
They say when you have a hammer in your hand all your problems start to look like nails. When you're a horse trainer you tend to see the world in terms of instinct and behaviour. Instinct, because the horse is 500kgs of lightning fast, hard-wired instinctive reaction and behaviour, because you spend your days nurturing and training some behaviours while carefully discouraging others. It is this intersection, the balance of both nature and nurture, that is at the heart of all good training.

(In fact, it often seems slightly ironic to me that we obsess over what we feed our bodies with more than what we feed our minds with. Our minds are just as much a product of the material that we consume as our bodies are a product of the material that we eat. Feeding your brain a daily dose of meaningless television must be about as nourishing, in the long term, as Maccas is for our bodies...)
Like the horse, our brains are very good at making connections between seemingly unrelated things. Russian scientist, Ivan Pavlov was the first person to discover this phenomenon and he called it classical conditioning. Pavlov rang a bell and then fed his laboratory dogs some meat and after a few dozen repetitions when he rang the bell the dogs would salivate without the presence of meat. Bob Bailey, one of the most articulate animal trainers around, says that as trainers we have Pavlov on our shoulder all of the time, because we cannot know the number and variety of responses that the animals we train have acquired via classical conditioning. Using classical conditioning you can train a killer whale to do backflips with a whistle and some herring. But unless you know its entire history you will never know what classically conditioned stimuli might cause it to attack a human. It's a very powerful learning modality. Remember classical conditioning because we're going to get back to it in a minute...

When you use horse trainer's reasoning the case against porn starts to really stack up. We have the human instinct to seek out sex, coupled with a changeable brain that (compliments of dopamine) finds porn extremely reinforcing. We also know that every porn useage makes a further useage more likely because behaviour that is reinforced will be repeated. And we also know that because of classical conditioning, powerful connections are being made in the brain during the use of porn.
Horse trainers also know that when training is unclear the horse will habituate to even very painful stimuli. Habituation occurs when the presence of a stimuli (such as a bit) produces less and less response over time. This is why good trainers usually advocate better training, rather than a bigger bit or bigger spurs. Humans habituate to stimuli too and this is why porn use has consistently been documented to escalate amongst regular users. Over time the stimuli that, in the past, would produce extreme excitement becomes less and less exciting. So to get the same dopamine hit the porn user has to turn to more and more extreme forms of porn to feel the same degree of excitement.
So while the kind of porn that's being used escalates, the dopamine that's being released is helping classical conditioning along and very powerful connections are being formed between things such as sex and violence (mostly against women), sex and degradation, sex and domination. It's a very unhealthy cocktail. And it's extremely disturbing when you consider that the most popular porn search on the internet in 2015, with over 18 billion hits worldwide, was for "teen sex". Because of the plasticity of our brains and classical conditioning there are an awful lot of people out there who have very strong connections in their brains between sexual arousal and teenage girls. As the mother of a teenage girl it makes me want to invest in a set of emasculator clamps...
I'm not qualified to suggest that there is a causal (rather than an associative) link between porn use and actual sexual violence in susceptible individuals (though there are plenty of studies out there that do) but I will say that as a horse trainer it wouldn't surprise me. At all. You get the behaviour you reinforce, not the behaviour you want and it's not hard to see what is being inadvertently reinforced when violent porn is viewed. Of more concern to the occasional porn user is the effect that even irregular use can have on sexual response. Because of classical conditioning, even low key porn use can change the brain to the extent that what used to float your boat may no longer be very exciting at all. Real sex may no longer be enough. And just like the drug user, the paraphernalia of porn use may cause a spike in dopamine levels and therefore become exciting. I bet that makes you wonder why the person next to you at work is smiling when they turn on their lap top...
See you on the arena. P