For the general public, the trouble with psychology is that it appropriates common concepts and redefines them in accordance with what it can measure. The result is that the public is taken for a dangerous ride.
Thus, when University of Toronto psychology professor, Jordan Peterson, tells his students that if they "don't buy IQ research" they might as well throw out the rest of psychology because IQ research is the best thing psychology has to offer, he is (a) bullying his students, warning them, in effect, that there is no place for them in psychology unless they buckle under and accept the psychologist's definition of intelligence, and (b) redefining intelligence as what psychological research says it is.
And how do psychologists define intelligence? By an overall score on certain paper and pencil tests of verbal, mathematical competence and the spatial interpretation of line diagrams. From these tests they come up with a number that they call an intelligence quotient, and based on their research, they say this score is the best available indication of a person's life success: it predicts life success better than anything else you can name.
Well the first thing to note is that intelligence assessed the way psychologists measure it considers only a narrow range of human capabilities. So IQ tests measure something very different from what is commonly understood to be intelligence.
According to the commonest dictionary definition, intelligence is "the ability to acquire knowledge and skills." By that definition, the hand to eye coordination of the surgeon, the hand to ear coordination of a violin virtuoso, or the kinesthetic coordination of a gymnast are all forms of intelligence unrecognized by the psychologists, who may dismiss reference to such gifts with a sneer about "prizes for everyone"
But playing the violin like Itzak Perlman constitutes what ordinary folk understand as a display of cleverness, talent or genius, and in the common acceptation of the term as well as by the dictionary definition such cleverness equates to intelligence.
Moreover, the common understanding of intelligence goes far beyond "the ability to acquire knowledge and skills." It includes, as the Oxford Dictionary defines it, "understanding and sagacity," or what one might otherwise call judgement. But beyond understanding and sagacity, intelligence is manifest in the display of wit, which is to say humor, imagination, strategic thinking, quickness of thought, none of which skills are in any apparent way evaluated with an IQ test.
The second thing to note is that when the psychologists say IQ is the best available indication of a person's life success this is not true. Heck, even IQ itself, when measured at one stage in life predicts IQ at another stage in life only poorly. In this Scottish study the correlation between IQ at age 11 and age 90 was 0.54, meaning that only 29% (i.e., r squared) of the population variation in IQ at age 90 was accounted for by variation at age 11. And if you look at the details of the study as it was reported when the subjects were aged 82, you will see that the poor correlation between 11 and 82 was not due solely to deterioration in intelligence with age since some individuals increased in IQ by several standard deviations between ages 11 to 82.
When psychologists talk of "life success" they of course mean success in following a career such as their own, and it is true that IQ test results correlate in some degree with academic achievement, although according to Charles Murray, traditional academic tests do as well or better. In fact, one would expect traditional academic tests to do better, at least for students in certain fields such as history or fine art, i.e., subjects that require judgement and imagination as much as raw verbal or numerical reasoning power. Traditional essay exams also allows the expression of gifts in language use that are beyond the purview of an IQ test.
But in any case, neither IQ tests nor academic performance at one stage in an individual's life predict academic success at another level with any accuracy. Many bright kids manage to be bottom of the class — Winston Churchill who remained in the fourth form for three years and had difficulty gaining entry to the military college at Sandhurst comes to mind, while many a dull drone destined for a career as a tax inspector, orthodontist, or proctologist manages in school to be top of the class.
So academic achievement really doesn't mean a thing. Well actually, reviewing my own experience perhaps it does. Of the only two of my fellow students who received honors from her majesty the Queen, one was absolutely bottom of the class while I, on at least one occasion was top; the other who received a knighthood, gained a lower second class degree while I won the faculty prize. Not fair, is it. But actually Geoff was, and I'm sure still is, a sound fellow: you know, judgement, moral character, diligence, hard work. Allow me therefore to say here, since I don't have his email address, well done Sir Geoffrey.
The important thing to remember about IQ is that it doesn't mean what the psychologists in their eternal quest for power wish you to think it means, and it pretty certainly means nothing whatsoever as far as your own success and happiness in life are concerned.
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