IQ is also highly heritable: https://pmc.ncbi.nlm.nih.gov/articles/PMC5985927.
No amount of education, experience, and grit can turn a 100 IQ person into Einstein. IQ is a massive multiplier.
It's also worth noting that none of these individuals ever took an IQ test. Their genius is entirely recognized through their work. Which again raises the question of what exactly IQ testing and what IQ is adding to our understanding of exceptional ability.
It appears that over a century of research in psychometrics has demonstrated nothing we already could not infer. We do not need some boring puzzle test to tell us someone with Down syndrome will not be a Nobel Prize winner. Nor do we need some boring puzzle test to tell us that von Neumann or Mozart had godlike childhood abilities and could maybe make large contributions for humanity.
Here is the abstract from the original paper: https://journals.sagepub.com/doi/abs/10.2466/pms.1989.69.1.2...
> The purpose of this research was to assess how well success in early combat training was predicted by scores on a test of general intelligence
It seems this research pertains to early combat training and not broad, post-training success in one's military career. Not to mention the research is essentially predicting test performance from test performance. I imagine the same predictions can be made about one's two-mile run and one's three-mile run.
> Analysis indicated that intelligence test scores AND run time significantly predicted success, each adding to the prediction provided by the other.
Which is not surprising. It shows that intelligence is just one of the multiple contributing factors. Being exceptionally tall is essential in the NBA, but being exceptionally tall, alone, is insufficient to make it to the NBA.
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.
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.
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.
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.
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.
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.
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...
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....
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.
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?
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.
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.
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.
https://en.wikipedia.org/wiki/Egalitarianism
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_.
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.
It's one thing to call out an interesting paper; it's another to act as if the matter has been settled simply by pointing to SIBS.
Find me any study that shows that IQ is more strongly correlated with SES than with parental IQ.
For the intuition think of height - a malnourished child will not reach their “genetic” height. A fully nourished child will be limited by their “genetics”. Why wouldn’t other biological characteristics be similar?