I am really tired of people talking about correlation and causation and completely ignoring carefully hedged phrases. Can we save them for when articles actually make concrete claims about causal links? There’s still interesting stuff here to discuss, and you can even soapbox your favorite theory. But there’s little to gain from actually discussing the (obvious) lack of causal link here.

Unless you can point out how you’d improve the study—it’s not entirely obvious to me what the next step would be as I’m not a scientist.

Fyi... in the abstract of the actual paper that the article is based on, the authors used less hedging and suggested more of a cause & effect:

https://www.sciencedirect.com/science/article/pii/S0049089X1...

Even if the underlying reality is that growing up around books is an effect of a shared hidden (genetic or otherwise) cause, the fact that it is a predictor even after for controlling for the identified alternative factors is quite a significant result.

(Though, as other comments point out, self-reporting may be a problem, though “people that are more successful than expected for their occupation, education, and parental education tend to overreport the number of books they grew up with compared to less successful individuals” would be an interesting result in its own way.)