There's a good proof of HBD here in Business Insider.
As I said earlier, BI is mostly crap, but they know their audience. Do you imagine the WSJ making an article on the Rothschilds? They're not supposed to exist, you know. They're a myth, a conspiracy theory, like Jewish influence in the USA.
Well they're very real, and doing very well. Privilege! You may say. Well sure. But come on, privilege doesn't make you a good violinist. Or it doesn't assure that your wineries or horse collections don't lose money. They are doing well because they are well bred. Well Nat doesn't look very bright, but maybe that's just me.
I always thought that the so called 'Regression to the mean' was just the result of rich and successful people marrying beautiful women, who aren't maybe that bright. So the offspring of a smart-but-horny father and a hot-but-dull mother is a regressed to the mean child. It seems that the Rothschilds have been choosing their mates well though. So their offspring don't show much regression. As I said elites tend to attract good genes, which makes them stable. When they don't, they decay.
But Jews, or at least elite Jews, care very much about how they mix their genes with. See Amy Chua's husband, it's a pity they didn't have boys.
Do they teach HBD in the Talmud or something? In centuries time they will talk about the Era of Jewish Dominance, and they will attribute it to their ancient understanding of eugenics. They let their left half of the Bell Curve marry off and assimilate, while the elite kept attracting other ethnies' elites and raising the children as Jewish. She couldn't complain about their dominance. We should do what they do.