Yo-Yo Ma's ear for music emerged not long after he learned to walk. By the age of seven, he was performing for President Kennedy; by fifteen he debuted at Carnegie Hall. Maya Angelou, by contrast, didn't write her iconic memoir, I Know Why the Cage Bird Sings, until she was 40. What propels some individuals to reach extraordinary creative heights in the earliest years of life while others discover their passions decades later? Are prodigies...