Update: I added where the study was published.
Perfect pitch, the ability to identify the absolute pitch of musical notes, looks to be the product of a small number of genes, according to a new University of California study.
Many traits, such as high blood pressure or height, have genetic links but span a broad spectrum with relatively few people having extreme measurements. But with perfect pitch, also called absolute pitch, a person either has it or doesn't, according to UC researchers in San Francisco and Los Angeles.
"This striking, bimodal distribution resolves the question of whether absolute pitch ability lies in the tail of a continuous perceptual spectrum or, rather, defines a distinct perceptual trait," the researchers said in a report in this week's Proceedings of the National Academy of Sciences. Judging by the fact that most people score either very well or very poorly, though, the researchers suggest that "AP ability could be governed by the influence of only one or a few genes."
Perfect pitch may seem an amazing gift, but as the study authors point out, the visual equivalent isn't. Humans generally are pretty good at identifying the frequency of light they're seeing with a color label.
Although perfect pitch appears to be a genetic trait, early exposure to music or musical training appears to influence its development in those with the right DNA.
The study tested 2,213 individuals, recruited via advertisements and a Web site, and 981 of them were categorized as having perfect pitch. The study found that about as many women as men have perfect pitch--47 percent and 53 percent, respectively--and that those with perfect pitch tend to err on the sharp side as they get older.
The researchers also found that people with perfect pitch appear to recognize tones produced by pianos' white keys--perhaps because of early exposure to music using those notes more often.
And researchers uncovered what they call a "perceptual magnet" around the note A, generally defined as a 440Hz vibration. Orchestras and instruments often tune to A, and perhaps as a result of that and some variation about which precise frequency is used for A, people with perfect pitch are likely to hear it even when it's not quite there.
"A statistical analysis shows that G-sharp is uniquely error-prone," the study said. "This widening of the 'bin' for frequencies perceived as A can be likened to a perceptual magnet effect previously described for speech."
In speech, people can distinguish among vowel sounds remote from perceptual magnets, but they have a hard time doing so with sounds that are close to them. "The perceptual magnet effect is a consequence of exposure to a specific language during infancy, when babies learn to bin ranges of vowel sounds into categories delineated by their native language," according to the study.