"Please elucidate the nature of this "direct" impact."
You are kidding right? You cannot figure it out for yourself?
The largest viewer category for hardcore porn is teenage boys between the ages of 12-17.
"Ninety-one percent of junior high school age and older boys and eighty-two percent of junior high school age and older girls, admitted seeing X-rated, hardcore pornography; two-thirds of the males and forty percent of the females tried some of the behavior; twenty-five percent of the males and fifteen percent of the females admitted doing some of the things within a few days after exposure." (Dr. Jennings Bryant as reported to Dr. Victor Cline.)
http://www.capalert.com/pornandkids.htm