An Overview of Absolute Pitch

rev. 16 November 2005

Contents


Absolute Pitch Defined

Absolute pitch (AP) is the ability to identify or produce any given tone without the aid of any reference tone. It is often contrasted with relative pitch (RP), which is the ability to identify or produce any tone with the aid of a reference tone. AP is also referred to as “perfect pitch” in many articles about AP and in popular usage, to such a degree that Merriam-Webster's Dictionary equates the two terms. However, Daniel J. Levitin at McGill University contends that “perfect pitch” should not be used synonymously with AP. The term “perfect pitch,” he says, misleadingly suggests that people with AP have the ability to tell how close a tone is to being perfectly in tune, an ability Levitin says they do not have in any greater degree than other people. On this page, I use only “absolute pitch” or “AP,” rather than “perfect pitch,” to avoid confusion.

How Do They Do That?

In 1994, Levitin proposed that people with AP connect pitch memory with pitch labeling. His studies suggested that most people have pitch memory. In one experiment, he asked subjects (not necessarily musicians) to sing favorite popular songs that were known to exist in only one version. Most of the subjects sang pitches identical to or very close to those of the original song. Although they exhibited pitch memory, these people may lack AP because they did not develop pitch labeling ability through early musical training (studies show the crucial learning period to be before age 6). For example, they may not be able to recognize or sing a middle C because they did not learn to call that pitch “middle C” or some other name at a sufficiently young age.

Physiological Features Associated with Absolute Pitch

Levitin's theory suggests that AP and language are closely related. Physiological features associated with AP seem to support this relation. In 1995, a research team under neurologist Gottfried Schlaug reported that musicians with AP have an enlarged planum temporale, a region in the left temporal lobe of the brain. Another group under Robert Zatorre, a cognitive neuroscientist at the Montreal Neurological Institute at McGill, studied brain activity in twenty different musicians listening to single pitches (Zatorre used a technique called positron emission tomography (PET), which tracks blood flow to different parts of the brain and thus measures activity level). Half of the musicians had AP and showed more activity in the left frontal cortex than the musicians without AP. Schlaug's and Zatorre's studies both suggest the importance of the left brain, responsible for verbal communication, in AP. They also challenge the traditionally-held prevalence of the right brain, responsible for creativity, in musical thinking.

Language and Absolute Pitch

If giving pitches a verbal label can help someone develop AP, perhaps AP can help someone learn a language. In 2001, Professor Jenny Saffran and other psychologists at the University of Wisconsin-Madison proposed that babies are born with AP and use it to learn how to speak. In one experiment, they played a three-minute sequence of pitches over and over for a group of adults and a group of eight-month-old infants. When they played the sequence at a slightly different pitch, the adults did not notice the difference, but the infants did (when infants are presented with previously-encountered information, for example, a repeated sequence of pitches, they get bored and stop paying attention. When presented with new information, like the slightly different sequence, they pay attention again because they perceive something new to learn. Psychologists call this phenomenon the “standard impulse” in infants).

Infant AP could be useful for learning some Asian languages, where the same sound pronounced at two different pitches often represents two different words with different meanings. Diana Deutsch, a psychologist at the University of California, San Diego, demonstrated that native Vietnamese and Mandarin Chinese speakers (not necessarily musicians) may use AP in speech. Researchers asked Vietnamese speakers to read rapidly a list of words spanning the range of tones in Vietnamese, then to perform the same task a day later. The subjects' pitch over the two days was very consistent, with an average variation of only 1.1 semitone. Mandarin speakers were also asked to read several words spanning the range of tones in their language, but their task was slightly different: to read one word, then to repeat it twenty seconds later. The next day, they performed the same task. The Mandarin speakers also exhibited great consistency in pitch, showing an average variation of only half a semitone between any two readings. In a way, these Vietnamese and Mandarin speakers displayed Levitin's pitch memory and pitch labeling, by associating certain pitches with certain words.

Williams-Beuren Syndrome and Absolute Pitch

People with Williams-Beuren Syndrome (WBS) lack approximately twenty genes on Chromosome 7 and demonstrate below-average spatial understanding and limited manual dexterity. They often have difficulty copying a simple drawing or tying shoelaces. On the other hand, they also exhibit remarkable skills in language and music. Levitin studied one WBS subject who spontaneously made up several different songs on the piano with fairly coherent verses, refrains, and rhyming lines.

In fact, AP may occur at a significantly greater incidence in WBS individuals than in the general population. Howard M. Lenhoff, professor emeritus of biology at the University of California, Irvine, asked five WBS subjects (age range 13 to 43) who were not known to have AP to identify single pitches in over a thousand tests. Although only one of the five had received musical training before age 6, the subjects demonstrated 97.5% AP in the tests. That the other four subjects had not received musical training during the period generally thought crucial to developing AP indicates that WBS individuals may be able to develop AP at a later age, perhaps at any age, even well into adulthood.

Why Doesn't Everyone Have Absolute Pitch?

A frequently cited statistic is that only one per ten thousand people have AP. Its rarity makes it a rather coveted ability and a great skill for impressing acquaintances, but AP is otherwise not very useful. Although Professor Saffran hypothesized that babies are born with AP, once they learn a language, they will probably lose it unless it is reinforced by musical training or unless the language, like the Asian languages studied by Deutsch, depends on pitch recognition. In understanding English, for example, having AP can be very distracting. Different people pronounce the same word at different pitches, but in each case, the word has the same meaning. Being able to recognize a word at only one pitch can impede understanding. Levitin argues that AP may not be very useful even for musicians. Musicians study melodic patterns, the understanding of which depends more on relative pitch than absolute pitch. In fact, skilled musicians can play a melody equally well in any key. People who have AP will generally lose it if it is useless to them.

The Absolute Pitch Gene(s)

Does it exist? Biomedical researchers at the University of California, San Francisco think they might have evidence that it does. In questionnaires sent to 620 students of several music schools (including the San Francisco Conservatory of Music, the Curtis Institute of Music in Philadelphia, and the Peabody Institute in Baltimore), 15% reported having AP, and 48% of those students reported having a relative with AP. On the other hand, only 12% of students not reporting AP reported having a relative with AP. Nearly half of those who received musical training before age 4, and nearly a third of those who received musical training between age 4 and 6, reported having AP.

Studying this data and the pedigrees of some of their subjects, the researchers hypothesized that a gene for a predisposition to AP is autosomal dominant with incomplete penetrance (“autosomal” means that the gene is on a chromosome other than the sex chromosomes (X and Y); “dominant” means that if you have the AP gene from one parent and a corresponding non-AP gene from the other parent, the AP gene will dominate, and you will have a predisposition for AP; “incomplete penetrance” means that this predisposition takes on different degrees of expression, often dependent on environmental factors, in this case, early musical training). The UCSF researchers would like to test their hypothesis further by comparing genetic material from subjects with and without AP and looking for recurring unusual patterns in those with AP. They have also considered studying the genetics of AP in Ashkenazi Jews, whose ancestors were from Central and Eastern Europe. Ashkenazi Jews did not often intermarry with other groups until recently, so their AP genes probably came from a gene pool of limited size. They also have a strong tradition of musical training, making them excellent subjects for the AP gene study, said one researcher.

Levitin, however, does not find the UCSF data to be convincing evidence of an AP gene. He argues that if AP runs in the family, the children of that family are naturally more likely to be trained to label pitches and to have their AP skills nurtured. Levitin says that if a study could show that children of AP families often fail to develop AP, he would be more convinced that AP is caused by a gene rather than by environmental factors. Still, Jane Gitschier, one of the UCSF researchers and also a coloratura soprano without AP, doubts that a person can develop AP without a genetic predisposition, despite several commercial products that claim to help people develop AP. Other debates surround the AP gene. Does early musical training encourage penetrance of AP? Or does a genetic predisposition to AP encourage early musical training? As with other questions of genetics, definite answers are hard to find.

Research in Absolute Pitch

Finding funding for research in AP can be difficult because AP research does not cure a disease or have any obvious direct benefit to society. Even if a researcher can find funding for AP studies, s/he might find it difficult to test for AP. Some people who claim to have AP may only be able to recognize one pitch (e.g., the A-440 to which concert musicians tune) and can use the one pitch as a reference tone and a well-developed RP to determine all other pitches. To combat this problem, Levitin has suggested that AP studies take reaction time into account; subjects with AP should be able to identify pitches immediately, without any intervening time to calculate intervals.

In addition, some people have AP only for their principal instrument or the instrument that they learned first. In 1981, G. R. Lockhead and R. Byrd reported that some of their pianist subjects could identify 90% of pitches played on a piano but only 60% of pitches on another instrument. “Absolute piano,” as Lockhead and Byrd called this phenomenon, may be a result of subjects using timbre, or tone color, to identify pitches. Accordingly, researchers would need to screen subjects for AP by playing pitches on a wide range of instruments. Finally, if AP is as rare as is commonly believed, researchers studying people with AP may have difficulty finding enough subjects to make their studies scientifically convincing. Still, AP's relationship with memory, language, early development, and genetics may make AP studies valuable in shedding light on all these areas.

Sources and Related Links

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www.provide.net/~bfield/abs_pitch.html - Perfect Pitch on the Internet, a list of online resources for AP.

ego.psych.mcgill.ca/levitin.html/home_research.htm - Home page of Dr. Levitin, a former researcher of the Center for Computer Research in Music and Acoustics (CCRMA) at Stanford University, now a researcher at McGill University. Levitin's page has links to his articles on AP and on Williams-Beuren Syndrome.

www.academicpress.com/inscight/03161998/grapha.htm - Academic Press Daily inScight article about Schlaug's and Zatorre's research on physiological features associated with AP.

news.bbc.co.uk/hi/english/in_depth/sci_tech/2001/san_francisco/newsid_1179000/1179664.stm - BBC News article about Saffran's research on AP in infants.

www.sciam.com/article.cfm?articleID=000E0423-66D1-1C75-9B81809EC588EF21 - Scientific American article about Deutsch's research on AP in native Vietnamese and Mandarin speakers.

today.uci.edu/news/release_detail.asp?key=566 - University of California at Irvine news release about Lenhoff's research on AP and Williams-Beuren Syndrome.

www.ucsf.edu/daybreak/1997/06/609_tone.htm and www.ucsf.edu/pressrel/1998/01/0130pitc.html - University of California, San Francisco releases about research on the AP gene.

www.hhmi.org/bulletin/sept2001/perfectpitch/perfectpitch2.html - Howard Hughes Medical Institute's interview with Gitschier, one of the UCSF geneticists researching the AP gene.

www.unconservatory.org/perfect_pitch/1.html - Kirk Whipple says that you can develop AP by teaching yourself to remember and label pitches. Here he gives some tips for people who would like to develop AP as well as the procedure he would use as a researcher to test people accurately for AP.