Big Think

M Stein on November 17, 2009, 5:39 PM

So, for instance, he holds that IQ tests predict future success***

There is a load of data showing this in relation to academics, job performance (particularly more complex jobs), health outcomes, and other socio-economic outcomes. This is at a group level – for instance a group who average 90 will have poorer outcomes on those indicators than a group who average 110.

Pinker believes IQ tests measure differences that are largely genetic. Other psychologists disagree.*

You link to an NY Times piece by Richard Nisbett. Nisbett’s article and similar comments in his recent book have been heavily critiqued in a recent review by James J Lee (Personality and Individual Differences Volume 48, Issue 2, January 2010, Pages 247-255).

The paper is pay only access, so here is a summary:

“Here’s my quick outline of the main points of the review:

1.1 Twin studies
1.1.1 Selective placement
Nisbett’s evidence is cherry-picked.

1.1.2 Biometrical models
Nisbett forgot that IQ heritability (like weight heritability, etc.) increases with age.

1.1.3 Genetic effects mediated by physical appearance
Nisbett thinks that twins raised apart have similar IQ because they look the same and people therefore treat them similarly. A study looking for correlation between physical attraction and IQ does not bear this out. And even if Nisbett is right on this, it would still leave IQ out of our control since we can’t make people (much) prettier.

1.1.4 Non-additive gene action
It’s almost all additive though…

1.2 Adoption Studies
1.2.1 Restriction of range
Nisbett claims that poorer families are inadequately sampled in adoption studies. Actually looking at the data for evidence of this effect comes up dry.

1.2.2 Adoption studies in France
Nisbett likes a particular group of studies that give him the answer he wants. Once again, he ignores the point that IQ heritability increases with age.

1.3 The relation between heritability and malleability
1.3.1 Environmental engineering
Sure, we could make IQ higher with the right environment. Just like we could cure Alzheimer’s or cancer with the right environment. It would help if we knew how though…

1.3.2 Genetic engineering
Nisbett says we can’t do this because it would take too long.

2 Racial differences
2.1 Stereotype threat
Stereotype threat evidence, despite all the theory, continues to be soft and wishy-washy.

2.2 Secular trends
The Flynn Effect could explain everything about the black-white IQ difference. But the closer we look, the less it appears to have to do with it.

2.3 Black and biracial children reared by European parents
Nisbett cherry-picks data from an ambiguous crowd of studies. He ignores data from studies that he uses when it contradicts his points.

2.4 “Direct” evidence of association between African ancestry and IQ

Nisbett uses unreliable studies for his evidence. Doesn’t matter, because before long we’ll have direct SNP evidence on this point, which will settle things one way or the other."

Pinker believes IQ tests measure differences that are largely genetic. Other psychologists disagree. Pinker believes we can map a line from genes to behavior.

M Stein on November 17, 2009, 5:49 PM

Pinker believes IQ tests measure differences that are largely genetic.*

Pinker isn’t alone – recent twin studies by UCLA neuroscientist Paul Thompson also suggests this, as reported here in MIT Technology Review:

“The new study is among the first to link a specific neural architecture to IQ in healthy individuals. “Most people have focused on grey matter,” says Shaw. “This is good evidence we should be looking at white matter as well.” Previous studies using DTI have linked white matter damage to Alzheimer’s disease, chronic alcoholism, and traumatic brain injury.

The UCLA researchers took the study a step further by comparing the white matter architecture of identical twins, who share almost all their DNA, and fraternal twins, who share only half. Results showed that the quality of the white matter is highly genetically determined, although the influence of genetics varies by brain area. According to the findings, about 85 percent of the variation in white matter in the parietal lobe, which is involved in mathematics, logic, and visual-spatial skills, can be attributed to genetics. But only about 45 percent of the variation in the temporal lobe, which plays a central role in learning and memory, appears to be inherited."

http://www.technologyreview.com/biomedicine/22333/page2/

Thompson & Yale’s Jeremy Gray also wrote a paper a few years ago summarizing the neurobiology of intelligence.

www.loni.ucla.edu/~thompson/PDF/nrn0604-GrayThompson.pdf

Also twin studies generally show a significant level of heritability for cognitive ability:

“Data from more than 8000 parent-offspring pairs, 25,000 sibling pairs, 10,000 twin pairs and adoption studies provide evidence that genetic factors play a substantial role in the variation of general intelligence, with heritability estimates ranging from 40 to 80%”

—Burdick et al, Cognitive variation in DTNBP1 influence general cognitive ability. Human Molecular Genetics, 2006, Vol 15, No. 10.

“Multivariate genetic analyses indicate that general intelligence is highly heritable, and that the overlap in the cognitive processes is twice as great as the overall phenotypic overlap, with genetic correlations averaging around .80.”

Plomin et al (2004) “A functional polymorphism in the succinate-semialdehyde dehydrogenase genes is associated with cognitive ability,” Molecular Psychology 9, 582-586.

M Stein on November 17, 2009, 5:59 PM

I’ll just add Steve Hsu’s observation about the use of psychometrics:

“What Pinker refers to as the major claim of Outliers: IQ above 120 doesn’t matter, is easily shown to be false. Randomly selected eminent scientists have IQs much higher than 120 and also much higher than the average science PhD (120-130); math ability within the top percentile measured in childhood is predictive of future success in science and engineering; advanced education and a challenging career do not enhance adult IQs relative to childhood IQ.

So, accomplished scientists tend to have high IQs, and their IQs were already high before they became scientists — the causality is clear. 10,000 hours of practice may be necessary but is certainly not sufficient to become a world class expert.

I recently remarked to a friend that many aspects of psychometrics which were well established by the 1950s now seem to have been completely forgotten due to political correctness. This leads to the jarring observation that recent social science articles (the kind that Gladwell is likely to cover) are sometimes completely wrong headed (even, contradicted by existing data of which the authors are unaware) whereas many 50 year old articles are clearly reasoned and correct. The data I cite in the links above comes from the Roe study of eminent scientists and the Terman longitudinal study of gifted individuals, both of which were conducted long ago, and the SMPY longitudinal study of mathematically precocious youth, which is ongoing. I’ve interacted with many social scientists whose worldview is inconsistent with the established results of these studies, of which they are unaware."

http://www.technologyreview.com/blog/post.aspx?bid=354&bpid=24410

M Stein on November 17, 2009, 6:44 PM

Those results don’t eliminate the possibility that there are biologically-based gender differences in math ability, even at the extreme high end of the scoring curve (which is what Summers wanted to talk about). But they certainly do show it’s too early to say for sure that male-female test gaps must be due to genetics. That’s not a political point. It’s a scientific one.*

What’s your point here? You said earlier that Summers only suggested it might be due to genetics – which is simply a scientific hypothesis.

that I believe there’s a temperamental difference (maybe it’s genetic!) between people who like science for its certainties and those who like it for its surprises. Pinker’s writing always made me think he’s at one extreme of the distribution, which shouldn’t bother anyone — until he starts claiming that there is no other end. The way he tells people to beware of Gladwell makes me wary of him.*

I think this criticism of Pinker is way off base. Pinker is totally open to surprises, but those are based on logic and evidence. And it is in terms of logic & evidence that Pinker finds Gladwell is overstating things – going beyond the empirical evidence – to suit his narrative.

Consider his claim about math skills and rice growing. Gladwell totally avoids adoption studies. If Asian academic success was really due to some special set of academic values inculcated by Asian parents (something not demonstrated by the data to begin with), then why do Asians do better academically than whites even when they are raised by white parents?

Transracial, same-race adoptions, and the need for multiple measures of adolescent adjustment. (Burrow, Anthony L.; Finley, Gordon E. American Journal of Orthopsychiatry. Vol 74(4), Oct 2004, 577-583.

http://www.gnxp.com/MT2/archives/004064.html

Orion Jones on November 17, 2009, 7:45 PM

Well, my reading of the article raises a much simpler point than above.

Even if David Berreby knows whether Pinker or Gladwell is right, the thrust of the article recognizes a pretty scientifically grounded debate between the two. Given that, even if the scientists at Harvard disagreed with Mr. Summer’s views, which are apparently close to Pinker’s, it is not grounds for dismissal (as proof, Pinker himself teaches at Harvard). Summers was dismissed for political reasons, or political correctness reasons.

When our highest learning institutions (in terms of who will have access to power) are vulnerable to politically motivated attack, they are not doing what they are meant for: shining light onto presently dark areas of research and meanwhile opening minds wide enough to allow for unthought-of possibilities.

David Berreby on November 19, 2009, 12:40 PM

It’s no endorsement of witch-hunters to say that non-witch-hunters also disagreed with Summers. I said some scientists thought he was wrong. I didn’t say they thought he should lose his job.

(In fact, Summers was canned because of his lousy political skills, which made the gender uproar both the last straw for Harvard and a pretext for his resignation. To say he was driven out for this one statement is inaccurate and naive.)

The PC attack on Summers was ridiculous. Why? It was all about roping off a subject so that debate can’t take place — in a place that should be dedicated to that debate. Pinker’s attack on Gladwell seems to me similar in spirit: We shouldn’t have to listen to this guy, he’s anti-intellectual, and anti-science. Nailing Gladwell for glibness and superficiality on the specifics is fair and helpful. But saying he’s a ``populist’’ is tantamount to saying he hasn’t got any place in the conversation at all. That’s different.

I don’t see how it serves a controversial topic in science to insist that it isn’t controversial. That’s the point of my post. I wasn’t saying Pinker is alone or surely wrong. I was just saying his claims for today’s analytical methods are not shared by all psychologists, nor by all biologists, nor by all scientists.

The idea that there are ``genes for’’ behavior, for example, stimulates many interesting hypotheses, but ``let’s assume x and see where it leads’’ is very different from ``x is true.’’

As Simon Fisher put it here (Cognition 101(2): 270-297, September 2006): `` [T]he deceptive simplicity of finding correlations between genetic and phenotypic variation has led to a common misconception that there exist straightforward linear relationships between specific genes and particular behavioural and/or cognitive outputs. The problem is exacerbated by the adoption of an abstract view of the nature of the gene, without consideration of molecular, developmental or ontogenetic frameworks.’’ Is this populism?

Why do Asians do better academically than whites even when the Asians are raised by white parents? I’d guess it’s because Americans expect Asians to do well academically.

This could be tested by comparing the test scores of Asians raised by whites in Asia with those Asians raised by whites in North America. According to one of the commenters, those scores should be the same. I’d expect them to be different. Because in the U.S. Asian academic effort takes place in the context of expectations about ``Asians.’’

An only-in-America racial category, by the way — in Japan it’s people of Korean ancestry who have lower test scores than their fellow-students. And Koreans in Korea score better than ethnic Koreans in Japan. Doesn’t make sense if scores reflect genetic differences in populations. Does make sense if scores reflect the effect of social status on performance.

M Stein on November 19, 2009, 5:31 PM

Steven Pinker replies:

What Malcolm Gladwell calls a “lonely ice floe” is what psychologists call “the mainstream.” In a 1997 editorial in the journal Intelligence, 52 signatories wrote, “I.Q. is strongly related, probably more so than any other single measurable human trait, to many important educational, occupational, economic and social outcomes.” Similar conclusions were affirmed in a unanimous blue-ribbon report by the American Psychological Association, and in recent studies (some focusing on outliers) by Dean Simonton, David Lubinski and others.

Gladwell is right, of course, to privilege peer-reviewed articles over blogs. But sports is a topic in which any academic must answer to an army of statistics-savvy amateurs, and in this instance, I judged, the bloggers were correct. They noted, among other things, that Berri and Simmons weakened their “weak correlation” (Gladwell described it in the New Yorker essay reprinted in “What the Dog Saw” as “no connection”) by omitting the lower-drafted quarterbacks who, unsurprisingly, turned out not to merit many plays. In any case, the relevance to teacher selection (the focus of the essay) remains tenuous.

http://www.nytimes.com/2009/11/29/books/review/Letters-t-LETSGOTOTHET_LETTERS.html?_r=1

M Stein on November 19, 2009, 6:12 PM

“I’d guess it’s because Americans expect Asians to do well academically.”

I wonder though why they expect them to do well though? Note that Asians who initially came to America were labourers, and in Brazil japanese were brought over as indentured labour. However, today they outperform other groups on average.

The things that make me suspect there is also a significant hereditary aspect is that there are also differences on reaction time measures which correlate with ‘g’ and there are differences in average brain size from birth (Whole-brain size and general mental ability: A review. International Journal of Neuroscience, 119, 691-731).

David C Rowe also did a large study including 8,582 whites, 3,392 blacks, 1,766 Hispanics, and 906 Asians. None of the analyses required a minority-unique developmental process or a cultural-environmental Factor X to explain the correlations between the achievement variables and the environmental variables in either of the minority groups.

“The results are consistent with the default hypothesis, as explained by Rowe et al: “Our explanation for the similarity of developmental precesses is that (a) different racial and ethnic groups possess a common gene pooi, which can create behavioral similarities, and that (b) among second-generation ethnic and racial groups in the United States, cultural differences are smaller than commonly believed because of the omnipresent force of our mass-media culture, from television to fast-food restaurants. Certainly, a burden of proof must shift to those scholars arguing a cultural difference position. They need to explain how matrices representing developmental processes can be so similar across ethnic and racial groups if major developmental processes exert a minority-specific influence on school achievement.”

Rowe et al (2004) Psychological Review, 101, 396-413.

M Stein on November 19, 2009, 6:13 PM

Sorry that should be Rowe (1994).

I do agree though that even given genetic influences your point about social conditions is still relevant. They could well play a role in whether people perform to their potential, and may explain the Korean in Japan data.

Orion Jones on November 21, 2009, 9:30 AM

Actually, you said that the Harvard scientists who took exception to Mr. Summers’ view about genes determining behavior were his “roasters”. Likewise you said he was “roasted” for his statement about women’s presence in the top ranks of science. But thank you for clarifying what you meant.

Mathew Crawford on December 7, 2009, 2:05 AM

“An only-in-America racial category, by the way — in Japan it’s people of Korean ancestry who have lower test scores than their fellow-students. And Koreans in Korea score better than ethnic Koreans in Japan. Doesn’t make sense if scores reflect genetic differences in populations. Does make sense if scores reflect the effect of social status on performance.”

No! This is terrible reasoning. Asians who move to the U.S. are subject to an immense selection bias that is demonstrably correlated to IQ. For this reason we should expect genetic lines of Chinese Americans to have higher IQs than Chinese in China. And this is in fact the case.

That Koreans in Japan have lower IQs could simply reflect a selection bias in Koreans who immigrated to Japan. Two of the biggest populations to immigrate to Japan from Korea include people seeking jobs to care for the aging population and subpar students who are crowded out of the Korean educational system. So, a lower IQ is exactly what we should expect of Koreans in Japan relative to Koreans in Korea…on a genetic basis.

You came to your conclusion without consideration of other possibilities.