YOU can close your eyes when you do not want to see. You can hold your breath when you do not want to smell. But you cannot really shut down your ears when you do not want to hear. The saying “to turn a deaf ear” is only a metaphor. Your hearing, like your heartbeat, goes on working even when you sleep.

Indeed, our ears are working all the time to keep us in touch with the world around us. They select, analyze, and decipher what we hear and communicate it to the brain. Within the confine...