Psychologist Marnia Robinson calls the “…plastic effects of sexual behaviours on the brain’s delicate reward circuitry” as vastly underestimated. She writes:
Actual experience, however, suggests that intense stimulation can alter sexual tastes in some brains. Indeed, some of today’s Internet porn users are undergoing unnerving changes in their brains and arousal patterns—a possibility now well explained by many experiments revealing the plasticity of the brain. These changes are difficult to reverse while porn use continues. In short, sexual cues that start out as insubstantial and meaningless as cobwebs can become cables, that is, can lay down brain pathways that are given high priority because they are associated with the intense reward of orgasm. 
Researchers from Queen Mary’s School of Biological and Chemical Sciences, and the Karolinska Institute in Stockholm report showed that homosexual behaviour is largely shaped by genetics and random environmental factors (that is, not necessarily societal attitudes, family or parenting) with exposure to certain hormones during foetal development as a key determinant. The studies show that genetic factors are of lesser importance than the early hormonal and individual environmental factors giving further credence to the hypothesis that sexuality is highly malleable and dependent on individual influences. So too, the plasticity of the brain open to change from both external factors and our own perceptions. In terms of sexual orientation what does this imply? Consider this description of present neuroplasticity  in the context of pornography:
A sensitive brain can wire up to a new sexual cue with a few intense orgasms. Thereafter, such a brain will respond to that cue (whether with arousal or repulsion) before the brain’s owner is even consciously aware of the cue. In short, the brain’s reward circuitry ignites a powerful reaction before the person’s frontal cortex has a chance to dismiss the cue.
In some brains, classic conditioning proves to be but the top of a slippery slope to more permanent alterations of the reward circuitry. These alterations produce a much higher level of dopamine release in key brain circuits (sensitization). This brain change is often accompanied by an overall decrease in the brain’s pleasure response (desensitization). Together these addiction-related changes drive cravings for increasingly stimulating material. 
What does say about the sexual imagery and multi-media content that is currently bombarding largely young males? Can we also infer that exposure to pathologies in early childhood can indeed help to determine – at least in part – the outcome of a child’s sexuality?
When these two factors are combined then we may begin to understand the fascination of agencies and perception mangers like the Rockefellers in shaping societies according to their own bizarre precepts. Yet, it remains difficult to study neuroplasticity, environmental factors, genetic crossovers and their relationship to sexual behaviours because misguided ethics committees will not allow it.  What is more pertinent is the connection between sexual orientation and the re-wiring of the brain’s neural pathways.
Gary Wilson, an anatomy and physiology teacher suggests that internet pornography is making male sexuality more plastic, with cyber-porn manufacturing superficial tastes, sometimes unrelated to sexual orientation. In relation to the how the brain works he quotes neuroscientist Norman Doidge who states: “The content of what [patients] found exciting changed as the web sites introduced themes and scripts that altered their brains without their awareness. Because plasticity is competitive, the brain maps for new, exciting images increased at the expense of what had previously attracted them.” 
Rather than revealing our deepest, sexual urges and letting our craziest fantasies run wild when surfing for pornographic material perhaps it merely reflects an exponential curve of greater extremes? As Wilson proposes: “Could this be why viewers who would never harm others are viewing violent porn? Why gay porn viewers are feeling baffled by their tastes for straight rape porn or lesbian porn? Why straight men are bewildered by their tastes for transsexual or gay porn?”  And as neuroscientist Jim Pfaus points out: “… the mating brain is opportunistic. It’s not strictly bound by intrinsic wiring, but rather it adapts to promising sexual cues.” 
And when the statistically highest user of internet porn is the adolescent male and his brain is in the developmental phase of wiring up for sexual cues, then this puts a whole new angle on how sexual orientation can be shaped and how porn can affect sexual identity in combination with other less overt sexual cues from cinema, magazines and other sources from daily life. Rewiring, desensitization, and sexual disorientation are the results.
Wilson quotes another young user who described this disorientation:
Ryan: I seriously thought I was turning gay. My obsessive thoughts about this issue were so strong that I was contemplating taking a dive off the nearest high-rise. I felt so depressed. I knew I loved girls and I couldn’t love another dude, but why did I have ED? Why did I now need transsexual/gay stuff to get off? It’s like I made a mistake that I cannot correct anymore. I want to go back to my old days when I was only turned on by the female body. […]
One 22 year-old:
During middle school and high school I watched porn for hours. After high school I dated a girl I really liked, but I didn’t feel as much arousal around her as I felt when watching porn. In college I got confused about my sexuality because I wasn’t feeling as much sexual attraction as other people. I was also turned on by gay porn and thought maybe I had latent homosexuality. My senior year I went to sexuality counseling and a coming-out support group for a quarter. Neither brought me closer to understanding sexual orientation or attraction. Yes, I got turned on by some gay porn, but I didn’t feel attraction to, or fantasize about, guys. The gay guys that I met seemed much more certain of their orientation. After a while I wasn’t sure I belonged there. I’ve started feeling more sexual attraction around women now that I’ve cut down on porn and masturbation. 
Factor in childhood events and shocking episodes (negative or positive) then sexual orientation turn out to be much more complicated than at first thought. We live in a culture that continues to thrive on sensation and shock with undercurrents of sexualisation pushing the young to experiment earlier and earlier. This is reflected in part, by the onset of puberty in girls as young as eight, then it should be no surprise that society responds in a Pavlovian manner to more extremes while being tricked into thinking this is quite normal.
As Gary Wilson observes: “Brains desperate for sensation can find anxiety-producing material particularly arousing. Such emotions release extra dopamine (and norepinephrine) in the brain. In essence, they are a response to risk-taking.”  It need not be porn that creates the conditioned response – the crucible of our daily lives can easily fit the bill.
As discussed in a previous post, the mainstreaming of pornography now includes the one time fetish for hairless genitals and anal sex now so much a part of sexual preference that it is part of any sexually active individual. Not only do women now consider any trace of hair on their body “gross” but men too are waxing up believing that these sexual cues have always been there.
With so much distortion on show in movies, reality T.V., magazines and the internet and the acceptance and accessibility of amateur and professional porn it is little wonder there are so many mixed messages for the young, where the discovery of one’s normal orientation is lost in a sea of sexual extremes, where the “mechanics of sex” and sensation are the only means to express. Indeed, when sex, seduction and the darker archetypes of the vampire, werewolf and demon are ubiquitous in movies and television series blurring the clear-cut delineation of Good vs. Evil: “… It is no great mystery that, in this confusion, hate and contempt is sometimes shunted over into channels which are normally designed for erotic gratification and for devotion.” 
Psychopathological strains will infiltrate any belief that offers fertile ground for distortion of the whole. Therefore: “Only when screened from normal stimuli by pathologic developments is man likely to respond specifically to those that are abnormal.” 
The result has been the progressive distortion, relegation and denigration of woman and the feminine and man and the masculine and by extension – the sacred. It is from this perspective (and putting aside Cleckley’s misunderstanding of the source) that we can follow his train of thought and his extraordinarily valuable insights into the nature of pathological narcissism and essential psychopathy.
(For one example of the latest research on the influence of digital media on the young see: The Great Porn Experiment: Gary Wilson at TEDxGlasgow)
[NOTE: As a summary of this series as well as adding many fascinating extra elements to the mix, the subject of sexuality, gender theory as related to the ponerisation of values in our Western societies has been recently covered in an excellent article by Pierre Lescaudron of Sott.net entitled: Mummy, why is Daddy wearing a dress? Daddy, why does Mummy have a moustache?]
 ‘Wiring Sexual Tastes to Hairless Genitals…Oops!’ Psychology Today, By Marian Robinson. January 2 2012.
 ‘Homosexual Behavior Largely Shaped By Genetics And Random Environmental Factors,’ScienceDaily, June 28, 2008. “This study looked at 3,826 same-gender twin pairs (7,652 individuals), who were asked about the total numbers of opposite sex and same sex partners they had ever had. The findings showed that 35 per cent of the differences between men in same-sex behaviour (that is, that some men have no same sex partners, and some have one or more) is accounted for by genetics.Rahman explains: “Overall, genetics accounted for around 35 per cent of the differences between men in homosexual behaviour and other individual-specific environmental factors (that is, not societal attitudes, family or parenting which are shared by twins) accounted for around 64 per cent. In other words, men become gay or straight because of different developmental pathways, not just one pathway.” For women, genetics explained roughly 18 per cent of the variation in same-sex behaviour, non-shared environment roughly 64 per cent and shared factors, or the family environment, explained 16 per cent.The study shows that genetic influences are important but modest, and that non-shared environmental factors, which may include factors operating during foetal development, dominate. Importantly, heredity had roughly the same influence as shared environmental factors in women, whereas the latter had no impact on sexual behaviour in men.[…].
This has reinforced by new studies Michael Bailey, a psychologist at Northwestern University in Illinois, [who] “… set out the findings at a discussion event held in conjunction with the annual meeting of the American Association for the Advancement of Science in Chicago: “Scientists tested the DNA of 400 gay men and found that genes on at least two chromosomes affected whether a man was gay or straight. A region of the X chromosome called Xq28 had some impact on men’s sexual behaviour – though scientists have no idea which of the many genes in the region are involved, nor how many lie elsewhere in the genome.Another stretch of DNA on chromosome 8 also played a role in male sexual orientation – though again the precise mechanism is unclear.” – ‘Male sexual orientation influenced by genes, study shows’ The Guardian, Ian Sample, February 14, 2014.
 The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science by Norman Doidge Published by Penguin 2008 | ISBN-10: 014103887X.
 op. cit. Robinson.
 ‘ Sex Research: The Orgasm Cycle’ May 31, 2010 by Marnia Robinson, Psychology Today.
 ‘Can You Trust Your Johnson?’ October 22, 2011 by Gary Wilson, Psychology Today.
 op. cit. Wilson.
 op. cit. Cleckley, (p.270)
 Ibid. (p.268)