In fact, strong attachments were a better predictor of success that IQ or test scores! That's amazing news, because giving our children an attentive caregiver is something we can all do! I think we all know people who are very smart, but ended up making terrible choices and being unhappy. Could this early childrearing be the answer to situations like that? It could also explain why homeschooled children do so much better on tests. Perhaps the early childhood attention they got gave them the head start to enjoy learning for the rest of their lives.
Even if you do not have the money to supply your child with everything you think they need in order to be smart, the good news is that you can create a "home-learning environment" no matter what your income level. Just choose your child's activities and toys carefully. More is not always better, sometimes it's just more. Books, educational toys, and exposing your child to a large vocabulary is all it takes to benefit your child even more than money. Spending time playing and reading with even young children has been shown to greatly increase their adult success. It takes more time, but turning off the TV and devices and actually talking to your kids is what is really going to benefit them.