CapitalistImperialistPig

Most of us have some idea of what we mean by intelligence, but putting it into precise words is not so easy. Arun Gupta, who has seemingly been obsessed with IQ for a while, has collected definitions of intelligence from a thirty odd people who spent much of their careers studying the question. While the definitions have considerable overlap, they are anything but isomorphic. Some of the definitions are peculiar enough than one might reasonably deduce that cockroaches are smarter than people and bacteria are smarter still. Francis Galton seems to have been the first to systematically attempt to measure intelligence, but the tests he devised were failures. Alfred Binet wasn't actually trying to measure intelligence - he called what he measured "mental age" - but the mainly verbal tests he devised to measure educational readiness became the first IQ tests. (See the Wikipedia article: Intelligence Quotient for this and much else. Unlike Galton's attempts, th...

In what the NYT has labelled an "enormous success" a big genome wide association study is reputed to have found a number of gene variants associated with intelligence: In a significant advance in the study of mental ability, a team of European and American scientists announced on Monday that they had identified 52 genes linked to intelligence in nearly 80,000 people. These genes do not determine intelligence, however. Their combined influence is minuscule, the researchers said, suggesting that thousands more are likely to be involved and still await discovery. Just as important, intelligence is profoundly shaped by the environment. Still, the findings could make it possible to begin new experiments into the biological basis of reasoning and problem-solving, experts said. They could even help researchers determine which interventions would be most effective for children struggling to learn. I'm not too impressed with the story. The second quoted paragraph is mislead...

Because why settle for a lousy 60 standard deviations when you can have almost 70,000. Fans of genetic engineering of the brain (like Lumo and Steve Hsu) think that human brains can be tweaked to produce IQs of 1000, whatever that might mean. Those who have studied biology are more dubious. One component of IQ is mental processing speed, and that has got to be limited by the physiology of nerves. Fundamental neural processes take milliseconds or longer, and the basic design is not going to permit much speedup. Silicon transistors, on the other hand, are 1 million times faster. Another component of IQ is memory, short term and long. Given enough disk space, a computer can remember everything it has ever read, heard, or seen. A number of humans have been reported to have eidetic memories , but psychologists who have attempted to study it are highly dubious, though some children have short term eidetic memories. It's physiologically improbable that a person could store all th...

The short answer is that IQ is what IQ tests measure. That answer is saved from total circularity by the fact that there is a high correlation between results of a bunch of different tests of reasoning. Typical IQ tests have questions designed to test short term memory, general knowledge, ability to follow written or spoken instructions, and ability to reason concretely and abstractly, ability to generalize and analyze relationships as well as speed of mental processing. Early intelligence researchers noticed that there was a strong correlation among the results of rather different tests and the statistician and psychologist Spearman hypothesized that the correlation was due to an underlying g-factor, the g standing for general intelligence. A century or so later, our knowledge of the underlying biological substrate of IQ has made only limited progress. We know of lots of genetic and environmental factors that limit IQ, but have only vague indications of what things produce higher...

We are rapidly gaining skill in genetic manipulation. In addition to such high priority goals as creating better athletes and prettier people, what are the prospects for smarter and healthier people? Steve Hsu has some thoughts and quotes on the former: .. I think there is good evidence that existing genetic variants in the human population (i.e., alleles affecting intelligence that are found today in the collective world population, but not necessarily in a single person) can be combined to produce a phenotype which is far beyond anything yet seen in human history. This would not surprise an animal or plant breeder — experiments on corn, cows, chickens, drosophila, etc. have shifted population means by many standard deviations (e.g., +30 SD in the case of corn). ... I think we already have some hints in this direction. Take the case of John von Neumann, widely regarded as one of the greatest intellects in the 20th century, and a famous polymath. He made fundamental contributions ...