I never have any idea where I am. I lived my whole childhood in the purple foothills of the same five-square-mile town and I still couldn’t tell you whether you turn left or right on the single thruway to get to the grade school or the grocery store, or how to find the houses of any of my childhood friends. I can’t tell you how to find the conspicuously modern angles of the apartment building in the small Mississippi town where I lived for three years in graduate school, or even easily direct you from my old house in Austin to the bright little bar where I wrote much of my first book. I never know how far I am from the airport or the highway. I can’t read a map effectively, and even though it’s less than half a mile from my current apartment in London, I couldn’t get to the Thames without the artificial voice on my cell phone—set to an Australian accent so its omnipresence is less tiresome—­calling out turn left every 250 feet. Half the time, to remember which way is left, I have to imagine for an instant that I am picking up a pen.

Even on a much smaller scale, space makes no sense to me. I walk all the way around the perimeter of a room to reach a door that’s immediately to my right, and I set my glass down half an inch from the edge of the table with such frequency that anyone who knows me well gets used to nudging it back again and again over the course of an evening in this small, choreographed two-step. As a girl, I put my shoes on the wrong feet so reliably that my parents directed me just to behave in defiance of my inclinations: if I thought a sneaker should go on one foot, put it on the other. This is a strategy I still use sometimes: if I’m certain an office is to the right out of the elevator, I go left down the hall. I’m almost always wrong about the layout of the world.

I come, after a while, to recognize landmarks—pale-blue awning of the nearest dry cleaner’s, wrought-iron railing along the railroad bridge, surprise of a green-painted storefront among all the brick—which is how I learn, eventually, to navigate some frequent paths of travel, but no collection of spaces, no matter how habitually I move through them, ever knits into any kind of coherent map inside my head. I’ll be wandering in the city convinced I’m miles away from anywhere I’ve ever been, and then turn a corner to see the shapes of my own block rising up as if transplanted, their familiarity more unsettling than encountering something new, proof I lack a homing instinct of any kind.

There’s a neurological explanation for at least some of this. The ability to process information about distance, angles, and direction—to reason, essentially, about the physical expanse around you—is called spatial cognition, and the oxygen deprivation at birth that caused my cerebral palsy resulted in some injury to the neural structures that make this kind of reasoning possible; it’s as if there’s a blown fuse in the wiring of my brain. Lights from down the hall provide a little glow, but the chamber is permanently dim.