But all these questions point to culture differences as I pointed out in my previous post, assuming no genetic root causes.
"There had, in fact, been evidence for a long time that poor children fell behind rich and middle-class children early, and stayed behind. But researchers had been unable to isolate the reasons for the divergence. Did rich parents have better genes? Did they value education more? Was it that rich parents bought more books and educational toys for their children? Was it because they were more likely to stay married than poor parents? Or was it that rich children ate more nutritious food? Moved less often? Watched less TV? Got more sleep? Without being able to identify the important factors and eliminate the irrelevant ones, there was no way even to begin to find a strategy to shrink the gap."
Further in the piece is this observation from some research:
"Hart and Risley showed that language exposure in early childhood correlated strongly with I.Q. and academic success later on in a childÂ?s life. Hearing fewer words, and a lot of prohibitions and discouragements, had a negative effect on I.Q.; hearing lots of words, and more affirmations and complex sentences, had a positive effect on I.Q. The professional parents were giving their children an advantage with every word they spoke, and the advantage just kept building up."
And then this: