I find things like that hard to perfectly square with observations like the Flynn Effect (“the substantial and long-sustained increase in both fluid and crystallized intelligence test scores that were measured in many parts of the world over the 20th century”): https://en.wikipedia.org/wiki/Flynn_effect
The Flynn effect has its own little nurture vs nature debate within it.
Was it better medicine and food that stopped both your height and your brain from being stunted?
Or was it people being trained from birth for a world where doing abstract brain teaser tests was important.
Notably both cause problems for the typical racist's use of IQs. If you can improve the scores with such interventions it makes a lot of their genocidal policy recommendations seem less scientifically sound, so they put a lot of effort into denying that IQ scores can be improved by interventions. Even though they have been, for decades.
Are you suggesting our brains are getting better? I find it far more likely that our improved education techniques and our skyrocketing access to information as being the cause.
Firstly, this is completely orthogonal. But it's also improper reasoning.
If Neanderthal had bigger brains (they did) or had different cognitive abilities, there's a chance they were baseline smarter than homo sapiens at the time.
Being perhaps a little smarter doesn't mean you win the evolutionary game. There are so many factors at play.
The Flynn effect isn’t real.
Why? Draw the line backwards, and in a couple of decades you are down at 0 IQ. That's clearly absurd, you can't draw any conclusions of IQ significantly before 1950 from how the line behaves after 1950.