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Fri 16 Jun, 2006 05:53 pm
In the future world of genetics and molecular biology, to what extent if any, will knowing an individual's DNA compostion and structure permit one to quantify that person's IQ, given additional information such as brain/skull dimensions?
( See WSJ for 6/16/06 )
much too early to speculate, i should think. Bruce Lahn of the university of Chicago found higher occurence of one gene variant affecting brain size among Europeans, North Africans, Middle Easterners, and South Asians, and lower incidence of another in sub-Saharan Africans. so, if you simplistically equate brain size with IQ, Europeans, North Africans, etc. should have highest IQ, followed by East Asians & American Indians, followed by sub-Saharan Africans. but unless i'm mistaken, East Asians outscore Europeans, with the exception of Jews, in IQ tests.
Apparently, intelligence doesn't have anything to do with the size of the brain, but how it grows.
Quote:Braininess in kids may not depend on the amount of gray matter so much as how fast it both thickens and thins as they grow up. Researchers at the National Institute of Mental Health and at McGill University used magnetic resonance imaging to scan the brains of 307 children from ages five to 19.
They focused on the cerebral cortex, or gray matter, which is responsible for higher thinking. In kids who scored highest on the most commonly used IQ tests, the cortex was actually relatively thinner in early childhood, thickening rapidly between ages seven to 11, and peaking later than in their average-IQ peers.
The delayed growth perhaps reflects a longer developmental window for high-level thinking circuitry. The cortex of the smart children also thins faster during the late teens, which could reflet withering of unused neural connections as the brain streamlines its operations. Scan the March 30 Nature for more details.
Source: Charles Q. Choi, Scientific American, June 2006, p. 17
It would appear then that intelligence has got little to do with the presence of the genes themselves and more to do with how they're expressed. Therefore, genetics is useless in determining intelligence and we must look to epigenetics for the answers.
makes sense, Wolf. the proponents of IQ-brain size correlation have difficulty explaining how women & men have the same average IQ despite men's larger brain size.
Quote:Therefore, genetics is useless in determining intelligence and we must look to epigenetics for the answers.
So, please explain to me then, why women who visit sperm banks to obtain donor "genes" to father their offspring, specify that the donors be physcians, lawyers or other HIGH IQ men?
But maybe a persons genetics could partially determine how long is takes someones brain to thicken. In that case genetics would be important.
Miller wrote-
Quote:So, please explain to me then, why women who visit sperm banks to obtain donor "genes" to father their offspring, specify that the donors be physcians, lawyers or other HIGH IQ men?
It is because they have seen a lot of TV programmes sponsored by physicians, lawyers and other High IQ men.
The sensible girls go for natural insemination by footballers and rock stars.
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