Tag Archives: g

Can intelligence be taught?

Klingberg, T., Forssberg, H., & Westerberg, H. (2002). Training of working memory in children with ADHD. Journal of Clinical and Experimental Neuropsychology, 24(6), 781-791.

It’s a good time for social scientists who like biology. From Shakespeare’s wordplay to accelerating human evolution, biology is being used to explain more and more of our world. This is also true of topics that some people react to very emotionally, such as the role of genetic and environmental causes of human diversity in general intelligence.

The New Yorker has a mostly good article criticizing the role of genetics. Aside from a personal attack near the beginning, the article mostly emphasizes that changing environment changes general intelligence. It got me thinking if general intelligence itself could be changed by instruction, especially considering the finding that working memory correlates almost perfectly with IQ.

Well, Torkel Klinberg and colleagues asked that same question in 2002 and the answer is yes.

The researchers looked not only at measures of working memory, such as visuospatial working memory, and measures of general intelligence, such as Raven’s progressive matrices, but also things you wouldn’t expect: like head bobbing.

The measurement of head movements has been described in previous publications (Teicher et al., 1996). An infrared motion analysis system (OPTAx Systems, Burlington, MA) recorded the movements of a small reflective marker attached to the back of the head of the child. A movement was designed to begin when the marker moved 1.0mm or more from its most recent resting location. The number of movements was recorded during a 15-min period when the child was performing a version of a continuous performance task. In this task subjects were asked to respond to a target and withhold response to nontargets, with no requirement of holding any information in WM. Stimuli were presented every 2.0 s, and 50% of stimuli were target

Why include head-bobbing, you ask? Well, head-bobbing among ADHD students is already subject to medication — so you can compare the benefits of training with the benefits of drugging:

The number of head movements was significantly reduced in the treatment group compared to the control group (Table 1, Fig. 1c). Again, this effect was evident in all subjects in the treatment group (Fig. 1c). The number of head movements during retest in the control group was about 6% higher than during the first testing. This is consistent with previous data on test-retest changes after administration of pharmacological placebo, where an increase of about 8% was found on the second testing (Teicher et al., 2000; Teicher, personal communication). The reduction of head movements in the treatment group was 74% (SEM 7). In comparison, a probe dose of methylphenidate (approximately 0.4 mg/kg) reduced the number of head movements by 62% (Teicher et al., 2000).

While the authors warn that more work is needed to see if this really leads to an increase in general intelligence, things look hopeful:

The present study showed that intensive and adaptive, computerized [working memory] WM training gradually increased the amount of information that the subjects could keep in WM (Tables 1 and 3, Figs. 1 and 2). The improved performance occurred over weeks of training, and is in this respect similar to the slow acquisition of a perceptual skill or a motor skill (Karni et al., 1995; Recanzone, Schreiner, & Merzenich, 1993; Tallal et al., 1996). Furthermore, the improvement from training was evident both for a group of children with ADHD (Experiment 1), as well as for adult subjects without ADHD (Experiment 2). This shows that an initial deficit inWMwas not necessary for improvement to occur.

All learners have two board sources of ability: knowledge of what they are doing, and the intelligence to apply it. Both of these can be improved with a positive environment, and both can be weakened by a bad environment.

To the extent that we wish to have a functioning systems administration at home and abroad, we must encourage those institutions that help develop skills and intelligence, and discourage those institutions that diminish them both.

The Hierachy of Intelligence(s)( Tests)

In the context of an attack on Howard Gardner’s theory of multiple intelligences (10 page PDF), David F. Lohman (of the University of Iowa) presents this visualization of the hierarchies of intelligence tests:

Hierarchy of IQ Tests

The closer to the center, the more general lintelligence (“g”) loads on the test. Some tests, such as identifying the correct endings of words, reading speed, or listening comprehension test “g” more indirectly than measures of verbal achievement, paper folding, or necessary arithemetic operations.

A good example is the Test Necessary Arithmetic Operations. This test was devised by Guilford to measure a specific cell in his Structure of the Intellect Model. Each item presents a short word problem. The examinee’s task is not to solve the problem, but to say which two operations she would use, and in what order. There are four operations: add, subtract, multiply, and divide. Thus, problems do not require advanced mathematics. Yet in the sample of over 100 Stanford undergraduates who were administered most of the tests in Figure 2, Necessary Arithmetic Operations had one of the highest loadings on the [fluid intelligence] factor (Marshalek, Lohman, & Snow, 1983).

I meant this because of Mark’s discussion of Dr. James Flynn on the Flynn Effect. Essentially, the Flynn effect explains the large-scale increase in measured general intelligence over the 20th century as reflecting increased society-wide patterns of practice on subtests. This implies two things: first, that tests should be renormalized every so often to make sure they still measure “g,” and not practice. Second, that ability improves with practice.

It strikes me that, when properly normalized, IQ measures something psychobioneurological… perhaps not working memory exactly, but something not too far apart from that concept.

This has implications for the heritability of IQ. Most obviously, the more environment changes, the more change in performance can be traced to the environment. (Of course, as environments become more similar, more of the variation in the population will be explained by environments.)

Genetic and Environmental Causes of Human Diversity

Just because a side in an argument uses bad arguments doesn’t mean it’s wrong. By far, the least logic and most emotional rhetoric I have ever seen was in the newsgroup talk.origins in the late 1990s, where evolutionists were bufeddled and angered by the repleis of the creationists. That doesn’t mean that descent with modification by natural selection is a wrong theory. It means that the truth was weaker in its rhetoric than the false.

With that said, Stephen Metcalf’s “Dissecting the IQ Debate: A Response to William Saletan’s Series on Race and IQ” (hat-tip to The Corner and South Dakota Politics) is awful.

After a lengthy ad hominem attack, Metcalf begins addressing evidence for racial differences in IQ.


Much of Saletan’s précis of the rest of the research surveyed in “Thirty Years of Research Into Race Differences on Cognitive Abilities” is highly questionable. His takeaway regarding the “admixture” studies is precisely the opposite of what an American Psychological Association task force concluded the studies show—that more “European” blood in a black American does not make him smarter.

Pay attention here. Metcalf attacks Saletan for citing a peer-reviewed journal article, when a politically selected task force disagreed with its conclusions. No one denies the factual claims of the article: that European admixture positively correlates with general intelligence among African-Americans. Indeed, that alone is not evidence of innate racial differences. But the correlation between miscegenation and g in the population does not go away even when corrected for other variables.


Saletan points up the problems with a favorite study of the environmentalists, into the IQ outcomes of children fathered by foreign soldiers and raised by (white) German mothers. This study showed that kids with African fathers scored the same as those with white fathers. But, Saletan says, it suffers from a fatal flaw: Blacks in the military had been screened for IQ. Saletan concludes, “Even environmentalists (scholars who advocate nongenetic explanations) concede that this filter radically distorted the numbers.” But this is flatly untrue. The two most prominent environmentalists, Richard Nisbett and James Flynn, have dismissed this very objection. Both have pointed out that white soldiers were also screened, and so had higher IQs than the general white population.

This regards a study that finds Germans with African-American fathers have an IQ about that of the German population. This might be explained by the fact that the military screens for IQ, rejecting a disproportionately high number of African-Americans for that reason. The counter-argument that European-Americans were also screened is besides the point: the US Army in WWII did not engage in affirmative action. The minimum IQ level for blacks was the same as the minimum IQ level for whites.


Saletan uses a sheer volume of statistics to create an aura of gathering unanimity, but many of his statistics have been taken at face value. To take one example: Saletan casually countenances the assertion that the mean IQ of sub-Saharan Africa is 70. The number arrives to us via a man named Richard Lynn. Lynn is the author of the 1996 volume “Dysgenics: Genetic Deterioration in Modern Populations.” In “historical societies,” Lynn wrote, “illegitimate children, born predominantly to parents with low intelligence and weak character, suffered high mortality.” Until the scourge of modern medicine, such culling assured the expulsion of weaklings from the gene pool, while the “operation of positive natural selection” ensured the “reproductive fitness of the leaders and of the upper and middle classes.” The instrument Lynn used to apprehend these depressed IQ scores is a supposedly culturally unbiased exam called Raven’s Progressive Matrices. “To use an instrument developed in the West on semi and possibly illiterate people is a fool’s errand,” says Nisbett, a Distinguished University Professor at the University of Michigan who studies cognition and social psychology. “Then they use the results to say that half the people in Africa are mentally retarded. It’s laughable.”

Here, the web can help out. The table in Flynn’s book is available online. Some tests use the Raven tool, others use other tool.

The next paragraph again relies on the political summary of an APA body, and thus is unoworthy of comment.


Furthermore, the APA task force lays out—finally!—the real heart of the conflict. To understand what is really being fought over when we fight over the IQ gap between blacks and whites, its authors explain, you must think through an analogy. Imagine two wheat fields. Now imagine two genetically identical sets of seeds. (The analogy was first made famous by the Harvard evolutionary biologist and geneticist Richard Lewontin.) Now imagine each field is planted with these two identical seed stocks. Field No. 1 is given the best possible inputs: sunshine intensity, rain, soil nitrates, etc. Field No. 2 is given much less of all of the above. Within each field, inputs are kept uniform. Inevitably, the first field grows a healthier supply of grain than the second. But here is the rub: Within each field, the variation in outcomes is entirely hereditary. Between the two fields, the variation in outcomes in entirely environmental.

An excellent analogy. Using it, one would expect that environment differences, such as parent’s income, drown out genetic differences, such as race.

But that is just not so. From the original Saletan article:

My first reaction, looking at this pattern, was that if the highest-scoring blacks are those who have lighter skin or live in whiter countries, the reason must be their high socioeconomic status relative to other blacks. But then you have to explain why, on the SAT, white kids from households with annual incomes of $20,000 to $30,000 easily outscore black kids from households with annual incomes of $80,000 to $100,000. You also have to explain why, on IQ tests, white kids of parents with low incomes ­and low IQs outscore black kids of parents with high incomes and high IQs. Or why Inuits and Native Americans outscore American blacks.

But Metcalf makes it clear that he believes that living in a good neighborhood, in a good home, with high-income parents, it itself drowned out by “the legacy of American racism.”

In the absence of some startling new evidence, the crux of the issue turns out to be this: Do you believe the legacy of American racism, in all its complexity, can explain depressed black IQ scores, even when controlling for all other factors, including socioeconomic status? Is the black experience, in other words, so unique as to constitute, for nearly all black Americans, a separate wheat field? If you say yes, then good news: You believe (along with the most prominent environmentalists) that the black-white IQ gap will close in the next 50 or so years. If you think no, then bad news: You believe, with the most prominent hereditarians, that blacks as a group must resign themselves to higher rates of poverty, unemployment, divorce, and violent criminality purely as a matter of genetic fate.

Indeed. This is the first good point that Metcalf makes in the entire article.

Such a “legacy of racism” must be indirect, as it does not seem to harm either Afro-Carribeans or immigrants from Africa.

More likely, such a legacy of racism is the profoundly broken African-American culture. This, and not “racism” as its commonly conceived, is the explanation that James Flynn and other environmentalists look for. And perhaps they are right.

But there is another explanation: as immigrant populations, both Afro-Carribeans and immigrants from Africa are self-selected: moving to a new country is dangerous, especially when it means weakening the strong family ties back home. It requires a special something — a something that can include general intelligence — to go through the time-consuming and dangerous immigration process. Perhaps the reason that black immigrants from Africa and the Carribean do better than African Americans on so many measures is precisely genetic.

General intelligence, working memory, and how American Public Schools hurt those who need them most

Colom, R., Rebollo, I., Palacios, A., Juan-Espinosa, M., & Kyllonen, P.C. (2004). Working memory is (almost) perfectly predicted by g. Intelligence, 32(3), 277-296. doi:10.1016/j.intell.2003.12.002.

Andrew Sullivan, Ezra Klein, Half Sigma, and other bloggers of note are going around on the question of the heritability of intelligence in general, and the possibility of biological causes for the differences in general intelligence obsered in different groups. While occasionally people speak carelessly, it’s remarkable how far the Standard Social Sciences Model (SSSM) of all human differences being the result of different environments has already collapsed. There are three traditional ways to attack the notion in biologically-driven racial differences in general intelligence

  1. There is no such thing as general intelligence
  2. There are no such things are races
  3. The environmental conditions in which the races tend to exist are unequal

The first two criticism are discredited. One can deny g or ancestry in the same way that one can deny darwinian selection or the old Earth: through determined dogmatism.

The third criticism remains, if only because of the horrifying inequalities in the world today. Of course, environmental inequalities can rapidly turn into biological inequalities. One only needs to look at the Inbred Gap to know that. Yet it’s also true that one can be trained to perform better on any subset of tests that are used to measure general intelligence. Thus the Flynn Effect: this or that measure will suddenly deviate from the rest, causing illusionary growth or shrinkage in differences.

One measure that very closely approximates g (“(almost) perfectly predicts,” in the word of the paper’s excited authors) is working memory.

This article analyzes if working memory (WM) is especially important to understand g. WM comprises the functions of focusing attention, conscious rehearsal, and transformation and mental manipulation of information, while g reflects the component variance that is common to all tests of ability. The centrality of WM in individual differences in information processing leads to some cognitive theorists to equate it with g. There are several studies relating WM with psychometric abilities like reasoning, fluid intelligence, spatial visualization, spatial relations, or perceptual speed, but there are very few studies relating WM with g, defined by several diverse tests. In three studies, we assessed crystallised intelligence (Gc), spatial ability (Gv), fluid intelligence (Gf), and psychometric speed (Gs) using various tests from the psychometric literature. Moreover, we assessed WM and processing speed (PS). WM tasks involve storage requirements, plus concurrent processing. PS tasks measure the speed by which the participants take a quick decision about the identity of some stimuli; 594 participants were tested. Confirmatory factor analyses yielded consistently high estimates of the loading of g over WM (.96 on average). WM is the latent factor best predicted by g. It is proposed that this is so because the later has much in common with the main characteristic of the former.

Working memory allows you to make sense of information, so that you can remember it. It is most important in that it makes it easier to memorize things. This also explains why school appears to lower general intelligence of high-performing populations, such as Chinese: if you are in an environment where high academic achievement is socially punished, excess working memory capacity naturally atrophies. Similarly, this may explain why the heritability of g increases in life: once out of the socialized public schools, an individuals’ environment is more under his control, and an individual that enjoys tasks that involve the comprehension of complex materials will strengthen those neural connections more.

If g really is working memory, the educational implications are huge. The soft bigotry of low expectations is especially brutal to those apparently with low working memory capacity. Because working memory does not matter once a task is memorized. Memorization is the way-out of the trap of low working memory. And what’s needed for memorization is clear: practice, academic discipline, and practice. Yet who believes that fifty years after Brown v. Board of Education most majority-black schools are models of academic seriousness and discipline?

Even more tragic — if the link between general intelligence and working memory is strong — working memory is trivially easy to test. There’s no need for race-conscious policies at all to battle what may be the worst racial inequality through education. We could close much of the achievement gap, regardless of average biological differences between races.

Instead, we have America’s public schools.

Global Guerrillaism or Idiocy?

There’s an ongoing debate about low intelligence, environmental instability, and the livint standards of a country. It’s worth reading about, but I will set that aside to re-join the discussion on global guerrillas, with my friends Schloky, Soob, and others.

I’ve criticized global guerrilla theory before. It is unfalsifiable, lacks metrics, and lacks any explanation of why someone would become a global guerrilla. About the only thing going for the theory is that there are “failed states” and “hollow states” in the world. Global guerrillas would want to create hollow states, so the argument goes, therefore, these hollow states may have been caused by global guerrillas.

Of course, this is like arguing in favor of aliens by saying there are lights in the sky. And it can be combated in the same way. The “alien hypothesis” for UFOs is not taken seriously because far more boring explanations (misidentified planets, military craft, etc.) work equally well. Likewise, the “global guerrilla” explanation for failed states falls because something far more obvious prevents societies from being stable.

Take, for example, Africa… a continent riddled with failed states since decolonization.

The African Gap

According to the latest failed states index, the hollowest countries in Africa are Sudan, Somalia, Zimbabwe, Chad, Ivoery Coast, Congo, Guinea, Central African Republic, Uganda, and Nigeria. An evidence of a global guerrilla swam? Hardly: the mean intelligent quotients of these countries are 72, unreported, 66, unreported, unreported, 65,59, unreported, 73, and 67.

Why don’t African states get better? Because the population, on the whole, has the intelligence of 12-year-olds.

Intelligence, besides making one “smarter,” is correlated with the ability to delay gratification and the ability to solve problems — precisely those skills needed for civilized life

To be persuasive, global guerrilla theory needs to explain failed states in a way better than other explanations. Lack of intelligence, combined with economic structure, alone is enough to explain most failed states. So why bother with “global guerrillas”?

Update: Tom adds his thoughts.

Askhanazim Jewry, g, and Higher Education

Askhanazim Jewry, g, and Higher Education

Jaschik, S. 2007. ‘The Power of Privilege.’ Inside Higher Ed. April 11, 2007. Available online: http://insidehighered.com/news/2007/04/11/soares.

A treasured friend & trusted reader sent this article in, which discusses possibly antisemitic reasons for the introduction of the SAT test in Yale University. The piece spends a lot of time on the quirks of the New Haven, Connecticut school, so I’ll just quote one part of it and talk in more general terms:

If colleges more closely understand their histories, Soares said, they might be more likely to adopt truly progressive policies today. His book ends with a series of recommendations along those lines, not just for Yale, but for other elite colleges. He calls for affirmative action policies based on socioeconomic status, a de-emphasis on standardized testing, and the elimination of preferences that defy true meritocracy (such as those for legacies and athletes).

Favoring athletes, he said, makes very little sense if talking about the social mission of higher education. Even at top universities, this has become “the doorway in,” and counter to the images many people have of athletics as a pro-diversity force on campuses, most of the beneficiaries are white. “What is it that athletics contributes to higher education? Why is it a part of higher education?” Perhaps showing the impact of his Oxford history, Soares noted that the admissions preferences offered by top American colleges make no sense to educators anywhere else in the world. “At Oxford and Cambridge, you are not going to be admitted just because you are good on the rugby field.”

Trying to discriminate against Jews by factoring in g (general intelligence would be odd, as Ashkenazim (“northern European”) Jews apparently have higher average g than most other races. This seems to be a result of intense selection pressure on Jews in the past thousand years, as cruel and mean regimes adopted policy after policy to limit Jewish mobility, wealth, and reproductive success. Average- and below-average Jews were selected against, while above-average Jews were selected for, by the European environment relative to other Europeans.

Thus, institutions of higher education used a variety of methods to keep Jews out, by defining merit as something other than general intelligence. From a century ago, Eastern universities used the idea of the “whole man” to discriminate against Jews. Because Jewish cultural traditional is relatively unathletic, Jewish history in Europe kept them seperated from the land and much physical exertion, and relatively higher rates of historical inbreeding (owing to ghetto living conditions), Jews were at a disadvantage under the “whole man” criteria. Likewise, modern affirmative action is a method of limiting the success of Jews and other market-oriented minorities.

See also: My series on feminism, leftism, and cash, covering the SAT and computer science.

Leftism, Feminism, and Cash

Agnostic. 2007. New GRE cancelled – the cost of attempted gap-reduction? Gene Expression. April 4, 2007. Available online: http://www.gnxp.com/blog/2007/04/new-gre-cancelled-cost-of-attempted-gap.php.

First, an excerpt from the excellent blog piece. Then a short discussion by me:

The NYT reports that a completely revised GRE has been deep sixed, not merely delayed (read the ETS press release here). The official story is that there is some insurmountable problem with providing access to all test-takers, an issue apparently too complicated for ETS to bother trying to explain it to us. You figure, since this was such a huge project that was suddenly halted, they’d want to clearly spell out why they dumped it — unless that’s the point. Although I’m no mind-reader, the true reason is pretty obvious: the made-over test was designed to narrow the male-female gap at the elite score level, but this diluted its g-loadedness such that it couldn’t reliably distinguish between someone with, say, a 125 IQ and a 145+ IQ, which is what graduate departments who rely on super-smart students worry about. Rather than admit that this psychometric magic trick went awry and lopped off a few limbs of g-loadedness, they spun a yarn about access to the te


We now ask why ETS intentionally stripped the SAT of some of its g-loadedness? Certainly not because they discovered IQ had little value in predicting academic performance, or that some items tap g more directly than others — so why re-invent the wheel? Since scores on various verbal tasks highly correlate, this change cannot have affected much the mean of any group of test-takers. But if getting a perfect score required scoring correctly on, say, 10 easy questions, 5 medium, and 5 difficult (across 3 sections), a greater number of above-average students can come within striking distance of a perfect score if the new requirement were 10 easy, 9 medium, and 1 hard. I don’t know exactly how they screwed around with the numbers, but that’s what they pay their psychometricians big bucks to do. Now, reducing the difficulty of attaining elite scores, without also raising mean scores (as with the 1994 recentering), can only have had the goal of reducing a gap that exists at the level of variance, not a gap between means. This, then, cannot be a racial gap but the male-female gap, since here the difference in means is probably 0-2 IQ points, although male variance is consistently greater.

In other words..

  • Some time ago, the SAT released a new test that kept the pre-existing group means (so that jews still scored higher than scotch-irish, and that asians still scored higher than blacks) but made it easy for pretty-good students to score the same as very-good students
  • The GRE seriously considered, openly planned on, announced, and then suddenly rejected a similar plan.

Ultimately, this is a tale of political correctness and money. Especially since fired Harvard President Larry Summers publicly asked if there was a genetic component to sexual differences, but since the birth of feminism in the early 20th century, the “polite” opinion is that males and females are genetically identical and apart from a few organs the sexes are in no way different. Thus intelligence testing, which consistently reveal that the highest-scoring males have higher intelligence than the highest-scoring females, is embarrassing. While the SAT and the GRE are technically aptitude tests, they are also rough measures of intelligence so the same issues that impact IQ testing impact the SAT and GRE.

The easy way to remove this shame is to ignore it, so the SAT lowered the bar for the highest-scoring students. Thus the highest-scoring females would score exactly the same as the highest scoring males – with a perfect 2400R.

For undergraduate schools this is just fine. Anything that increases the student body size while avoiding public embarrassment puts money into the hands of the Universities,. Likewise, compared to graduate schools undergrad institutions tend to be non-competitive (excluding quotized areas sex as race, where it is hard to change race from penalized categories such as oriental or white to preferred categories such as black or indian). Thus, the SAT combined easy leftism with easy commercialism: the change stands!

For graduate schools this is not fine. Graduate students are investments in ways that undergrads just aren’t. Grad students take up more of professors’ face time, often have the responsibility of assisting in research or teaching undergraduates, and are actually paid. Thus a non-productive grad student can more easily become a cash dog than can a non-productive undergrad. There, within grad schools capitalism defeated easy leftism: the change is rejected!

Update: Darth Quixote at gnxp examines the results of the latest SAT.