Interestingly enough, no, not really. If you want to look it up, they call it the 'Matthew Effect' (from the biblical parable in matthew about the servants being given tithes by the master and using them).

Kids who read more get more from what they read later. If you've read ten books and your neighbor only one, you retain more and understand more from the next book you've read. Unless you completely stop reading, or they suddenly start reading way more, the earlier start with your reading will give you far greater benefits. A humorous little fact is that you can predict college gpa better with the amount of books read by age five (I think, it might be by grade five, it's been a while since I read the study) than by the SAT/ACT tests.

No they don't. Not in my experience.

Remember, half of people are below average and average isn't that impressive.