Adam Brownell
2 min readDec 31, 2021


Hey Rex, thanks for the response!

I’m happy to respond to the 3 questions you posed in the opening paragraph, as best I can:

Q: Why don't you think g as well as analytic ability is impacted by nutrition and education and so on?

(1) I actually do think that g, analytic ability, and all other measures of intelligence are impacted by environmental factors such as nutrition and education; that is my Utility argument. I focused on IQ but I’d imagine most areas of intelligence can be greatly swayed by one’s environment.

Q: Why don't you think that g is just analytic ability because that's really what correlates?

(2) After reading this question over a few times, it sounds like you’re taking the position that g-factor is really a measures of “just” analytical ability and not general intelligence, and so IQ is measuring g-factor. If this were the case I would agree with you. My argument was focused more on addressing the idea that IQ measures general intelligence, which g-factor is considered to measure (“General intelligence, also known as g factor, refers to the existence of a broad mental capacity that influences performance on cognitive ability measures” from

Q: Have you noted the difference between cross-sectional and longitudinal studies of cognitive aging? The longitudinal ones generally show less decline vs cross-sectional ones, suggesting that in fact older people do, to some extent, simply have lesser cognitive abilities (of the analytical sort that tend to be tested on cognitive aging tests).

(3) Cognitive aging is a really interesting subject, please send me a few papers you like on the subject! I believe the discrepancies you noted between the analytical decline based on age within a generation vs. across generations are the same observations that underly the Flynn Effect.

I would also push slightly on the idea that “little is accomplished” by noting a flaw in JP’s argument. Maybe in a literal sense there is little accomplished in this conclusion, but the point of this article was to help others process/qualify arguments around the relationship between IQ Scores and real world outcomes beyond the viral JP video. So if this conclusion helps a few individuals develop a more nuanced understanding of what IQ Scores, then this is an accomplishment worth mentioning.

And absolutely agree with your aside that we are not developing IQ in all people as best we could.

Please let me know if I misunderstood any of your positions!