Earlier quoted context omitted.
The latter 3 are not too interesting IMO, because porn and masturbation have been around for centuries, and whatever effects they've had have become part of society. The first one might be an interesting one to consider. Of course this is assuming children get hold of the pornography at an earlier age than they should and continuously have easy access to it. And in my opinion, the only thing that occurs is that child…
Masturbation is as at least as old as Onan[1], but I doubt porn is a few centuries old. Maybe erotica. [1] http://en.wikipedia.org/wiki/Onan
But my idea of "pornography" was simply depictions of sexual nature (which is centuries old as stated in Wikipedia)