Stand up and reach out your arms, fingers extended. Wave them up, down, and sideways. Make great big circles from over your head down past your thighs. Swing each leg out as far as you can, and with the tips of your toes trace arcs on the ground around you. Swivel and tilt your head as if you were craning out your neck to butt something with your forehead or touch it with your lips and tongue. This invisible volume of space around your body out to arm’s length—what neuroscientists call peripersonal space—is part of you
