Freethought & Rationalism Archive

Totalitarianist · 12-04-2002, 09:32 AM

<a href="http://www.loni.ucla.edu/~thompson/MEDIA/NN/nyt.html" target="_blank">http://www.loni.ucla.edu/~thompson/MEDIA/NN/nyt.html</a>

This is an old article, but it is worth reading for those of you who still believe in the false conception that environment is the chief determinative in human intelligence

Philosoft · 12-04-2002, 12:52 PM

I presume you have some ulterior motive for posting this, Vir?

So, how big is your frontal lobe?

fando · 12-04-2002, 01:10 PM

Pay special attention to this paragraph:

Quote:

Dr. Plomin, who wrote a commentary on the study in the journal, said the larger volume of gray matter could be the cause of higher intelligence, or it could be the other way around - people with a stronger motivation, say, might exercise their brains harder and develop a higher density of neurons.

And then the final paragraph:

Quote:

The size of gray matter in the frontal lobes cannot be used to measure an individual's intelligence, he said. Some potential uses, such as scanning to compare the intelligence of different groups, would be unethical, he added. "It would be remiss to use technology developed for disease for those types of goals," he said.

I don't see the article favoring either side of nature vs. nuture. It just provides a clearer idea of how heredity might influence intelligence. It's a starting point for more research, nothing more.

ps418 · 12-04-2002, 01:21 PM

I pointed out this study a few weeks ago in the thread on the Bell Curve. The following is reposted from that thread. The second, more-recent paper (Posthuma et al) demonstrates that frontal grey matter volume is not altered by experience, thus addressing Plomin's statement that larger brains might be an effect of 'brain exercise.'

The article by Thompson et al (2001) reports data from 40 subjects, 2 pairs each of identical and fraternal twins. Grey matter volume was determined for several brain regions using 3D MRI images. Cognitive tests consisted of 17 Wechsler Adult Intelligence Scale domains, including verbal and spatial working memory, selective and divided attention, verbal knowledge, motor speed, and visuospatial ability. They report a correlation of 0.37-0.40 between frontal grey matter volume and IQ. Plomin and Kosslyn (2001) in their commentary on Thompson et al state that the results "suggest that 'g' is not simply a statistical abstraction that emerges from factor analyses of psychometric tests; it also has a biological substrate in the brain" (Genes, brain and cognition, Nature neuroscience 4, p. 1154). They also cite 14 earlier studies of ~700 individuals in which correlations between brain volume and 'g' are roughly 0.4 (Vernon et al, in Handbook of Intelligence (ed. Sternberg, R.J.) 254-264, Cambridge University Press, 2000), and argue that Thompson et al underestimate the association of 'g' with individual brain regions due to the assumptions in their statstical analysis. The Posthuma et al (2002) data includes 258 Dutch subjects, and also used the Wechsler Adult Intelligence Scale to assess IQ and MRI scans to assess grey matter volume. They report a correlation of 0.25 between IQ and total brain grey matter volume.

One clarification. A lot of the media blurbs describing the Thompson et al paper say things like 'genes determine IQ, scientists say,' which is obviously not quite correct. The correlation of grey matter volume among monozygotic twins is almost perfect, like 0.9. But the correlation between grey matter volume and IQ is about 0.3-0.4, still a very significant correlation of course, but hardly one that supports a rigid more-brain=more intelligence.

Thompson PM, Cannon TD, Narr KL, van Erp T, Poutanen VP, Huttunen M, Lonnqvist J, Standertskjold-Nordenstam CG, Kaprio J, Khaledy M, Dail R, Zoumalan CI, Toga AW, 2001. Genetic influences on brain structure. Nature Neuroscience 4(12):1253-8.

<a href="http://www.loni.ucla.edu/~thompson/MEDIA/NN/genetics_article_NN.pdf" target="_blank">http://www.loni.ucla.edu/~thompson/MEDIA/NN/genetics_article_NN.pdf</a>

Quote:

Here we report on detailed three-dimensional maps revealing how brain structure is influenced by individual genetic differences. A genetic continuum was detected in which brain structure was increasingly similar in subjects with increasing genetic affinity. Genetic factors significantly influenced cortical structure in Broca's and Wernicke's language areas, as well as frontal brain regions (r2(MZ) greater than 0.8, p less than 0.05). Preliminary correlations were performed suggesting that frontal gray matter differences may be linked to Spearman's g, which measures successful test performance across multiple cognitive domains (p greater than 0.05). These genetic brain maps reveal how genes determine individual differences, and may shed light on the heritability of cognitive and linguistic skills, as well as genetic liability for diseases that affect the human cortex.

Posthuma D, De Geus EJ, Baare WF, Hulshoff Pol HE, Kahn RS, Boomsma DI. , 2002. The association between brain volume and intelligence is of genetic origin. Nature Neuroscience 5(2):83-4.

Patrick

**makTHRAX** · 12-04-2002, 03:30 PM

There is a more recent study that examines 6 genes that determine the size of the cerebral cortex. The article can be found here: <a href="http://www.sciencenews.org/20021116/bob8.asp" target="_blank">'Brain Boost'</a>. However, they don't conclude that bigger means more intelligent means better.

thx,
makTHRAX

echidna · 12-04-2002, 04:16 PM

Sorry about leaving that thread Patrick. I kinda get guilt pangs every now and again & it�s still on my to-do list, but then again, so�s my tax and that�s 2 years late already ...

ps418 · 12-04-2002, 04:34 PM

Quote:

Originally posted by echidna:
Sorry about leaving that thread Patrick.

Don't be. After 4 pages, I pretty much exhausted my curiosity in the subject.

echidna · 12-04-2002, 06:12 PM

Whew.

In my case, just exhausted, but still a tad curious. We must do it again sometime.

abe smith · 12-06-2002, 05:22 AM

Regarding quoting/referring to any *studies which indicate...* blah-blah-blah: I'd like to reiterate what "Everybody here @ EyeEye Knows" (for your benefit Bax, & others's) >>>>> that a *study* doesn't PROVE a damn thing...... Cordially, Abe

ps418 · 12-06-2002, 01:11 PM

Quote:

Originally posted by abe smith:
Regarding quoting/referring to any *studies which indicate...* blah-blah-blah: I'd like to reiterate what "Everybody here @ EyeEye Knows" (for your benefit Bax, & others's) >>>>> that a *study* doesn't PROVE a damn thing...... Cordially, Abe

No one ever mentioned proof in this thread, Abe.

If everyone at II already knows something (e.g. a *study* doesn't PROVE a damn thing), then there is clearly no reason to reiterate it.

Who is this Bax fellow you are referring to? Maybe you're referring to makTHRAX, but couldn't be bothered to spell his username correctly?

Did you have a point, or was this post only a way for you to express your cordiality?

[ December 06, 2002: Message edited by: ps418 ]

12-04-2002, 09:32 AM	#1
Totalitarianist Banned Join Date: Apr 2002 Location: Canada Posts: 1,234	Study Finds Genetic Link Between Intelligence and Size of Some Regions of the Brain <a href="http://www.loni.ucla.edu/~thompson/MEDIA/NN/nyt.html" target="_blank">http://www.loni.ucla.edu/~thompson/MEDIA/NN/nyt.html</a> This is an old article, but it is worth reading for those of you who still believe in the false conception that environment is the chief determinative in human intelligence

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12-04-2002, 12:52 PM	#2
Philosoft Veteran Member Join Date: Feb 2002 Location: Southeast of disorder Posts: 6,829	I presume you have some ulterior motive for posting this, Vir? So, how big is your frontal lobe?

12-04-2002, 03:30 PM	#5
makTHRAX Junior Member Join Date: Nov 2002 Location: Knoxville, Tennessee Posts: 51	There is a more recent study that examines 6 genes that determine the size of the cerebral cortex. The article can be found here: <a href="http://www.sciencenews.org/20021116/bob8.asp" target="_blank">'Brain Boost'</a>. However, they don't conclude that bigger means more intelligent means better. thx, makTHRAX

12-04-2002, 04:16 PM	#6
echidna Veteran Member Join Date: May 2001 Location: Melbourne, Australia Posts: 2,832	Sorry about leaving that thread Patrick. I kinda get guilt pangs every now and again & it�s still on my to-do list, but then again, so�s my tax and that�s 2 years late already ...

12-04-2002, 06:12 PM	#8
echidna Veteran Member Join Date: May 2001 Location: Melbourne, Australia Posts: 2,832	Whew. In my case, just exhausted, but still a tad curious. We must do it again sometime.

12-06-2002, 05:22 AM	#9
abe smith Veteran Member Join Date: Apr 2001 Location: springfield, MA. USA Posts: 2,482	Regarding quoting/referring to any studies which indicate... blah-blah-blah: I'd like to reiterate what "Everybody here @ EyeEye Knows" (for your benefit Bax, & others's) >>>>> that a study doesn't PROVE a damn thing...... Cordially, Abe

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