UCSF researchers report that the musical gift of “perfect pitch” requires both an inherited predisposition and very early musical training, offering new insight into the role of genes and environmental influences on human aptitude.
In a survey study of 612 professional and student musicians nationwide, the researchers report that 40 percent of those who began formal musical training by age four reported developing perfect pitch. In contrast, only four percent of those who began training after age nine did. The decline in between was remarkably steady.
At the same time, the researchers found that musicians with perfect pitch were four times more likely to report a family member with perfect pitch than those without it. Forty eight percent of those with perfect pitch said they had a first degree relative with the skill, while only 14 percent of those without perfect pitch did.
The study, while interesting in itself, also identifies perfect pitch as a model trait for exploring the relative roles of “nature and nurture” in human behavior, says Jane Gitschier, PhD, a professor of medicine and pediatrics at UCSF and a co-principal investigator of the study.
The investigation is reported in the February 1 issue of the American Journal for Human Genetics, accompanied by an editorial. The research is also reviewed in the February 1 issue of Nature/Genetics.
Perfect, or absolute, pitch, is the ability to recognize the pitch of a musical tone without an external reference, such as a piano tone.
Although much is known about the anatomy and physiology of the human auditory pathway, the specific neural mechanisms involved in pitch perception remain unclear. Psychophysical and physiological experiments suggest that high-level brain processes are involved, but there is no evidence regarding underlying developmental mechanisms that may play a roles in these processes.
Previous studies of the aptitude have been small and have investigated either genetic or environmental influences, identifying compelling evidence in both. The UCSF investigation is the first large scale study to examine both factors.
While the researchers relied to an extent on the musicians’ self evaluations—15 percent reported having the skill—many were subsequently evaluated with a computer-based acoustical test, and the majority did prove to have perfect pitch based on the researchers’ stringent criteria.
Working from this data, the researchers are now attempting to delineate the genetic component of the skill. Investigation of individuals who performed extremely well on the auditory test has already led them to identify several families that will be suitable for such studies.
The inheritance pattern for perfect pitch observed in these families resembles the model suggested by another genetics study, namely autosomal dominant transmission with incomplete penetration. This finding suggests that only one of the two copies of the gene for perfect pitch would be required for developing the skill, but that other mitigating or co-existing factors, such as a genetic or environmental influence, could prevent the aptitude from being manifested either at all or to its full potential.
“Under such a model, the penetration of perfect pitch may be influenced by early musical training,” says Gitschier.
But just as most people who acquire language skills do not develop the verbal flair of poets, most people who receive early musical training do not acquire perfect pitch.
Much of the UCSF researchers’ future genetics studies will focus on Ashkenazi Jews, descendants of a relatively small number of families in Central and Eastern Europe. Because until recently these people did not often intermarry with other groups, those individuals with a given trait such as perfect pitch have probably inherited it in common from a few ancestors, says Nelson Freimer, MD, an associate professor of psychiatry and a co-principal investigator of the study, making them ideal for identifying genes for human traits.
“Whatever genetic predisposition there is for perfect pitch, it is likely that it will be identical in a majority of Ashkenazi Jews,” says Freimer. Ashkenazi Jews also have a strong tradition of early musical training, which suggests, he says, that perfect pitch may be highly expressed in these people.
The suggestion that a specifically timed environmental influence is necessary to spark the potential of a genetic predisposition is not new. Researchers have determined that there is a critical period in the development or reinforcement of certain neural circuits in the brain for singing behavior in song birds and for language development in humans.
“It may be,” says Gitschier, “that there is a developmental period for perfect pitch, during which the brains of some people are particularly amenable to establishment of new circuits or fine-tuning of pre-existing circuits involved in pitch perception.”
This period parallels the stage that appears to be most critical for the development of language skills, says Siamak Baharloo, a co-author of the UCSF study and a graduate student in Freimer’s lab.
Alternatively, says Gitschier, it is possible that individuals who are genetically predisposed to developing perfect pitch may be more likely than others to start musical training early in life. “Perfect pitch may thus be part of the general phenomenon of musicality,” she says, “and an early interest in music could result from greater tonal acuity and increased awareness for sounds in predisposed children.”
If this is the case, Gitschier theorizes, genetic predisposition for perfect pitch might be prompting an early interest in music, but early training would still be necessary for cultivating the skill.
Gitschier, herself a singer, has respect for the innate factor leading to perfect pitch. “I don’t have even good `relative pitch,’” she says, “but I have had lots of accompanists and teachers who have it. It has always amazed me that people have this ability.”
“Teasing out the roles of genes and the environmental influence is going to be a really interesting, really, really complex problem that’s going to take a long time to solve,” says Gitschier, “but we made a nice first pass at the problem.”
Individuals interested in learning more about the UCSF study or participating in the researchers’ planned genetics studies may contact the investigators via the following outlets: website: www.perfectpitch.org or
e-mail: [email protected]