Listen for breathless silence. Then, the unicorn stilled, all was silent again. A breath, a sigh, a salute. -- Bosevo, 44 Rue D'Assas (2000) "When you expect an event to occur, your brain is highly sensitized to that possibility," suggests Dr. Katya Rubia of France's national Institute of Psychiatry. Hearing expert Pierre Fonlupt of the Inserm institute explains: "The auditory cortex is activated when a subject is attending to and listening to silence, when expecting an upcoming sound" (BBC News, 2004). To sensitize your brain to notice unicorn sounds, take special notice of silence, which is available locally in many areas. Focus on the spaces between sounds. Here are some things to practice listening for, as suggested by New Zealand naturalist Pete McGregor in his essay "Sounds and Silence" (2006): a fumbling and buzzing bumble bee settling onto a blue clothes peg a lone swallow swooping past without a sound