Absolute pitch (commonly referred to as perfect pitch) is the rare musical ability to distinguish notes and pitches without a given reference. For example, people with AP can automatically spot the difference between an "Gb" (G-flat) and a Db (D-flat) without any hints given. The odds of being born with AP is 1 in 47,000 people, making this phenomenon rare. Absolute pitch can be distinguished in people who are blind since birth, and in most cases, people affected by Williams Syndrome and autistic spectrum disorders. Some famous examples of absolute pitch include John Phillip Sousa, Ludwig van Beethoven, Julie Andrews, Freddie Mercury, Yanni, Steve Vai, Mariah Carey, Michael Jackson, Wolfgang Amadeus Mozart, Franz Schubert, the Mendelssohn siblings, Leonard Bernstein, Stephen Sondheim, and Andrew Lloyd Webber.
Wolfgang Amadeus Mozart is said to have been born with absolute pitch, playing one of his father's piano sonatas correctly four minutes after listening to it. He was at the age of four at the time.