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