It is hard to ignore how many highly visible men in recent years (indeed, months) have behaved in sexually self-destructive ways. Some powerful men have long been sexually voracious; unlike today, though, they were far more discreet and generally used much better judgment in order to cover their tracks.

Of course, the heightened technological ability nowadays to expose private behavior is part of the reason for this change. But that is precisely the point: so many of the men caught up in sex-tinged scandals of late have exposed themselves - sometimes literally - through their own willing embrace of text messages, Twitter, and other indiscreet media.

What is driving this weirdly disinhibited decision-making? Could the widespread availability and consumption of pornography in recent years actually be rewiring the male brain, affecting men's judgment about sex and causing them to have more difficulty controlling their impulses?

There is an increasing body of scientific evidence to support this idea. Six years ago, I wrote an essay called "The Porn Myth," which pointed out that therapists and sexual counselors were anecdotally connecting the rise in pornography consumption among young men with an increase in impotence and premature ejaculation among the same population. These were healthy young men who had no organic or psychological pathology that would disrupt normal sexual function.

The hypothesis among the experts was that pornography was progressively desensitising these men sexually. Indeed, hardcore pornography's effectiveness in achieving rapid desensitisation in subjects has led to its frequent use in training doctors and military teams to deal with very shocking or sensitive situations.

Given the desensitisation effect on most male subjects, researchers found that they quickly required higher levels of stimulation to achieve the same level of arousal. The experts I interviewed at the time were speculating that porn use was desensitising healthy young men to the erotic appeal of their own partners.

Since then, a great deal of data on the brain's reward system has accumulated to explain this rewiring more concretely. We now know that porn delivers rewards to the male brain in the form of a short-term dopamine boost, which, for an hour or two afterwards, lifts men's mood and makes them feel good in general. The neural circuitry is identical to that for other addictive triggers, such as gambling or cocaine

This dopamine effect explains why pornography tends to become more and more extreme over time: ordinary sexual images eventually lose their power, leading consumers to need images that break other taboos in other kinds of ways, in order to feel as good. Moreover, some men (and women) have a "dopamine hole" - their brains' reward systems are less efficient - making them more likely to become addicted to more extreme porn more easily.

As with any addiction, it is very difficult, for neurochemical reasons, for an addict to stop doing things - even very self-destructive things - that enable him to get that next hit of dopamine. Could this be why men who in the past could take time-delayed steps to conduct affairs behind closed doors now can't resist the impulse to send a self-incriminating text message? If so, such men might not be demons or moral ciphers, but rather addicts who are no longer entirely in control of themselves.