[okusername]

That's probabaly the wrong causation. Instead, parents of higher intelligence, education and cultures that values education make more money - and not only pass on their genes, but also are more vigillent or capabale to educate their kids.

[Yoric]

Or perhaps they have more time to spend with children, because they don't need to work three jobs, or failing that, can afford to have someone else spend time with their children.

Also, yes, there is a tie between income, education and culture, and it goes both ways. Starting one's life around cultured and educated people does help you grow into someone who has access to a better job, which gives you access to better education and culture, etc.