For most of us, quick and accurate perception of the visual world is essential for getting around in life; we take for granted our instant recognition of color, shape, distance, and the physical relationships between objects. Many aspects of the auditory world are also apprehended in an effortless manner: a nighttime whistle is easily identified as a distant train, without any deliberation. However, identifying the pitch of an isolated whistle is beyond the abilities of most people.
This is also the case for most musicians, despite the fact that they spend every day working in the context of a standardized system of pitch relationships. Those rare individuals who can instantly recognize the pitch of a random piano tone or passing car horn, without the use of a reference pitch, possess a cognitive ability that is termed “absolute pitch. “The range of useful musical pitches is 20-5,000 Hz, which is, roughly the range of a piano keyboardPitch is a one-dimensional attribute defined by the number of vibrations, per second, emanating from a sound source, such as a plucked stringThe peripheral auditory organs are designed specifically for frequency analysis. The cochlear basilar membrane vibrates, at each point along its length, with an optimal resonant frequency. The fact that all humans are quick to appreciate the differences in timbre between instruments illustrates the extreme sensitivity of this organ to complex frequency spectra.
Therefore, AP perception is not dependent on a special kind of ear; it reflects a particular ability to analyze frequency information, presumably involving high-level cortical processingDuring the last century, scientific opinion about the etiology of AP has been spread widely across the “nature-nurture” continuum (Ward and Burns 1982). Many studies have suffered from low statistical power, a lack of controls, and a minimal appreciation for the complexities of genetic causation. The report by Baharloo et al. (1998 in this issue), with Nelson Freimer and his colleagues at the University of California San Francisco (UCSF), marks the dawn of a refreshing new era in this regard.
By surveying and testing a large population of musicians, the authors have begun to generate basic information on the prevalence and familial aggregation of AP and on environmental factors that influence the development of AP. Particularly important is the careful attention paid by Baharloo et al. to defining the phenotype. Although AP is qualitatively distinct from the relative-pitch ability possessed by all trained musicians, it nevertheless exhibits some phenotypic heterogeneity, and this is likely to be an important consideration for successful mapping studies.A second major finding of the UCSF group is that musicians with AP tend to start their musical education quite early in childhood, nearly all at
