Effects of pornography
The effects of pornography on individuals or their sexual relationships depend on the type of pornography used and differ from person to person. Pornographic material has been studied particularly for associations with addiction as well as effects on the brain over time. Some literature reviews suggest that pornographic images and films can be addictive, particularly when combined with masturbation, while others maintain that data remains inconclusive. Other research has looked at pornographic material's relation to sexual violence, with varying results.
Methodology and hypotheses
Issues with research
Pornography has many different forms which are difficult to cover in blanket form. Pornographic internet videos, for example, have been found to have different effects on viewers than material such as pornographic magazines. Within the field of pornography research, there are also other challenges that arise due to strong opinions and feelings on the topic. Confirmation bias has been prevalent on both sides due to societal taboos surrounding pornography. Studies have looked into both negative effects of pornography as well as potential benefits or positive effects of pornography. A large percentage of studies suffer from methodological issues. In one meta-study by researchers at Middlesex University in England, over 40,000 papers and articles were submitted to the team for review: 276 or 0.69% were suitable for consideration due to the low quality of research within the field.Addiction
is a purported behavioral addiction characterized by compulsive, repeated use of pornographic material until it causes serious negative consequences to one's physical, mental, social, and/or financial well-being. However, there is no diagnosis of pornography addiction in the current Diagnostic and Statistical Manual of Mental Disorders. The DSM-5 considered the diagnosis of hypersexuality-related behavioral disorders, but rejected it because "there is insufficient peer-reviewed evidence to establish the diagnostic criteria and course descriptions needed to identify these behaviors as mental disorders." Instead, some psychologists suggest that any maladaptive sexual symptoms represent a manifestation of an underlying disorder, such as depression or anxiety which is simply manifesting itself sexually, or, alternatively, there is no underlying disorder and the behavior simply is not maladaptive. These psychologists do not recognize the concept of addiction, only chemical dependence, and some believe the concept and diagnosis to be stigmatizing and unhelpful.Two 2016 neurology reviews found evidence of addiction related brain changes in internet pornography users. Psychological effects of these brain changes are described as desensitization to reward, a dysfunctional anxiety response, and impulsiveness. Another 2016 review suggests that internet behaviors, including the use of pornography, be considered potentially addictive, and that problematic use of online pornography be considered an "internet-use disorder".
Introductory psychology textbook authors Coon, Mitterer and Martini, passingly mentioning NoFap speak of pornography as a "supernormal stimulus" but use the model of compulsion rather than addiction.
Other effects on human behavior
Research at Alliant International University found that participants who consumed internet pornography more frequently had increased rates of delay discounting. The researchers state, "The constant novelty and primacy of sexual stimuli as particularly strong natural rewards make internet pornography a unique activator of the brain's reward system, thereby having implications for decision-making processes."A study by Professor Kathryn C.Seigfried-Spellar and Professor Marcus Rogers found results which suggested deviant pornography use followed a Guttman-like progression in that individuals with a younger “age of onset” for adult pornography use were more likely to engage in deviant pornography compared to those with a later “age of onset”.
Sexual violence
Controlled studies
A controlled study describes the relationship between given behaviors or environmental conditions and health effects in a laboratory setting in which conditions other than those under study are effectively held constant across groups of participants receiving various levels of the experimental condition. Since it is considered that the only functional difference between groups is the level of experimental condition received, researchers can strongly infer cause-and-effect relationships from statistically significant associations between experimental condition and health consequences. Thus, if executed properly, controlled studies have high levels of internal validity. However, such studies often suffer from questionable external validity due to the considerable differences between real-world environments and the experimental context, and the consequent belief that results cannot be generalized beyond that context.The link between pornography and sexual aggression has been the subject of multiple meta-analyses. Meta-analyses conducted in the 1990s suggested to researchers that there might not be an association of any kind between pornography and rape supportive attitudes in non-experimental studies. However, a meta-analysis by Hald, Malamuth and Yuen suggests that there is a link between consumption of violent pornography and rape-supportive attitudes in certain populations of men, particularly when moderating variables are taken into consideration.
A meta-analysis conducted in 2015 found that pornography "consumption was associated with sexual aggression in the United States and internationally, among males and females, and in cross-sectional and longitudinal studies. Associations were stronger for verbal than physical sexual aggression, although both were significant. The general pattern of results suggested that violent content may be an exacerbating factor."
In an earlier review of this literature Ferguson and Hartley argued that "it is time to discard the hypothesis that pornography contributes to increased sexual assault behavior". They stated that the authors of some studies tended to highlight positive findings while deemphasizing null findings, demonstrating confirmation bias in the published literature. Ferguson and Hartley concluded that controlled studies, on balance, were not able to support links between pornography and sexual violence.
Epidemiological studies
An epidemiological study describes the association between given behaviors or environmental conditions, and physical or psychological health by means of observation of real-world phenomena through statistical data. Epidemiological studies generally have high levels of external validity, insofar as they accurately describe events as they occur outside of a laboratory setting, but low levels of internal validity, since they do not strongly establish cause-and-effect relationships between the behaviors or conditions under study, and the health consequences observed.Danish criminologist Berl Kutchinsky's Studies on Pornography and sex crimes in Denmark, a scientific report ordered by the Presidential Commission on Obscenity and Pornography, found that the legalizing of pornography in Denmark had not resulted in an increase of sex crimes. Since then, many other experiments have been conducted, either supporting or opposing the findings of Berl Kutchinsky, who would continue his study into the social effects of pornography until his death in 1995. His life's work was summed up in the publication Law, Pornography, and Crime: The Danish Experience. In 1998 Milton Diamond from the University of Hawaii noted that in Japan, the number of reported cases of child sex abuse dropped markedly after the ban on sexually explicit materials was lifted in 1969; however, in Denmark and Sweden, there was an increase in reported rapes after the liberalization of their pornography laws during the same time period.
Some researchers claim there is a correlation between pornography and a decrease of sex crimes, including Diamond. The effects of Pornography: An International Perspective was an epidemiological study which found that the massive growth of the pornography industry in the United States between 1975 and 1995 was accompanied by a substantial decrease in the number of sexual assaults per capita - and reported similar results for Japan - but not for Denmark and Sweden. Findings of this nature have been critiqued by Robert Peters, president of Morality in Media, on the grounds that the results are better explained by factors other than the increased prevalence of pornography: "a more plausible explanation is that if there is a decline in "forcible rape," it is the result of a tremendous effort to curb rape through community and school-based programs, media coverage, aggressive law enforcement, DNA evidence, longer prison sentences, and more."
In 1986, a review of epidemiological studies by Neil M. Malamuth found that the quantity of pornographic material viewed by men was positively correlated with degree to which they endorsed sexual assault. Malamuth's work describes Check, who found among a diverse sample of Canadian men that more exposure to pornography led to higher acceptance of rape myths, violence against women, and general sexual callousness. In another study, Briere, Corne, Runtz and Neil M. Malamuth, reported similar correlations in a sample involving college males. On the other hand, the failure to find a statistically significant correlation in another previous study led Malamuth to examine other interesting correlations, which took into account the information about sexuality the samples obtained in their childhood, and pornography emerged as the second most important source of information. Malamuth's work has been criticized by other authors, however, such as Ferguson and Hartley who argue Malamuth has exaggerated positive findings and has not always properly discussed null findings. Malamuth has declared to Quartz that porn is like alcohol: "whether it’s bad for you depends on who you are".
Occupational safety and health
Because pornographic film making involves unsimulated sex, usually without condoms, pornographic actors appear to be particularly vulnerable to sexually transmitted diseases.The AIDS Healthcare Foundation tried several times to have California's Department of Industrial Relations, Division of Occupational Safety and Health's Appeals Board force companies in the pornography industry to treat actors and actresses as employees subject to occupational safety and health regulation; in a 2014 case brought against Treasure Island Media an administrative judge found that the company did have to comply with regulations.