Note however that IQ is not a property of individuals measurable on an individual basis like, say, height or weight is. Its utility lies in its statistical power to predict the average performance of large groups of people. When it comes to testing a specific individual, except perhaps for the greatest extremes (like diagnosing mental retardation), the fact that you achieved a certain score gives only probabilistic information about you.
Moreover, for individuals scoring in high percentiles, to which you probably belong if you find the stuff written on this blog interesting, there are strong diminishing returns to high scores even statistically. It’s like e.g. wondering about your height with regards to your basketball prospects: your potentials are indeed likely to be much greater if you’re, say, 6′2“ rather than 5′10”, but if you already know that you’re more than a few inches above average, the difference between, say, 6′9“ and 6′5” won’t matter anywhere as much.
Moreover, for individuals scoring in high percentiles, to which you probably belong if you find the stuff written on this blog interesting, there are strong diminishing returns to high scores even statistically.
This doesn’t seem to be so up to at least the 1 in 10,000 level. However, I agree that the predictive power of theses tests is still small relative to the remaining sources of variation (although it is one which we are relatively good at measuring) and they shouldn’t be over-weighted.
Strictly speaking, the weight of an individual can fluctuate even in the course of a day, due to the consumption or excretion of fluids. It can fluctuate more permanently when you lose or gain body mass in the form of fat or muscle.
I’m under the impression that, in contrast, measured I.Q. of an individual is supposed to stay more or less within the same approximate range throughout the course of that individual’s life (with obvious caveats for brain damage, senility, and as you say, exceptional individuals at the extremes of the distributions).
From what I know, there are high correlations between an individual’s IQ test scores at different times, especially in the short run. Depending on the study, it ends up being something like 0.95 in the short run and 0.7-0.9 between different ages (I’m just quoting rough ballpark figures from memory—they of course differ between studies and age spans). Some impressively high correlations were found even in a study that compared test scores of a group of individuals at 11 and 77 years of age.
On the other hand, people can be coached to significantly improve their IQ test scores. At least so says Rushton, of all people.
Then of course, as with all issues where you might want to make some sense of what IQ scores exactly imply, the Flynn effect throws a wrench into any attempt to come up with a neat, plausible, and coherent theory.
But even regardless of all this, one should still not forget that the connection between IQ and any realistic measure of success is itself just probabilistic. This is especially true for high-scoring individuals: instead of worrying whether one’s score is 120, 130, 140, or whatever, one would be better advised to worry about whether one is deficient in other factors important for success and accomplishment in life.
On the other hand, people can be coached to significantly improve their IQ test scores. At least so says Rushton, of all people.
I’d point out that this should be extremely obvious a point, given how some subtests are Gc-loaded. You can ‘improve’ your IQ by studying some vocab, quite aside from the usual practice effects.
(And one of the standing questions about dual n-back is whether it doesn’t (partially) amount to training for matrix-style Gf IQ tests.)
Why would that be true? Isn’t it relative difference in height that matters for basketball? I would have thought that 6′9″ would be great news, all other things being equal.
Note however that IQ is not a property of individuals measurable on an individual basis like, say, height or weight is. Its utility lies in its statistical power to predict the average performance of large groups of people. When it comes to testing a specific individual, except perhaps for the greatest extremes (like diagnosing mental retardation), the fact that you achieved a certain score gives only probabilistic information about you.
Moreover, for individuals scoring in high percentiles, to which you probably belong if you find the stuff written on this blog interesting, there are strong diminishing returns to high scores even statistically. It’s like e.g. wondering about your height with regards to your basketball prospects: your potentials are indeed likely to be much greater if you’re, say, 6′2“ rather than 5′10”, but if you already know that you’re more than a few inches above average, the difference between, say, 6′9“ and 6′5” won’t matter anywhere as much.
This doesn’t seem to be so up to at least the 1 in 10,000 level. However, I agree that the predictive power of theses tests is still small relative to the remaining sources of variation (although it is one which we are relatively good at measuring) and they shouldn’t be over-weighted.
Thanks for the link, I wasn’t familiar with these results.
Strictly speaking, the weight of an individual can fluctuate even in the course of a day, due to the consumption or excretion of fluids. It can fluctuate more permanently when you lose or gain body mass in the form of fat or muscle.
I’m under the impression that, in contrast, measured I.Q. of an individual is supposed to stay more or less within the same approximate range throughout the course of that individual’s life (with obvious caveats for brain damage, senility, and as you say, exceptional individuals at the extremes of the distributions).
From what I know, there are high correlations between an individual’s IQ test scores at different times, especially in the short run. Depending on the study, it ends up being something like 0.95 in the short run and 0.7-0.9 between different ages (I’m just quoting rough ballpark figures from memory—they of course differ between studies and age spans). Some impressively high correlations were found even in a study that compared test scores of a group of individuals at 11 and 77 years of age.
On the other hand, people can be coached to significantly improve their IQ test scores. At least so says Rushton, of all people.
Then of course, as with all issues where you might want to make some sense of what IQ scores exactly imply, the Flynn effect throws a wrench into any attempt to come up with a neat, plausible, and coherent theory.
But even regardless of all this, one should still not forget that the connection between IQ and any realistic measure of success is itself just probabilistic. This is especially true for high-scoring individuals: instead of worrying whether one’s score is 120, 130, 140, or whatever, one would be better advised to worry about whether one is deficient in other factors important for success and accomplishment in life.
I’d point out that this should be extremely obvious a point, given how some subtests are Gc-loaded. You can ‘improve’ your IQ by studying some vocab, quite aside from the usual practice effects.
(And one of the standing questions about dual n-back is whether it doesn’t (partially) amount to training for matrix-style Gf IQ tests.)
Why would that be true? Isn’t it relative difference in height that matters for basketball? I would have thought that 6′9″ would be great news, all other things being equal.