University of California Genetics of Absolute Pitch Study
What is absolute pitch?
Absolute pitch, commonly referred to as perfect pitch, is an intriguing cognitive trait involved in music perception and is defined as the ability to identify the pitch of a musical tone without an external reference pitch. To be considered an absolute pitch possessor, an individual must have the ability to identify pitches accurately and instantaneously.
The primary goal of this study is to discover the genes that are involved in the development of absolute pitch (perfect pitch). This investigation will allow us to better understand the interplay of genetics and musical training in the development of this cognitive trait. These findings may also be applicable to other traits, such as language ability, and, more broadly, to neurodevelopment.
The goals of this website are to inform the public about the University of California Genetics of Absolute Pitch Study and to recruit individuals to take part in this study. This study is being conducted in the laboratory of Dr. Jane Gitschier at the University of California, San Francisco and has been approved by the UCSF Committee on Human Research. All information collected on individual participants will be kept confidential.
How to participate in the UC Genetics of Absolute Pitch Study
It is easy to participate in our study by filling in a brief survey and taking our pitch-naming test online. Since we are attempting to unravel many factors that could contribute to the development of absolute pitch, both absolute pitch possessors and non-possessors are needed for the study. Everyone's contribution is valuable.
If you indicate in the survey that you are willing to participate in the study, we will need an e-mail address to contact you for follow-up. Some participants may be recontacted for further information about their family history of absolute pitch. We may follow up on the answers to other survey questions as well. Some participants might also be invited to participate further by contributing a DNA sample for our genetic study. This level of participation is, of course, optional.
After filling in the survey, you will be linked to a page informing you how to take the pitch-naming test for absolute pitch. We use this auditory test to objectively assess the pitch naming abilities of our study participants. Our auditory tone test consists of two parts, one test of 40 "pure" tones and one test of 40 piano tones. Since some computer speakers have trouble reproducing a few of the tones, we recommend the use of headphones during the test if you have them.
In each trial, a tone plays for 1 second, followed by a silent interval of 2 seconds. Participants record their guesses within the brief intervals by clicking on a screen keyboard. Tones are given in blocks of ten, allowing participants to rest between blocks if needed. When you are finished, you will be informed of your score and if it exceeds a certain threshold, you meet our study's criteria for being an absolute pitch possessor.
Filling in the survey and taking the pitch-naming test should take less than 20 minutes. Click here to begin.
Our findings to date
Nature vs. nurture
Based the absolute pitch survey and auditory test data we have collected to date, we learned that the majority of individuals with absolute pitch began formal musical training before age 7. This finding supports the hypothesis that early musical training may be necessary for the development of absolute pitch. However, early musical training alone is not sufficient for development of absolute pitch, because many individuals with musical training initiated before age 7 do not possess absolute pitch.
We also observed that absolute pitch aggregates in families, indicating a role for genetic components in its development. Indeed we found that a sibling (with early musical training) of an absolute pitch possessor is about 15 times more likely to possess absolute pitch than is another individual with early musical training but with no family history of absolute pitch.
Together, these observations implicate a genetic predisposition to the development of absolute pitch, which, when coupled with an environmental stimulus such as early musical training, can give rise to the perceptual trait. The development of our pitch-naming test and these initial results were reported in two papers in the American Journal of Human Genetics (1998 and 2000).
These findings encouraged us to develop the project further and to establish an efficient mechanism for recruiting additional subjects and their families into a genetic study. We have now employed our website to recruit thousands of individuals, both absolute pitch and non-absolute pitch possessors, into our study.
Absolute pitch perception as a distinct trait
Based on the results from 2213 subjects who completed our web-based survey and pitch-naming test within a 3-year time span, we learned that absolute pitch (perfect pitch) ability is a discrete perceptual trait, not simply the one end of a continuous "normal" distribution of pitch ability.
The figure below shows a "scatterplot" of the distribution of scores from both the piano tone test (Y-axis) and pure tone test (X-axis) for these subjects. Each dot represents the pair of scores from at least one individual. The area of the dot is proportional to the number of people who scored identically at those piano and pure tone scores.
The scores cluster into two groups. One group is centered at the low range of scores. These scores lie within a box that defines the range of scores expected by random guessing. The other group clusters at the opposite end of the figure, near or at the maximum score of 36 for both the pure and piano tone tests. (Although each test involves 40 tones, we do not score 4 tones, in either test, that lie at the extreme ends of the frequency range.) The vertical line shows the cut-off point for designation of "AP1" in our study. The probability of scoring above this cut-off by chance alone is about one in a trillion!
(Reproduced with permission from Athos et al. 2007. Click to view full article.)
This finding shows that for the population who has entered our study, most people score either very high or very low. A fewer number of subjects score in between these two ranges, and they generally score better on the piano tone test than the pure tone test. We suspect that these individuals have learned to identify some pitches and employ relative pitch to make calculated guesses in pitch-naming.
Changes in pitch perception with age
Absolute pitch possessors sometimes indicate a frustration with their pitch perception as they get older. They sometimes tell us that it goes "off".
The study data corroborate these anecdotal experiences. None of our subjects past the age of 51 identified all of the tones perfectly, unlike their younger counterparts. We discovered that pitch perception tends to go sharp as subjects age. Some subjects name notes consistently a semi-tone sharp by middle-age, while others name tones a full tone sharp as they enter their 60's. We suspect that there is some property in the ear that changes as people age to cause this perceptual shift. Age-related changes are common, such as the need for reading glasses and hearing loss. It is interesting that this change can be observed and quantified only in people who have absolute pitch!
Distortion in pitch perception
By analyzing the vast archive of perceptual data accumulated over the Web, we found something unexpected: absolute pitch possessors tend to err on G# far more than any other tone, an error that occurs only on pure tones. Most often, G# pure tones are misidentified as "A" tones. We hypothesize that this phenomenon reflects the use of A as the universal tuning pitch in Western music. Since the actual frequency of A used in tuning varies widely, from A415 in early music to A446 in some orchestras, we suspect that absolute pitch possessors accommodate a wide range of frequencies in their naming of A. We further speculate that this accommodation is not used in piano tones, since pianos are generally tuned to A440. This phenomenon is reminiscent of a property referred to as "perceptual magnet" in language acquisition.
The above findings on pitch perception have been published in the Proceedings of the National Academies of Science - click here for the article.
The first step in discovering genes that enable the development of absolute pitch is to pinpoint the regions of the human genome that contain them. With generous contributions from 73 families, we have made significant inroads on the path to discovery. We performed a “genome-wide” genotyping and linkage analysis on the DNA collected from a total of 281 participating family members. The majority of these families (45) self-identified as being of mixed European, non-Ashkenazi ancestry, and the data from this subset of participants clearly indicated a region on chromosome 8 (8q24.21) with linkage to absolute pitch. Three other regions of the human genome, 7q22.3, 8q21.11, and 9p21.3, also showed suggestive linkage in these 45 families, implicating more than one gene responsible for absolute pitch.
The study also involved 19 families of East Asian ancestry, in which the linkage peak of 7q22.3 was additionally apparent. Interestingly, the 8 participating families of Ashkenazi Jewish origin showed no evidence for linkage at any of the four regions, showing the need for further augmentation of participants of this ancestral origin.
All of these findings on genetic linkage have been published in the American Journal for Human Genetics – click here for the article.
Based on our recent findings of genetic linkage (above), we are now engaged in the second step in the process of gene discovery, namely, sequencing the identified genomic regions of linkage to find genetic variants (i.e., DNA changes) that are enriched in individuals with absolute pitch. To carry out this step, we have chosen to “capture” the genomic regions from 10 individuals with absolute pitch and perform “deep” DNA sequencing on them. This method, which exploits exciting new technological advances, will allow us to examine both DNA coding and DNA regulatory information that could alter gene and protein function.
If successful, this experiment will reveal a number of potential variants that might give rise to absolute pitch in individuals of European ancestry, but they will require extensive further analysis and validation. First, we will ask whether variants track with absolute pitch within a family, since we would expect that everyone within a given family with absolute pitch should have a variant if it is causative. Second, we will ask whether variants are found in other unrelated individuals of European ancestry, both “cases” with absolute pitch and “controls” without absolute pitch but with early musical training. By comparing the data derived from these two groups, we can make a statistical assessment as to the likeliness that a certain variant gives rise to absolute pitch. Similarly, any variants discovered in the 7q22.3 linkage region can be analyzed and validated in an East Asian cohort of unrelated absolute pitch possessors and non-possessors with equivalent musical training.
The genetic basis for absolute pitch in the Ashkenazim remains an intriguing open question and one that we are actively pursuing. Because there were too few families enrolled in the linkage study to generate meaningful results, we are employing a different approach to the problem, namely “genetic association”. Because the Ashkenazi population has been subjected to a number of population bottlenecks and was genetically isolated until recently, it is possible that absolute pitch in this population could have a unique origin. We are actively recruiting individuals with absolute pitch as well as training-matched control individuals without absolute pitch to answer this question with dense genome-wide genotyping analysis.
In short, there are many ways to participate in our study, both now and in the future. Keep in mind that participation in all stages of our study is optional and kept confidential. To start your journey with us, click below.