Attacking IQ test is like vaccine denialism. People don’t like the fact that requiring individuals to cooperate can enhance health outcomes for the group as a whole. Similarly, people don’t like the idea that some individuals are just born smarter than other individuals.
> People don’t like the fact that requiring individuals to cooperate can enhance health outcomes for the group as a whole.
I am not certain where you are deriving this claim from.
> Similarly, people don’t like the idea that some individuals are just born smarter than other individuals.
Nor this claim, as well.
I have had many discussions on the topic of IQ, and I have never once seen anybody ever argue that there is no variance in human intelligence. There is a large range of variance in every human attribute. That is not the focus of the debate. Rather, most of the debate seems to be surrounding the construct validity of IQ. Statistical validity != construct validity.
There's no debate on construct validity of IQ among the experts in the field. The consensus position is that IQ tests measure something real, that the tests enjoy extremely high measurement invariance (which implies construct validity), and that the results have extremely high predictive validity (relative to literally anything else in the entire field of psychology). The current debate is more along the lines, whether the contribution of genes to variance in IQ is closer to 30% or to 80%.
Wait, this comment starts out with an assertion about one scientific question (the construct validity of a quantitative psychological metric) and ends with a statement about the range of a totally different question, and it's one studied by different fields than the former question.
I’m really struggling to understand what your point is. The person I replied to was wrong as to where the current debate is among experts, so I pointed it out, and gave an example of where the debate currently is. Is that really so strange thing to say?
Sure. But in science, we regularly postulate the existence of some construct, and confirm that construct by conducting many empirical tests that return results consistent with the existence of that construct. General intelligence is like that. We can’t see it directly. But we have myriad results that are statistically consistent with its existence.
Results consistent with the existence of a construct are not sufficient evidence for the existence of a construct. We can talk about statistical correlations till the Sun goes down, and I will not dispute that this ethereal 'g-factor' can infer minor to moderate predictions in some domains of people's lives at a population level.
However, I have one question. What evidence is there that this 'g-factor' is actually representative of general intelligence? You may not use the correlation values used to derive the g-factor to support your argument. My understanding is that correlations cannot be used to explain the general factor because the general factor should be what explains the correlations.
If you are interested, I implore you to read this blog from the statistician, Cosma Shalizi, of CMU. His explanation is far better than anything I could attempt to make.
> If you are interested, I implore you to read this blog from the statistician, Cosma Shalizi, of CMU. His explanation is far better than anything I could attempt to make.
Ah, this essay is very, very good. I’m not surprised, Shalizi is a genius, but I hadn’t read this particular one before. Thanks for the link.
Sorry, what exactly do you mean by "is representative of general intelligence"? This is a very abstract statement. What does this mean in scientific, empirical terms? What kind of facts we would observe in the world where this is true? What empirical observations we'd make in the world where it's false?
> Sorry, what exactly do you mean by "is representative of general intelligence"? This is a very abstract statement.
No need to apologize. Perhaps my g is too low to describe my thoughts properly.
> "is representative of general intelligence"?
This factor that is derived from the positive correlations, g, is called general intelligence. So, g is nominally general intelligence, but is g actually what the name implies? One can take n number of positively correlated but independent things, and there will always be a some factor that can be derived from it. However, that does not mean the underlying factor is necessarily causal.
> This is a very abstract statement.
We are discussing abstract concepts.
> What does this mean in scientific, empirical terms?
That causality would be scientifically and empirically verifiable.
> What kind of facts we would observe in the world where this is true? What empirical observations we'd make in the world where it's false?
Alas, that is precisely the point I was trying to paraphrase from Shalizi. Whether g be true or false -- the result wouldn't look any different. The methodology being used cannot determine what is true nor false, and that is the crux of this entire problem.
One can take n number of positively correlated but independent things, and there will always be a some factor that can be derived from it.
I hope you understand that your vague question cannot be seen as equivalent to this rather more concrete statement. That’s why I asked for clarification, and your patronizing comments were really not called for.
In any case, Shalizi is very wrong, probably because he is entirely unfamiliar with the literature. He is wrong on multiple accounts.
First, yes, any number positively correlated measurements will yield a common factor. However, when talking about g, this is not an artifact of how we constructed IQ tests. Shalizi says:
What psychologists sometimes call the “positive manifold” condition is enough, in and of itself, to guarantee that there will appear to be a general factor. Since intelligence tests are made to correlate with each other, it follows trivially that there must appear to be a general factor of intelligence.
But this is just not true. Tests are not made to correlated with each other. Any time anyone attempts to construct a test of general mental ability, we always find the same g factor, even if they explicitly attempt to make a battery that tries to measure distinct, uncorrelated mental aptitudes. Observe how Shalizi fails to provide a single example of a test that does not exhibit the positive manifold with other tests.
Second, unlike Shalizi, we know that g is the predictive component of the IQ tests. IQ predicts real world outcomes very well, but what is really interesting is that the predictive power of individual subtests of an IQ test is practically perfectly correlated with g-loadings of the subtest. This would be very surprising if g was just a statistical artifact.
Shalizi says
So far as I can tell, however, nobody has presented a case for g apart from thoroughly invalid arguments from factor analysis; that is, the myth.
But this is just baffling if you have any familiarity with the literature.
Whether g be true or false -- the result wouldn't look any different. The methodology being used cannot determine what is true nor false, and that is the crux of this entire problem.
That’s just not true. For example, if g was a statistical artifact, one of the hundreds of intelligence tests devised would have not exhibited the positive manifold with all the others. It would not be correlated with heritability. It would not be correlated with phenotype features like reaction time. The world where g is a statistical artifact looks much different than our world.
> I will not dispute that this ethereal 'g-factor' can infer minor to moderate predictions in some domains of people's lives at a population level
The U.S. military won’t hire people below an 83 IQ to peel potatoes, because experience shows that such people can’t effectively be trained. So it’s more than just “minor” predictions.
One, you are conflating IQ and g, which are not the same thing. IQ is a proxy for the measurement of g, but it does not measure g directly.
Two, the military does not administer protected IQ exams, but rather, the ASVAB which correlates with IQ.
Three, our entire global society does not revolve around who can do what for the military.
Four, what can someone with an IQ of 84 do that one with an IQ of 83 cannot?
Five, the US military has plenty of uses for low scores. If one can't peel potatoes, then I'm sure the military would just send them out to stomp for land mines. However, Federal law is what disallows this, not the military: https://codes.findlaw.com/us/title-10-armed-forces/10-usc-se...
And why do you think Congress has passed this law? What prompted them to micromanage the military in this manner? I encourage you to research this topic, “McNamara’s folly” will serve as a good starting keyword. Spoiler: it has everything to do with unsuitability of low IQ enlisted.
FWIW, ASVAB is an IQ test. Any intelligence researcher will tell you so, because it exhibits the usual positive manifold, you find the usual g factor in it, and it shows high correlation with other IQ test. The military doesn’t usually call it as such for political reasons, but will happily admit in private that ASVAB and WAIS measure the same thing: https://web.archive.org/web/20200425230037/https://www.rand....
I don’t mean to suggest that an IQ test doesn’t have any value, only that they don’t account for many subtleties across (sub)cultural boundaries and are too heavily considered in determining one’s intellect, and often worth, by society.
You’re using Motte-and-Bailey tactics to conflate IQ test results with vaccines denialism, on the basis that they are both “for the greater good”, which conveniently paints my point in a certain political light. How exactly does selectivity on the basis of IQ test results “enhance health outcomes for groups as a whole”? Maybe you could back up this argument with some historical context.
> “Similarly, people don’t like the idea that some individuals are just born smarter than other individuals.”
What data do you have to support this claim? And how much of this inherent intellect factors into IQ test results?
> You’re using Motte-and-Bailey tactics to conflate IQ test results with vaccines denialism
No, I’m pointing out that in both cases people attack the science because the implications of the science are in tension with their ideological priors. The fact that top-down coercion is an effective response to pandemics is inconvenient for libertarian-conservatives. Likewise, the fact that people differ in their intellectual capabilities from birth is inconvenient for liberal egalitarians.
> Likewise, the fact that people differ in their intellectual capabilities from birth
Yes, of course people differ in intellectual capabilities at birth. That is not the argument. The argument is how much that actually impacts IQ test score results.
Your point suggests that “science” supports the idea of IQ being predetermined at birth.
> Likewise, the fact that people differ in their intellectual capabilities from birth is inconvenient for liberal egalitarians.
It is? Egalitarianism is usually considered to be the position that all humans have equal moral worth, not the position that all humans have equivalent physical and mental capacities. Not even actually existing Communists believed the latter, as far as I’m aware.
But just to double check:
> Egalitarian doctrines are generally characterized by the idea that all humans are equal in fundamental worth or moral status. As such, all people should be accorded equal rights and treatment under the law.
Nor does the existence of special laws or practices concerning low (or high, for that matter) IQ people pose any great obstacle to egalitarianism, assuming the laws or practices in question do not infringe upon moral personhood.
Rawls is a typical egalitarian philosopher and he takes care to account for these natural variations in the human condition during both the classic _A Theory of Justice_ and the modern “restatement” in _Justice as Fairness_.
Attacking IQ is nothing whatsoever like vaccine denialism. The valid/meaningful uses of IQ are widely debated in several hard science fields. That's not true of vaccines.
> ttacking IQ is nothing whatsoever like vaccine denialism. The valid/meaningful uses of IQ are widely debated in several hard science fields
You’re shifting the goal posts from the first sentence to the second sentence. What I said was: “IQ is real and highly heritable.” Responding to that by asserting that IQ tests are “skewed” and culturally biased, as OP did, is up there with vaccine denialism.
If you want to make a more nuanced point about what you can use IQ to prove, sure, that’s up for debate. But that’s not what we were talking about.
