Driving 1% of the variance is not the same as reducing your brain mass by 1%. Without knowing anything about the brain, Reducing your brain mass by 1% sounds pretty crazy to me, and probably has extreme negative effects very far before hitting 100% loss.
It’s not absurd to say the negative effects of air pollution on this specific outcome are mostly negligible but still not want air pollution for other reasons. Which is a hypothetical statement of course because we don’t have any data here.
It’s not absurd to say the negative effects of air pollution on this specific outcome are mostly negligible but still not want air pollution for other reasons. Which is a hypothetical statement of course because we don’t have any data here.