Why don't all humans have absolute pitch?

Question

I'm not looking for an evolutionary reason. I'm looking for answer based on how the brain works. I believe the way the brain works is not solely determined by natural selection. Sometimes natural selection will select for a certain ability and then the brain will use its own method of gaining that ability that wasn't selected for. I think natural selection just selected for the bare minimum of being able to sense intonation in conversation and maybe also for some small partial ability to sense whether a change in pitch is large or small, but since the brain is like a Conway's game of life which is as powerful as a universal turing machine, we developed a sense a fifths because the brain learned that sinousoidal soundwaves a fifth apart go together all the time because the second and third harmonic of any periodic function are always a fifth apart.

I didn't have absolute pitch in my childhood. However, after season 2 of "The Worst Witch" came out and I watched just a few episodes when I was about 30, I developed the ability to play the song in the introduction in my head at the correct pitch. I'm quite often able to play songs I've heard before in my head at the correct pitch but am not always able to do it. Do you think everyone has the potential to eventually develop absolute pitch? If so, why does it take so long to? I'm guessing the brain needs time to develop the ability and keeps improving with time. In the case of not having absolute pitch, maybe gaining it early was selected against because it would have slightly impaired the ability to gain the minimal extent of relative pitch. Now what's the reason given the way the brain works? Maybe people were born with the type of brain that would consider absolute pitch an unimportant ability. Then the brain had no reason to develop the ability to recall the absolute pitch of something many hours later. The brain would temporarily store the memory and use that to develop a sense of relative pitch. Later, now that the brain has a sense of relative pitch, it would have the ability to recall the relationship between multiple notes played close together in time but not to recall the absolute pitch of them.

Answer 1

The consensus among most psychologists who have studied absolute pitch is that it usually requires some sort of musical training before the age of 5-6. There are rare instances of children acquiring it a bit later. I also remember reading of a case of an adult who had absolute pitch but did not have any musical training beforehand. (He had to be tested using a different protocol since he didn't know about note letter names, but otherwise showed pitch identification abilities similar to musicians with absolute pitch.)

Basically, the research consensus is that usually children acquire the standard kind of absolute pitch during a so-called "critical period" where musical training or at least note-naming exercises are usually started around ages 2-4. (This idea of a "critical period" is common in other tasks, like the ability to learn a language without an accent is much harder once a child gets past a certain age, as young children have a better capacity to learn new phonemes, but older children are more "stuck" with the set they've learned.)

What you're describing about being able to replicate the correct pitch of a well-known piece of music consistently is not usually what researchers call "absolute pitch," though it may be somewhat related. Many if not most adults actually have the ability to recall familiar songs very close to the original pitch. This is a standard pitch memory effect, but it generally does not imply the ability to do more advanced tasks that those with normal "absolute pitch" can do, like instantly associate a given stimulus with a specific note name. While there is anecdotal evidence of adults gradually acquiring absolute pitch abilities with a lot of effort, there is some controversy among researchers about whether it can compare with the ability when learned in the critical period of childhood around 2-5 years of age.

However, when you begin to discuss whether absolute pitch is actually a more "evolved" skill or not, I think you may be hinting at the so-called "unlearning theory" of absolute pitch. Basically, it's the idea that all humans are born with some sort of "absolute pitch" ability on a basic level, but we actually "unlearn" it during childhood in favor of the more useful skill of relative pitch. The "unlearning theory" isn't a common view among absolute pitch researchers, but there are a minority of psychologists who hold to it.

Personally, I think the unlearning theory is pretty plausible, as there are various studies on animals that show they have some version of absolute pitch, at least in the sense that they can be trained to respond to stimuli within a narrow frequency range. And the basic recognition of a frequency/pitch is a more rudimentary cognitive process in general compared to a skill like relative pitch.

One might think of an analogy with color recognition. Humans all seem to be born with some ability to recognize color (excepting rare forms of total color blindness), which is effectively a visual frequency distinction. But small children need to be taught color categorization in order to understand which frequency bands correspond to which color names. Different languages may subdivide the spectrum differently, causing children raised with different color names to vary in their speed and ability to differentiate color.

In any case, even without training as a small child, there are strong cognitive and even survival advantages to color recognition. Blood is red, for example. Noticing these sort of consistencies in the environment will happen whether or not language is introduced for color differentiation. However, the ability to understand how colors may be related, say, artistically -- that's a much more higher-order skill that few people achieve.

Turning back to pitch recognition, there's not really a similar survival or environmental need for absolute pitch recognition. It's not like many naturally occurring things always make the sound of a B-flat or whatever. Of course absolute pitch on a wider scale is important -- to be able to tell whether a sound is likely coming from a man or woman or child, for example. But to be able to discriminate pitch identification on a semitone level occurs in fewer contexts. So perhaps small children exposed to music and asked to do pitch-naming tasks are usually the only ones who develop that skill further. There's further circumstantial evidence of this in that absolute pitch incidence is higher among groups of people who speak "tonal" languages where the rough absolute pitch of a word can be important to its meaning. That may indicate that there may be a much wider group of children capable of acquiring absolute pitch, but only some actually develop it.

Meanwhile, relative pitch relationships tend to be a strong part of our culture otherwise. Even in most spoken language, a rise or fall in pitch carries semantic meaning relative to the previous pitch, not to a specific absolute pitch. Musical training in most cultures also tends to focus on the ability to relate pitches relatively, where a given song retains its identity regardless of key/pitch: only the relative pitch matters. Children who are exposed to such stimuli and taught song X in the key of C is "the same" as song X in the key of F will thus quickly learn that absolute pitch isn't a very useful skill in many contexts.

To come back to your question and summarize (TL;DR): there are some absolute pitch researchers who think all people (or at least most) have the ability to acquire absolute pitch, but they lose the ability to do so if they don't have training before around age 5. Other researchers estimate the capacity to acquire AP is less common but still quite possible for many people if they learn it during this critical period of early childhood. Your ability to remember the pitch of one specific song or musical piece is actually a distinct (and very common) ability that most researchers wouldn't say qualifies as "absolute pitch" as commonly understood, nor does it seem to help much with acquiring AP as an adult.

As I said, it sounds like you're interested in the so-called "unlearning theory" for AP, so you may find more information on your hypothesis by searching for that topic. It was originally proposed by Abraham (1901) but promoted more recently by Dixon Ward. Here's a good intro to some of your questions about AP.

Answer 2

Short answer: It's a developed skill, not evolution.

I'm going to add a quote here from the book "Peak: Secrets from the new science of expertise" by Andrew Eircsson and Robert Pool [Link to book]

The true character of perfect pitch was revealed in 2014, thanks to a beautiful experiment carried out at the Ichionkai Music School in Tokyo and reported in the scientific journal Psychology of Music. The Japanese psychologist Ayako Sakakibara recruited twenty-four children between the ages of two and six and put them through a months-long training course designed to teach them to identify, simply by their sound, various chords played on the piano... After completing the training every one of the children in the study developed perfect pitch and could identify individual notes played on the piano.

This is an astonishing result. While in normal circumstances only one in every ten thousand people develops perfect pitch, every single one of Sakakibara's students did. The clear implication is that perfect pitch, far from being a gift bestowed upon only a lucky few, is an ability that pretty much anyone can develop with the right exposure and training. The study has completely rewritten our understanding of perfect pitch.

Take the time to read that journal paper, it's an amazing read.

Answer 3

I'll risk the wrath of the gods and try to answer differently: I think all humans do have (the potential for) perfect pitch. As others have pointed out, it is a learned skill, as it logically must be, at least if you take 'perfect or absolute pitch' you mean 'the ability to identify musical tones'.

I have had the same experience as you: I have realised at a fairly late stage that I remember the 'right' pitch of songs and music, and to me it is unconfortable to listen to a 'wrong' rendition. I think it is simply that we remember well how something sounded when we first heard it, and that becomes the 'right' sound, to our minds. This explanation is not quite 'neurological', only 'functional', but I think it is a realistic guess at what is going on.

And now for the part you don't want: evolution. I think this ability is an example of something that is innate in the function of neural networks, which has turned out to be adaptive, I think the word is, in social animals: many animals need to be able to quickly identify their mate and offspring in a group, where smell isn't effective (because of too many sources of smells), and in darkness, where sight is useless. Sound works well in both settings.

Answer 4

This question I asked myself at 14 y.o. when discovered, that people around me, even from my music school, don't hear notes of every clean sound around. And I still want to find the answer why I get this ability, so I regularly do research of different publications. Most of the articles say, that it is possible to train the absolute pitch. You gave us the example of you experience, and I would like to share my.

Unfortunately, I don't remember exactly, when I started to hear sounds as notes, but almost sure it was just after learning note's names in 1st grade piano class at 7. I didn't train it. But maybe it was trained because of this situation: I didn't have my own instrument at home, so I prepared to the lessons on the picture of piano keys, 2 octaves, which were drawn in a simple notebook. When I "played piano" that year, I needed to sing the notes in my head, because It was impossible to hear something. But I also noticed that my mother, who hasn't any musical education, always sing songs in their original tonality. Maybe genes has their role, too. I am like her, plus can say note's names, recognize whistles, sounds of glasses or boiling kettle without the effort. When someone ask to check it with a tuner in their hands, I also can calculate the frequency of the sound in Hz very closely (it is with a help of knowledge and calculator, of course) .

At the moment I think and feel that the absolute pitch I have it is some kind of memory. It is like having a strong standard model in the head and every sound is comparing to it automatically. And that is why I can't play friend's piano, which is tuned half a ton below, it is not easy to shift this deeply rooted model half a tone below, too. Why don't all humans have it? I don't know how to use this ability, and think that it is not the most important thing to evolve/be developed in all humans.

Answer 5

My explanation gathered from multiple sources:

Having some kind of pitch is inherited as dominant allele. Some people don't have it and they can't be trained to hear it.

Relative and absolute pitch are trained. Actually, the absolute pitch is the easier task, but relative one is related to most everyday hearing tasks (relating multiple frequencies to a single sound source) so most non-musicians develop only the relative pitch.