Wednesday, November 28, 2012
Jensen and Flynn
Anyone who has followed the decades-long controversies over the role of genes in IQ scores will recognize the names of the two leading advocates of opposite conclusions on that subject-- Professor Arthur R. Jensen of the University of California at Berkeley and Professor James R. Flynn, an American expatriate at the University of Otago in New Zealand.
What is so unusual in the academic world of today is that Professor Flynn's latest book, "Are We Getting Smarter?" is dedicated to Arthur Jensen, whose integrity he praises, even as he opposes his conclusions. That is what scholarship and science are supposed to be like, but so seldom are.
Professor Jensen, who died recently, is best known for reopening the age-old controversy about heredity versus environment with his 1969 article titled, "How Much Can We Boost IQ and Scholastic Achievement?"
His answer-- long since lost in the storms of controversy that followed-- was that scholastic achievement could be much improved by different teaching methods, but that these different teaching methods were not likely to change I.Q. scores much.
Jensen argued for educational reforms, saying that "scholastic performance-- the acquisition of the basic skills-- can be boosted much more, at least in the early years, than can the IQ" and that, among "the disadvantaged," there are "high school students who have failed to learn basic skills which they could easily have learned many years earlier" if taught in different ways.
But, regardless of what Arthur Jensen actually said, too many in the media, and even in academia, heard what they wanted to hear. He was lumped in with earlier writers who had promoted racial inferiority doctrines that depicted some races as being unable to rise above the level of "hewers of wood and drawers of water."
These earlier writers from the Progressive era were saying, in effect, that there was a ceiling to the mental potential of some races, while Jensen argued that there was no ceiling but, by his reading of the evidence, a difference in average IQ, influenced by genes.
When I first read Arthur Jensen's landmark article, back in 1969, I was struck by his careful and painstaking analysis of a wide range of complex data. It impressed me but did not convince me. What it did was cause me to dig up more data on my own.
A few years later, I headed a research project that, among other things, collected tens of thousands of past and present IQ scores from a wide range of racial and ethnic groups at schools across the United States. Despite serious limitations in these data, due to constraints of time and circumstances, these data nevertheless threw some additional light on the subject.
A feature article of mine in the Sunday New York Times Magazine of March 27, 1977 pointed out that any number of white groups, here and overseas, had at some point in time had IQs similar to, and in some cases lower than, the IQs of black Americans. During the First World War, for example, white soldiers from some Southern states scored lower on army mental tests than black soldiers from some Northern states.
Professor Jensen read this article and came over to Stanford University to meet with me and discuss the data. That is what a scholar should do when challenged. But the opposite approach was shown by Professor Kenneth B. Clark, who earlier had sought to dissuade me from doing IQ research. He said it would "dignify" Jensen's work, which Clark wanted ignored or discredited instead.
Unfortunately, Professor Clark's ideological approach became far more common in academia, so much so that Jensen's attempts to speak on campuses around the country provoked dangerous disruptions, instead of reasoned arguments.
Years later, Professor James R. Flynn created the biggest challenge to the hereditary theory of intelligence, when he showed that whole nations had risen to much higher results on IQ tests in just one or two generations. Genes don't change that fast.
Professor Flynn told me that he would never have done his research, except that it was provoked by Jensen's research. That is just one of the reasons for having a free marketplace of ideas, instead of turning academic campuses into fortresses of politically correct intolerance.
Sowell's comments are those of an unusually decent man but his argument is unpersuasive. You can to this day find some whites who are dumber than some blacks but it is the groups OVERALL (and preferably across time) that are of greatest interest and the overall black/white gap has been consistent as far back as it has been measured. But there are exceptions to every rule and some blacks are very bright. Sowell is one of them.
Posted by jonjayray at 10:05 PM
Friday, November 2, 2012
High IQ as just one part of biological good functioning
I have for some years been putting forward evidence in favor of the view that high IQ is just one aspect of general biological good functioning. I never thought to get the NYT on my side but you can read it below
FEW of us are as smart as we'd like to be. You're sharper than Jim (maybe) but dull next to Jane. Human intelligence varies - and this matters because smarter people generally earn more money, enjoy better health, raise smarter children, feel happier and, just to rub it in, live longer as well.
But where does intelligence come from? How is it built? Researchers have tried hard to find the answer in our genes. With the rise of inexpensive genome sequencing, they've analysed the genomes of thousands of people, looking for gene variants that clearly affect intelligence, and have found a grand total of two.
One determines the risk of Alzheimer's disease and affects IQ only late in life; the other seems to build a bigger brain, but on average it raises IQ by all of 1.29 points.
Other genetic factors may be at work. A report last year concluded that several hundred gene variants taken together seemed to account for 40 per cent to 50 per cent of the differences in intelligence among the 3500 subjects in the study.
But the authors couldn't tell which of these genes created any significant effect. When they tried to use the genes to predict differences in intelligence, they could account for only 1 per cent of the differences in IQ.
"If it's this hard to find an effect of just 1 per cent," Robert Plomin, a professor of behavioural genetics at King's College London, told New Scientist, "what you're really showing is that the cup is 99 per cent empty."
But is the genetic cup really empty, or are we just looking for the wrong stuff?
A developmental neurogeneticist Kevin Mitchell at Trinity College Dublin, thinks the latter. In an essay he published in July on his blog, Wiring the Brain, Mitchell proposed that instead of thinking about the genetics of intelligence, we should be trying to parse "the genetics of stupidity," as his title put it. We should look not for genetic dynamics that build intelligence, but for those that erode it.
The premise for this argument is that once natural selection generated the set of genes that build our big, smart human brains, those genes became "fixed" in the human population; virtually everyone receives the same set and precious few variants affect intelligence. This could account for the researchers' failure to find many variants of measurable effect.
But in some other genetic realms we do differ widely, for example, mutational load - the number of mutations we carry. This tends to run in families, which means some of us generate and retain more mutations than others do. Among our 23,000 genes, you may carry 500 mutations while I carry 1000.
Most mutations have no effect. But those that do are more likely to bring harm than good, Mitchell says , because "there are simply many more ways of screwing something up than of improving it".
Open the hood of a smooth-running car and randomly turn a few screws, and you'll almost certainly make the engine run worse than before. Likewise, mutations that change the brain's normal development or operation will probably slow it down. Smart Jane may be less a custom-built, high-performance model than a standard version pulling a smaller mutational load.
We also inherit - through genes yet to be identified, of course - a trait known as developmental stability. This is essentially the accuracy with which the genetic blueprint is built.
Developmental stability keeps the project on track. It reveals itself most obviously in physical symmetry. The two sides of our bodies and brains are constructed separately but from the same blueprint of 23,000 genes. If you have high developmental stability, you'll turn out highly symmetrical. Your feet will be the same shoe size, and the two sides of your face will be identical.
If you're less developmentally stable, you'll have feet up to a half size different and a face that's like two faces fused together. Doubt me? Take a digital image of your face and split it down the middle. Then make a mirror image copy of each half and attach it to its original. In the two faces you've just made - one your mirrored left side, the other your right - you'll behold your own developmental stability, or lack thereof.
Both those faces might be better looking than you are, for we generally find symmetrical faces more attractive. It also happens that symmetry and intelligence tend to run together, because both run with developmental stability. We may find symmetrical faces attractive because they imply the steadiness of genetic development, which creates valuable assets for choosing a mate, like better general fitness and, of course, intelligence - or as Mitchell might put it, a relative lack of stupidity.
These ideas don't strike geneticists as radical or contrary. A geneticist at Princeton University Leonid Kruglyak, who studies yeast and flatworms, noted that geneticists had long recognised that mutations could "throw sand in the gears of the brain" and that complex traits arose in complicated ways.
"Talking about 'a gene for a trait' is a shorthand at best," he wrote, "and a well-known fallacy at worst."
Mitchell agreed. "This isn't a brand new idea," he says. "But it's not one that has been generally adhered to in intelligence studies."
Not brand new, perhaps, but it's this kind of "inversion of thought" that can spark new approaches to intractable problems.
Dr Jay Giedd, who studies brain development at the US National Institutes of Health, has done research suggesting that the brain blooms through many small arcs of development that make it responsive to experience - and vulnerable to error. At first, he says, he was sceptical of Mitchell's idea. Then he discussed it with colleagues at a neuroscience meeting.
"My initial thought was that it would be easy to sink the argument," Giedd says. But the more they discussed it, the more sense it made. "Everybody I ran it by seemed to feel the logic is sound."
Posted by jonjayray at 10:08 PM