Intelligence is far too complex to be meaningfully described with a single number like IQ. Measures of physical capability don't suffer from this issue - a person might be strong, or they might be fast, and everyone knows that the power lifter and the marathon runner use wildly different training regimens to improve their abilities.
If physical capabilities are highly trainable, up to some genetic limit that the vast majority of people never even get close to, then it seems that intelligence must work the same way - e.g. prodigious feats of memorization can be achieved via training regimes (memory palaces etc.), as can one's three-dimensional visualization skills (e.g. a chessboard layout, or rotating a platonic solid, etc.) or the ability to rapidly construct arguments using logic and reason - but we don't seem to be able to classify different areas of mental ability as easily as with physical abilities.
Sadly, this is one of those politically difficult topics as the blank slatists and the genetic determinists (Lysenko vs. Galton) have tried to use all kinds of pseudoscience to support their ideological arguments, when the underlying point is just that training your mind is as beneficial as training your body, and everyone should do it at least to some extent.
However iq is the most correlated number in psychology. It’s a heavy predictor of many many things. It’s the one thing in psychology that has the most scientific validation.
Yes iq can’t measure everything that intelligence represents. But it does measure something extremely important and meaningful to us.
I think wealth might be more correlated, as it can be estimated without testing based on tax data. It's also a heavy predictor of many, many things, with scientific validation. Including IQ test scores.
Then my main point is that wealth and/or income is likely more studied than IQ, because it is/they are easier information to acquire. Even in psychology, I suspect it's quicker to assess someone's "socioeconomic status" than IQ.
The article you linked me to is paywalled. By "wealth" I mean family wealth even when one is 12 years old and have no income. The abstract says of another line of research: "Sibling comparisons ensure factors like the resources available during childhood, the impact of growing up in particular neighborhoods and genetic predispositions are all controlled, without explicitly adding these variables to the research."
If they normalize for parental wealth, then the paper you linked to concerns a different topic.
If physical capabilities are highly trainable, up to some genetic limit that the vast majority of people never even get close to, then it seems that intelligence must work the same way - e.g. prodigious feats of memorization can be achieved via training regimes (memory palaces etc.), as can one's three-dimensional visualization skills (e.g. a chessboard layout, or rotating a platonic solid, etc.) or the ability to rapidly construct arguments using logic and reason - but we don't seem to be able to classify different areas of mental ability as easily as with physical abilities.
Sadly, this is one of those politically difficult topics as the blank slatists and the genetic determinists (Lysenko vs. Galton) have tried to use all kinds of pseudoscience to support their ideological arguments, when the underlying point is just that training your mind is as beneficial as training your body, and everyone should do it at least to some extent.