Race is based on phenotype, not directly on the genes. This is an important point I think.
https://en.wikipedia.org/wiki/Phenotype
https://en.wikipedia.org/wiki/Genoty...pe_distinction
Originally Posted by Andrew Sabisky
If the mean black American IQ is (best estimate based on a century’s worth of data) around 85, as compared to a mean white American IQ of 100, then if IQ is normally distributed (which it is), you will see a far greater percentage of blacks than whites in the range of IQs 75 or below, at which point we are close to the typical boundary for mild mental retardation. Typically criminals with IQs below 70 cannot be executed in the USA, I believe.
That parsimoniously explains the greater diagnostic rates for blacks when it comes to “Intellectual disability”. It simply a consequence of the normal distribution of cognitive ability, because there are significant differences in the group means.
Precisely about this quote, there are several issues.
First of all, the mean American IQ for the 1900s was estimated around 70. Were they in average mentally disabled? No.
Originally Posted by in Smarter than ever?
Over the past 100 years, Americans' mean IQ has been on a slow but steady climb. Between 1900 and 2012, it rose nearly 30 points, which means that the average person of 2012 had a higher IQ than 95 percent of the population had in 1900.
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If you mean, on the other hand, something like: Were people just as adapted to their circumstances in 1900 as they are today? Well, of course they were. They were able to do factory work, to hunt. They could cope with the world as it existed then. They had an average IQ of 70, but they weren't all mentally retarded. So in that respect there's been no gain in intelligence.
https://www.apa.org/monitor/2013/03/smarter
Secondly, the time when the mean American IQ crossed 85 was around the 1940s. Were they inferior in some way? No.
Originally Posted by in It’s a Smart, Smart, Smart World
The Flynn Effect should upend some of the smugness among those who have historically done well in global I.Q. standings. For example, while there is still a race gap, black Americans are catching up — and now do significantly better than white Americans of the "greatest generation" did in the 1940s…
https://www.nytimes.com/2012/12/13/o...art-world.html
Thirdly, the gap can be explained by other factors than simply genetics:
Originally Posted by in The unwelcome revival of ‘race science’
This finding has been reinforced by the changes in average IQ scores observed in some populations. The most rapid has been among Kenyan children – a rise of 26.3 points in the 14 years between 1984 and 1998, according to one study. The reason has nothing to do with genes. Instead, researchers found that, in the course of half a generation, nutrition, health and parental literacy had improved.
So, what about the Ashkenazis? Since the 2005 University of Utah paper was published, DNA research by other scientists has shown that Ashkenazi Jews are far less genetically isolated than the paper argued. On the claims that Ashkenazi diseases were caused by rapid natural selection, further research has shown that they were caused by a random mutation. And there is no evidence that those carrying the gene variants for these diseases are any more or less intelligent than the rest of the community.
But it was on IQ that the paper’s case really floundered. Tests conducted in the first two decades of the 20th century routinely showed Ashkenazi Jewish Americans scoring below average. For example, the IQ tests conducted on American soldiers during the first world war found Nordics scoring well above Jews. Carl Brigham, the Princeton professor who analysed the exam data, wrote: “Our figures … would rather tend to disprove the popular belief that the Jew is highly intelligent”. And yet, by the second world war, Jewish IQ scores were above average.
A similar pattern could be seen from studies of two generations of Mizrahi Jewish children in Israel: the older generation had a mean IQ of 92.8, the younger of 101.3. And it wasn’t just a Jewish thing. Chinese Americans recorded average IQ scores of 97 in 1948, and 108.6 in 1990. And the gap between African Americans and white Americans narrowed by 5.5 points between 1972 and 2002.
No one could reasonably claim that there had been genetic changes in the Jewish, Chinese American or African American populations in a generation or two. After reading the University of Utah paper, Harry Ostrer, who headed New York University’s human genetics programme, took the opposite view to Steven Pinker: “It’s bad science – not because it’s provocative, but because it’s bad genetics and bad epidemiology.”
Originally Posted by in Race, Genes, and IQ
In fact IQ is a great example of a trait that is highly heritable but not genetically determined. Recall that what makes toe number genetically determined is that having five toes is coded in and caused by the genes so as to develop in any normal environment. By contrast, IQ is enormously affected by normal environmental variation, and in ways that are not well understood. As Herrnstein and Murray concede, children from very low socio-economic status backgrounds who are adopted into high socio-economic status backgrounds have IQs dramatically higher than their parents. The point is underscored by what Herrnstein and Murray call the “Flynn Effect”: IQ has been rising about 3 points every 10 years worldwide. Since World War II, IQ in many countries has gone up 15 points, about the same as the gap separating Blacks and Whites in this country. And in some countries, the rise has been even more dramatic. For example, average IQ in Holland rose 21 points between 1952 and 1982.
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