Why IQ Tests Don't Measure Intelligence

Consider a surgeon, a composer, an artist, and a physicist. Each is the world's best. Each therefore is highly intelligent as the Oxford English Dictionary defines intelligence:

the ability to acquire and apply knowledge and skills,

And as they are all highly intelligent, then, according to the psychologist's understanding of the term intelligence, they must all have really high IQ's. But do they? And even were it so, what would that mean?

The surgeon for all his astonishing deftness with a scalpel, and his knowledge of human anatomy, may be dumb as a brick at math, and not especially articulate either. The composer probably can't draw, and the artist may be unable to carry a tune. And the physicist,  may, like the great Paul Dirac,  be linguistically monosyllabic. So to say that these highly intelligent people are equally intelligent, even in the unlikely case that they scored equally on an IQ test, would be meaningless. They are not equally intelligent at all. They are each vastly more intelligent, than all the rest in their own particular way.

What's hard to understand about that? Everyone knows that that is how it is. Intelligence is not one thing, one faculty, one gift: it is an array of abilities, each person having intellectual strengths and weaknesses. How then did psychologists come to adopt the seemingly nonsensical idea that one number, the so-called Intelligence Quotient, could measure a persons intellectual worth?

The answer to that question is two-fold. First, IQ testing is like the busted science of phrenology — the reading of cranial bumps: it allows the practitioner to claim to know a person's intellectual standing in the world, and hence their future potential. It is this claimed ability to judge the worth of a man that places the psychologist in a position of authority.

The second reason that psychologists proclaim the power of IQ tests to measure mental horse-power is a piece of mathematical data manipulation invented by a Victorian eugenicist and statistician, Karl Pearson. The math in question is called factor analysis, and what factor analysis does is to examine the relationships among various characteristics of some class of things, for example, towns, countries, planets, acorns, or apples, thereby to discover whether there is a common factor or factors underlying these relationships.

An underlying factor, is exactly what the psychometricians — as the quantifiers of mental capacity call themselves — found when they examined variation from individual to individual in mental abilities. Those who score high on mathematical logic, tend to do relatively well on other tests such as verbal reasoning, or the interpretation of geometric puzzles. This factor, quantified by Pearson's factor analysis, they named "G" for "General Intelligence."

Having gone thus far, it was a small step to the conclusion that a person's mean score on the various components of a test of cognitive abilities was a valid way to estimate General Intelligence, hence the results of tests of multiple cognitive tasks was called an "Intelligence Quotient" or IQ, and the test itself, an IQ test.

This view led to a general belief that intelligence is just one thing, underlain by some as yet unidentified common factor, which determines a person's overall intellectual capacity.

But the correlations among cognitive capacities are low. In fact, mostly very low. See here, for example, where correlation coefficients (r values) among a large number of tests averaged less than 0.3. That means that, on average, less than 10% (r squared values) of the variation in any one ability is explained by variation in any other ability.

So yes, mental capacities share at least one common underlying factor, but its effect is weak, meaning that an individual's relative ability at one kind of mental activity will rarely be an accurate guide to their ability at another type of mental task.

It is the weakness of G, and the dependence upon it of their conception of IQ as a measure of intelligence, that psychologists have been loathe to admit. Thus has emerged a widely held idea that G as estimated from an IQ test score measures the essence of intelligence, just as chip speed measures the power of a computer central processing unit. What this is widely understood to imply is that intelligent mental activity depends on either a common mechanism, or a common feature of nerve cells that dictates the scope and power mental activity. However, the slightest awareness of brain anatomy and physiology would disabuse one of the notion that the brain has anything equivalent to a CPU, or even a uniform functional cellular capacity. On the contrary, different mental activities depend on different neural lobes, networks and ganglia, or on hierarchies of lobes, networks and ganglia.

Moreover, these components of the brain are far from identical in physiology and structure. There are many types of nerve cells or neurons and their supporting glial cells, as there are many different signalling methods within the brain, these involving at least eighty neurotransmitters. Despite the subjective unity of mind, the brain is thus a collection of many neurological machines, each with its own genetic determinants and its own history of past experience.

Thus, G or general intelligence, far from representing a fundamental component of intelligence, reflects only the dependence of the functioning of the entire brain on either other organs or some weakly influential characteristic of all brain tissue.

For example, brains without oxygen die within seconds, which means that brain function depends on lungs, heart and the vascular system. Moreover, without a continuous supply of glucose brains cannot function, which means a dependence on the liver and on the endocrine system that controls blood sugar. And without means to dispose of waste products, the brain is rapidly poisoned, meaning dependence on the kidneys. As to general properties of brain tissue, effective function depends on  many general features such as mitochondria, ribosomes, microtubules, and much else, all of which must function properly or the brain will function poorly or not at all.

Thus the mystery of G is revealed. It is a reflection, simply, of the brain's dependence on the rest of the body and on the cellular machinery common to all nerve cells. If all supporting systems and sub-cellular components are in the highest working condition, then the multiple components of the brain can all function at the peak capacity. But all defects or limitations in the performance of supporting systems and cellular organelles limit mental performance. Thus, beside variation in relative power of the various components of the brain there will be variation from brain to brain due the functionality of the brains support systems and components.

Thus just as a large town will tend to have more crime, traffic congestion and air pollution than a small town, so those with the best overall health and the best cellular machinery, will tend to have higher IQ's than those whose mental function dependent on defective support systems or cellular machinery. But still, among individuals, the big differences in intellect, are on specific tasks not on overall performance, or G, as assessed by a so-called IQ test.

So, yes, IQ-ism is largely bunk and the sooner we're rid of it the sooner will psychologists be able to study intelligence more intelligently.

IQ-ism: the Third Phase in the Development of Psychology as a Pathological Discipline

One of the things I have to tell you about IQ research is this: if you don't buy IQ research, you might as well throw away all the rest of psychology. And the reason for that is that the psychologists who developed "intelligence testing" were among the early psychologists that instantiated the statistical techniques that all psychologists use to verify and test all of their hypotheses. So you end up throwing the baby out with the bath water.

And the IQ people have defined intelligence in a more stringent and accurate way that we have been abnle to define almost any other psychological construct. So if you toss out the one that is most well defined, then you're kind of stuck with the problem [of] what are you going to do with all the other ones that you have left over.... whose predictive validity is much less.
Jordan B. Peterson

In a comment thread at the Unz Review, among the most thoughtful and well-informed participants remarked on  what they held to be the importance of IQ research. The claim prompted me to the following remarks dismissing the entire business of what may be called IQ-ism as, at best, a scholastic blunder of epic proportions, and at worst, a grotesque fraud:

Speaking of "reasons to support IQ research," I would say that there are none. IQ-ism is just a phase in the development of psychology as a pathological intellectual discipline. IQ-ism is the latest in a series of attempts to comprehend the vast complexity of the operation of the brain by alchemically simplistic means.

First, in the history of this crackpot discipline was psychoanalysis, aptly described by Peter Medowar as:

... like a dinosaur or a zeppelin; no better theory can ever be erected on its ruins, which will remain for ever one of the saddest and strangest of all landmarks in the history of twentieth century thought.

Then there was Behaviorism, which sought to explain human behavior and personality in their entirety solely in terms of the acquisition of operant conditioned reflexes. That theory crashed and burned as cybernetics confirmed what Behaviorists had denied, namely, that humans are conscious beings and that what consciousness tells of our feelings and intentions is a valid source of information.

And now we have IQism, which claims to be able to quantify a person's intelligence on a unidimensional scale by means of a simple paper and pencil test involving a few logical puzzles plus, depending on the test of choice, miscellaneous other items.

How do the IQ-ists sell this idea? Primarily by the artful use of language. Their little test, they call an "intelligence test," thereby establishing in the minds of the masses the unquestioned assumption that intelligence is what the IQ-ist's test measures. In fact, however, as a Google search will confirm, intelligence is the ability to acquire and to use information, whereas an IQ test measures neither except in an incredibly limited domain and with a test the results of which are subject to massive circumstantial bias.

But the IQ-ist scam has worked so well for so long that psychology has yet to even broach the real scientific questions that must underlie the measurement of  intelligence: namely, how to measure the capacity for information acquisition; and how to measure skill, effectiveness, Darwinian fitness, or whatever, in the use of information.

When one considers the measurement of intelligence in those terms, one is immediately confronted with the complexity of reality, and in particular, the fact that information is acquired via multiple channels, auditory, olfactory, visual, proprioceptive, etc. with data from each channel processed by a specialized brain module, or probably in most if not all cases, by multiple specialized brain modules.

So now if we take account of the fact that there are hundreds if not thousands of structural genes that impact the development and characteristics of those sensory channels and processing modules, we see that the capacity for the acquisition of information is not dependent on a single characteristic of the brain but on a large collection of independent variables. This fact is well known to common sense. People vary hugely in powers of memory and, moreover, that variation is type specific. Mozart transcribed the entire Allegri miserere after a single hearing, Stephen Wiltshire sketched the whole of Red Square from memory after a brief visit. But, so far as we know, Mozart had no special gift of visual memory, and Stephen Wiltshire is no musical genius. Others do more or less brilliantly remembering faces, voices, poetry, the numbers of pi, conversational tittle tattle, etc., but as far as is known, no one able to remember the first ten thousand places of pi, has composed  a decent symphony or a popular opera.

So in only the matter of data acquisition, we see that intelligence is multiple not unitary. But much more complex to analyse than the capacity for information acquisition is the capacity for the use if information. In fact, perhaps, that is an impossibly difficult challenge. But it is a challenge that must be faced by anyone who claims to measure intelligence in a scientific and quantitative way.

As for the innateness of intelligence, something about which IQ-ists are most emphatic, it is axiomatic that the potentiality is entirely innate. Moreover, we know that there are hundreds, perhaps thousands of genes that direct brain development, plus probably many thousands of hereditary controlling elements, most yet to be identified, that shape the development of the brain and hence intelligence.

But the function of the brain is to record both sensory inputs, i.e., experience, and the internal workings of the brain, i.e., the development of our ideas, both of which shape the way we use information. So it is beyond question that environmental factors, through their effect on the contents of mind, have a huge impact on the degree to which the innate intellectual potential is expressed. Thus focusing on the genetic basis of intelligence to the exclusion of environmental factors, such as education and culture, cannot result in a comprehensive understanding of the phenomenon.

Are You a Mispronunciation Moron?

Over at the Unz Review, a strange concoction of anti-Semitism, Hitler apologetics, racism and IQ-ist fake science, the latest in the promotion of IQ bollocks is the claim that the way you pronounce a few dozen English words pretty well defines you intellectually.

The idea seems more bonkers than most of what Ron Unz publishes since, in Britain at least, pronunciation is chiefly a matter of social class and regional affiliation.

Thus, if you are very high class indeed, you will quite likely pronounce girl as gel.

If you're a graduate of Oxford University, you will pronounce Oxford as Awksfud, off as awf, and Magdalen College as Maudlin College (It's as though they're constantly sucking in their cheeks.).

 If you are from Glasgow, you may pronounce football, as fitbah.

If you are from the English Midlands, you will pronounce the city of Leicester, Lester, and the town of Bicester, Bister.

If you are from one of the more prosperous parts of London, you will pronounce Cardigan Gardens as Caduggan Gardens.

And if you are from certain parts of East London, you will pronounce Heathrow Airport as Eefro Airpor!.

And if your friend is named Mainwaring, he most likely pronounces it Mannering, whereas, if his name is Meagher he probably introduces himself as Marr. However, there can be some flexibility in the pronunciation of names. Thus, when the First World War era politician and crook, Horatio Bottomly, called upon Lord Cholmondley, the conversation with the butler who answered the door went as follows:

Bottomly: My name's Bottomly, I've come to see Lord Chol-mond-ly
Butler: Do you mean Lord Chumley
Bottomly: Yes, tell Lord Chumley it's Mr. Bumley.

But I suppose there is something to be said forUnz promoting this IQ-ist this nonsense. It helps expose the absurdity of the idea that non-entities with a bachelor's degree in Psych. are qualified to assess the intelligence of their mental superiors from Isaac Newton and J.S. Bach to Alan Turing and Richard Feynman: a claim that seems particularly absurd, as these self-proclaimed experts haven't even a decent theory of what intelligence is. All they have, beside the word pronunciation test and other wacky schemes to pigeon-hole you, are a few simple tests of reasoning, verbal, numerical, and diagrammatic, results of which naturally enough correlate moderately well with academic performance, although not quite as well, according to IQ specialist Richard Lynn, as traditional subject-based exams. And, happily for those like Winston Churchill, Prime Minister, victorious war leader, Nobel Laureate in Literature, who languished at the bottom of the class during his school days, neither IQ tests nor exams, let alone pronunciation predict future academic achievement, income, or career success to any useful degree. What such tests may show, is if you are a complete moron, which was the sole purpose of the original intelligence test, that devised by Alfred Binet.

IQ-ism, a Fake Science Serving the Fascist New World Order

Psychologists generally assert that IQ tests provide the best predictive measure of individual life success, hence the need to give everyone an IQ label, the better for schools, employers and the world at large to judge their intellectual merit.

This notion is tremendously appealing to those intent on creating the Fascist New World Order, which is to say a bureaucratic global dictatorship, controlled by the Money Power, which requires a submissive populace brainwashed into a belief in its own mental inadequacy, and therefore, its own incapacity for democratic, national self-government.

What the promoters of IQ-ism assert by implication is that:

You have an IQ less than those set in authority over you, which means that your judgement is invariable inferior to that of those who dictate the conditions of your existence. Hence, cease your clamor, do as you are told, and be content with whatever rights and freedoms we, your rulers, in our wisdom, are prepared to grant you.

Here for instance is Jordan Peterson with expert-level hand-waving, brainwashing and bullying a University of Toronto undergraduate psychology class:

One of the things I have to tell you about IQ research is that if you don't buy IQ research, you might as well throw away all the rest of psychology, and the reason for that (blah, blah, blah (watch it here) Or in other words: Question what I have to say about IQ and you will be judged mentally unfit for education as a psychologist, and you might as well quit the course now.

In a discussion of the recent Boeing 737MAX crashes at the Unz Review, many commentators seemed content to attribute these disasters to the presumed low IQ of the Third World pilots flying the planes. Here, for example, is one that gets right to the point:

Boeing is great/ dumb Third World pilots.

In response to such views, I quoted a couple of paragraphs from an essay on IQ by the well known financial analyst, Nassim Taleb:

“IQ” is a stale test meant to measure mental capacity but in fact mostly measures extreme unintelligence (learning difficulties), as well as, to a lesser extent (with a lot of noise), a form of intelligence, stripped of 2nd order effects — how good someone is at taking some type of exams designed by unsophisticated nerds. It is via negativa not via positiva. Designed for learning disabilities, and given that it is not too needed there (see argument further down), it ends up selecting for exam-takers, paper shufflers, obedient IYIs (intellectuals yet idiots), ill adapted for “real life”. The concept is poorly thought out mathematically by the field (commits a severe flaw in correlation under fat tails; fails to properly deal with dimensionality; treats the mind as an instrument not a complex system), and seems to be promoted by: — racists/eugenists, people bent on showing that some populations have inferior mental abilities based on IQ test=intelligence; those have been upset with me for suddenly robbing them of a “scientific” tool, as evidenced by the bitter reactions to the initial post on twitter/smear campaigns by such mountebanks as Charles Murray. (Something observed by the great Karl Popper, psychologists have a tendency to pathologize people who bust them by tagging them with some type of disorder, or personality flaw such as “childish” , “narcissist”, “egomaniac”, or something similar). — psychometrics peddlers looking for suckers (military, large corporations) buying the “this is the best measure in psychology” argument when it is not even technically a measure — it explains at best between 2 and 13% of the performance in some tasks (those tasks that are similar to the test itself)[see interpretation of .5 correlation further down], minus the data massaging and statistical cherrypicking by psychologists; it doesn’t satisfy the monotonicity and transitivity required to have a measure (at best it is a concave measure). No measure that fails 80–95% of the time should be part of “science” (nor should psychology — owing to its sinister track record — be part of science (rather scientism), but that’s another discussion). — It is at the bottom an immoral measure that, while not working, can put people (and, worse, groups) in boxes for the rest of their lives. — There is no significant correlation (or any robust statistical association) between IQ and hard measures such as wealth. Most “achievements” linked to IQ are measured in circular stuff s.a. bureaucratic or academic success, things for test takers and salary earners in structured jobs that resemble the tests. Wealth may not mean success but it is the only “hard” number, not some discrete score of achievements. You can buy food with a $30, not with other “successes” s.a. rank, social prominence, or having had a selfie with the Queen. Read more

This prompted a response to me from University of London IQ psychologist, James Thompson:

Have you have also read my replies to Taleb? http://www.unz.com/jthompson/swanning-about-fooled-by-algebra/ http://www.unz.com/jthompson/in-the-wake-of-the-swan/

Which provided the opportunity to express more fully than before why I believe that IQ-ism is fake science:

I've had a look. But as I'm sure you will agree, to review your response to Taleb adquately would demand a lengthy paper, which I will not attempt to compose here. I will, though, address the first point that you make in your January 3, article. Taleb criticizes the poor statistics used by intelligence researchers... I have assumed he means that more than half of intelligence research findings are wrong, and for malicious reasons. If this is his point, he is factually wrong. Your assumption is surely incorrect. Taleb neither said nor implied that more than half of intelligence research findings are wrong, for malicious reasons. Rather, he was presumably drawing an inference about the invalidity of most intelligence research findings from the well known "replication crisis in psychology" and other fields of research, and the well known fact that across the board, the majority of research papers are so poorly designed and analysed that most research claims must be false. So no, Taleb is not accusing you or those who labor in the IQ field of malicious fraud. You attempt to bury Taleb beneath a mountain of technical details and journal references that few here will ever read, but you do not confront Taleb's key point, which is that, yes, IQ tests measure something, and yes whatever they measures correlates in some degree with behavior, success, income, whatever, but so what? The key questions Taleb raises to which you offer no answer are: does IQ usefully quantify intelligence as that term is generally understood and as it is defined by the dictionary? and, more fundamentally, is it even theoretically possible to quantify intelligence, as that term is generally understood, by a single number? Taleb answers both questions in the negative. I agree. Furthermore, I believe that if you stopped calling whatever it is that you measure with you tests intelligence, then no one would question your work. Indeed, they might pay it no attention at all, which does raise a question of whether some psychologists, by mislabeling their product, are deliberately selling a bill of goods.

In the event that that draws a crushing rebuttal, I promise to post it here.

So far, all I've had is reference to a fact-free rebuttal by Stephen Pinker:

Irony: Replicability crisis in psych DOESN'T apply to IQ.S. Pinker

Great to be a famous author innit. No need to argue a point. Just assert an opinion and the world will defer — LOL

Except:

Most Reported Genetic Associations with General Intelligence Are Probably False Positives. Psychol Sci. 2012 Nov 1; 23(11): 1314–1323.

Or if you prefer a more mainstream source: The Telegraph's Science Correspondent reports:

IQ tests 'do not reflect intelligence' 

Or something even more downmarket: Daily Mail:

IQ tests are 'meaningless and too simplistic' claim researchers 

And I like this from the Psychologist:

What intelligence tests miss 

It is a profound historical irony of the behavioural sciences that the Nobel Prize was awarded for studies of cognitive characteristics (rational thinking skills) that are entirely missing from the most well-known mental assessment device in the behavioral sciences – the intelligence test. Intelligence tests measure important things, but not these – they do not assess the extent of rational thought. This might not be such an omission if it were the case that intelligence was an exceptionally strong predictor of rational thinking. However, research has found that it is a moderate predictor at best and that some rational thinking skills can be quite dissociated from intelligence.

Perhaps others will join in the amusing quest for quotes sending up S. Pinker.

Related:
CanSpeccy: Posts From the Past: About Intelligence (12)

Posts From the Past: About Intelligence

2020:

Why IQ Tests Don't Measure Intelligence

2019:

The IQ-ist Creed

What Is Intelligence?

IQ-ism, a Fake Science Serving the Fascist New World Order

2018:

Jordan Peterson's hysterical rant about people of low IQ

2017:

Dumb Intelligence Tests: Or Why IQ Testers Need to Improve Their Understanding of Intelligence

IQ-ism, Or Psychologists Pedaling Bunk 

Nation-Destroying Stupidity In the Age of Universal Higher Education

2016:

The stupidity of IQ Testing

2015:

Down With IQ-ism

2013:

IQism, Racism and the Decay of the Great American University