Thread by @MatsVinnaren

Arthur R. Jensen on Eysenck (hanseysenck.com by @KirkegaardEmil):
“Eysenck was a kind of genius...or at least a person of very unusual talents, and the only person of that unusual caliber that I have come across in the field of psychology."

amren.com/news/2018/10/a…

"Still, Prof. Jensen did not abandon his conventional beliefs in the power of environment to raise or lower intelligence, and went on to publish 30 papers and build a non-controversial reputation before he finally concluded that Eysenck and Burt were right."

"In 1969 he shocked the country with his famous Harvard Educational Review article, “How Much Can We Boost IQ and Scholastic Achievement?” This 123-page paper, which demolished the view that proper instruction could raise children’s IQs, may have been the most sensational..."

"...scholarly article ever published in America. Although only five percent of it was about racial differences in intelligence — which Prof. Jensen concluded had a substantial genetic component — it was enough to make him a pariah and a household name"

"“One of the tenets of my own philosophy is to be as open as possible and to strive for a perfect consistency between my thoughts, both spoken and published, in their private and public expression. This is essentially a Gandhian principle, one that I have long considered..."

"...worth striving to live by.”"

"He refuses to think something just because others do. “If anything, my attitudes are based on a rather lifelong antipathy to believing anything without evidence,” he says, noting that he was “more or less kicked out of Sunday school” because..."

"...he did not see enough evidence for the things he was told to believe."

"“I have only contempt for people who let their politics or religion influence their science,” he says."

🙌

"Group differences are an important aspect of the study of intelligence, and to dodge the race question would have been, for him, an act of intellectual cowardice."

👏

"He says that since the appearance of his famous article, he has become even more convinced that education and social milieu have little effect on IQ, and that it is almost misleading to talk about “environmental” influences on intelligence:"

"I prefer the terms ‘genetic influences’ and ‘nongenetic influences’ because so many people think environment means just the psychological, social, and cultural milieu in which a person grows up. These nongenetic influences begin virtually at the moment of conception."

"They have direct effects on the brain’s development and are probably the most important of all environmental effects on g [general cognitive ability — see below]. They include intrauterine conditions related to the mother’s age, health, and blood type; incompatibility..."

"...between mother and fetus; nutrition; certain medications; and substance abuse. Then there are perinatal conditions such as anoxia, birth trauma, and extreme prematurity. And also post-natal conditions — mainly early nutrition and the various childhood diseases.”"

"“these microenvironmental effects may contribute as much as 20 to 25 % of the total variance in IQ”"

"home or social environment may influence what field a person may enter, and what he does with his intelligence, but they have little effect on intelligence itself. "

"People who believe in the power of environment over intelligence should expect a deaf child, who has heard nothing his entire life, to be severely afflicted. In fact, children born deaf perform normally on non-verbal intelligence tests."

"strong group tendencies at many different genetic locations add up to consistent racial differences. These differences are more than skin deep: “Given the fact that as many as 50 percent of the genes in the human genome are involved with the structural and functional aspects..."

"... of the brain, it would be surprising indeed if populations that differ in a great many visible characteristics and in various genetic polymorphisms...did not also differ in some characteristics associated with the brain, the primary organ of behavior.”"

"As Prof. Jensen points out, in nature, when animals differ in form and appearance, they differ in behavior, and there is no reason to think humans are any different. He notes that Robert Plomin of England has already identified four genes, or DNA segments, that affect IQ."

"As more are discovered, it is extremely unlikely that the different forms of these genes will be distributed equally among all races."

“The fact that g is more strongly genetic than most other psychological variables is not really controversial among empirical researchers..."

"... in this field,” says Prof. Jensen. “It is highly controversial only in the popular media. Just try to find any real controversy among the experts who know the research on this issue.”"

"Even when it comes to racial differences, he can find no one in the field willing to debate him seriously. Non-genetic arguments simply do not hold up: “The purely environmental or ‘culture-only’ theory . . . has had to fall back on a series of ad hoc hypotheses."

"They lack any underlying theoretical basis and are often inconsistent with each other, since each one was invented to explain some single phenomenon.”"

👆important point

"“Undergraduate psychology textbooks are misinforming hundreds of thousands of college students on this subject every year,” says Prof. Jensen. “It almost sickens me even to thumb through most of the introductory psychology books published in recent years."

“I myself don’t feel inclined or properly qualified to think through what others may consider the ‘politics’ of my work.”...he adds, “My aim in this is to produce good science, as best I can, not to change the world or push any social or political program.”"

True scientist.

"Also: “The acquisition of factual knowledge should stand apart from policy. But to be effective, policy making must take into account our best factual knowledge about the alternatives under consideration.”"

"“Too many politicians take research results less seriously than purely political considerations. The popular media seldom help either, as they are also more politically than scientifically oriented.”"

"“[T]here is a greater disparity in birthrates between poorly educated and well-educated Blacks than is true for Whites. If this trend continues over a number of generations, the Black and White populations will be pulled increasingly further apart in average IQ"

"Reducing population seems more urgent to me than eugenics per se. But unless people in the upper half of the bell curve for g have at least as many offspring as those of the lower half, there will inevitably result a dysgenic trend in the overall ability level and the..."

"...educability of the population as a whole.”"

"“No First World country can expect to have an open border with a Third World country without serious risk to its own economy and quality of life.” This view follows logically from an understanding of..."

"...group differences in ability, but politicians who refuse to countenance even the possibility of these differences, will not take even the most basic steps to save our civilization."

I agree.