Brain Structure and IQ

Thanks to ThePenileFamily for binging to my attention the Steve Pinker video on Jewish IQ. I have a few comments and an additional reference.The interesting biochemical explanation is testable but single factorial explanations for IQ seem unlikely. This is especially ironic because of the attitude of some that IQ is some sort singularity. No, it is probably more like being a jock, the result of multiple innate abilities plus training.

It is interesting that other middlemen cultures such as the Chinese and Indian also produce an excess of high achievers in academia. Is there a biochemical basis for this? You can read this link.

I read this article in Scientific American that looked for the genetic linkages for IQ. There is no single gene or combination of genes controls IQ. Intensive DNA probing for genetic links to IQ have found no magic gene or combination of genes.

“ The researchers found only six genetic markers that showed any sign of having an influence on the test scores. When they ran stringent statistical tests to see if the results were flukes, only one gene passed. It accounted for 0.4 percent of the variation in the scores. And to cap it all off, no one knows what the gene does in the body.”

Many neuroscientists look at the brain not as an all purpose computer that may vary in power from one individual to another but as a coordinated system of behavior generating modules. Crude measures of brain weight are not sufficient . Sophisticated scans of the cortex show no one IQ center.

“Recently Haier and Rex Eugene Jung of the University of New Mexico surveyed 37 studies examining regional brain size or activity to look for an overall pattern to their results. As Plomin would have predicted, Haier and Jung found no one “intelligence spot” in the brain. Instead they identified a number of significant regions scattered around the cortex. Other studies have implicated each of these regions in different kinds of cognition. “It looks like intelligence is built on these fundamental cognitive processes, like attention and memory, and maybe language ability,” Haier says.

In Pinker’s lecture one of the possible causes of high Jewish IQ was the that people who have one copy of genes that promote various glycolipid accumulations in the brain, might lead to better neural transmission and hence a higher IQ . There is evidence that high IQ persons have larger amounts of white matter, possibly indicating better neural transmission within the brain.

“Along with describing the gray matter tissue that makes up the cortex, these studies also find the signature of intelligence in the white matter that links distant parts of the cortex to one another. People with high intelligence tend to have tracts of white matter that are more organized than other people. “The white matter is like the wiring,” Haier says. “If you think about it, you know intelligence really requires processing power and speed; the white matter would give it the speed; the gray matter would give it the processing power.”

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Thanks Dave

No, thank you.

You did what I'm supposed to do. Create commentary on a video. I'm glad somebody found it interesting. Although the quality is disturbingly bad.

Have you read the "Mismeasure of Man" - Stephen Gould. It seems to be a rather emotional attack on the Bell Curve and IQ in general. That's one "popular" account out of hundreds. There is some very good research which is not public at the moment. Far from public scrutiny (good and bad) but usually a much more robust and solid statistical framework. Statistics need to be handled with great care.

Given the criticisms of IQ tests, and the suspicions people have with the legitimacy of the entire subject, I will be addressing that hurdle, I'm sure, moving forward at some point (well, I hope so). Of course, when talking to the public, you must use public information.

Is IQ important? Is information from the Bell Curve beneficial to addressing social problems? Was the Bell Curve complete hogwash? Should anyone care about IQ? Is IQ legitimate? Why are people so emotional about IQ and should they be? IQ tests... which one? Does IQ = Intelligence and/or success?

Maybe this should have come before the video, but I was in the moment and posted anyway.

Thanks again,


Anyone Can be a PhD

One thing I like about Steve Pinker is the way he sometimes points out rank hypocrisy. For example he points out how academics whose focus in their professional life is the cultivation of their innate ability and judging the ability of others such as colleagues and students, will then turn around and deny that ability has innate elements. Do these “brilliant” people think of themselves as no different from the school janitor? If so, why don’t they share their jobs with the cleaning staff and vise versa in order to be fair and just?

IQ is probably

IQ is probably (approximately) normally distributed because there are so many different genes all contributing a small amount.

My most recent post is on The Bell Curve and Glenn Loury.