Do you have a friend who’s surprisingly good at recognizing songs? Someone whose ear for melodies is uncanny? Who at concerts cringes if one of the musicians is playing slightly out of tune? What if that person had an even more uncanny ability—that they could tell you, hearing only a single note, that the note the violinist was playing was a C sharp, and not a C? Most of us probably do not know even one person who has this ability, it is considered to be so exceptional.
This skill, or absolute pitch, is the idea that some folks are able to identify the label of a note without hearing another note. They just know what “C” sounds like, no matter the octave, no matter the instrument.
How good do you think your perception of musical tones is? (Click here to take the NIH Distorted Tunes Test).
Some areas of cognition and perception—most prominently native-like language comprehension and production—are thought to be highly sensitive to a “critical period”, the end of which prevents nearly all individuals from acquiring a skill fully. Absolute pitch has been proposed to be one of these skills. The argument is based in part on the apparent rarity of people with absolute pitch (or APers, as I’ll refer to them here). Estimates vary from a purported 1 in 10,000 (!) to something like 4% of musicians.
Some theories claim that a genetic predisposition must be present, as many people experience intense musical training but never acquire absolute pitch. On this account, becoming an APer requires the perfect combination of nature and nurture.
But, even though the definition of absolute pitch requires near-perfect naming accuracy in many different contexts, this high level of performance does not always hold in practice. For example, when listening to and judging slightly unfamiliar instruments, in unfamiliar timbres, or in unfamiliar octaves, APers can be fooled. This curious finding suggests that absolute pitch is not as absolute as it might seem. We have also discussed before how perception of whether something is in tune or out of tune, for example, can be acquired and honed by a lifetime of experience with music.
We might wonder, then, whether absolute pitch can actually be learned with enough time and effort. In other words, can we learn or acquire absolute pitch? To date, studies had either shown mixed evidence for the possibility of acquiring absolute pitch, or were done on small samples with very short training periods. Long-term evidence ―after weeks or months of training―is needed to settle the issue one way or another. This feat was recently accomplished by researchers Yetta Wong, Kelvin Lui, Ken Yip, and Alan Wong in a study that appeared in the Psychonomic Society’s journal Attention, Perception, & Psychophysics.
One of the biggest barriers to testing the feasibility of acquiring absolute pitch in adulthood is the need to test over many training hours over a long period of time. Nearly all prior studies were small in scale, with 1 to 4 hours of training, which could explain why earlier results appeared so mixed.
Wong and colleagues conducted three experiments, the first of which is the main focus of this post. The first experiment used a twelve-hour training regime to test how rigid the window for acquiring absolute perception actually is. If any participant or participants in this first experiment acquired the ability to label notes almost perfectly, this would be evidence that there is not necessarily a critical period for pitch learning.
In general, the training regime followed a simple pattern, with the experiment broken into 80 separate levels. With each block of 10, training trials became increasingly complex, incorporating at first a small number of tones and labels, to a wider variety, presented in different timbres (synthetic and piano), and octaves (4 and 5). Participants stayed at the same level if they did not achieve 90% accuracy within a level, limited to taking no more than 12 hours in total.
Training lasted three weeks, with participants coming into the lab four days per week. Wong et al. recruited 10 participants, all of whom were tested for their pre-existing knowledge of pitches and notes, and none of whom tested within the range of absolute pitch at the outset.
The experiment was broken up into a training phase, a testing phase, and a generalization phase. In the training phase, participants heard tones and named which tone they heard by pressing a key. In alternating levels, they received feedback after their responses. The figure below provides an overview of the training regime.
To test generalization, participants heard unfamiliar octaves (3 and 6) and an unfamiliar timbre (the violin) and were asked to identify, as before, the note they heard from the full scale. The generalization task came after the training task on a separate day, and then was performed again a month later to test whether AP learning could be sustained after the intense training had ceased.
The general idea behind absolute pitch is that APers should be able to name notes independent of what scale they are, without context. Quantitatively, the requirements have varied across studies. Wong and colleagues therefore decided on a criterion of 90% correct for all 80 levels with all 12 pitches that they tested, which was consistent with a minimum definition of absolute pitch in over 83% of published studies on APers.
If APers are very rare, it would be a good bet that none of the participants in the studies by Wong and colleagues would have met these criteria. However, one participant of the 10 they tested did in fact fulfill the criteria, suggesting that it is possible in adulthood to acquire absolute pitch.
The possibility that absolute pitch can occur outside the “critical period” raises some interesting problems for theories of absolute pitch and auditory processing. If the critical period is rigid, how can an adult in their 20s learn to perform this task? Are there other root causes that could explain why one of these ten participants mastered this skill?
In Experiment 2, Wong and colleagues followed up on how someone becomes an APer (among several other questions) by comparing musicians to non-musicians. One way that absolute pitch could be acquired is through fine-tuning one’s knowledge of musical notes and turning memory representations of notes into better representations of tones.
If this is the case, then musicians, who have more fine-grained representations of musical notes, should be more easily trained to learn absolute pitch than non-musicians. The results of Experiment 2, which used fundamentally the same procedure as Experiment 1, showed that musicians learned over two more pitches on average than non-musicians. Surprisingly, another small batch of participants in this study (3 of the 22 tested) mastered the entire scale, meeting the criteria for absolute pitch.
The results of these experiments are truly surprising from the perspective of research that believes that auditory perception is relatively fixed after roughly the end of puberty. In contrast to this established claim, the results of Wong and colleagues clearly demonstrate that AP, or fine-grained, abstract, reference-free auditory category judgments, can be acquired in adulthood.
Wong and colleagues conclude that a major component of learning pitches is grounded in learning perceptual categories. More importantly, additional evidence against the idea that an absolute pitch level of performance should be incredibly rare actually suggests that with enough training, roughly one in ten people can emerge as an APer. This is a much larger fraction of people than the field has claimed so far.
Considering these results in light of other findings that the familiarity of a particular timbre, octave, or environment can alter the labeling judgments of APers, Wong and colleagues conclude that the statistical regularities and individual experiences we have had with specific notes played in different ways does influence our representations of those notes. Since it is clear that genetics and age play less of a role than previously thought, the new frontier is better pinning down the contributions of learning and memory in the development of absolute pitch.
Psychonomics article highlighted in this post:
Wong, Y. K., Lui, K. F. H, Yip, K. H. M., & Wong, A. C.-N. (2019). Is it impossible to acquire absolute pitch in adulthood? Attention, Perception, & Psychophysics. 10.3758/s13414-019-01869-3