Yeah, it's not. There's no question that culture and development (the nurture) side have an effect, but the point of Rushton's data-based conclusions is that there are genetic differences, on a broad, repeatable scale. The part most people get wrong is that they can't tell the difference between an average and an individual. I.e., the average IQ score for black Americans vs. Thomas Sowell.
Yeah, it's not. There's no question that culture and development (the nurture) side have an effect, but the point of Rushton's data-based conclusions is that there are genetic differences, on a broad, repeatable scale. The part most people get wrong is that they can't tell the difference between an average and an individual. I.e., the average IQ score for black Americans vs. Thomas Sowell.
You can read his book here; focus on the difference between Flynn and Jensen effects: https://archive.org/details/J.PhilippeRushtonRaceEvolutionAndBehaviobOk.xyz/page/n13/mode/2up