Thanks, very clear! I guess the position I want to take is just that the data in the post gives reasonable evidence for g being at least the convenient summary statistic in 2 (and doesn’t preclude 3 or 4).
What I was really trying to get at in the original quote is that some people seem to consider this to be the canonical position on g:
Factor analysis provides rigorous statistical proof that there is some single underlying event that produces all the correlations between mental tests.
There are lots of articles that (while not explicitly stating the above position) refute it at length, and get passed around as proof that g is a myth. It’s certainly true that position 5 is false (in multiple ways), but I just wanted to say that this doesn’t mean anything for the evidence we have for 2.
I agree that a simple factor analysis does not provide anything even close to proof of 3 or 4, but I think it’s worth noting that the evidence on g goes beyond the factor-analytic, e.g. with the studies I linked.
Thanks for pointing out those papers, which I agree can get at issues that simple correlations can’t. Still, to avoid scope-creep, I’ve taken the less courageous approach of (1) mentioning that the “breadth” of the effects of genes is an active research topic and (2) editing the original paragraph you linked to to be more modest, talking about “does the above data imply” rather than “is it true that”. (I’d rather avoid directly addressing 3 and 4 since I think that doing those claims justice would require more work than I can put in here.) Anyway, thanks again for your comments, it’s useful for me to think of this spectrum of different “notions of g”.
Thanks, very clear! I guess the position I want to take is just that the data in the post gives reasonable evidence for g being at least the convenient summary statistic in 2 (and doesn’t preclude 3 or 4).
What I was really trying to get at in the original quote is that some people seem to consider this to be the canonical position on g:
Factor analysis provides rigorous statistical proof that there is some single underlying event that produces all the correlations between mental tests.
There are lots of articles that (while not explicitly stating the above position) refute it at length, and get passed around as proof that g is a myth. It’s certainly true that position 5 is false (in multiple ways), but I just wanted to say that this doesn’t mean anything for the evidence we have for 2.
I agree that a simple factor analysis does not provide anything even close to proof of 3 or 4, but I think it’s worth noting that the evidence on g goes beyond the factor-analytic, e.g. with the studies I linked.
Thanks for pointing out those papers, which I agree can get at issues that simple correlations can’t. Still, to avoid scope-creep, I’ve taken the less courageous approach of (1) mentioning that the “breadth” of the effects of genes is an active research topic and (2) editing the original paragraph you linked to to be more modest, talking about “does the above data imply” rather than “is it true that”. (I’d rather avoid directly addressing 3 and 4 since I think that doing those claims justice would require more work than I can put in here.) Anyway, thanks again for your comments, it’s useful for me to think of this spectrum of different “notions of g”.