Turns out my manic fixation with silence while I'm writing is not just an odd personal foible (shared by many geniuses). It is a scientifically valid strategy for better performance, proven and endorsed by none other than Stanford psychologist Clifford Nass, who has studied the effects of rampant multitasking and how it turns you into a twitching, jabbering pile of mush. Here, via Kevin Drum at Mother Jones, is Nass on what he discovered in his studies of hardcore multi-taskers:

We were absolutely shocked. We all lost our bets. It turns out multitaskers are terrible at every aspect of multitasking. They're terrible at ignoring irrelevant information; they're terrible at keeping information in their head nicely and neatly organized; and they're terrible at switching from one task to another.
And: 
T]he truth is, virtually all multitaskers think they are brilliant at multitasking. And one of the big new items here, and one of the big discoveries is, you know what? You're really lousy at it. And even though I'm at the university and tell my students this, they say: "Oh, yeah, yeah. But not me! I can handle it. I can manage all these," which is, of course, a normal human impulse. So it's actually very scary....