Certainly modern parenting methods factor into why the late maturity of brains is occurring. Our culture does tend now to idolize little ones, making them feel that everything they do is wonderful and perfect, that our children aren't like "other children" and that our children are better, smarter, savvier than any other kids and that they aren't responsible for anything wrong that they do. American children have more done for them, less responsibility and way more "free time" than ever before. And it really hasn't been a good thing.
However, I personally think it is a bit simplistic to think that over-nurturing parenting styles are the only factor. We also have more toxins in our waters and our lands than ever before. We have toxins in the air we breathe. Our foods are filled with chemicals and toxins. When our children aren't breathing, drinking and eating toxins, we are injecting toxins into their systems along with their vaccines.
As a culture, we have made the choice to allow vile and violent games and movies to be "entertainment" not only for ourselves but for the young also. We offer these entertainments to those whose brains lack the maturity to properly deal with the assault on their senses. Study after study has shown violence as entertainment is harmful to children. Study after study has shown that sitting infants in front of tv, even "good" programs or dvd's such as Einstein's baby, results in shorter and shorter attention spans and more and more dependence on the part of the child to have others constantly entertain them----in very short sound bytes!
It all adds up, and what is mentioned above is only the tippytop of the huge mountain of why this delay in maturity is being noted.
