Since much of what people know about the effects of pornography on viewers comes from porn's detractors, here's ome positive mentions of the effects. Unfortunately for the detractors it's all scientific peer-reviewed stuff.
http://www.sexarchive.info/BIB/DIAM/effects_pornography.htm#_ftnf21
"The Effects of Pornography: An
International Perspective#
Milton Diamond, Ph.D.
University of Hawai`i, John A. Burns School of Medicine
Department of Anatomy & Reproductive Biology
Pacific Center for Sex and Society
"CONCLUSIONS
The concern that countries allowing pornography and liberal anti-obscenity laws would show increased sex crime rates due to modeling or that children or adolescents in particular would be negatively vulnerable to and receptive to such models or
that society would be otherwise adversely effected is not supported by evidence. It is certainly clear from the data reviewed, and the new data and analysis presented, that
a massive increase in available pornography in Japan, the United States and elsewhere has been correlated with a dramatic decrease in sexual crimes and most so among youngsters as perpetrators or victims. Even in this area of concern no "clear and present danger" exists for the suppression of SEM.
There is no evidence that pornography is intended or likely to produce "imminent lawless action" (see Brandenberg v. Ohio, 1969). It is reasonable that the U.S. Supreme Court has consistently rejected the principal that speech or expression can be punished because it offends some people's sensibilities or beliefs. Compared with "hate speech" or "commercial speech" there seems even less justification for banning "sex speech."
http:// www. violence. de/prescott/bulletin/article .html
"Body Pleasure and the Origins of Violence"
by James W. Prescott From "The Bulletin of The Atomic Scientists", November 1975
"These figures again raise the question of the special relationship between sexuality and violence. In addition to our rape statistics, there is other evidence that points to preference for sexual violence over sexual pleasure in the United States. This is reflected in our acceptance of sexually explicit films that involve violence and rape, and our rejection of sexually explicit films for pleasure only (pornography). Neighborhood movie theaters show such sexually violent films as Straw Dogs, Clockwork Orange, and The Klansman, while banning films which portray sexual pleasure (Deep Throat, The Devil in Miss Jones). Attempts to close down massage parlors are another example of our anti-pleasure attitudes. Apparently, sex with pleasure is immoral and unacceptable, but sex with violence and pain is moral and acceptable.
A questionnaire I developed to explore this question was administered to 96 college students whose average age was 19 years. The results of the questionnaire support the connection between rejection of physical pleasure (and particularly of premarital and extramarital sex) with expression of physical violence."
http://www.safekids.com/2011/12/17/so-your-kid-is-looking-at-pornography-now-what/
"So your kid is looking at porn. Now what?"
"This column isn’t about young children or children who accidentally come across unwanted sexual material. Those are different issues. The question I want to explore is how a parent should react if they discover their growing child — typically 12 or older — is deliberately looking at sexually explicit material on the Internet.
Nothing new or unusual
First, recognize that there’s nothing new about teens looking at such material.
We didn’t have the Internet when I was 14, but that didn’t stop kids from getting their hands on copies of Playboy. Porn has been around for centuries and we’re far from the first generation of parents who have had to deal with it.
There are a number of reasons why kids look at pornography. For some, it’s to be “cool.” There are reported cases of relatively young children using porn to impress their friends, much as kids sometimes smoke to show their independence.
Sometimes it’s curiosity, but in many cases — especially for males past puberty, it’s for stimulation at times when no one else is around.
Interest in sex and voyeuristic behavior to satisfy sexual urges are completely normal. Whether the young person makes up images in his head, gets them from television shows, movies, magazines or images on the Internet, the process is much the same.
Engage but don’t overreact"