[TaupeRanger]

This is pretty silly. Your memory obviously gets a little worse as you age, with most of the noticeable decline coming in very late age. But the artificial measures/definitions of things like "fluid" intelligence are mostly useless. Just pulling up one of the studies cited in the article which is supposed to measure the "reasoning" aspect of "fluid" intelligence, presents a huge host issues immediately [1].

Aside from the lack of randomization, you have obvious validity problems. The interpretation of nebulous words like "reasoning" as being accurately measured by e.g. accuracy on Raven matrices (construct validity?) and younger participants having been primed by recent test-taking experience while real-world reasoning skills aren't really reflected - it's all quite specious.

Real-world decisions are value-laden and constraint-laden! "Intelligence" does not mean "maximizing abstract pattern detection". If you keep your brain active with a wide range of creative, interesting problems, you will be fine apart from neurodegenerative diseases, which have real effects.

https://pubmed.ncbi.nlm.nih.gov/30211596/

[scotty79]

> accuracy on Raven matrices

That's exactly how intelligence in measurement setting is defined. That's how the word is defined. What's interesting is that it correlates with so many unrelated real world outcomes. And other definitions and measurements do not.

[TaupeRanger]

You're apparently alluding to "IQ" without saying it. But once you get above "low IQ" performance on these tests, their predictive value trends to zero. The correlation is very one sided (as explained by people like Nassim Taleb). Also, when I say "real world problem solving", that doesn't mean "income". A predictor can look powerful even if it's not measuring real-world skills, as long as institutions use it to distribute opportunities and labels that later show up as "job success".