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The existence of 'general intelligence' is a pretty different question from "can we measure 'general intelligence'"? The analysis demonstrated does not account

by yxwvut 5y ago

The existence of 'general intelligence' is a pretty different question from "can we measure 'general intelligence'"? The analysis demonstrated does not account for the possibility of confounding by some external factor unrelated to intelligence (income, tutoring, etc), which is what many will argue. At best you can claim a notion of 'general test-taking ability' with no ambiguity. Once you recognize the problem-solving patterns in these tests, doing well becomes significantly easier, which is an almost inescapable measurement problem. And re: normal distribution implying some fundamental truth, the same can be said of an iterated guessing game (eg: take the sum of your correct guesses over 100 coin-flips - the population's scores on that game will be normally distributed).

runarberg 5y ago
Also regarding the normal distribution. As pointed out by Stephen J. Gould, intelligence is not normally distributed. The IQ test results are. But IQ test results are standardized to be normally distributed. It is an assumption that intelligence is normally distributed, and evidence suggests it is not. More likely—if it exists at all—it is log-normally distributed. Psychometricians believe that there is some fundimental truth in the normal distributions, and then standardize their test scores so that it follows this distribution in order to gain validity. It is a pseudo-scientific self fulfilling prophesy.
- deleted 5y ago
  [deleted]
- NoImmatureAdHom 5y ago
  This viewpoint is generally acknowledged as wrong by the scientific community, and Gould is generally acknowledged as a hack who sold out by telling people what they wanted to hear in exchange for book sales.
  - runarberg 5y ago
    > Gould is generally acknowledged as a hack who sold out by telling people what they wanted to hear in exchange for book sales. It’s funny you should say that. Because I generally regard the authors Gould is addressing in his book Mismeasure of Man, including S.G. Morton, C. Murray, A. Jensen, etc. as hacks that used questionable scientific means to tell people what they wanted to hear—namely the superiority of white men—in exchange for book sales.
- xyzzyz 5y ago
  Stephen J Gould was a scientific fraud, with an ideological axe to grind, and repeatedly lied and misrepresented reality to smear what he saw as his ideological opponents. His most famous work on the topic, The Mismeasure of Man, for example, discussed Morton’s skull measuring experiments, who found that people of various races have different average cranial capacities. This is now a well established scientific fact, nevertheless Gould found this so offensive, that he claimed Morton fudged results by putting finger on the scale, based on no evidence whatsoever, simply disbelieving this sort of human variation between populations. Morton’s skulls have been in fact remeasured, and found to match Morton’s measurements within error margin appropriate to the method. This has been communicated to Gould himself, but he did not issue any correction or indeed mention any of it for the second edition of his book, showing clear evidence for his ideologically driven lack of scientific integrity.
  - ZeroGravitas 5y ago
    This is a suspiciously specific rebuttle. Morton was wrong. https://en.wikipedia.org/wiki/Samuel_George_Morton https://en.wikipedia.org/wiki/Samuel_George_Morton It's great that you found some super specific thing where his wrong answer isn't provably the result of fudging of numbers, but he's still wrong for various reasons. And someone else measured other skulls at roughly same time and came to the correct conclusion that you couldn't really make any such claim based on the data they had.
    - xyzzyz 5y ago
      Morton was wrong on many counts, to be sure, just as any scientist worth of salt must be. However, he was not wrong on the very thing Gould accused him of, which was ideologically based fudging of data, something that Gould was in fact guilty himself.
      - ZeroGravitas 5y ago
        He did ideologically fudge his data, though, to the point that he could, incorrectly, make the claim that he already believed, but that wasn't actually there in the data. Gould's point was about inadvertant bias in science and he was correct in this case.
- duvenaud 5y ago
  I'm not sure I understand the objection. I agree that standardizing to a normal distribution might be arbitrary, but how could one argue what the true transform of the distribution is? After all, a log-normally distributed variable is just exp() of a normally distributed one. Would anything be different if instead of IQ, we called it log-IQ?
  - runarberg 5y ago
    I don’t think there is any research into finding “the true distribution” of intelligence. But intuitively intelligence should have a pretty skewed distribution with a long tail on the lower end where people with varying levels of mental handicap are skewing it, most people above average and a handful of people slightly more intelligent then the mode. This aligns with observation of non-IQ measures of intelligence like school grade or the SAT. This also works intuitively how we think of IQ. If you have an IQ of 70 there is probably something wrong, if you have an IQ of 130, you are probably just a normal person that might be slightly smarter then me. The problem is assuming standard normal distribution as the true distribution for intelligence is simply bad science. Whatever the distribution truly is (if there even is one) it is not this one. And then psychometricians (including OP) use this as a point in favor of the validity of IQ as a good measure.
    - duvenaud 5y ago
      I don't understand what one could mean by the true marginal distribution of a latent quantity that's only defined in terms of its joint distribution with measurements. What difference would it make if we transformed IQ scores to a skewed distribution? To give an uncontroversial example, we use logarithmic scales for earthquakes precisely because the underlying phenomenon is heavy-tailed. It's just for convenience, it doesn't imply anything about the phenomenon being quantified.
      - runarberg 5y ago
        From OP: > The mere fact that the results of these types of tests on large population groups tend to follow a normal distribution is alone good evidence that they're indicative, as in most things diverse large population groups tend to fall on a normal distribution. The claim here is that OP is wrong. Firstly OP is wrong because normal distribution is not a sufficient indicator for some underlying phenomenon. Or as yxwvut puts it: > [...] normal distribution implying some fundamental truth, the same can be said of an iterated guessing game (eg: take the sum of your correct guesses over 100 coin-flips - the population's scores on that game will be normally distributed). And then secondly because intelligence doesn’t even follow a normal curve (only IQ does because it is transformed to). What matter here is not the true distribution of intelligence. I’m not even sure there is one. What matters is that proponents of general intelligence use the normal distribution of IQ as a justification. By arguing that intelligence does not fall on normal distribution but rather on a skewed distribution, I’m simply pulling the rug away from this argument. I admit this is not a strong argument against the existence of general intelligence, since if there exists such a thing, then there is nothing that says such a thing couldn’t exist on a skewed distribution (except psychometricians and proponents of IQ which only accept standard bell curve [I wonder why]). However in this subthread we’re only trying to correct OP’s claim that a normal distribution is indicative for general intelligence.
NoImmatureAdHom 5y ago
The challenge for you becomes: find some set of traits where people are systematically "good" at them but bad (low) on g. (It doesn't exist)
- yxwvut 5y ago
  You're making the same mistake of conflating 'good' with 'scores high on a measure'.
  - kbelder 5y ago
    What is something that you can be demonstrably good at, that is immeasurable?
    - yxwvut 5y ago
      Virtually everything even slightly abstracted from directly quantifiable tasks: sporting skill, driving skill, intelligence, etc. None of those are measurable without significant confounding or a 'dumbing down' to some adjacent task (that still probably suffers from some degree of confounding via 'teaching to the test'). Sport performance depends on your cohort, driving accident rates depend on your environment, intelligence tests have a learned component, etc. Trying to develop a system that allows rank-ordering of ability along an axis that isn't subject to influence from an irrelevant external factor is impossible.
      - dTal 5y ago
        It kinda sounds like you're using "abstracted" to mean "poorly defined".
- nialse 5y ago
  There is some evidence that bodily-kinesthetic and musical ability does not correlate that well will g as other things, but they're still very correlated. See for instance: Castejon, J. L., Perez, A. M., & Gilar, R. (2010). Confirmatory factor analysis of Project Spectrum activities. A second-order g factor or multiple intelligences?. Intelligence, 38(5), 481-496. Visser, B. A., Ashton, M. C., & Vernon, P. A. (2006). Beyond g: Putting multiple intelligences theory to the test. Intelligence, 34(5), 487-502.

by yxwvut 5y ago

runarberg 5y ago

Also regarding the normal distribution. As pointed out by Stephen J. Gould, intelligence is not normally distributed. The IQ test results are. But IQ test results are standardized to be normally distributed. It is an assumption that intelligence is normally distributed, and evidence suggests it is not. More likely—if it exists at all—it is log-normally distributed. Psychometricians believe that there is some fundimental truth in the normal distributions, and then standardize their test scores so that it follows this distribution in order to gain validity. It is a pseudo-scientific self fulfilling prophesy.

deleted 5y ago
[deleted]
NoImmatureAdHom 5y ago
This viewpoint is generally acknowledged as wrong by the scientific community, and Gould is generally acknowledged as a hack who sold out by telling people what they wanted to hear in exchange for book sales.
- runarberg 5y ago
  > Gould is generally acknowledged as a hack who sold out by telling people what they wanted to hear in exchange for book sales. It’s funny you should say that. Because I generally regard the authors Gould is addressing in his book Mismeasure of Man, including S.G. Morton, C. Murray, A. Jensen, etc. as hacks that used questionable scientific means to tell people what they wanted to hear—namely the superiority of white men—in exchange for book sales.
xyzzyz 5y ago
Stephen J Gould was a scientific fraud, with an ideological axe to grind, and repeatedly lied and misrepresented reality to smear what he saw as his ideological opponents. His most famous work on the topic, The Mismeasure of Man, for example, discussed Morton’s skull measuring experiments, who found that people of various races have different average cranial capacities. This is now a well established scientific fact, nevertheless Gould found this so offensive, that he claimed Morton fudged results by putting finger on the scale, based on no evidence whatsoever, simply disbelieving this sort of human variation between populations. Morton’s skulls have been in fact remeasured, and found to match Morton’s measurements within error margin appropriate to the method. This has been communicated to Gould himself, but he did not issue any correction or indeed mention any of it for the second edition of his book, showing clear evidence for his ideologically driven lack of scientific integrity.
- ZeroGravitas 5y ago
  This is a suspiciously specific rebuttle. Morton was wrong. https://en.wikipedia.org/wiki/Samuel_George_Morton https://en.wikipedia.org/wiki/Samuel_George_Morton It's great that you found some super specific thing where his wrong answer isn't provably the result of fudging of numbers, but he's still wrong for various reasons. And someone else measured other skulls at roughly same time and came to the correct conclusion that you couldn't really make any such claim based on the data they had.
  - xyzzyz 5y ago
    Morton was wrong on many counts, to be sure, just as any scientist worth of salt must be. However, he was not wrong on the very thing Gould accused him of, which was ideologically based fudging of data, something that Gould was in fact guilty himself.
    - ZeroGravitas 5y ago
      He did ideologically fudge his data, though, to the point that he could, incorrectly, make the claim that he already believed, but that wasn't actually there in the data. Gould's point was about inadvertant bias in science and he was correct in this case.
duvenaud 5y ago
I'm not sure I understand the objection. I agree that standardizing to a normal distribution might be arbitrary, but how could one argue what the true transform of the distribution is? After all, a log-normally distributed variable is just exp() of a normally distributed one. Would anything be different if instead of IQ, we called it log-IQ?
- runarberg 5y ago
  I don’t think there is any research into finding “the true distribution” of intelligence. But intuitively intelligence should have a pretty skewed distribution with a long tail on the lower end where people with varying levels of mental handicap are skewing it, most people above average and a handful of people slightly more intelligent then the mode. This aligns with observation of non-IQ measures of intelligence like school grade or the SAT. This also works intuitively how we think of IQ. If you have an IQ of 70 there is probably something wrong, if you have an IQ of 130, you are probably just a normal person that might be slightly smarter then me. The problem is assuming standard normal distribution as the true distribution for intelligence is simply bad science. Whatever the distribution truly is (if there even is one) it is not this one. And then psychometricians (including OP) use this as a point in favor of the validity of IQ as a good measure.
  - duvenaud 5y ago
    I don't understand what one could mean by the true marginal distribution of a latent quantity that's only defined in terms of its joint distribution with measurements. What difference would it make if we transformed IQ scores to a skewed distribution? To give an uncontroversial example, we use logarithmic scales for earthquakes precisely because the underlying phenomenon is heavy-tailed. It's just for convenience, it doesn't imply anything about the phenomenon being quantified.
    - runarberg 5y ago
      From OP: > The mere fact that the results of these types of tests on large population groups tend to follow a normal distribution is alone good evidence that they're indicative, as in most things diverse large population groups tend to fall on a normal distribution. The claim here is that OP is wrong. Firstly OP is wrong because normal distribution is not a sufficient indicator for some underlying phenomenon. Or as yxwvut puts it: > [...] normal distribution implying some fundamental truth, the same can be said of an iterated guessing game (eg: take the sum of your correct guesses over 100 coin-flips - the population's scores on that game will be normally distributed). And then secondly because intelligence doesn’t even follow a normal curve (only IQ does because it is transformed to). What matter here is not the true distribution of intelligence. I’m not even sure there is one. What matters is that proponents of general intelligence use the normal distribution of IQ as a justification. By arguing that intelligence does not fall on normal distribution but rather on a skewed distribution, I’m simply pulling the rug away from this argument. I admit this is not a strong argument against the existence of general intelligence, since if there exists such a thing, then there is nothing that says such a thing couldn’t exist on a skewed distribution (except psychometricians and proponents of IQ which only accept standard bell curve [I wonder why]). However in this subthread we’re only trying to correct OP’s claim that a normal distribution is indicative for general intelligence.

NoImmatureAdHom 5y ago

The challenge for you becomes: find some set of traits where people are systematically "good" at them but bad (low) on g. (It doesn't exist)

yxwvut 5y ago
You're making the same mistake of conflating 'good' with 'scores high on a measure'.
- kbelder 5y ago
  What is something that you can be demonstrably good at, that is immeasurable?
  - yxwvut 5y ago
    Virtually everything even slightly abstracted from directly quantifiable tasks: sporting skill, driving skill, intelligence, etc. None of those are measurable without significant confounding or a 'dumbing down' to some adjacent task (that still probably suffers from some degree of confounding via 'teaching to the test'). Sport performance depends on your cohort, driving accident rates depend on your environment, intelligence tests have a learned component, etc. Trying to develop a system that allows rank-ordering of ability along an axis that isn't subject to influence from an irrelevant external factor is impossible.
    - dTal 5y ago
      It kinda sounds like you're using "abstracted" to mean "poorly defined".
nialse 5y ago
There is some evidence that bodily-kinesthetic and musical ability does not correlate that well will g as other things, but they're still very correlated. See for instance: Castejon, J. L., Perez, A. M., & Gilar, R. (2010). Confirmatory factor analysis of Project Spectrum activities. A second-order g factor or multiple intelligences?. Intelligence, 38(5), 481-496. Visser, B. A., Ashton, M. C., & Vernon, P. A. (2006). Beyond g: Putting multiple intelligences theory to the test. Intelligence, 34(5), 487-502.