Highest IQ???


by Dooga Blackrazor
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Monique
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#91
Jul7-04, 11:49 AM
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What I'd like to see is a study that compares correlation of IQ scores of monozygotic twins raised apart to correlation of IQ scores of unrelated matched individuals.
selfAdjoint
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Jul7-04, 11:52 AM
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There is a major new paper on the physical correlates and heritabilitiy of g.

See the summary at GNXP, and then follow the link there to read the whole PDF file. To all those people who claim IQ and g are fictions, here's the evidence they are real.

And Monique, it's not very productive at this late date to quote Gould's Mismeasure of Man against Jensen. That book has been shown by professionals to be tendentious and misleading. It's agit-prop, not science.
Monique
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Jul7-04, 12:09 PM
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I agree cognitive abilities can be inheritable.

But you have to agree that the effect is most clear in MZ twins, less clear in DZ twins, even less clear in siblings, disappearing in cousins. So how would you justify extending MZ twin data to a whole population.

I will believe data on restricted purified groups, not on undefined populations such as Asians and whites.
shonagon53
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Jul7-04, 12:10 PM
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Quote Quote by selfAdjoint
It's agit-prop, not science.
I just read your article. If that isn't agit-prop, then what is.

It's full of subjective appreciations and bold statements which are open for ideological debate. It's a highly political article, using a warrior tone and a combattant style of reasoning.


Just one quote (about the ideological relevance of HapMap):

"We will know that we are triumphant when educated people believe that human genetic differences matter and they matter intensely."

-Now that's the tautology of the matter: the HapMappers will need a lot of lobbying to shove that up "educated people's" throats. They believe what they want to believe. (They use the word "believe" themselves.)

-For me, and for many "educated people" (they're called "nihilists" by the HapMap fundamentalists) genetic differences are so small, that they don't matter very much; the equality is far greater and far more important.

Deciding how "intensely" they matter is a purely social, cultural, political and ideological matter.

Sorry, no escape from politics on this one.

You know, many educated people (the ones who will be triumphant) have read Fukuyama's "Our Posthuman Future" and they understand the basic fact that whenever you're trying to assess the "importance" of genetic differences, you're out of science and into politics.
Tigers2B1
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Jul7-04, 12:43 PM
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Quote Quote by Monique
What I'd like to see is a study that compares correlation of IQ scores of monozygotic twins raised apart to correlation of IQ scores of unrelated matched individuals.
Well - here is a chart (linked below) showing IQ results and the correlation with the degree of genetic relatedness (including unrelated individuals) -

Note that this guy doesn’t appear to be an advocate based on the subscript -- so, I suspect that if pushed, I could find stats that are more compelling than these -

http://www.mun.ca/biology/scarr/IQ_Correlations.htm
selfAdjoint
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Jul7-04, 02:49 PM
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Quote Quote by shpnagon53
I just read your article. If that isn't agit-prop, then what is.
I agree that GNXP and related sites like Steve Sailer and Griffe du Lion are political to the max, and their use of genetics and statistics is racist (although you know, you have to refute the statistics and genetics, not just call names).

But the paper is not racist and the bullet point summary of it is good, comments apart. This is genuine scientific data.
hitssquad
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Jul7-04, 03:09 PM
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Quote Quote by shonagon53
Quote Quote by selfAdjoint
There is a major new paper on the physical correlates and heritabilitiy of g.

See the summary at GNXP, and then follow the link there to read the whole PDF file. To all those people who claim IQ and g are fictions, here's the evidence they are real.

And Monique, it's not very productive at this late date to quote Gould's Mismeasure of Man against Jensen. That book has been shown by professionals to be tendentious and misleading. It's agit-prop, not science.
I just read your article. If that isn't agit-prop, then what is.
selfAdjoint said "summary." The GNXP text linked to by selfAdjoint contains, according to the introduction "First, a bulleted list. Then, my commentary, and finally the full Thompson/Gray PDF."



Quote Quote by shonagon53
It's full of subjective appreciations and bold statements which are open for ideological debate.
The summary ("bulleted list") section - aside from the use of the word "Intriguingly" in Point 4 of the "Behavioral Genetics of IQ" section - does not appear to contain agitprop. In contrast, the commentary section that follows it does appear to contain, or be, agitprop. Here is the former:


  • these are the points reviewed by the article, divided by subheading:


    Neurobiological determinants of intelligence as measured by IQ:

    1. Posterior lesions often cause substantial decreases in IQ. Duncan and colleagues suggested that the frontal lobes are involved more in Gf and goal-directed behaviour than in Gc (Fig. 2). In addition, Gf is compromised more by damage to the frontal lobes than to posterior lobe...
    2. MRI-based studies estimate a moderate correlation between brain size and intelligence of 0.40 to 0.51
    3. g was significantly linked to differences in the volume of frontal grey matter, which were determined primarily by genetic factors... the volume of frontal grey matter had additional predictive validity for g even after the predictive effect of total brain volume was factored out
    4. Only one region is consistently activated during three different intelligence tasks when compared to control tasks...The surface features of the tasks differed (spatial, verbal, circles) but all were moderately strong predictors of g (g LOADING; range of r, 0.55–0.67), whereas control tasks were weaker predictors of g (range of r, 0.37–0.41). Neural activity in several areas, measured by a positron emission tomography (PET) scan, was greater during high-g than low-g tasks.
    5. Speed and reliability of neural transmission are related to higher intelligence (reviewed in Refs 15,20). Early neuroimaging studies using PET found that intelligence correlated negatively with cerebral glucose metabolism during mental activity54 (for a review, see Ref. 55), leading to the formulation of a 'neural efficiency' hypothesis...
    6. Gf is mediated by neural mechanisms that support the executive control of attention during working memory...greater event-related neural activity in many regions, including the frontal, parietal and temporal lobes, dorsal anterior cingulate and lateral cerebellum. Crucially, these patterns were most distinct during high-interference trials, even after controlling for behavioural performance and for activity on low-interference trials within the same regions
    7. RAPM scores obtained outside the scanner predicted brain activity in a single left parietal/temporal region, and not in the frontal lobes.
    8. An exploratory fMRI study60 (n = 7) indicated that parietal areas are involved in inspection time tasks, specifically Brodmann area (BA) 40 and the ventrolateral prefrontal cortex (BA47) but not the dorsolateral prefrontal cortex


    Behavioral Genetics of IQ:

    1. Monozygotic twins raised separately following adoption show a correlation of 0.72 for intelligence
    2. For 48 identical twin pairs separated in early infancy and reared apart, Bouchard et al.83 found remarkably high between-twin correlations for verbal scores on the WAIS (0.64) and for the first principal component of special mental abilities (0.78)
    3. Psychometric g has been shown to be highly heritable in many studies, even more so than specific cognitive abilities (h2 = 0.62, Ref. 87 compare with Ref. 88; h2 = 0.48, Ref. 89; h2 = 0.6–0.8, Refs 90,91)...
    4. Intriguingly, the influence of shared family environments on IQ dissipates once children leave home — between adult adoptive relatives, there is a correlation of IQ of -0.01


    Molecular Genetics of IQ:

    1. Chorney et al.104 discovered an allelic variation in a gene on chromosome 6, which codes for an insulin-like growth factor-2 receptor (IGF2R), that was linked with high intelligence...
    2. Later studies identified a second IQ-related polymorphism in the IGF2R gene, and others in the cathepsin D (CTSD) gene, in the gene for an acetylcholine receptor (CHRM2)106, and in a HOMEOBOX GENE (MSX1) that is important in brain development107, 108.
    3. Influence of each polymorphism was minimal — variants of CHRM2 accounted for a range of only 3–4 IQ points, whereas different forms of CTSD accounted for about 3% of the variation between people...None of these associations has yet been replicated by other research groups
    4. Some patients with microcephaly also possess the ASPM mutation, indicating that a shortened version of the gene might lead to the development of fewer cerebral neurons and a smaller head.
    5. Polymorphism in the human brain-derived neurotrophic factor (BDNF) gene is associated with impaired performance on memory tests
    6. Catechol-O-methyltransferase (COMT) gene influences the activation of working memory circuits. COMT polymorphisms seem to be highly specific to some prefrontal cortex-dependent tasks in children.
    7. Dopamine receptor (DRD4) and monoamine oxidase A (MAOA) polymorphisms are associated with differences in performance and brain activity during tasks that involve executive attention


Quote Quote by shonagon53
You know, many educated people (the ones who will be triumphant) have read Fukuyama's "Our Posthuman Future" and they understand the basic fact that whenever you're trying to assess the "importance" of genetic differences, you're out of science and into politics.
It appears that the commentary section that follows the above-quoted article summary may gave been written intentionally in an agitprop style.
shonagon53
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#98
Jul7-04, 03:12 PM
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Quote Quote by selfAdjoint
I agree that GNXP and related sites like Steve Sailer and Griffe du Lion are political to the max, and their use of genetics and statistics is racist (although you know, you have to refute the statistics and genetics, not just call names).

But the paper is not racist and the bullet point summary of it is good, comments apart. This is genuine scientific data.

I agree that the article is sound science, but there's a tad of propaganda in it too. I think we can agree on that.

The basic question remains: do you agree that judging to which extent "genetic differences" matter ("intensely" or not), is always a cultural, political, social and ideological judgement?

Isn't that what makes science mere science, and once you're out of that realm, politics begins?

Most scientists agree that global warming, caused by humans, is a scientific fact. But the extent to which this matters, and what, if anything, we should do about it, is always a political question. (In this case: there are sound arguments to say that Kyoto is important, but that there are far more important things, like the war against terror, aids, hunger, or providing sanitation and clean water to people).

So once again, genetic research is genetic research. Nothing more, nothing less. What we do with it, and how important we judge these scientific findings to be, is always a socio-political problem, open for debate. The HapMap people simply "state" that they think that genetic differences in IQ matter very much. But this is clearly an ideological debate.

Wouldn't you agree with that?
Tigers2B1
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#99
Jul7-04, 04:06 PM
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A question on the correlation of brain size and IQ results. While I understand that this correlation exists in both men and women (when compared within sexes) -- women, on average, have a smaller brains and fewer neurons than men even after correcting for body -- without similar differences in IQ results. Is the reason for this diffference known?

Is this related to the differences in male and female brains -- that is, men are more aggressive and the areas thought to control agression are proportionally larger in men --- while the portion that links the right and left sides of brains is larger, after considering body size, in women. Maybe women use their brains in less of a lopsided manner?
Vance
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Jul7-04, 04:19 PM
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Quote Quote by Tigers2B1
A question on the correlation of brain size and IQ results. While I understand that this correlation exists in both men and women (when compared within sexes) -- women, on average, have a smaller brains and fewer neurons than men even after correcting for body -- without similar differences in IQ results. Is the reason for this diffference known?

Is this related to the differences in male and female brains -- that is, men are more aggressive and the areas thought to control agression are proportionally larger in men --- while the portion that links the right and left sides of brains is larger, after considering body size, in women. Maybe women use their brains in less of a lopsided manner?
I am sorry for my ignorance but may I ask what makes you think men are more aggressive than women since I think it depends on each person and on circumstances in which each individual is educated and grown up ?
Or am I misreading your post at any points up there ?

Thanks,
Monique
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#101
Jul7-04, 04:31 PM
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LOl, I google the words agression and testosterone and out came a PF thread
Agression: Men vs Women

Tigers2B1, efficiency of the neuron routing is important too and not just neuron mass :)
selfAdjoint
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#102
Jul7-04, 07:09 PM
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Quote Quote by shonagon53
So once again, genetic research is genetic research. Nothing more, nothing less. What we do with it, and how important we judge these scientific findings to be, is always a socio-political problem, open for debate. The HapMap people simply "state" that they think that genetic differences in IQ matter very much. But this is clearly an ideological debate.

Wouldn't you agree with that?
Yes I would. Part of my problem is that the folks I call the "tabula rasists" - including Gould and Lewontine but also a lot of vaguely leftist journalists - have for decades tried to tell the public that the good science is bad science, that the people who do it are in the line of the bad old eugenicists, and so on. Not in our Genes and Mismeasure of Man were salvos in that war. All I want is for the scientific tradition that this paper represents, and that Jenson represents be allowed to continue without smearing.
hitssquad
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#103
Jul8-04, 06:06 AM
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Quote Quote by selfAdjoint
There is a major new paper on the physical correlates and heritabilitiy of g.

See the summary at GNXP
That is a summary of a (his most recent) Paul Thompson paper. You can read all of Paul Thompson's brain imaging peer-reviewed articles at his site.
shonagon53
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Jul8-04, 11:25 AM
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Quote Quote by selfAdjoint
Yes I would. Part of my problem is that the folks I call the "tabula rasists" - including Gould and Lewontine but also a lot of vaguely leftist journalists - have for decades tried to tell the public that the good science is bad science, that the people who do it are in the line of the bad old eugenicists, and so on. Not in our Genes and Mismeasure of Man were salvos in that war. All I want is for the scientific tradition that this paper represents, and that Jenson represents be allowed to continue without smearing.

Gould was a child of his time. I think most non-experts today (like you and me) would agree that both nature and nurture are important, and it's all a very complex combination of factors.

The only ones I'm wary of are the ones who generalize. And you still find those in both camps.
selfAdjoint
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Jul8-04, 04:18 PM
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I agree that nature and nurture are both important. If you look at the Gray-Thompson paper you will see that they adopt the fluid g, GF and crystalized g, GC formalism. In this view the common cognitive factor g is composed of two parts, one of which increases through childhood but becomes fixed at maturity and doesn't change afterward, except to decline in old age. The other component, is basically th result of environment and increases throughout life. So an old fart like me may have lost some IQ points, but might make up for it by knowing a lot of cagy tricks.
shonagon53
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Jul8-04, 04:32 PM
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Quote Quote by selfAdjoint
So an old fart like me may have lost some IQ points, but might make up for it by knowing a lot of cagy tricks.
Good for you, eh.

Also, I think most people couldn't bare to live with the idea that everything they do, think, and feel is genetically predetermined in some sense. They would refuse to know and keep some mystery.

This is what that old misunderstood chap Nietzsche thought of when he wrote about "der Übermensch". The Übermensch is the one who fully accepts fate as it comes, while the Untermenschen still need religion or other cultural superstructures to cope with it.

I think we will all remain Untermenschen for a very long time. :-)
hitssquad
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Jul8-04, 08:12 PM
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Quote Quote by selfAdjoint
I agree that nature and nurture are both important. If you look at the Gray-Thompson paper you will see that they adopt the fluid g, GF and crystalized g, GC formalism.
Actually, it is a Cattellism.



In this view the common cognitive factor g is composed of two parts,
No. Cattell's investment theory (his theory of Gf/Gc) is incompatible with the existence of g.

  • ...Cattell and Horn prefer not to extract the third-order factor, or g, contrary to the practice of most factor analysts. The Cattell-Horn model of abilities, therefore, is called a truncated hierarchy. That is, it lacks the apex of the hierarchy of factors, which is g. Cattell has stated in italics 25 that "there can be no such thing as a categorical general factor" (p. 87 )....

    At the time that only two factors, Gf and Gc, stood at the highest level of Cattell's "truncated" hierarchy, there was a valid reason not to extract a thirdorder g. The reason is not that g doesn't exist in the test battery, but that a thirdorder hierarchical g is mathematically indeterminate when there are no more than two second-order factors. That is, there is only one correlation (i.e., the correlation between the two second-order factors, e.g., Gf and Gc) and all that can be determined is the geometric mean of the these factors' g loadings, which is equal to the square root of the correlation between the two second-order factors. Although we can know the average of the two factors' g loadings, we can't know the exact g loading of each factor separately, and ipso facto we cannot properly calculate the g loadings of each of the tests in the battery or calculate the g factor scores of the subjects who took the tests.
Arthur Jensen. The g Factor. p124.



one of which increases through childhood but becomes fixed at maturity and doesn't change afterward, except to decline in old age.
Fluid g peaks and starts declining somewhere in the late-teens to mid-twenties, except in persons who adopt comprehensive anti-senescence regimens.



The other component, is basically th result of environment and increases throughout life.
The phrase result of environment makes no sense in this context, and using the word environment to describe what Gf (fluid g) is applied to in order to arrive at the accumulated knowledge of Gc (crystallized g), after first using it in the same paragraph to refer to the environmental component of heredity, amounts to an instance of equivocation.

In heredity, variance in genetic code and variance in environment each, and only each, account for a portion of total variance in phenotype. In development of fluid g, theoretically, both of the environments, biological environment and intellectual environment, play roles. In development of crystallized g, theoretically, of the two aforementioned types of environment, only intellectual environment plays a role. Although both Gf and Gc are substantially heritable and to almost equal degrees, according to theory, the non-environment component of Gf is genetic and the non-environment component of Gc is Gf (such that you need Gf in order to get Gc, but Gc is what you would remember even if you lost your Gf - as in the case of growing old and still retaining your cagey smarts, if not your general mental ability at its former youthful level, as you noted selfAdjoint).
selfAdjoint
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#108
Jul8-04, 08:16 PM
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There's a neat cartoon in this week's New Yorker. A long line of steps, with on the lowest some animal, and then an ape, and then a neanderthal, and finally a modern man, standing on the middle step visible, looking pensive. And the neanderthal says, "Ah! Now you notice how many steps are still ahead!".


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