Most of us "hear" our world in a generalised way, missing the intricacy of individual sounds. However, a tiny number of people are armed with perfect pitch, able to pinpoint every tone and note.
These folks have fascinated scientists for years, and now researchers are launching an unprecedented study to find out if this talent is more than just a learned skill.
They think perfect pitch may be inherited, its secrets encoded in a human gene that only shows up in a few people.
"I've known people who have perfect pitch, and they are able to do something that to me is almost otherworldly," says Jane Gitschier, a professor of medicine at the University of California at San Francisco who is recruiting musicians for the study. "My gut feeling is that this has got to be genetic."
The concept of pitch
Non-musicians may have difficulty understanding the concept of pitch when it is explained in words, but they know it when they hear it: for instance, you know something has gone awry when your uncle Fred's rendition of "I do it my way" has you headed for the hills.
Most musicians have so-called "relative pitch," which allows them to identify a pitch only when it is surrounded by pitches at nearby levels. This is akin to being able to identify the colour pink only because red and white are around it.
What is “perfect pitch”?
However, those with perfect pitch don't need other notes as a reference.
"You're just sitting around, and someone happens to play a note on the trombone, and you can tell what that note is," Gitschier explains.
Perfect pitch is a coveted skill in the musical world. Mozart was said to have had perfect pitch, allowing him to perfectly copy the work of other composers as a child playing on the piano.
However, perfect pitch can be both a blessing and a curse, says Karen Keltner, resident conductor at the San Diego Opera. "Anything that's vaguely out of tune drives somebody crazy."
Can perfect pitch be acquired?
Nadia Boulanger, a famous French composer and music teacher, believed perfect pitch could be learned. Boulanger argued it "could be taught just as colours are taught," recalls Keltner, who studied under her.
While musicians like the late Boulanger may disagree with their conclusions, researchers have shown perfect pitch usually develops only if a person received musical training before age 6, Gitschier says.
"You need to know what the scale is, and get some familiarity and listen to those different sounds on instruments to be able to lock it in and solidify it," Gitschier says.
Interestingly, young children are also very adept at learning languages and typically learn to speak them without an accent. Researchers suspect children eventually lose that innate ability to make certain sounds if they don't use them in their language.
Perfect pitch as a result of genetics
However, researchers in San Francisco suspect perfect pitch is genetic. So far, they've enlisted 100 musicians with perfect pitch for a study, and they hope to study their DNA and the genes of their relatives, especially any who also have perfect pitch.
Siblings of people with perfect pitch are 15 times more likely to also develop the skill than other people with early musical training are, Gitschier says.
The results of the study will help researchers figure out how the ear and brain work together to understand sound, Gitschier says. However, she admits the findings may not be biologically breathtaking.
Even so, she says, "it's an incredibly interesting scientific curiosity."