12 March 2009

Intelligence is Inherited, More Than You Know

THE first images to reveal the quality of the brain's wiring show that more aspects of intelligence are inherited than previously known. The finding hints at ways to boost intelligence. _NewScientist
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Intelligence is between 50% and 80% heritable. Probably closer to 80 than 50. It has been difficult to locate specific genes and gene clusters that account for differences in intelligence between matured human brains, but scientists keep trying.

The speed of brain processes correlates with IQ, and brain speed is partially determined by the integrity of the myelin wrapping around nerve axons that make up the communication pathways (white matter) in the brain. To explore the issue of inheritance and brain speed further, UCLA researcher Paul Thompson conducted a twin study comparing 23 sets of identical twins with 23 sets of fraternal twins.
It is clear that intelligence is at least partly genetically determined. This was supported by the discovery in 2001 that the volume of the brain's grey matter, made up of "processor" cells, is heritable and correlates with certain elements of IQ (Nature Neuroscience, DOI: 10.1038/nn758). The amount of white matter, which provides the connections between these processors, has since been shown to be heritable too (Journal of Neuroscience, vol 26, p 10235).

...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).

...Identifying the genes that promote high-integrity myelin could lead to ways to enhance the genes' activity or artificially add the proteins they code for. This may in turn provide therapies for multiple sclerosis, autism and attention deficit disorder, which are associated with degraded myelin. Intelligence enhancement in people who just want help passing an exam, say, is also "within the realm of possibility", Thompson reckons. _NS
So you can see that high heritability for intelligence can make it easier for biomedical scientists to intervene in order to raise intelligence levels. As long as the underlying causes of higher intelligence are held to be mysterious, humans are doomed to exist in a low IQ state.

The leftist ideologues who frequently occupy university faculty and staff positions are opposed to the study of human biodiversity, and population / genetic differences in brain function. Such leftist Luddism in high places is one of the majour obstacles in the path to a better future for all humans. And now the US has to live with a leftist Luddite president who is also a fascist, economically. Quite a setback to the human enterprise, but not insurmountable.

Hope for the best, prepare for the worst.

Bonus: This study shows that the human brain collects traces that reveal the steps to navigate a landscape -- virtual landscapes and probably real landscapes as well. This suggests that good enough brain imaging combined with clever and powerful psycho-informatics technology will allow psychoneurologists to trace much of a person's inner life, before long. Lie detectors will be easy. Testing intelligence using interactive imaging will be easy. Reproducing a person's entire inner mental world will take a bit longer.

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“During times of universal deceit, telling the truth becomes a revolutionary act” _George Orwell

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