Virtual polygyny?

Polygyny is accepted to varying degrees around the world. In some countries it is permitted by law (dark blue) or by customary law (medium blue). Or the law may permit polygyny if the marriage has been performed in another country (light blue). (Wikicommons)

In my last two posts I presented evidence that repeated exposure to porn desensitizes the male brain, eventually causing atrophy in those areas that process erotic stimuli. In addition, porn seems to influence psychosexual development differently in young European American males and young African American males.

If porn is virtual polygyny, the male brain should tolerate porn overload to the extent it has coevolved with polygyny. The threshold for desensitization would therefore be higher in cultures with generalized polygyny (20-50% of all marriages) and lower in cultures with limited polygyny (less than 10%).

The ‘virtual polygyny’ hypothesis was first put forward by Shepher and Reisman (1985):

Pornography creates a world of polygynous fantasy, in which there are always sufficient consenting females who unhesitatingly display their naked bodies, or body parts, thus signaling their preparedness for immediate sexual intercourse.

This fantasy world is very different from real life, especially where monogamy is the norm:

Of course, this fantasy world of unlimited numbers of young, beautiful, seductive females, eagerly and enthusiastically engaging in every sort of sexual and violent activity, contrasts sharply with everyday reality. (Shepher and Reisman 1985, p. 107)

It is even different from real life in polygynous cultures:

No power struggle, no competition between males for sexual access to a specific female is involved, because mass production makes the pornographic dream easily available to everyone. (Shepher and Reisman 1985, p. 108).

As a result, porn leads to desensitization and a desire for more and harder porn:

The result of fantasy-directed expectations may be a deterioration of male-female relationships, perhaps a deterioration of heterosexual comradeship and even love. Surely many males become disillusioned with their female partners' ability to arouse them. Any consistent use of pornographic magazines could also find readers thus disillusioned with their partners and their own sexual performance. The consequence for males may be, among other dysfunctions, conditional impotence. (Shepher and Reisman 1985, p. 110)

[...] habitual viewing often seems to result in a loss of arousal. We have found then, not illogically, that pornography is pushed to seek novelty: oral sex, anal penetration, sex with children, bestiality, pseudolesbianism, and sadistic sexuality. What this extension of repertoire tends to do to the male-female relationship is not difficult to imagine. (Shepher and Reisman 1985, p. 110)

[...] Arguably, as pornography use grows, male-female relationships deteriorate, aggression against women increases, sexuality is pushed towards more and more extravagant forms, more and more detached from sexuality's basic function in human life. (Shepher and Reisman 1985, p. 112)

Given that the incidence of polygyny varies considerably among human cultures, could some human populations be less vulnerable than others to porn desensitization? The two authors seem to raise this question:

Among 847 human cultures, 708 (83.4%) were found to condone polygyny, 137 (16%) monogamy, and 4 (0.47%) polyandry' (Murdock 1967). About half of the polygynous cultures permit polygyny, but actually not many males are married polygynously. The other half practices systematic polygyny.

This is a classic sample of coevolution: natural selection working on the individual favors polygyny; cultural selection working on the group favors monogamy. The most "successful" cultures, in the sense of their having the largest populations (Europe, the Americas, Japan, China, India), are monogamous, and most individuals in polygynous cultures are monogamous as well. (Shepher and Reisman 1985, p. 112)

Shepher and Reisman (1985) don't pursue this line of reasoning. One reason may have been the view, common in evolutionary psychology, that human nature has evolved very little since the Pleistocene. Because the high incidence of polygyny in sub-Saharan Africa is associated with agriculture (African hunter-gatherers have a very low incidence), and because agriculture began to develop there only some six thousand years ago (Vansina 1994), Shepher and Reisman might have concluded that the male brain never coevolved with generalized polygyny in sub-Saharan Africa. But why, then, the reference to coevolution? I suspect they simply floated this idea in the hope that someone else would pick it up. Or perhaps they had discussed this idea at greater length in their original manuscript ...

Shepherd and Reisman were writing in the 1980s, at a time when porn desensitization was probably much less common than it is today. Malamuth and Billings (1986, p. 93) reviewed the literature at that time:

Varied studies conclude that repeated exposure to erotica will, under many circumstances, result in less sexual arousal to and reduced interest in such materials. These studies include both experimental and survey research.

The first clear experimental study demonstrating habituation was conducted as part of the research of the commission [on Obscenity and Pornography] (Howard, Reifler, & Liptzin, 1971). This study found that repeated exposure of male college students to erotica for 90 min a day, 5 days a week for 5 weeks, resulted in a reduction in sexual arousal to erotic stimuli as well as reduced interest in such pornography. Following 2 months of nonexposure, however, there was a recovery in sexual arousal to levels that were not significantly different from those prior to the repeated exposure procedure [...]

Malamuth and Billings (1986) noted that this study had been criticized on the grounds that the levels of exposure were not "realistic." Today, such levels are common. According to a study of 16-year-old boys in two Swedish towns, 10% of them viewed porn every day, and about a third of these frequent users viewed porn for more than ten straight hours several times a week (Mattebo et al. 2013). In addition, young men are viewing porn for much longer than five weeks.

With the current high levels of porn consumption, more research is needed on the ‘virtual polygyny’ hypothesis, especially on its prediction that some human populations are more vulnerable than others to erotic desensitization and atrophy.

References

Malamuth, N.M. and V. Billings. (1986). The functions and effects of pornography: Sexual communications versus the feminist models in light of research findings, in J. Bryant and D. Zillmann (eds) Perspectives on Media Effects, Hillsdale, New Jersey: Erlbaum.

http://www.sscnet.ucla.edu/comm/malamuth/pdf/86PME_C5.pdf

Mattebo, M., T. Tyden, E. Häggström-Nordin, K.W. Nilsson, and M. Larsson. (2013). Pornography consumption, sexual experiences, lifestyles, and self-rated health among male adolescents in Sweden, Journal of Developmental and Behavioral Pediatrics, 34, 460-468.

https://s3.amazonaws.com/academia.edu.documents/40260257/Pornography_Consumption_Sexual_Experienc20151122-22933-105aqic.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1508277205&Signature=diuNG%2BPn%2FznAqGmAlmlPKmFZ8mU%3D&response-content-disposition=inline%3B%20filename%3DPornography_Consumption_Sexual_Experienc.pdf

Shepher, J. and J. Reisman. (1985). Pornography: A sociobiological attempt at understanding, Ethology and Sociobiology, 6, 103-114.

https://www.reuniting.info/download/pdf/Ethology_.pdf  

Vansina, J. (1994). A slow revolution: Farming in Subequatorial Africa, Azania: Archaeological Research in Africa, 29-30(1), 15-26.

http://www.tandfonline.com/doi/abs/10.1080/00672709409511658?journalCode=raza20

The unexplored confound

First page of an underground porn comic, c. 1930s (Wikicommons). Pornography is now much more available and better in quality.

My last post presented a German study whose findings suggest that prolonged exposure to porn atrophies those portions of the male brain that process erotic stimuli (Kühn and Gallinat 2014). On the other hand, the arrow of causality might point the other way. Perhaps a man will seek out and view more porn if he already has less of the gray matter for sexual arousal.

The jury is still out. In this debate, we should keep in mind that people have argued against porn for different reasons. Refuting one argument doesn't necessarily refute the others.

Historically, porn has been condemned for three reasons:

It incites men to commit rape and other forms of sexual abuse. This is the oldest argument and is still used.

It objectifies women and causes men to treat women with less respect. This is the feminist argument of the 1960s and 1970s.

It desensitizes men to erotic images and causes them to seek more porn and harder porn to achieve the same effect. This argument is recent.  

The first argument has always been problematic. A recent review article concludes that "[i]t has been found everywhere it was scientifically investigated that as pornography has increased in availability, sex crimes have either decreased or not increased" (Diamond 2009).

The second argument likewise seems weak. A Danish survey found that porn actually seems to improve male attitudes toward the opposite sex:

The self-perceived effects of "hardcore" pornography consumption were studied in a large representative sample of young adult Danish men and women aged 18-30. Using a survey that included the newly developed Pornography Consumption Effect Scale, we assessed participants' reports of how pornography has affected them personally in various areas, including their sexual knowledge, attitudes toward sex, attitudes toward and perception of the opposite sex, sex life, and general quality of life. Across all areas investigated, participants reported only small, if any, negative effects with men reporting slightly more negative effects than women. In contrast, moderate positive effects were generally reported by both men and women, with men reporting significantly more positive effects than women. (Hald and Malamuth 2008)

Of course, this is self-report, which often reveals not what people think but rather what people think they're supposed to think. Self-report showed that Trump was going to lose the 2016 election. In a liberal society, male respondents might think twice before saying their attitudes toward women have worsened. For this reason, it's interesting that similar results have been obtained from a sample of university students in Indonesia—a conservative, Muslim majority country with strict anti-pornography laws (Mulya and Hald 2015).

With regard to the third argument, two American studies have presented findings that seem to contradict those of the German study. In the first one, male and female participants were exposed to erotic and neutral images, and their neurological response was measured during the first second of exposure. Hypersexuals (heavy consumers of porn) showed no signs of habituation or desensitization to erotic images in relation to neutral images (Prause et al. 2015).

The other American study likewise found no signs of desensitization:

Data from a large sample of men (N = 280) across similar studies were aggregated to test the hypothesis that consuming more VSS [visual sexual stimuli] was related to erectile problems. These men answered questions about their sexual behaviors and feelings, including their consumption of VSS, and viewed sexual films in the laboratory. Those who reported viewing more VSS in their own life reported higher sexual arousal to films in the laboratory. Self-reported erectile functioning with a partner was not related to the hours of VSS viewed weekly. Finally, those who viewed VSS more also reported higher desire for both partnered sexual behaviors and solo sexual behaviors. This pattern suggests that those who view more VSS likely have a higher sexual drive and experience a stronger sexual response to standardized VSS than those who view less VSS. Sexual arousal responsivity may not be impaired by viewing more VSS at home, as it actually was related to stronger desire and sexual arousal in two of the three relationships tested. (Prause and Pfaus 2015)

Some of these findings are compatible with those of the German study. The latter study looked for long-term effects of porn consumption and found evidence of atrophy in some areas of the brain. Viewing porn in a laboratory won't produce any measurable atrophy because the time spent viewing isn't long enough (the films varied in length from 20 seconds to three minutes). The same kind of objection holds for the other American study discussed above, which found that porn consumption didn't reduce sexual arousal during the first second of exposure to an erotic image. Perhaps porn consumption makes sexual arousal less sustainable even though the initial response remains as strong as ever.

On the other hand, it's harder to dismiss the self-report data from the second American study: men who viewed more porn had a higher level of sexual desire than those who viewed less. So what gives?

Perhaps the two groups of men were different to begin with. This is plausible because the pool of participants was much more diverse in this American study than in the German study. The latter study excluded participants with psychiatric, medical, and neurological disorders or with substance abuse problems, whereas the American study had much weaker exclusion criteria. Furthermore, the German study had German participants, whereas the American study had participants who were 53.3% white, 23.1% Hispanic, 16.0% black, and 7.6% other or unknown (Kühn and Gallinat 2014; Prause and Pfaus 2015).

No one seems to have considered that ethnic/racial background might be confounded with sexual arousal or hours spent viewing porn. It's not as if this kind of confound is unlikely. Brown and L'Engle (2009) found higher porn consumption by young African Americans than by young European Americans. Ybarra and Mitchell (2005) reported that "Hispanic youth were almost three times as likely to report online seeking versus offline seeking behavior versus otherwise similar youth of non-Hispanic ethnicity (p = .02)." Price and Miller (1984) found that African Americans were also more likely than European Americans to use sexual fantasy to achieve arousal.

Just as importantly, according to a recent review article (Collins et al. 2011), erotic content in music, movies, and magazines seems to have different impacts on the development of sexual behavior in young white and black Americans:

Brown and colleagues subsequently expanded on this work by linking exposure to sexual content in a broader variety of media to intercourse initiation and advances in noncoital behavior. They surveyed 1,017 North Carolina youth when they were 12-14 years old and again two years later. Sexual content exposure in television, music, movies, and magazines predicted advancing sexual behavior, even after other variables were controlled for statistically, but only among white youth, who comprised about half of the sample. No relationship was observed among African-American teens, who made up the other half of the study sample. 

Most recently, Hennessy and colleagues analyzed web surveys of 506 Pennsylvania teens aged 14-16 years at baseline and followed them annually for a total of three surveys. They examined television, music, movies, magazines, and video games with a sexual content exposure measure. Data were analyzed using growth curves, testing whether changes in exposure to sexual media over time are correlated with changes in sexual behavior during the same period. They found that changes in exposure to sexual content were associated with changes in behavior among white teens (the r = 0.46 correlation just missed statistical significance, perhaps due to the small sample), but there was no association among African-American youth.

Whether these differences between white and black Americans are innate or learned is beside the point. These differences exist, and they should be controlled in any study with a mixed pool of participants. Otherwise, it’s no longer clear which way the arrow of causality points. In this case, the American research team found that porn consumers have a higher level of sexual desire. They concluded that porn consumption increases a man’s desire for sex. Well, perhaps. Or perhaps there is a subset of men who consume lots of porn because they have a stronger desire for sex.

In any study of this sort, the pool of participants should be as homogeneous as possible, i.e., it should be limited to people who probably shared the same potential for sexual arousal when some of them began viewing porn.

Conclusion

Research on the harmful effects of porn is shifting to the hypothesis that excessive consumption desensitizes the male brain. It seems, however, that this effect varies from one man to another, both within racial/ethnic groups and between them. It may be that porn desensitization is a greater problem for men whose ancestors were overwhelmingly monogamous, i.e., from Eurasia. For them, porn has created something entirely novel that their ancestors never experienced and never had to adapt to: a virtual environment where a man can have sex with as many women as he wishes. In contrast, porn may be less problematic for men with ancestors from sub-Saharan Africa, where polygyny has long been the norm (Goody 1973; Pebley and Mbugua 1989).

References

Brown, J.D., and K.L. L'Engle. (2009). X-rated: Sexual attitudes and behaviors associated with U.S. early adolescents' exposure to sexually explicit media, Communication Research, 36, 129-151.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.664.4770&rep=rep1&type=pdf

Diamond, M. (2009). Pornography, public acceptance and sex related crime: a review, International Journal of Law and Psychiatry, 32(5), 304-414.

https://www.geekparadize.fr/wp-content/uploads/2016/08/pdf-86.pdf

Collins, R.L., S.C. Martino, and R. Shaw. (2011). Influence of New Media on adolescent sexual health: evidence and opportunities, Working Paper, Rand Health, April 2011

https://www.researchgate.net/profile/Rebecca_Collins8/publication/265231336_Influence_of_New_Media_on_Adolescent_Sexual_Health_Evidence_and_Opportunities/links/54f4cd9b0cf2eed5d7359159.pdf

Dupanloup, I., L. Pereira, G. Bertorelle, F. Calafell, M.J. Prata, A. Amorim, and G. Barbujani. (2003). A recent shift from polygyny to monogamy in humans is suggested by the analysis of worldwide Y-chromosome diversity, Journal of Molecular Evolution, 57, 85-97.

http://www2.webmatic.it/workO/s/113/pr-457-file_it-Journal%20of%20Molecular%20Evolution%2057.pdf

Goody, J. (1973). The Character of Kinship, Cambridge: Cambridge University Press.

Hald, G.M. and N.M. Malamuth. (2008). Self-perceived effects of pornography consumption, Archives of Sexual Behavior, 37(4), 614-625.

https://www.researchgate.net/profile/Gert_Hald/publication/5988339_Self-Perceived_Effects_of_Pornography_Consumption/links/0912f507bc978a257e000000/Self-Perceived-Effects-of-Pornography-Consumption.pdf

Kühn, S. and J. Gallinat. (2014). Brain structure and functional connectivity associated with pornography consumption. The brain on porn, JAMA Psychiatry, 71(7), 827-834. http://jamanetwork.com/journals/jamapsychiatry/fullarticle/1874574?=  

Mulya, T.W. and G.M. Hald. (2014). Self-perceived effects of pornography consumption in a sample of Indonesian students, Media Psychology, 17(1), 78-101.

http://www.tandfonline.com/doi/abs/10.1080/15213269.2013.850038

Pebley, A. R., & W. Mbugua. (1989). Polygyny and Fertility in Sub-Saharan Africa. In R. J. Lesthaeghe (ed.) Reproduction and Social Organization in Sub-Saharan Africa, Berkeley: University of California Press, pp. 338-364.

Prause, N. and J. Pfaus. (2015). Viewing sexual stimuli associated with greater sexual responsiveness, not erectile dysfunction, Sexual Medicine, 3(2), 90-98.

http://www.medsci.cn/webeditor/uploadfile/201503/20150321110618701.pdf

Prause, N., V.R. Steele, C. Staley, D. Sabatinelli, and G. Hajcak. (2015). Modulation of late positive potentials by sexual images in problem users and controls inconsistent with "porn addiction," Biological Psychology, 109, 192-199.

https://s3.amazonaws.com/academia.edu.documents/44169223/Modulation_of_late_positive_potentials_b20160328-20967-7vvhnt.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1507835633&Signature=buIAnKDHGZ66%2B7JKhw8K3ldMnIQ%3D&response-content-disposition=inline%3B%20filename%3DModulation_of_late_positive_potentials_b.pdf 

Price, J.H. and P.A. Miller. (1984). Sexual fantasies of Black and White college students, Psychological Reports, 54(3), 1007-1014.
http://journals.sagepub.com/doi/abs/10.2466/pr0.1984.54.3.1007

Ybarra M. and K.J. Mitchell. (2005). Exposure to Internet pornography among children and adolescents: a national survey, CyberPsychology & Behavior, 8(5), 473-486.

https://innovativepublichealth.org/wp-content/uploads/2009/04/cpb.2005.8.pdf

The canary in the coal mine?

Magazine rack in a Japanese store (Wikicommons - Corpse Reviver)

Hugh Hefner's death has ended an era that actually ended around the turn of the millennium. Gone are the days of porn in limited supply. During my teen years Playboy wasn’t sold in my town. You had to go to a drugstore 15 kilometers away and buy it in person, while hoping the cashier wouldn't blab to others. Then you had to find a place to hide it. Videocassettes were starting to come on market, but they had to be bought even farther away, and there was still the problem of finding a hiding place.

Fast-forward to the year 2017. From my computer I can access porn of almost any description in almost any quantity. And the access is fast, free, and anonymous. There is no comparison to the world of my youth, and even less to the world of 1953, when Playboy made its debut. That same year King Farouk of Egypt was described as a "self-indulgent playboy" with "carloads of erotica" (Gunther, 1953, p. 205). Carloads? That's nothing. Today, anyone with an Internet connection can stash away thousands upon thousands of erotic images.

This is a new sensory environment for humans. An analogy would be the increasing availability of food to native peoples in the far north. In the past their environment offered meat in limited amounts, and sometimes none was available. Hunters were thus highly motivated to seek out food and not let any go uneaten. Now fast-forward to the present. High-calorie snacks are available in any store, and they’re tasty with lots of salt, sugar, and fat—the very nutrients that were once in short supply. As a result, obesity is reaching epidemic proportions in the North.

No surprise really. And should we be surprised to learn that the increasing availability of porn today may have similarly adverse effects?

This question was addressed by a recent study on how porn consumption affects the male brain. Sixty-four men had their brains scanned, and the results were compared with the number of hours they spent viewing pornography per week. The results? Prolonged exposure to porn seemed to atrophy those portions of the brain that process erotic stimuli. The volume of gray matter was smaller in those subjects who viewed the most porn, and functional connectivity was likewise reduced. They seemed to require more porn (or harder porn) to achieve the same stimulation.

Taken together, one may be tempted to assume that the frequent brain activation caused by pornography exposure might lead to wearing and downregulation of the underlying brain structure, as well as function, and a higher need for external stimulation of the reward system and a tendency to search for novel and more extreme sexual material. This hypothesized self-perpetuating process could be interpreted in light of proposed mechanisms in drug addiction where individuals with lower striatal dopamine receptor availability are assumed to medicate themselves with drugs (Kühn and Gallinat 2014)

This interpretation is supported by a recent review of the literature:

Some internet activities, because of their power to deliver unending stimulation (and activation of the reward system), are thought to constitute supernormal stimuli, which helps to explain why users whose brains manifest addiction-related changes get caught in their pathological pursuit. [...] In short, generalized internet chronic overuse is highly stimulating. It recruits our natural reward system, but potentially activates it at higher levels than the levels of activation our ancestors typically encountered as our brains evolved, making it liable to switch into an addictive mode.

[...] previously established brain maps for "natural" sexuality cannot compare to the newly developed and continuously reinforced maps generated by continued compulsive watching of Internet pornography, and thus the addicted individual progresses to more explicit and graphic Internet pornography in order to maintain the higher level of excitement. (Love et al. 2015)

Of course, the arrow of causality might point the other way. Perhaps a man will seek out and view more porn if he already has less of the gray matter for sexual arousal. Only a longitudinal study can tell us which is causing what.

Let's suppose the first explanation is the right one. What can we do? Frankly, I'm pessimistic about legislative solutions. Give politicians the power to ban Internet porn (or Islamist extremism), and they'll use it to ban … the Alt-Right. Our political class lives in another age and sees reality through the lens of yesterday's issues and yesterday's priorities.

A second problem is that politicians try to ban child porn much more than the adult stuff. This is a classic case of going after a soft target that is secondarily important and perhaps not important at all. If porn has a desensitizing effect, it should cause pedophiles to lose interest in real children and focus on electronic images, since only the latter can be viewed in sufficient quantity to cause sexual arousal. So what’s the problem?

We should worry more about porn desensitization that disrupts relationships between adult men and women. A similar phenomenon has been noted with TV viewing: the more people watch TV, especially programming with romantic content, the more dissatisfied they feel with their marriages (Reizer and Hetsroni 2014). We may be becoming too good at creating virtual alternatives to reality.

The Japanese case

This desensitization may be most acute in Japan. In comparison to the United States, porn is more freely available there and less "compartmentalized":

Nudity is evident in both sexually identified and general circulation magazines. For instance, the weekly general-interest magazines will often include several photographs of nude women (plus ratings of local massage parlors). Although such magazines are oriented predominantly for businessmen, the inclusion of sexual photographs is also assumed to interest the business audience. In this regard, it is apparent that rigid boundaries do not exist for the publication of sexual material. In fact, nudity or sexual themes appear in Japanese teen magazines, sports magazines, fashion magazines, and so on. 

[...] Japanese public television is also different from its American counterpart. Overtly sexual material and nudity are permissible. For example, a Japanese television program known as the 11 P.M. Show can feature a strip tease, bare breasts and buttocks, reportage on massage parlors, expert authorities on sex, and so on. Similarly, the Japanese public-access movie channels can feature R-rated movies such as Emmanuelle (with some air-brushing). Finally, even Japanese commercials and advertisements have more flexibility in sexual content. (Abramson and Hayashi 2014, p. 179)

This ubiquitous porn is viewed by Japanese men, who are less polygynous than most human males and have lower blood levels of 5a-reductase—the enzyme that converts testosterone into the more physiologically active DHT (Ross et al. 1992). Lower testosterone activity seems to be an adaptation to monogamy and high paternal investment:

Numerous studies reveal a negative correlation between testosterone concentration and paternal care in diverse mammals including nonhuman primates and humans. Several researchers suggest that spousal investment accounts for the lower testosterone of married men compared to unmarried men, but findings that the lowest testosterone levels are observed in married men with children implicate paternal care as particularly relevant. Thus testosterone reduction may reflect a facultative shift in male reproductive strategy from intrasexual competition and copulation to care of young. (Shur et al. 2008)

Some Japanese authors have reached this sort of conclusion, seemingly echoing J. Philippe Rushton (although the book in question predates his publications by several years):

Finally, a number of Japanese authors (e.g., Komatsu, 1974) have also suggested that Asian populations are less sexualized than Caucasian or black populations. They cite secondary sex characteristics (less public hair, smaller breasts, etc.) as evidence. Unfortunately, the data on sexual frequencies (intercourse, etc.) are not particularly reliable, and it is not clear whether competing responses (such as nurturance) are mediating sexual expression. (Abramson and Hayashi 2014, p. 182)

Japanese men and women may thus be especially vulnerable to porn consumption. More and more couples no longer have sex, the percentage rising from 31.9% in 2004 to 36.5% in 2008 and to 47.2% in 2016 (McCurry 2017; Moriki 2012). The major reasons given are "tired from work," abstention from sex after a birth, and "sex is too troublesome" (Moriki 2012). These reasons are probably proximal, and in any case it is far from clear why they would be growing in importance.

There is some indication that the Japanese realize that porn is becoming a problem. But it’s not clear where this realization will lead. In this, as in many other things, they follow the lead of other Western countries, especially the United States. Concern about porn is thus limited to child porn.

References

Abramson, P.R. and H. Hayashi. (1984). Pornography in Japan: Cross-cultural and theoretical considerations, in N.M. Malamuth and E. Donnerstein (eds) Pornography and Sexual Aggression, pp. 173-184, Orlando: Academic Press.

https://books.google.ca/books?id=p1KLBQAAQBAJ&printsec=frontcover&hl=fr&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Gunther, J. (1953). Inside Africa, New York: Harper & Brothers.

Kühn, S. and J. Gallinat. (2014). Brain structure and functional connectivity associated with pornography consumption. The brain on porn, JAMA Psychiatry, 71(7), 827-834. http://jamanetwork.com/journals/jamapsychiatry/fullarticle/1874574?=

Love, T., C. Laier, M. Brand, L. Hatch, and R. Hajela. (2015). Neuroscience of Internet pornography addiction: a review and update, Behavioral Sciences, 5(3), 388-433.

http://www.mdpi.com/2076-328X/5/3/388/htm

McCurry, J. (2017). Record numbers of couples living in sexless marriages in Japan, says report, The Guardian, February 14

https://www.theguardian.com/world/2017/feb/14/record-numbers-of-couples-living-in-sexless-marriages-in-japan-says-report

Moriki, Y. (2012). Mothering, co-sleeping, and sexless marriages: implications for the Japanese population structure, The Journal of Social Science, 74, 27-45.

https://icu.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1542&item_no=1&attribute_id=18&file_no=1  
Reizer, A. and A. Hetsroni (2014). Media exposure and romantic relationship quality: A slippery slope? Psychological Reports, 114(1), 231-249.
http://journals.sagepub.com/doi/abs/10.2466/21.07.PR0.114k11w6

Ross, R.K., Bernstein, L., Lobo, R.A., Shimizu, H., Stanczyk, F.Z., Pike, M.C., and Henderson, B.E. (1992). 5-apha-reductase activity and risk of prostate cancer among Japanese and US white and black males. Lancet, 339, 887-889.

http://www.sciencedirect.com/science/article/pii/014067369290927U

Shur, M.D., Palombit, R.A., and Whitten, P.L. (2008). Association between male testosterone and friendship formation with lactating females in wild olive baboons (Papio hamadryas anubis). Program of the 77th Annual Meeting of the American Association of Physical Anthropologists, p. 193.

http://onlinelibrary.wiley.com/doi/10.1002/ajpa.20806/epdf

Young, male, and single

 

The Babylonian Marriage Market, by Edwin Long (1829-1891). There are too many young men on the mate market, particularly in the White American community.

 

It sucks being young, male, and single. Don't think so? Go to the Interactive Singles Map of the United States and see how it looks for the 20 to 39 age group. Almost everywhere single men outnumber single women.

And the real picture is worse. For one thing, the imbalance is greater among singles without children. This is not a trivial factor, since single mothers are "single" only in the sense of being available for sexual relations. They are still raising offspring from a previous relationship and many are not interested in having more children.

Then there's polygamy—or "polyamory," to use the preferred term—where a minority of men controls sexual access to a larger number of women. If we compare the 1940-1949 and 1970-1979 cohorts of American adults, we find an increase in the number of median lifetime partners from 2.6 to 5.3 among women and from 6.7 to 8.8 among men (Liu et al., 2015). Because this figure is more variable for men than for women, young women are more likely to be sexually active than young men. This is crudely seen in infection rates for chlamydia—the most common sexually transmitted disease. Hispanic Americans still show the traditional pattern of greater sexual activity among men than among women, the rates being 7.24% of men and 4.42% of women. White Americans display the reverse: 1.38% of men and 2.52% of women (Miller et al., 2004).

Finally, there’s a racial angle. This sex ratio is more skewed among White Americans than among African Americans, mainly because the latter have a lower sex ratio at birth and a higher death rate among young men.

It's hard to avoid concluding that a lot of young white men are shut out of the marriage market ... or any kind of heterosexual relationship. This wife shortage was once thought to be temporary, being due to baby-boomer men getting divorced and marrying younger women from the smaller "baby bust" cohort. With time, they would get too old to compete with young men, and the problem should resolve itself.

Today, the crest of the baby boom is entering the seventh decade of life, yet the update to the Interactive Singles Map shows no change to the gender imbalance. So what gives? It appears that demographers have focused too much on the baby-boomer effect and not enough on other factors that matter just as much and, more importantly, show no signs of going away. These factors can be summarized as follows.

Re-entry of older men into the mate market

We have a mate market where 20 to 50 year old men are competing for 20 to 40 year old women. That in itself is nothing new. But something else is.

The baby boom eclipsed an equally important but longer-term trend: more and more men are living past the age of 40. With or without the baby boom, we’ll still see large numbers of older men getting divorced and marrying younger women. The cause isn’t just liberal divorce laws. It’s also the fact we have far more older guys out there as a proportion of the population.

Sure, we will also see younger men pairing up with "cougars" but there are limits to that option, as noted in a New Zealand study:

The male partner may want to partner up with someone younger or have children, which may not be possible with an older woman (for physical reasons or because she chooses not to have (more) children). The younger male partner may not want to become a step-father to existing children. Research has shown that childbearing can be the ultimate deal breaker in this kind of relationship. (Lawton and Callister, 2010)

Persistence of the imbalanced sex ratio at birth

About 105 males are born for every 100 females among people of European origin. This sex ratio used to decline to parity during childhood because of higher infantile mortality among boys. It then declined even farther in early adulthood because of war, industrial accidents, and other hazards. This isn't the distant past. If you talk with women who came of age in the postwar era, they will tell you about their fears of remaining single past the age of thirty. At that age, very few single men were left to go around.

Well, things have changed. The skewed sex ratio at birth is now persisting well into adulthood, thanks to modern medicine and the relative peace that has prevailed since 1945. Women begin to outnumber men only in the 35-39 age group in the United States and in the 40-44 age group in the United Kingdom.

Equalization of male and female same-sex preference

Historically, same-sex preference was more common among men than among women. This gender gap appears to be closing, according to a recent study:

The percent distributions were quite similar for men and women; however, a higher percentage of men identified as gay (1.8%) compared with women who identified as gay/lesbian (1.4%), and a higher percentage of women identified as bisexual (0.9%) compared with men (0.4%). (CDCP, 2014, p. 5) 

Disparities in outmarriage

At present, there are more White American women outmarrying than White American men, particularly in younger age groups. This disparity is mainly in marriages with African American men, there being no gender difference in marriages with Hispanic Americans and the reverse gender difference in marriages with Asian Americans (Jacobs and Labov, 2002; Passel et al., 2010). Overall, this factor further skews the ratio of young single men to young single women in the White American community. 

This disparity isn't new. What is new is its extent, for both legal and common-law marriages. An idea may be gleaned from statistics on children born to White American women, specifically the proportion fathered by a non-White partner. For the U.S. as a whole the proportion in 2013 was between 11% and 20% (the uncertainty is due to 190,000 births for which the father's race was not stated). By comparison, the proportion in 1990 was between 5% and 13% (Centers for Disease Control and Prevention, 2013; see also Silviosilver, 2015).

Whenever this issue comes up for discussion, there are often reassurances that the disparity will disappear in a post-racial world that has been cleansed of "White privilege." I'm not so sure. The European female phenotype seems to be very popular, and this was so even when white folks were geopolitical weaklings. Today, the term “white slavery” is merely a synonym for prostitution, but it originally meant the enslavement of fair-skinned women for sale to clients in North Africa, the Middle East, and South Asia.  At the height of this trade, between 1500 and 1650, over 10,000 Eastern Europeans were enslaved each year for export (Kolodziejczyk, 2006; Skirda, 2010). The overwhelming majority were young women and pre-pubertal boys who were valued for their physical appearance. And yet they were powerless.

No, I don't think this kind of preference will disappear as whites lose "privilege."

Exit strategies

So more and more young men are being left on the shelf, particularly in White America. How do they cope? Mostly by turning to porn from Internet websites, videocassettes, or magazines. Love dolls are another option and may grow in popularity as they become more human-like, not only physically but also in their ability to talk and interact.

Another option is outmarriage. In the past, this trend largely concerned older men marrying East Asian or Hispanic women, but we’re now seeing plenty of young men outmarrying via Internet dating sites. Despite the local supply of single women in the African American community, there is a much stronger tendency to look abroad, generally to women in Eastern Europe, South America, or East Asia.

Then there's gender reassignment, which means either entering the other side of the mate market or tapping into the lesbian market. It’s a viable strategy, all the more so because many white boys can be turned into hot trans women. I'm not saying that some young men actually think along those lines, but gender reassignment is functioning that way.

Finally, there's "game." My attitude toward game is like my attitude toward gender reassignment. Both are attempts to push the envelope of phenotypic plasticity beyond its usual limits, and neither can fully achieve the desired result. A lot of boys aren't wired for game, and there are good reasons why, just as there are good reasons why some people are born male. Male shyness isn't a pathology. It's an adaptation to a social environment that values monogamy and high paternal investment while stigmatizing sexual adventurism. Our war on male shyness reflects our perverse desire to create a society of Don Juans and single mothers.

But if game works, why not? Whatever floats your boat.

Conclusion

Ideally, this gender imbalance should be dealt with at the societal level, but I see little chance of that happening in the near future. If anything, public policy decisions will probably worsen the current imbalance. Changes to public policy generally result from a long process that begins when people speak up and articulate their concerns, yet it's unlikely that even this first step will be taken any time soon. Young single men prefer to remain silent and invent nonexistent girlfriends. They also tend to be marginal in the main areas of discourse creation, like print and online journalism, TV, film, and radio production, book writing, etc. Leaf through any magazine, and you'll probably see more stuff about the problems of single women.

So this imbalance will likely continue to be addressed at the individual level through individual strategies.

References 

Centers for Disease Control and Prevention. (2014). Sexual Orientation in the 2013 National Health Interview Survey: A Quality Assessment, Vital and Health Statistics, 2(169), December

http://www.cdc.gov/nchs/data/series/sr_02/sr02_169.pdf 

Centers for Disease Control and Prevention. (2013). Vital Statistics Online

http://www.cdc.gov/nchs/data_access/Vitalstatsonline.htm  (for discussion, see Silviosilver, 2015 http://www.unz.com/pfrost/the-last-push-back-against-liberalism/#comment-896920) 

Jacobs, J.A. and T.B. Labov. (2002). Gender differentials in intermarriage among sixteen race and ethnic groups, Sociological Forum, 17, 621-646.

http://link.springer.com/article/10.1023/A:1021029507937 

Kolodziejczyk, D. (2006). Slave hunting and slave redemption as a business enterprise: The northern Black Sea region in the sixteenth to seventeenth centuries, Oriente Moderno, 86, 1, The Ottomans and Trade, pp. 149-159.

http://www.jstor.org/discover/10.2307/25818051?sid=21105312761261&uid=3737720&uid=3739448&uid=2&uid=4 

Lawton, Z. and P. Callister. (2010). Older Women-Younger Men Relationships: the Social Phenomenon of 'Cougars'. A Research Note, Institute of Policy Studies Working Paper 10/02

http://ips.ac.nz/publications/files/be0acfcb7d0.pdf 

Liu, G., S. Hariri, H. Bradley, S.L. Gottlieb, J.S. Leichliter, and L.E. Markowitz. (2015). Trends and patterns of sexual behaviors among adolescents and adults aged 14 to 59 years, United States, Sexually Transmitted Diseases, 42, 20-26.

http://journals.lww.com/stdjournal/Abstract/2015/01000/Trends_and_Patterns_of_Sexual_Behaviors_Among.6.aspx 

Miller, W.C., C.A. Ford, M. Morris, M.S. Handcock, J.L. Schmitz, M.M. Hobbs, M.S. Cohen, K.M. Harris, and J.R. Udry. (2004). Prevalence of chlamydial and gonococcal infections among young adults in the United States, JAMA, 291, 2229-2236.

http://jama.jamanetwork.com/article.aspx?articleid=198722

Passel, J.S., W. Wang, and P. Taylor. (2010). One-in-seven new U.S. marriages is interracial or interethnic, Pew Research Center, Social & Demographic Trends,

http://www.pewsocialtrends.org/2010/06/04/ii-overview-2/

Skirda, A. (2010). La traite des Slaves. L'esclavage des Blancs du VIII^e au XVIII^e siècle, Paris, Les Éditions de Paris Max Chaleil. 

Soma, J. (2013). Interactive Singles Map

http://jonathansoma.com/singles/

 

Why are girls and boys maturing earlier?

For girls, the age of puberty has been falling since the 19th century. The same period has seen a similar decline for boys (source)

In the United States and other Western countries, girls have been reaching puberty at earlier and earlier ages. A recent longitudinal study has examined this trend in white Americans born between 1928 and 1992. Its conclusion? Girls are reaching puberty earlier because of an interaction between a lifestyle factor and a pre-existing genetic predisposition:

Our data also show, for the first time, that the effect of menarche SNPs on prepubertal BMI was stronger in children born more recently compared to those born earlier in the century, thereby suggesting that the developmental genetic susceptibility to elevated BMI may have only been ''uncovered'' in the more obesogenic environments of the recent past. (Johnson et al., 2013)

For the study's authors, the lifestyle factor is that girls are eating more, exercising less, and accumulating more body fat. Because fatty tissue is a significant source of estrogen, an increasing percentage of body fat tends to hasten puberty in young girls (Frisch & Revelle, 1970; Frisch & McArthur, 1974; Kaplowitz et al., 2001; Siiteri & MacDonald, 1973). This effect is stronger in girls with a certain genetic background:

It is possible that over the examined time period, individuals with higher genetic burden for accelerated sexual development are for the first time ''allowed'' by liberalization of the environment to alter dietary intake and energy expenditure to support their genetic potential for rapid weight gain and earlier sexual development. (Johnson et al., 2013)

But why are boys too maturing earlier?

In boys, body fat is not linked to early puberty. In fact, there seems to be a negative correlation, perhaps because fatty tissue is a significant source of estrogen (Wang, 2002). Overweight boys often present signs of disrupted male sexual development, e.g., breast budding, higher voice pitch, etc.

Yet boys likewise are reaching puberty at an earlier age. This is the conclusion of a recent American study:

We observed that onset of secondary sexual characteristics in US boys as seen in office practice appears to occur earlier than in previous US studies and the 1969 British study commonly used for pubertal norms. […] White boys in our study entered stage 2 genital growth 1.5 years earlier than the British boys (10.14 vs 11.60 years of age).

[…] These data are consistent with recent trends from other countries, such as Denmark, Sweden, Great Britain, Italy, and China. For example, urban Han Chinese boys achieve a testicular volume of ≥4 mL (13% by age 9) and spermarche earlier than studies conducted several decades ago; Danish boys achieve a testicular volume >3 mL more than 3 months earlier now than 15 years ago. (Herman-Giddens, 2012)

This trend has also been observed in the age when a boy's voice begins to change:

According to records kept by the Leipzig choir, the most common period of voice breaking for male singers in the mid-18th century was between 17.5 and 18.5 years of age (Daw, 1970); in contrast, children enrolled in the Copenhagen Municipal Choir School from 1994-2003 had a median age of voice breaking of 10.4 years (Juul, Magnusdottir, Scheike, Prytz, & Skakkebæk, 2007), which is consistent with the choir's subjective reports of difficulty retaining children as singers past the age of 12 or 13 years. (Mendle & Ferrero, 2012).

This is a challenge for Occam's Razor, and the task is no easier if we look at other possible causes. If the cause isn’t a higher proportion of body fat, could it be a higher level of estrogens and estrogen-like substances in the environment? (see earlier post). Yes, that might hasten puberty in girls and increase accumulation of body fat. But in boys it would delay puberty by offsetting the rising level of male hormones.

In trying to figure out the causal chain of events, we should keep in mind that the relationship between body fat and age of puberty runs in both directions. On the one hand, estrogen from body fat lowers the age of puberty in girls. On the other hand, earlier puberty increases ovarian production of estrogen, which in turn stimulates deposition of body fat, particularly on the hips, buttocks, and breasts (Van Lenthe et al., 1996). So perhaps some unknown factor is causing earlier sexual development in both sexes and thus greater deposition of body fat in girls.

A response to social cues?

This unknown factor might be something in the social environment. As Hawley (2011) argues, humans unconsciously monitor their social environment for reproductive opportunities and accordingly speed up or slow down their pace of sexual development:

[...] human children, especially girls, may be sensitive to their early socioecological conditions in ways that entrain development toward either a faster (earlier pubertal maturation, more sexual partners, less stable relationships) or slower (later pubertal maturation, fewer sexual partners, more stable relationships) life history strategy.

With the transition to post-traditional societies, there has been an increase in the erotic stimuli that preteens encounter in their surroundings:

Common in traditional societies are adult-supervised adolescent initiation ceremonies (Schlegel & Barry, 1980) that are designed to commemorate the transition from childhood to adulthood and inculcate the adolescent with adult values, duties, behaviors, and sex roles associated with the culture (Schlegel, 1973). That is, these adolescents are taught adult sex roles by adults. We now appear to have a complete turnaround. In modern, Western cultures, adolescents derive sexual relationship expectations from television, cable, music, purveyors of racy lingerie (who target teenage girls), and pornography that they can now access on the Internet and thereby carry around on their cell phones. (Hawley, 2011)

Erotic imagery in particular is today available to a degree that was impossible not so long ago. Young boys and girls have virtual access to an endless supply of picture-perfect sexual partners. Whatever the media—films, TV, magazines, the Internet—we're exposed to images that can stimulate sexual desire as efficiently as what normally exists in the real world. More so, in fact. These images are ‘supernormal’ stimuli.

To date, only one study has looked into possible relationships between erotic imagery and pubertal timing:

The aim of this study was to investigate associations between pubertal timing and boys' Internet use, particularly their viewing of pornography. We used a sample comprising of 97 boys in grade 8 (M age, 14.22 years) from two schools in a medium-sized Swedish town. This age should be optimal for differentiating early, on-time, and later-maturing boys. Boys responded to self-report questionnaires on their Internet use and pubertal timing. Early, on-time, and late-maturing boys did not differ in terms of most Internet activities. However, early maturers reported downloading and viewing pornography more often than the other boys did (p<.001). (Skoog et al.,2009)

Admittedly, the arrow of causality might point in the other direction, i.e., early maturing boys have a stronger sex drive and thus a greater interest in porn. This was, in fact, the authors' explanation. We should also remember the well established correlation between early puberty in girls and the absence of a father in the home. It was long thought that father absence triggers early puberty in girls. In fact, a twin study has shown a genetic cause: absent fathers tend to have genes that favor earlier sexual development in their progeny (Mendle et al., 2006).

One might also object that the decline in the age of puberty began long before the Internet. Before the Internet, however, there were porn magazines. And before them, there were pictures garnered from art books, fashion magazines, or the lingerie sections of mail-order catalogues. One could also bring erotic images to mind by reading certain novels. Thus, modern pornography is merely the latest stage of a lengthy co-evolution between, on the one hand, improvements in photography and other imaging technologies and, on the other hand, a weakening of taboos against masturbation. At the beginning of this co-evolution, in the 19th century, masturbation was much less developed among young boys and girls as a sexual lifestyle. Visual aids were scarce and of poor quality, religious injunctions were strong, and adult supervision inside and outside the home was omnipresent.

Conclusion

The age of puberty might be declining because boys and girls are being exposed to ever more and ever better erotic imagery, but this hypothesis needs confirmation by longitudinal studies to determine which is the cause and which is the effect. Another drawback with current research is its focus on the most extreme forms of pornography, such as child porn. Yet the usual stuff is the kind that most people consume ... and in unparalleled quantities. As the authors of a recent Dutch study remarked:

[...] we can only emphasize that Dutch youth are confronted with and expose themselves to an unprecedented amount of R-rated and Xrated material in the media. Research on its consequences for adolescents' sexual socialization is largely missing but, as this study has shown, is urgently needed. (Peter & Valkenberg, 2006)

And erotic imagery isn't confined to X-rated websites or magazines. It is in fact ubiquitous in modern social environments. Girls might accelerate their sexual development by leafing through fashion magazines just as boys might accelerate theirs by viewing porn.

The erotic imagery hypothesis will have to fit the data better than rival hypotheses. Two of these, the body fat and environmental estrogen hypotheses, can explain the decline in the age of puberty for girls but not for boys. Another possible cause is better nutrition. Yet, among white Americans at least, much of this decline has happened since the 1950s—when nutrient levels were already adequate for this population. Finally, there is the possibility that puberty is happening earlier because genes that favor that developmental trajectory are spreading within the population. Modern social environments favor a reproductive strategy of early puberty, low parental investment and, especially, low paternal investment—in short, the ‘cads’ are outbreeding the ‘dads’ (see earlier post).

References

Frisch, R.E., R. Revelle. (1970). Height and weight at menarche and a hypothesis of critical body weights and adolescent events, Science, 169, 397-399.

Frisch, R.E. & J.W. McArthur. (1974). Menstrual cycles: fatness as a determinant of minimum weight necessary for maintenance or onset, Science, 185, 949-951.

Hawley, P.H. (2011). The evolution of adolescence and the adolescence of evolution: The coming of age of humans and the theory about the forces that made them, Journal of Research on Adolescence, 21, 307-316.

http://www.people.ku.edu/~phawley/Publications/Hawley%202011%20JRA%20Evo%20of%20Adol.pdf

Herman-Giddens, M.E., J. Steffes, D. Harris, E. Slora, M. Hussey, S.A. Dowshen, R. Wasserman, J.R. Serwint, L. Smitherman, & E.O. Reiter. (2012). Secondary sexual characteristics in boys: Data from the Pediatric Research in Office Settings Network, Pediatrics, 130, e1058-e1068.

http://pediatrics.aappublications.org/content/130/5/e1058.full.pdf+html

Johnson, W., A.C. Choh, J.E. Curran, S.A. Czerwinski, C. Bellis, T.D. Dyer, J. Blangero, B. Towne, & E.W. Demerath. (2013). Genetic risk for earlier menarche also influences peripubertal body mass index, American Journal of Physical Anthropology, 150, 10-20

Kaplowitz, P.B., E.J. Slora, R.C. Wasserman, S.E. Pedlow & M.E. Herman-Giddens. (2001). Earlier onset of puberty in girls: relation to increased body mass index and race, Pediatrics, 108, 347-353.

Mendle, J. & J. Ferrero. (2012). Detrimental psychological outcomes associated with pubertal timing in adolescent boys, Developmental Review, 32, 49-66.

Mendle, J., E. Turkheimer, B.M. D'Onofrio, S.K. Lynch, R.E. Emery, W.S. Slutske, N.G. Martin. (2006). Family structure and age at menarche: a children-of-twins approach, Developmental Psycholpgy, 42, 533-542.

Peter, J. & P.M. Valkenberg. (2006). Adolescents' exposure to sexually explicit material on the Internet, Communication Research, 33, 178-204.

Siiteri, P.K. & P.C. MacDonald. (1973). Role of extraglandular estrogen in human endocrinology. In S.R. Geiger (ed.), Handbook of Physiology, Washington D.C. American Physiology Society, sect. 7, vol. 2, part 1, pp. 615-629.

Skoog, T., H. Stattin, & M. Kerr. (2009). The role of pubertal timing in what adolescent boys do online, Journal of Research on Adolescence, 19, 1-7.

Van Lenthe, F.J., C.G. Kemper & W. van Mechelen. (1996). Rapid maturation in adolescence results in greater obesity in adulthood: the Amsterdam Growth and Health Study, American Journal of Clinical Nutrition, 64, 18-24.

Wang, Y. (2002).Is obesity associated with early sexual maturation? A comparison of the association in American boys versus girls, Pediatrics, 110, 903-910.

http://www.pediatricsdigest.mobi/content/110/5/903.short