May 20, 2009

Review of Nisbett's IQ book

16 comments:

Anonymous said...

Neat.

Melykin said...

"...One of us (JPR) traveled to South Africa to collect new IQ data from highly-select Black students at the prestigious University of the Witwatersrand in Johannesburg. Seven independent studies were published yielding a median IQ of 84 (range 77 to 103). Assuming that African university students score 1 SD (15 IQ points) above the mean of their population, as university students typically do, a median IQ of 84 is consistent with a general population mean of 70...."-------------------------------

Because there is sidespread corruption in the education system in Africa, I don't think it should be assumed that all, or even most, of these students in these universities got there because of merit. This is a serious problem in many countries, and likely contribute to the dysfuntional nature of these countries.

Mark Wethman said...

Pretty devastating.

ben tillman said...

Rushton and Jensen embarrass themselves:

Building on this line of argument, Dickens and Flynn [19] presented analyses in 2006 to show that in the US, the 15-point IQ gap between Blacks and Whites narrowed by 5.5 points between 1972 and 2002.... As Nisbett [5, p. 100] stated, it reduces the ratio of Whites to Blacks with an IQ of 130 (the level needed to be a highly successful professional) from of 18 to 1 to only 6 to 1.The ratio of blacks to whites in the US is 5:1. Even if whites had an average advantage of just 10.5 points indtead of 15 points, thye "the ratio of Whites to Blacks with an IQ of 130" would be significantly higher than 6:1.

Anonymous said...

Could you yourself summarize and review the review for us laymen?

albertosaurus said...

Rushton and Jensen complain that they have been writing the same arguments for forty years. I know. I have been reading these same arguments for forty years.

Arthur Jensen is a smart guy. How much better the world might have been if the world had just accepted his reasoning about education in 1968. He wouldn't have have been stuck in this endless pointless debate with intellectually dishonest boobs.

Jensen might then have done something more fruitful with his life. At some point the world must acknowledge the reality of racial differences in IQ. On that happy day we can at last get started on developing rational social and educational policy. Alas we do not seem any closer to that day than we were forty years ago. We remain in a cycle of denial.

Josh said...

"ben tillman said...
Rushton and Jensen embarrass themselves:

Building on this line of argument, Dickens and Flynn [19] presented analyses in 2006 to show that in the US, the 15-point IQ gap between Blacks and Whites narrowed by 5.5 points between 1972 and 2002.... As Nisbett [5, p. 100] stated, it reduces the ratio of Whites to Blacks with an IQ of 130 (the level needed to be a highly successful professional) from of 18 to 1 to only 6 to 1.The ratio of blacks to whites in the US is 5:1. Even if whites had an average advantage of just 10.5 points indtead of 15 points, thye "the ratio of Whites to Blacks with an IQ of 130" would be significantly higher than 6:1."

You should email them with any suggestions, as they say comments are welcome. It's sad that Nisbett has to be so deceptive to get a book out.

*E-mail: rushton@uwo.ca
Email: Nesnejanda@aol.com

Blode0322 said...

ben tillman, could you rephrase that? What should their numbers be? At first blush, it looks like somebody is taking population size into account (how many of a given race of a given IQ in the population) and somebody isn't (how likely an individual is to be of a given IQ).

Anonymous said...

After reading that, it's obvious one side in this argument is being terribly dishonest. This cannot be attributed ignorance.

Ivy said...

And I'm sure the New York Times will post a lengthy and comphrensive summary of Rushton and Jensen's paper, right?

Hilarious how eager the race denialists are to believe their own crap. This is a group of people who use a study from 1951 (the Eyferth study that clearly has a misrepresentative sample of blacks) as their best data. If that isn't good enough, they'll find incredibly minor flaws in the Bell Curve or other important work for the herediatarian side. Of course, these tactics are ineluctably concurrent with accusations of racism.

It's so funny how simple the debate can be resolved. Look at the US Military (ASVAB) average racial scores from 1917 to the 1980's. During this time period, it's absolute fact that educational opportunities, quality of life, and social standing vastly improved for blacks. Yet, the black-white gap has remained almost entirely constant despite this HUGE improvement in environment. Of course, this is reflected in the notion that some biological cause (which is generally associated with g) creates the racial gap. Somehow, the reality deniers seem to ignore this very simple argument. You don't need factor analysis or a PhD to understand the above.

pzed said...

rushton and jensen are misrepresenting nisbett from the first sentence. nisbett hasn't claimed he thinks iq is 100% culture only. he's only gone so far as to say genetics is "something less than 50 percent." saying iq <= 49% is a far cry from saying iq = 0% genetic.

rushton and nisbett really disagree on degree.

Blode0322 said...

rushton and jensen are misrepresenting nisbett from the first sentence. nisbett hasn't claimed he thinks iq is 100% culture only. he's only gone so far as to say genetics is "something less than 50 percent." saying iq <= 49% is a far cry from saying iq = 0% genetic. - pzed

Naw, I think there are two different possible statements which are easy to mistake for one another:

"The differences between the IQ of one individual and another are entirely caused by environment/culture." As far as I know none of the scientists are saying this; presumably they've all heard of Down Syndrome. (I do know plenty of leftist-on-the-street types who believe this.)

"The differences between the average IQ of one ethnic group and another are entirely caused by environment/culture." AFAIK this is Nisbett's position (though I am quoting Wikipedia, not a primary source, so take this with a grain of salt): "There is not a shred of evidence in this literature, which draws on studies having a total of five very different designs, that the gap has a genetic basis."

Summing Nisbettism up as "IQ is all environmental!" is incorrect, but Rushton and Jensen haven't done this. They sum his position up in two sentences, first talking about "observed mean ethnic group differences" and then talking about Nisbett's position "that cultural factors alone are sufficient to explain" them. There contention that group differences are 50-80% heritable is almost compatible with Nisbett's position that (unspecified) differences are less than 50% derived from genetics, but not with his "not a shred of evidence" contention.

Anonymous said...

Two sentence summary for those who didn't or won't read the paper.

Nisbett: However, a study from X has shown that the differnces here are not in fact differences or were completely the result of environment.

Rushton and Jensen: Nisbett claims Z, using study X, but he forgets to include studies A, B, C, D and F, which exactly contradict his conclusion and support ours. Morevever, his study X was done using questionable methodolgy, as we will now explain.


Steve, maybe you could give your opinion here to help sort this out. Does this paper accurately represent the facts as you understand them?

Pat Shuff said...

Heady Theories on the Contours of Einstein's Genius

Author's comment in comment section: "Very good point. In my column, I note that brain size by itself is no measure of intelligence. In fact, Einstein's brain was smaller overall than most. Stephen Jay Gould wrote a masterful book called the Mismeasure Of Man about the wrong-headed use of measures of cranial capacity and such to prove the supposed superiority of one or another racial or national group. I included a link to his book, and others, with my column.

http://tinyurl.com/phban2

TH said...

rushton and jensen are misrepresenting nisbett from the first sentence. nisbett hasn't claimed he thinks iq is 100% culture only. he's only gone so far as to say genetics is "something less than 50 percent." saying iq <= 49% is a far cry from saying iq = 0% genetic.

rushton and nisbett really disagree on degree
.

Nisbett argues that the heritability of IQ within a population is substantial but less than 50%. He also thinks that the the heritability of IQ differences between races is zero. Rushton & Jensen disagree on both accounts.

Josh said...

Pat Shuff,

If you read the paper Rushton & Jensen note that Einstein was aged 76. If you compared the size when he was in his 20's it would be quite different.

Also, are you kidding about Gould's 'Mismeasure of Man' book? His comments regarding brain size were incorrect at the time and subsequent research has further shown this.

As long ago as the 1980's, there was a clear correlation between the physical size of a brain (as measured carefully by NMR) and IQ. Twin studies are overwhelmingly clear that genetics are at least 50% responsible for differences in intelligence.

Modern MRI imaging has confirmed a positive correlation. Recently Richard Haier, at Brain Research Institute, UC Irvine College of Medicine, found that general human intelligence appears to be correlated with the volume and location of gray matter tissue in the brain.

See this article in New Scientist dated 11 March 2009, discussing the recent twin studies on myelination & intelligence:

" By comparing brain maps of identical twins, which share the same genes, with fraternal twins, which share about half their genes, the team calculate that myelin integrity is genetically determined in many brain areas important for intelligence. This includes the corpus callosum, which integrates signals from the left and right sides of the body, and the parietal lobes, responsible for visual and spatial reasoning and logic (see above). Myelin quality in these areas was also correlated with scores on tests of abstract reasoning and overall intelligence (The Journal of Neuroscience, vol 29, p 2212).

Just because intelligence is strongly genetic, that doesn't mean it cannot be improved. "It's just the opposite," says Richard Haier, of the University of California, Irvine, who works with Thompson. "If it's genetic, it's biochemical, and we have all kinds of ways of influencing biochemistry."

http://www.newscientist.com/article/mg20126993.300-highspeed-brains-are-in-the-genes.html?DCMP=OTC-rss&nsref=online-news

"In healthy adults, greater intelligence is associated with larger intracranial gray matter and to a lesser extent with white matter. Variations in prefrontal and posterior temporal cortical thickness are particularly linked with intellectual ability." Cerebral Cortex 2007 17(9):2163-2171

The differences are seen in children's brain development:

"The researchers found that the relationship between cortex thickness and IQ varied with age, particularly in the prefrontal cortex, seat of abstract reasoning, planning, and other "executive" functions. The smartest 7-year-olds tended to start out with a relatively thinner cortex that thickened rapidly, peaking by age 11 or 12 before thinning. In their peers with average IQ, an initially thicker cortex peaked by age 8, with gradual thinning thereafter. Those in the high range showed an intermediate trajectory (see below). While the cortex was thinning in all groups by the teen years, the superior group showed the highest rates of change."

http://www.medicalnewstoday.com/articles/40646.php