This study was kind of mediocre...comparing only those who are not religiously affiliated, born-again Protestants and Catholics, and Protestants who don't identify as being born again. None of these are "outside of the mainstream." This study would have been more interesting if it had a better sample representation, including atheism and non-Western religions.
Maybe subscribing to a pre-formed dogma in elementary school and never questioning it again led to brain atrophy. I'm not anti-religious, but I think religion is best served individually, not filtered down through an institution that requires unthinking, whole-sale and lifelong acceptance, and that describes doubt/lack of faith grounds for everlasting torment. If you have your world view handed to you, and forsake a critical analysis of the world you live in, you aren't going to learn too much new.