So “The Bell Curve” differs from 19th century Christianity?
As with any kind of thinking, it can be used or misused.
One of the authors of the book died before it hit the bookstores. I caught the other author on CSpan before I bought the book. He talked about the learning that children are exposed to in their homes before they reach school age, while their brains undergo their maximum lifetime growth.
Cultures can either provide or deprive children of the kind of stimulus that can impact their lives for better or worse.
It's been years since I read the book, but I don't think it went into the genetics of race, which would be a pointless discussion. Arguing the superiority of one kind of culture over another, OTOH, is something that could improve the lives of some if it wasn't against the rules of PC to do so.