their parents) is between lessons of different levels of difficulty. A belief in freedom of choice is a value shared with pride by virtually all social and political groupings in the West: so, a century after the introduction of compulsion to attend school, it is time to deliver freedom and choice for schoolchildren. As one British political commentator puts it:

"It will soon be an article of faith among educationalists that mixed-ability classes are bad because they cheat clever children, middling children and dull children. There is nothing wrong with streaming so long as it is easy for children to move from one stream to another." (Massie, 1991)

A proper understanding of human intelligence does not lead to segregated schooling decreed by experts - whether by teachers or by psychologists. Anyhow, schooling is increasingly segregated already by what parents can pay for their house-locations so that their children can escape the low standard of much state education (Wooldridge, 1994). Rather, a proper understanding of g discloses the need to allow constant niche-selection by children themselves - at school as much as at home. To associate belief in genetic g with some kind of brutal pessimism and educational nihilism may seem progressive and radical; but it is actually a distraction from how egalitarian policies waste children's time in the name of communal harmony yet still require repeated and expensive state intervention in family life. Today's understanding of g requires full acknowledgement of the deep roots of human individuality; and of human non-malleability and obstinate unimprovability unless individuality is respected. Knowledge of g requires a drive towards individualization with regard to both family planning and education. Obliging parents to insure for the likely costs of educating their children to desired levels would ensure that thoughtful responsibility was taken for individual members of the next generation; and allowing education to be adapted to individual children via their choices would revolutionize our antiquated schools, keep parental costs down and make the taking of responsibility worthwhile.

Burt and the other IQ-testers first brought the opportunity of a good education to children from ordinary homes whose genuine capacities for learning had been neglected by the educational systems of their own day. Today, the abiding yet neglected phenomenon of IQ-differences points to expansion of choice in education. The scientific understanding of general intelligence shows the way out of the follies of an educational egalitarianism that tries to ignore g . Instead of defying the realities of intelligence, psychologists and educators must make use of them. These realities should be recognized both as licensing freedom of choice and as able to guide the provision of appropriately individualized opportunities for children. A century of successful intelligence testing and of failed schemes of egalitarian uniformity in the schools might thus end with appropriate educational provision for all children - the original goal of Binet as much as of Burt.



  1. (1) The idea that general intelligence is important is easier to accept while there is a prospect of substantial IQ-boosting. Till recently, such hopes were seriously entertained - especially of pre-school Head Start programmes and of vitamin and mineral supplements. However, as Neisser et al. (1995) report for the American Psychological Association: "By the end of elementary school, there are usually no significant IQ or achievement-test differences between children who have been in [Head Start] programs and controls who have not." For the present, only increases in the proportions of infants that are breast-fed or adopted into high-IQ families offer much prospect of IQ-boosting.

  2. (2) Lately, direct criticisms of the relevance of the g factor have proved popular. In particular, James Flynn has claimed that the twentieth-century worldwide IQ rise has had few noticeably good effects; and that the economic achievements of the East Asian peoples (in their own countries and in North America) cannot be attributed to their IQ's. Arguably, however, the worldwide expansion of university education is a direct and agreeable result of higher g levels; and group-administered IQ tests require a willingness to sacrifice accuracy for speed which probably makes them unfair to Asians. In the USA, Herrnstein & Murrary's (1994) The Bell Curve provides an extensive survey of thirty-year-olds who had been followed from mid-adolescence. It shows IQ to be quite the main predictor of lifestyle variables such as employment and law-abidingness; in particular, IQ today is much more predictive than an adolescent's social class of origin.

  3. (3) Contrary to the rejection of 'streaming' by many Western educational experts, reflection and research continue to suggest the wide benefits of adapting the difficulty level of school classes to children's g levels. Streamed schoolchildren of all ability levels have been found to be happier and to reach higher levels of attainment. In interaction with appropriate educational provision, g is thus a most consequential variable in education: g and tailored education are the two pillars of the main aptitude x treatment interaction effect to be found in studies of school learning. Far from belief in IQ being what Walter Lippman once called 'a dogma' in which the task of education had given way to the doctrine of predestination, serious education begins precisely when g-levels are recognized.

  4. (4) Achieving gains for children by g-adjusted education does not require expert adjudicators or IQ tests to stream children, nor even any insistence on assigning children according to expert advice. Very likely, in view of the sorts of choices they make about their friends, hobbies and TV programmes, children themselves would make sensible choices of school classes if they were only allowed to do so: they would choose classes pitched at their own g-levels - perhaps by joining children of a different chronological age. Instead of state schools providing a cross between a child-minding service and a reformatory, children should be allowed, at any time of day, a choice of classes of varying difficulty levels. After sampling classes arranged primarily for children of different chronological ages, children would usually settle to cleasses of the right degree of difficulty for them - though IQ test results would be provided if parents wished. Such liberation would unleash the power of g to produce improved attainments when coupled with appropriate teaching: it would counter the 'dumbing down' of education for which the past generation of educational experts and politicians has been responsible. As Gerard (1995) has remarked: "The literature is full of case studies of clever children who have been let down by the [educational] system. Under-occupied, bored and often bullied, many become alienated and disruptive.... ....Why is it such an outlandish idea for children to sit in different classes for different lessons? Is it such a threat to the order of our system to allow a primary school child to attend lessons at a secondary school, if he or she is able? No, we will have to do better. In the bold, difficult world of the new century, there can be no such concept as "too forward"." After years of stagnation, perhaps young people themselves will "smash the old oligopolies of learning" (Jenkins, 1995).


  1. Way ahead of his time, Burt became convinced of the intellectual equality of men and women by 1912 - on the basis of how the two sexes performed on the Binet tests. The idea that there were no differences in general intelligence levels between the sexes was to prove central to the most radical educational changes of the twentieth century. The higher level of g in Jews was known to psychologists in Hitler's Germany and has long been widely accepted (Lynn, 1992b). Galton's disparaging view of Jews and women was complemented by his marked admiration for the Scots: though one of his many surveys once recorded the women of Aberdeen as being the least physically attractive in Britain, Galton took Scottish genius very seriously - comparing 18th century Scotland to ancient Greece (as Winston Churchill would do subsequently).

  2. Yerkes' (1921) US Army studies had found 89% of black recruits to be below MA 12. However, whites only scored around MA 13, educational provision for black children in those days was segregated, and black illiteracy rates meant that, in the absence of express validation of the tests for illiterate testees, estimated levels of intelligence were only an informed guess. - See Chapter 1 for problems of interpreting the US Army study.

  3. Shockley particularly observed that the crime rate in Denmark was only 2% of that in Washington and attributed this to the long-standing Danish discouragement of reproduction by feeble-minded persons. When the magazine Atlanta Constitution claimed that Shockley's ideas derived from Hitler, Shockley sued them for libel and won.

  4. The effects of specific coaching on test performance can sometimes be considerable. After reading a relevant book and attending a training session, Dutch students showed gains equivalent to 15 IQ points on a well-validated test of numerical aptitude after being told how to search number sequences for regularities allowing prediction of the number that should 'come next'. However, an intelligence test using verbal analogies showed a coaching gain of only about 2 IQ points (Van der Molen et al., 1995). Probably, much depends on whether, prior to coaching, testees are familiar with items of the type used. Young children, to whom tests are more of a novelty, might thus be expected to show substantial gains from 'teaching the test'.

  5. If admission to the prestigious University of California at Berkely accorded to educational grades rather than to race, the percentage undergraduates of Asian extraction would rise from 39% to >50% (Hodges, 1995).

  6. As well as showing withdrawal, ritualistic behaviour and literalism, autists find it especially hard to recognize that people have their own beliefs and intentions. For example, if 'Sally' place a toy in a basket, but 'Anne' is seen to move the toy into a cupboard while 'Sally' is out of the room, autistic children expect 'Sally' to look in the cupboard for the toy on her return.

  7. The degree of human superiority in intelligence defies quantification because of species' numerous differences in particular faculties (see Preface). But, though human symbol use in combination with reasonable g can be presumed to confer considerable powers of learning, there are equally clearly many forms of learning at which human beings have no conspicuous advantage or are possibly inferior. Classical, operant and identificatory types of learning would be examples - but there may well be others in association with special abilities such as long-distance navigation.

  8. Further to this publication, the Irish Journal of Psychology carried discussions by Brand and Flynn that ended in accusations of logical errors and exhortations to undertake further work.

  9. Peritz (1994) reports on 409 Californian adolsecents given vitamin-mineral supplementation for three months. Compared to 101 placebo controls, there was a gain of 1.6 points of Wechsler Performance IQ and a loss of 0.1 point on Verbal IQ. This difference between the Wechsler scales cannot be interpreted simply as a (modest) gain in gf unaccompanied by any change in gc - for three of the Wechsler verbal scales require active mental work as much as stored knowledge (see Chapter 1) Anyhow, Peritz freely allows that further research will be needed to show whether his effect "is large enough to be of practical importance."

  10. A research team at the University of Glasgow reports that breastmilk-fed babies show superior development of the grey matter of the brain; and the researchers trace this finding reasonably enough to the fatty acids that are contained in breast milk but not as yet in man-made formulae for infant feeding. (BBC Radio IV UK News, 16 iii 1995) Fatty acids might boost IQ via their contribution to the development of the insulating myelin sheaths around nerves: myelinisation (the very process studied in animals by the young J.B.Watson for his doctorate - see Chapter I) speeds electrical transmission and is an important development across the first two years of life (Miller, 1994). Since individual differences in IQ only become reliably measurable after the second year of life, they might have their physical basis in how adequately the process of myelinization had proceeded in infancy.

  11. University examining boards provide no public evidence of the correlations between component parts of their exams. This failure to provide elementary evidence of validity of their tests would be intelligible if such correlations are in fact often modest. That this is so is suggested by tbe notorious bunching of final marks in the middle of the range. This happens for many subjects having less than clear-cut academic standards - by contrast, law and mathematics yield a broader spread of marks (reported in Times Higher Educational Supplement, 26 v 1995, p.2). Bunching yields the familiar phenomenon of universities endlessly exhorting markers to use extreme marks - particularly in the hope of producing more First Class results. However, using a wider range of marks for individual exam papers will not help much when the different papers are poorly correlated; and low correlations may sink still lower when markers struggle to award high marks against their own better judgment. [The general decline of clear academic standards and the rise of 'anything-goes' relativism in the universities (especially in the humanities and social sciences) is well documented by Reading (1996).]

  12. A person's IQ can be expressed in terms of standard deviations, upwards or downwards from the population mean: e.g. an IQ of 85 is '1 standard deviation low'. The relative SES of a person's parents can be expressed similarly. Thus people can be selected in research who are 'similarly low' in both IQ and SES.

  13. Proving the hypothesis of 'increasing social stratification according to IQ' is hard because of limited historical data about IQ levels. However, few students at prestige universities today have any good friends who differ from themselves by more than fifteen IQ points: at least, they are unable to persuade any such friends to participate in psychological researches, as the many psychology theses testify which involve only student subjects. Apparently, little survives of the mixing of the social classes that used to occur in churches and soccer clubs - or in the University settlements of Burt's day.

  14. Waller's finding was that father-son IQ differences correlated .29 with father-son SES differences. Difference scores are particularly unreliable (since they are affected by the unreliability from both of the variables that contribute to them), so the 'true' correlation between Waller's variables would be around .50.

  15. Like Rushton (1995), Flynn views the East Asians as more conscientious and controlled than Caucasians; though Flynn presumably believes these traits to be of environmental rather than genetic origin.

  16. Wiegman et al.(1992) describe their work as follows. "....two cohorts of children [N =466], from old, city-centre districts and the suburbs participated... [Peer nomination assessment was used, based on the work of Eron (e.g. 1987). Positive significant correlations were found between TV-violence-viewing during the first two years and aggressive behaviour in the third year (boys .23, girls .29). Then] the influence of the starting level of aggression was statistically controlled for. The regression coefficients for both boys (.07) and girls (.10) were not significant.... The only variable which correlated significantly with both aggressive behaviour and TV-violence-viewing was intelligence. For the boys, significant negative correlations were found between intelligence on the one hand and aggressive behaviour (-.45) and TV-violence-viewing (-.28) on the other. For the girls, the correlations were not significant but pointed in the same direction.... Aggression of the parents was not correlated significantly with the child's aggressive behaviour or TV-violence-viewing.... For both the boys and girls, socio-economic status (SES) did not correlate significantly with aggressive behaviour.... it may be assumed that intelligence is one of the underlying factors which explain the relation between TV-violence-viewing and aggression."

  17. The fact that children of normal intelligence do not seek out friends of lower intelligence makes the formation of relationships especially hard for the small minority of duller children who are present in 'integrated', mixed-ability classes.

  18. Of course, mere antiquity of opinionation is of little merit of its own accord. Individualization of educational handling was expressly rejected by Saint Augustine, Martin Luther, Ignatius Loyola and John Knox (Snow & Yalow, 1982).

  19. (I) Itard's empiricism was derived from reading John Locke and was well suited to pedagogic optimism. However, he was unable to train Victor, 'the wild boy', to use symbols - perhaps because (strangely) he did not try sign language; and the process of civilising Victor came to an end as Victor's sexual urges assumed paramount importance. (ii)Itard believed that intelligence was the result rather than the cause of experience; yet even he insisted on the importance of individuation of treatment - in response to whatever level of development was already detectable in a child.

  20. Jack Straw (1992), a British Labour Party spokesperson on education, has claimed that the very name of Britain's "comprehensive" schools "conveys the clear understanding of those who developed the notion that it is precisely because children have individual talents and needs, and widely different aptitudes and abilities, that they should be offered a comprehensive range of courses and teaching and should not arbitrarily be sorted into separate categories of schools at 11...."

  21. Eysenck (1993) notes that some researches show clearly "the success of educational methods differing according to the children's scores on Extraversion, Neuroticism and Psychoticism."

  22. BBC IV UK on 30th March, 1993 (on a phone-in programme compèred by Nick Ross).

  23. Researches find small classes do no better for children, or even that they are worse; but teachers and their unions pay no attention (Eysenck, 1975, p.134; Daily Telegraph, 14 viii 1978; BBC IV UK, 4 ix 1994). A small class will usually have the same ability range as a bigger one, so teachers can still not adopt differentiated methods that take pupils' abilities into account (Sunday Times, 20 ii 1983). In 1995, the Chief Inspector for Schools in England and Wales was reported as concluding from research that class size bears no simple relation to educational outcomes-though small classes may possibly help in the first two years of primary school (BBC IV UK, 10 xi, 0800hrs).

  24. This extract is taken from the original research paper in The American Educational Research Journal, 1982.

  25. Croker (1995) outlines Early Enrolment Scheme arrangements and gives detail of Patrick Morris-Suzuki, who was born in Bradford-on-Avon, England in 1976. He was accepted for the University of New South Wales in 1991, achieved first class honours with a mark of 95%, and registered there in 1994 for a Ph.D. on operator algebras (a branch of mathematics related to physics). Interviewed, Patrick, who also plays the flute for the UNSW orchestra, said: "I have no regrets with what I've done. When I first came here, there were some who thought I'd be better off socially with my own age level. In my case, that wasn't correct. I got along very well with fellow students. A friend of two years' acquaintance and another I'd known for 18 months who didn't know my age were both surprised when they found out."

  26. St-John Brooks (1989) gives this summary of work by Professor N. Bennett (see also N.Bennett & J.Kell, A Good Start).

  27. Even in Russia under communism, selective schools took in the top 2% of age cohorts at age14 (Sunday Times, iii 1980). That English grammar school pupils outperformed pupils of the same IQ's and social backgrounds at comprehensive and secondary modern schools was reported in The Times, 20 v 1983. (Indeed, it has been claimed that grammar schools are just about the only form of education to improve on the levels of attainment that would be expected from children's IQ's under under any educational provision at all (Vernon, 1979, Chapter 10).) In 1994, the New South Wales Board of Studies published thirty pages of 'Guidelines for the Selection of Students for Accelerated Progression' (i.e. guidelines for which pupils to accelerate). The Board accepted evidence that 60% of gifted children otherwise underachieve in school by at least 3 or 4 years, and that perhaps a fifth of them drop out of high school in frustration. Typical candidates for acceleration would be expected to have "a large, advanced vocabulary for their age, the ability to discuss complex ideas and concepts, quick mastery and recall of factual information, creativity and imagination, enjoyment of reading, the ability to work independently...." - and many other attributes that are largely predictable from measured levels of g .


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