1255: Arthur Jensen
Author(s): Scott Douglas Jacobsen
Publication (Outlet/Website): Medium (Personal)
Publication Date (yyyy/mm/dd): 2025/05/30
1969
“We can attribute no particular portion of intelligence to heredity and no particular portion to the environment.”
1970
“The layman usually asks: ‘Is intelligence due to heredity or environment?’ The scientist promptly answers: ‘Both.’”
“It is equivalent to arguing that a column of mercury in a glass tube cannot be regarded as synonymous with temperature, or that temperature cannot really be measured with a thermometer.”
1972
“The IQ, interestingly enough, shows a higher degree of assortative mating in our society than any other measurable human characteristic… the correlation between spouses’ intelligence test scores averages close to +0.60.”
“There is a perhaps understandable reluctance to come to grips scientifically with the problem of race differences in intelligence… There is often a failure to distinguish clearly between scientifically answerable aspects of the question and the moral, political, and social policy issues.”
1978
“There is no way to discriminate or distinguish between the average ten‑year‑old black and the average 8½‑year‑old white. The tests look the same, but the black child has a lower mental age. It looks more like a developmental lag than a cultural difference.”
1980
“As the number of studies increases… the investigator is then prompted to examine the anomalous study to find out in what crucial conditions it differs from other studies yielding contrary results. Scientific investigation is the analysis of variables, not just a box score tallying how many studies are pro or con some conclusion.”
“One cannot treat a fever by throwing away the thermometer.”
“Compensatory education has been tried and it apparently has failed.”
“The four socially and personally most important threshold regions on the IQ scale are those that differentiate with high probability between persons who… can or cannot graduate from an accredited four‑year college with grades that would qualify for admission to a professional or graduate school (about IQ 115).”
1980
“Most standard tests of intelligence and scholastic aptitude measure a general factor of cognitive ability that is common to all such tests — as well as to all complex tasks involving abstraction, reasoning, and problem-solving.”
1981
“Should the discovery of fire have been avoided because arsonists can misuse it? Any kind of information can be misused by those who are determined to do so. The place to stop the misuse of knowledge is not at the point of inquiry, but at the point of misuse.”
1987
“It was little consolation that I had been ‘in good company’ in my ignorance of genetics; in fact, that aspect of the situation seemed even more alarming to me. I was overwhelmed by the realization of the almost Herculean job that would be needed to get the majority of psychologists and educators fully to recognize the importance of genetics for the understanding of variation in psychological traits.”
“Any argument between persons who were not in at least ninety percent agreement on the issues was a total waste from a scientific standpoint, although he conceded that a poorly informed audience might find it entertaining.”
1998
“It is a common misconception that psychological measurements of human abilities are generally more prone to error or inaccuracy than are physical measurements… The reliability coefficients for multi-item tests of more complex mental processes, such as measured by typical IQ tests, are generally about .90 to .95. This is higher than the reliability of people’s height and weight measured in a doctor’s office!”
2000
“It is amazing to see a reference to Wissler’s (1901) primitive study, which has been used in generations of psychology textbooks to discredit the Galtonian analytical‑physical approach to the study of individual differences in mental ability. The great amount of fruitful research in recent years showing highly significant and theoretically important relationships between chronometric measures of information processing speed in various experimental tasks has completely contradicted the conclusions nearly every psychologist in the past (except Spearman, 1904) drew from Wissler’s conspicuously flawed study.”
“Indeed, the uncritical acceptance of Wissler’s findings inhibited research on mental chronometry for more than half a century. In recent years, all these variables have been found to be correlated with g.”
“At this point in history, however, arguments that genetic factors do not play a major role in human variation in mental abilities, particularly in the component of test score variance identified as g, can truly be likened to the creationists’ rejection of evolution by natural selection.”
“But the most frequently heard objection to further research into human genetics is that the knowledge gained might be misused. I agree. Knowledge also, however, makes possible greater freedom of choice. I completely reject the idea that we should cease to discover, to invent, and to know (in the scientific meaning of that term) merely because what we find could be misunderstood, misused, or put to evil and inhumane ends. For a scientist, it seems to me, this is axiomatic.”
“We must clearly distinguish between research on racial differences and racism. Equality of rights is a moral axiom: it does not follow from any set of scientific data.”
“I have always advocated dealing with persons as individuals, and I am opposed to according differential treatment to persons on the basis of their race, color, national origin, or social‑class background. Purely environmental explanations of racial differences in intelligence will never gain the status of scientific knowledge unless genetic theories are put to the test and disproved by evidence.”
2002
“I have only contempt for people who let their politics or religion influence their science. And I rather dread the approval of people who agree with me only for political reasons.”
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