Effects of pornography

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.[11]

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."[23]

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 (bestiality or child) compared to those with a later "age of onset".[24]

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(s). Since it is considered that the only functional difference between groups is the level of experimental condition(s) received, researchers can strongly infer cause-and-effect relationships from statistically significant associations between experimental condition(s) 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.[25]

The link between pornography and sexual aggression has been the subject of multiple meta-analyses.[26] 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.[27] However, a meta-analysis by Hald, Malamuth and Yuen (2000) 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.[26]

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."[28]

In an earlier review of this literature Ferguson and Hartley (2009) argued that "it is time to discard the hypothesis that pornography contributes to increased sexual assault behavior".[29] 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.

Ferguson and Hartley updated their review with a 2020 meta-analysis. This meta-analysis concluded that mainstream pornography could not be linked to sexual violence and was associated with reductions in societal violence at the societal level. Small correlations were found between violent porn viewing and sexual aggression, but evidence was unable to differentiate whether this was a causal or selection effect (i.e. sexual offenders seeking out violent porn).[30]

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.[25]

Danish criminologist Berl Kutchinsky's Studies on Pornography and sex crimes in Denmark (1970), 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.[31] 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 (1999). 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.[32]

Some researchers argue that there is a correlation between pornography and a decrease of sex crimes,[33][10] including Diamond (author of a review from 2009).[34] 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.[35] 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."[36]

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.[37] Malamuth's work describes Check (1984), 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, (1984) 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.[37] Malamuth's work has been criticized by other authors, however, such as Ferguson and Hartley (2009) who argue Malamuth has exaggerated positive findings and has not always properly discussed null findings.[29] In a Quartz publication, Malamuth argued that porn is like alcohol: "whether it's bad for you depends on who you are" (stating that it increases violence in a few people, not in most people; it makes most people more relaxed).[38]