In the Christmas edition of Weltwoche, psychologist Elsbeth Stern gave an enlightening interview on the heredity of intelligence. In it, she concluded that variations in intelligence are 100% genetically determined, “when all people find conditions to develop their intelligence optimally.” This statement can be seen as truly indisputable but also as a given, at least since the results of the research on twins. However, it is also clear that a challenging and intellectually encouraging environment and a good education have a positive effect on measured intellectual capacity. Conversely, a background lacking in education, an environment without challenges, lack of or poor school education can negatively affect measurable intellectual activity.

Through tests of intelligence, measured variations in intelligence, therefore, fundamentally always have a hereditary and an environmental component. Thus, we speak of genotypical, or inherited intelligence, and phenotypical, or intelligence influenced by environmental factors.

Intelligence of Twins

Intelligence tests today measure pretty reliably the differences of intellectual capacity, and thus allow a good comparability of intellectual performance capacity. The results are also stable in the longitudinal comparison for the individual as soon as adulthood is reached. Only in advanced years do the test results deteriorate.

The test results, of course, are not regarded individually as to which parts are determined genetically and which parts environmentally.

However, we are not totally helpless here. With complete heredity, the correlation of variations in intelligence between physical siblings or parents and their children must lie at 50 percent, that of identical twins, however, amounts to 100 percent. The influence of environmental components can thus be calculated by distinguishing between test groups where, in one case, the test individuals have grown up with their parents and siblings, and in the other case separately from them. Such categorizations allow for a tighter perimeter in the components of heredity.

The results for identical twins who were separated after birth and those separated as adults are especially enlightening. Measured intelligence matched up to 80 percent among them. On the safe side, one acts with the conclusion that the measured variations in intelligence in latitudinal comparison are 50 to 80 percent hereditary. With the lower bounds, the consideration is taken into account for those case groups in which the test individuals come from very different educational levels or cultures.

Yellow Beats White

The influence of the environment upon the measured level of intelligence has also been discussed for some decades under the key words “Flynn Effect.” Intelligence tests are constantly normalized so that the average test result amounts to 100 points for a representative random sample. From time to time a new normalization is necessary because the average test results increase over decades. American psychologist James R. Flynn has been investigating this phenomenon for a few decades, thus one talks of the Flynn Effect. The increase in the educational level and the greater intellectual demands of modern society apparently cause persistent training effect that leads to the increase in intellectual capacity. The Flynn Effect, however, is not an argument against the fundamental heredity of intelligence, which Flynn himself constantly emphasizes.

Two questions inevitably come up in the heredity of intelligence, that cover a minefield in their analysis, namely:

1 – the definition of measured intelligence variations between ethnicity or races;

2 – the class-specific effect of differing reproduction rates (number of children) upon averagely inherited intelligence.

Since the beginning of systematic IQ measurements, the results for Ashkenazic Jews (or those that come from Europe) lie in average at around a standard deviation (or 15 IQ points) over the results for other whites and the results for the black population in the US on average around a standard deviation under the result for whites. The gap, though, has reduced somewhat in the last few decades. Also, the results for eastern Asian nations and the descendants of immigrants from these regions lie above the average results for whites. In the measured average results for Africa, Turkey, the Near and Middle East, and for immigrants from these regions, the performance, however, is the opposite.

This, therefore, is not trivial because the results of intelligence measurements stand in very close correlation with the average educational performance (for example, as it is measured in the Pisa test or in the test for college entrance in the US, the SAT test), but also quite closely with achieved career and social positions, income, and even with life expectancy.

Europe receives its immigrants primarily from Turkey, Africa, and the Near and Middle East. In the US, however, besides the immigration from Central and South America, immigration from the Far East dominates. The same also applies for Australia and Canada. In these countries, immigration increases the educational capacity on the basis of their structure of origin, in Europe, however, the structure of immigration decreases the average educational capacity.

Besides the targeted control of immigration, the answer to this notable trend for Europe can only come through better early childhood education and increased educational effort for all children and adolescents to enable them to use their genetic intelligence potential the best they can.

In this respect, one can only agree with Elsbeth Stern and all the other education researchers.

No answer can be derived directly from the group-specific varying results of intelligence tests (regardless of whether they deal with ethnic groups or various social strata) to which part the variations are culturally determined and to which part they are genetically determined. Where these variations show as stable over generations, this question loses practical significance anyway because extremely stable cultural factors have the same effects as genetic differences.

Where the Star Professor Errs

An answer, though, can’t be: no answer! However, one behaves in a way open to scientific attack and carelessly when, like Elsbeth Stern – and here is where the enlightening part of her interview in Weltwoche begins – in the search for truth, she makes compromises in favor of political correctness and thereby avoids recognizable erroneous statements and logical errors.

Out of concern, that the halted force of evolutionary selection would lead to a reduction in intelligence, like that which US evolution geneticist Gerald Crabtree expressed, she says: “I think that is senseless. Because the characteristics of evolutionary selection don’t have much to do with intelligence. [.?.?.] What we understand today about intelligence didn’t exist in prehistoric times at all. There were physical forces that were primarily crucial for survival.

More intelligent, Fewer children

If in evolution it was primarily a matter of physical forces, as Elsbeth Stern claims, then the giant dinosaur tyrannosaurus rex should still rule the world, however, at least among the primates, the gorilla would have had to thwart the development of humanity through natural selection, and today, instead of man, populate the world in the billions (Eur. ‘milliards’). She primarily passes over Crabtree’s core argument that the level of our intellectual and emotional abilities are so fragile just because it depends on so many genes.

“The the consistency of intelligence within families isn’t all that great. Children are only moderately similar to their parents in this respect. Through the recombination of the genes, less intelligent parents can have gifted children – and vice versa. Because the genes responsible for the development of intelligence are recombined at conception.”

The fact that genes are recombined at conception is common knowledge. Otherwise it isn’t easy to bring this statement into agreement with the stand of science. This is as follows:

– With complete heredity of intelligence, the IQ correlation between identical twins would have to lie at 1. According to studies of twins, it lies at 0.86 for twins who grew up together; for those who grew up separately, it lies at 0.78. According to this, around 80 percent of measurable intelligence is hereditary.

– For parents and children, fraternal twins and siblings with two common physical parents, the IQ correlation with full heredity would have to amount to 0.50. In fact, with a common home for parents and children it comes to 0.42; for siblings, 0.47; with separation through adoption, 0.24.

Smart parents, of course, could just as well have a stupid as two blue-eyed East Frisians could have a brown-eyed daughter. The latter occurrence, however, doesn’t change any of the fact that eye color is completely hereditary. In the above-cited empirically ensured assumptions of heredity, it cannot persist without consequences if the level of reproduction negatively correlates with the parental genotypical intelligence over longer periods of time. This means that on average the number of children drops with an increasing degree of education of the parents and vice versa. We have been observing this very thing for some decades in Germany, and it is shamefully becoming gradually more of an issue, for example, when the government’s Federal Institute for Population Research writes: “A portion of the German low-fertility situation can be explained by the low birth level among the highly qualified.”

Following this in particular: If being highly qualified stands only partly in correspondence with genotypically inherited intelligence, then a long-term lower birth rate of highly qualified people cannot persist without effects on average genotypical intelligence. This is a purely logical truth that one can dispute at most over the magnitude and the practical significance in the short run. Elsbeth Stern dodges this problem by posing the absurd claim: “Only then is a slight reduction of the intelligence of a population imaginable if all people with an IQ over the average of 100 would have absolutely no children over a longer period.” It appears with Elsbeth Stern as though the fear of the controversial argument is leading to a self-imposed interdiction of thought.

In the question of the varying separation of blacks and whites in IQ tests, Stern turns the burden of proof around:

“There is no evidence that races differ in intelligence if they are supported similarly.”

The interviewer briskly produces the title “Blacks aren’t more stupid” from this. Now that’s exactly what cautious Elsbeth Stern isn’t saying. There truly is no evidence for that, and in addition, the claim wouldn’t be very conclusive that natural selection, which is bound with evolution, which, besides skin color, has led to various capabilities in sports, various hereditary sicknesses, various temperaments and various medication intolerances, would spread a broad bow somewhat principally around the characteristic of intelligent capability of all things.

The subject is, of course, laden with taboo, and therefore many researchers stop at a certain point. James R. Flynn makes it clear in his most recent publication that the Flynn Effect cannot be used as proof that the measured differences between blacks and whites is environmentally conditioned. Ultimately, the variance remains undefined.

What I Never Said

At a certain point, interviewer Alex Reichmuth interjects: “German publicist Thilo Sarrazin warns that less intelligent immigrants from the islamic region will reduce the intelligence of overall society – because they bear more children than others.” Apparently Alex Reichmuth hasn’t read my book “Germany is abolishing itself,” otherwise he would have noticed that the heredity of intelligence plays absolutely no role in the discussion of immigration and integration. It comes more in play in the analysis and evaluation of class-specific, varying reproduction rates in Germany. This set of facts has nothing to do with the issue of immigration and integration, even if it does overlap with it somewhat.

Using an example to explain this: Of course, a Turkish schoolboy whose parents came from Anatolia has it more difficult because of lacking stimuli at home than a child born and educated in Germany, and in an intelligence text he would presumably come out worse. But that doesn’t have to mean that this Turkish schoolboy has an inherited lower intelligence than the German schoolchild. This can only be determined when both pupils have the same conditions in order to develop their inherited intelligence optimally.

Elsbeth Stern doesn’t necessary correct the incorrect statement of the interviewer in her answer, but rather gives the answer: “Not much can be made of that. Thilo Sarrazin goes on the basis of naïve belief that a certain gene determines intelligence.” I have never claimed that. Also, Elsbeth Stern has apparently not read my book. That is even more astounding, as she did a few interviews over it right after the appearance of the book. Apparently she has not used the two years to catch up on what she has missed.

Why Primates Stand Out

I wrote much way in “Germany is abolishing itself” – and I find myself truly in the mainstream of science with it:

“Since Charles Darwin published his work “The Origin of the Species” In 1859, and Johann Gregor Mendel his essay “Experiments on Plant Hybrids” in 1865, it is clear that living nature – including man – develops through mechanisms of selection and inheritance of characteristics. Belonging also to hereditary characteristics belong the capabilities of the brain. This is the only way possible for mammals to develop differing intelligence profiles and levels of intelligence in fundamentally similar basic structures of the brain, so that the primates especially stand out among the mammals, and that man even more distinguishes himself from the rest of the primates through his intelligence.”

I don’t say one word about the role of individual genes, and nowhere do I speak of an “intelligence gene.” Moreover, inherited intelligence, as well as body size and a multitude of characteristics of humans and other living beings, are dependent upon so-called traits, and therefore, upon hereditary characteristics that result from the collaboration of numerous genetic factors. With the rejection of an “intelligence gene,” Elsbeth Stern starts a phoney debate over that from which genetic research has long since departed. The very one who demonstrates this is Gerald Crabtree whom she criticizes. He goes particularly on the assumption that the collaboration of 2000 to 5000 genes is necessary for the proper function of our intellectual capacity.

I will end with a quote from John Stuart Mill, which I found with James R. Flynn: “When you suppress an idea, you suppress every debate it might inspire for all ­time.”

(Thilo Sarrazin in week before last’s WELTWOCHE. He writes often there! Thanks for the tip from Freespeech!)

Posted by kewil on PI / Translation: Anders Denken

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