Earlier this year, two American bloggers triggered a global media convulsion by embarking on what they called a "mirror fast": covering the mirrors in their homes, and shunning mirrors elsewhere, in an effort to reduce what one of them called "the overriding self-consciousness that's taken up residence in my psyche". Since the social pressure to conform to ideals of beauty falls mainly on women, I can only guess what it's like to be so aware of one's appearance: I assume it's related to what I feel whenever a badly-angled photo reminds me how astoundingly bald I am. But for the fasters, the experiment proved a liberation. "All the other interests in my life – my goals, passions, friends, family, favourite hobbies, etc – have attracted the energy and attention I used to give to my looks," wrote Kjerstin Gruys, while Autumn Whitefield-Madrano said she felt "calmer and more serene". They'd pulled off an ingenious psychological trick. In a world obsessed with appearances, it's impractical just to decide you're going to think differently. What they'd done, instead, was to deny themselves the feedback that fuelled the fixation.