Since you ask, we would describe tolerance as an outgrowth of novelty-seeking. Day one, you get aroused by bikini models. Day two, bikini models don't do it for you but Playboy centerfolds do. Day three, the centerfolds barely register for you and it's on to hardcore pictures. You see where this leads.

So, yes, we agree viewing time alone is not an indicator of tolerance, but we disagree that tolerance is the same as needing "ever more" content to get you hard (unless perhaps it's "ever more" of the bikini models when you're on day sixteen). Nor is getting hard necessarily the be all end all. An erection and orgasm may be the (often unwanted) end to a porn bender, but we know plenty of sufferers who spend hours in a "ludic loop" of porn viewing at least partially limp.

Porn addicts often describe being disappointed when they orgasm. They may "edge" for hours on the verge of climax but a bender may just as easily end in exhaustion as it does in ejaculation. Which makes sense since orgasm essentially signals coming down from the high, and the intensely negative feelings that addicts of all stripes commonly experience after a binge.