Tuesday, December 17, 2013

Absolute Pitch: Inquiry, and Methods for Learning It

It's time for another edition of my Piano Whatever Blog.  Today's subject is the contentious and misunderstood topic of "Perfect Pitch."

Absolute Pitch:
Inquiry, and Methods for Learning It

I. Introduction

In the Fall Semester of 2012, I became interested in being able to identify what note I am hearing.  As a motive, I thought it would be pretty awesome to be able to do this, obviously.  At one point, my mother thought I had this talent, as I was good at playing the piano by ear as a young child.  One of my tricks was reconstructing pieces I had heard from memory by slowly finding the right notes of something that I had heard.  However, that was a long time ago, and I hadn't had musical training since then until very recently as an adult.  I wasn't convinced I had this talent at all because if you played a note, I had no idea what it was and had no idea how I was supposed to find out.  I suspected that I had what they called 'Relative Pitch' instead.  If there was a note blaring somewhere, with time and some guesses, I could find the note on the piano because I could tell the difference between the notes.  It is also true my pitch memory was fairly keen, and to a very limited extent I could do this from memory.  Of course, I didn't actually know what Relative Pitch was, and so I went off in search of answers to these and other questions.  Over the semester I got involved in reading various materials online, both scientific and amateur, about the phenomenon of Perfect Pitch and what the research says about it, the experiences of people who have it, and the various attempts people have made to acquire it.  I also made the attempt to learn the skill myself by using computer software and lots and lots of mental practice and drilling.

II. Resources

When I first looked into the subject of Perfect Pitch on the internet, it was like beholding a giant ocean stretching from horizon to horizon from the shore.  I dived in, swimming from one island of insight to the next (yay, lame extended metaphors.)  All of it was very interesting to read of course, but there seemed to be a great deal of conflict in concepts and definitions of what Perfect Pitch actually is.  The first reference I examined was an article that was already present in a piano technique book I was reading, which is C.C. Chang's Fundamentals of Piano Practice.  This excellent manual can be found here:

This large reference manual was a labor of love by Mr. Chang and is full of wonderful information about practicing at the piano.  I have enormous respect for this project, and it should give you a good idea of its scope that it includes information about everything from Absolute Pitch to piano tuning.

In his article about Perfect Pitch, he makes the following claims:

  1. Perfect Pitch doesn't really exist.  Instead, there is Absolute Pitch and Relative Pitch.
  2. Absolute pitch is being able to identify an exact note (at the piano for example), whereas Relative Pitch is being able to identify that note with a few tries.
  3. Absolute Pitch can be acquired later in life if one already has relative pitch, but it is difficult and fragile and requires constant mental practice to maintain.
  4. Potentially, all individuals with early musical training should be able to develop Absolute Pitch automatically.
  5. Fundamentally, Absolute Pitch is a learned trait.

These claims were the starting point for my research into this subject.  Particularly, I was interested in the definitions he was using because they pointed the way to greater clarity on the subject.  Of course, Wikipedia has a entry about the subject:

The Wikipedia article asserts that Absolute Pitch can not truly be acquired later in life, but 'psuedo-absolute pitch' can be with a great deal of time, motivation, and effort.  This seems to be more or less what C.C. Chang is claiming, with a slight definition difference.  Perfect Pitch seems to be a more old-fashioned term and is tied more to the belief that nature and not nurture decides if you possess it.  The big question of course is what the real difference between Absolute Pitch and 'pseudo-absolute pitch' happens to be.  What is really going on there?  I continued searching.

The following study, conducted by the UC San Francisco, is attempting to determine the genetic basis for Absolute Pitch:

They assert that Perfect Pitch (which seems to be more or less synonymous with Absolute Pitch in the literature) cannot be acquired later in life as there are no documented cases of an adult developing it, and also that it most likely has a genetic basis due to their distribution graph which shows that individuals either have it, or don't have it, with very few lying somewhere in between the distribution.

Thus, they argue that the scientific evidence argues strongly in favor that Absolute Pitch is largely nature, not nurture, especially because there are individuals with early musical training that still do not develop Absolute Pitch.  This stands against the more optimistic claims of C.C. Chang.  It also is more in line with the traditional view of 'Perfect Pitch', as either you have it, or you don't.

In addition to looking at the theory and ideas surrounding the phenomenon, there were some excellent blogs and forum threads I had read about individuals with varying experiences attempting to acquire this ability when they did not have it.  There were failures, successes, and cases in between.    There was one blog in particular that was readable, fascinating, and documented an individuals research and personal investigations over a long span of time.  Unfortunately it escapes me and I can't dig it up right now.  However I do remember it led me to this website:

This is one of the best sources for Absolute Pitch ear training - in the research and theory sections, there are an enormous number of references.  This websites asserts optimistically that Absolute Pitch can be learned as an adult and has excellent software developed around a number of theories relating to 'chroma' or sound quality.

Another highly developed software training application exists here:

This game is fun to play and challenging - the only downside is that once it gets to higher levels where accuracy as high as 95% is required, it feels like it comes down a lot to luck and grinding it out than progressively learning.  However if you've reached those levels than you are more than good to go when it comes to functionally having the skill.

III. Personal Investigations

This was the literature and theory I read and the games I played over the Fall and Spring semesters while I investigated acquiring this skill.  I will complete this article with my own experiences and opinions on how best to acquire Absolute Pitch as an adult.

First, I will state the results of my training.  For all intents and purposes, I now have Absolute Pitch.  The skills I have developed over two semesters are for all intents and purposes functionally equivalent to 'Perfect Pitch'.  Where they are best labeled 'psuedo-absolute pitch' or 'Perfect Pitch', I think, is more of an academic debate rather than a reality of the usefulness of the skill.

When a note is played, I can nearly instantly (within 3 seconds) identify what it is with an accuracy somewhere between 90%-100%, and with a small amount of time to check and cross reference my near-instant response, the accuracy of my answer will be just under 100%.   I always make the very occasional mistake.  The more practice I am in, the more rare mistakes are.  As I think about and work with music less (such as over the Summer of 2013), they start to wane and deteriorate, although so far I haven't seen anything approaching a reversal of the intense drilling and training I undertook.  Mistakes are so rare at this point that I never worry about it, and I have never been off by more than 1 semitone since the end of last semester.

When multiple notes are played, I can slowly pick them all out one by one and identify them, using knowledge of theory Relative Pitch skills to assist me.  This means that in practice, soon I will be able to identify entire harmonies and therefore chord qualities and inversions being played, all in the correct key.  My current limit of what I can handle is around three to four notes played at once - more than that and it is unlikely I will be able to distinguish them all at my current level of training.  Because of my extensive knowledge now of theory and relative pitch ear training, I can use these skills to fill an enormous number of gaps.  I'm sure that in time, I will be able to arrange and transcribe ensemble pieces with a very high degree of accuracy in the correct key and even play my instrument the piano in this fashion, although my technique and familiarity with the instrument will limit me for quite some time.  In the meantime, I can sing any melody or play it on the piano if it is simple, by ear, in the correct key.

Compared with Fall 2012, this is an enormous amount of progress to say the least.  In the Fall of 2012, if you played a note, I would give you a blank stare.  I could not identify notes, let alone sing them back to you in the right key.  I had difficulties in my singing group, the ECC Chorale, matching the right pitches.  It wasn't so much that I was singing the wrong notes.  Rather, I had difficulties hearing myself, singing the right parts, and not getting confused, suggesting that at least I had some degree of Relative Pitch.  I could still eventually find the note on the piano if I remembered the piece and reconstruct it on the piano slowly, which I could do as a child as well.  So it seems I came into this learning experience with some degree of musical ability already: a relatively strong and accurate pitch memory.  This will be the starting point for describing my experiences in learning Absolute Pitch, and also it's basis.

It all began in my theory class where we were first learning Ear Training.  The teacher explained that we would have to identify an interval of notes.  Someone in the class asked in bewilderment if we had to know what note it was.  The teacher replied that what he was describing was known as Perfect Pitch, and that is not required for the class because it is not something everyone has.  Instead, we will be given the note.  He also went on to explain that by using a device called an 'incipit', which is a melodic idea or tune that illustrates the interval, we can learn to identify or sing intervals without knowing the notes involved.

At the time, I happened to be obsessed with this gorgeous piece of music:

http://www.youtube.com/watch?v=n6f6wTjVmCs - Op.87 Prelude & Fugue No.7 A major, perf. by Keith Jarrett

I had listened to it about fifty times because it is so lovely.  The subject of the Fugue (beginning around 1:10) begins on an A Major Triad.  I had heard it so many times, I could hear the glorious A Major subject in my head fairly clearly.  That's when an idea dawned on me.  If what I remembered was fairly accurate, couldn't I use this an incipit for the note A?  

Thus, I learned my first note.  Of course, the success of this idea rested on whether or not I could clearly remember and perceive the piece in the key that I first heard it.  In this case, it seems I could for the most part - perhaps because I had heard it enough times, or that my pitch memory was already strong.  At first, I was concerned with just singing the note or thinking about it, and then comparing the result with the right note on my instrument.  The largest error I remembered experiencing was no more than a whole tone (rare), or semi-tone (somewhat frequently thinking G# or Bb, for example).  Heartened by the consistent accuracy, I went on to see if I could hear the note and identify it around me.

This next step proved to be much, much harder.  In fact, the immediate and brutal failure was very disheartening and discouraging to the point that I became convinced for awhile that I merely had decent Relative Pitch and was kidding myself about the ability to acquire anything more.  While attempting to listen for the note, I was consistently thrown off, thinking that the note I was hearing was A when it was not.  I also noticed that as I listened to the piece less and less, my memory of the note became somewhat less precise.  I could still hold on to it but since the entire basis of this trick was my memory, I speculated that this situation was temporary and too difficult to sustain over any long period.  I was stuck for about a month with no progress and struggling to hold on to the one note I had.

Nevertheless, as with any obsession of mine, I continued on, if only for kicks.  I purchased a software to train absolute pitch that threw notes at you in quick succession while you had to identify what they are by clicking them on a piano.  I was terrible at the game, but I had some success at nailing A when it did come up.  I was restricted to within one octave - C4 to B4.  I had to set the software to play the notes very slowly so I had time to make the necessary 'calculations'.  It also had a mode where it would play notes so that you could learn them.  This mode didn't work for me at all - I would have it play a note over and over for me and I would try to 'memorize' it or 'learn it' so that I could identify it later, and it was hopeless.  It was fleeting - I would lose it quickly.

Despite these difficulties, I pressed on with the greater challenge of learning more incipits for more notes!  I was struck by the idea of using the Well-Tempered Clavier which had a piano piece in every key in my instrument (I play piano), and thought I would learn all of the themes.  This didn't work so well - a lot of the themes were not necessarily singable or memorable, plus the amount of themes and tunes you would have to learn seemed overwhelming.  I learned an important lesson about this method - in order for it to work, you are better off using melodies that you already know very well, and are very, very tuneful and easy to remember.  A lot of the subjects are complicated, don't always begin on the tonic, and the tonic is obscured by other harmonies.  The fact that this Shostakovich piece rings like a bell on A (and, as I learned later, A440, the tuning note), was a happy coincidence and this is why it worked so well for this purpose.

Bit by bit, I assembled an arsenal of tunes for every key.  I remember that for the note Bb, there was this choral piece our Chorale was working on - the Pergolesi Magnificat in B-Flat Major.  The tuneful theme, beginning on B-Flat, was looping around in my head endlessly.  However, later on in the piece, the tune is stated in the dominant key, and other keys.  This resulted in hilarious errors.  I remember at one point I was going to boldly sing a B-Flat out loud.  Instead, much to my dismay I sung the right tune, but in the wrong key - F Major, the dominant.  I was also very flat.  It's hard to be more far off than that in terms of the actual note!  But another lesson was learned - you have to make sure you are remembering the right part of the song.  Later on, when my skills improved, I noticed how many other students would remember tunes, and, thinking that they were way off, were actually more correct than they could ever give themselves credit for - they were right on the money, but just in the wrong part of the song!  Our chorale director is always trying to remember works in key but is not always successful - but I don't know if she realizes how often she is 100% accurate but is either singing another voice part or is singing a part of the piece where the theme has modulated.

After learning lessons about what tunes worked and what didn't, I collected a motley list of tunes for every note.  Circa late Fall 2012, it looked something like this:

C: Prelude and Fugue in C (Bach, Shostakovich), Invention No. 1 in C Major (Bach)
C#: Fugue in C# Minor WTC 1, Fantasia Impromptu (Chopin, 5 to 1)
D: Piano Concerto No. 3 (Rachmaninoff), Invention No. 4 in D Minor (Bach), Cum Sancto Spiritu (Vivaldi)
Eb/D#: Prelude in Eb, WTC 1 (Bach), Don't You Worry 'bout a Thing (Stevie Wonder)
E: Prelude in E WTC 2 (Bach), Menuet in E (Haydn), Shenandoah (Mack Wilberg)
F: Piano Concerto No. 19 in F (Mozart), Invention No. 8 in F (Bach)
F#: O Vos Omnes 1st ending (Luis Salazar)
G: Prelude in G, WTC 2 (Bach), 5th Symphony (Beethoven)
Ab/G#: Concerto for Solo Piano (Alkan), Fantasia Impromptu (Chopin), Agnes Aria (S.J. Pettersson)
A: Fugue in A Major (Shostakovich), Fugue in D Major (Shostakovich, 5 to 1)
Bb: Prelude in B Flat WTC 1 (Bach), Magnificat (Pergolesi)
B: O Vos Omnes (Luis Salazar), Spasinye Solidelal (Tchesnokov), Mass in B Minor (Bach)

However, I noticed that as old songs became less clear in my memory, I needed to replace them with new repertoire that I was actually working on.  For rare keys though, this posed a challenge.  I came up with the idea of burning a CD of these tunes and listening to them frequently to keep my 'brain tuned'.  I still use this idea, and every once in awhile I make a new CD reflecting my current mental practice music.  I need to listen to it every so often to stay on target.

What about my pitch memory itself, the lynch pin holding everything together?  It was difficult to assess it's strength relative to before these experiments, as I had not really been a musical person or particularly involved in music until late as an adult, and not to this extent until that very semester.  I did notice however that to a small degree, my memory itself improved and became more stable with practice.  Before these tests and early on in my self-training, I would remember things fairly accurately, being off sometimes by a semi-tone or less occasionally a whole tone, or sometimes remembering the right material but in the wrong part of the song.  By fall 2014, I would be remembering music in the right key nearly all the time, the right part of the material, and with the only error being one semi-tone off and even then rarely so.

With the first piece of training software and my arsenal of tunes, I began bit by bit to succeed in identifying notes that I was hearing.  The basic procedure is this - I would hear the note, mirror it internally in my mind, and see if it related to any one of the tunes I had learned.  If it did, and I could clearly remember the tune, by knowing what note the song began on, I could then assert that the note I was hearing was that note.  This process at first was naturally quite slow and subject to confusion and error.  Often I would resort to heuristics (short cuts) to make more educated guesses if I wasn't sure of my answer.  I worked on developing a series of cross-reference checks in my mind - using tunes I was more sure of and interval comparison for example, or using the context of the music I was hearing to help narrow down the options (for example, it's less likely to hear this note in this key, because it's chromatic - etc.).  I found that the more notes you know, in a sense it becomes easier to identify them because you know more about what a note is NOT, as well as what it is.  Also, I learned that in order to progress, you had to just be confident and go ahead and give a note your best guess and then do your best to learn what error you made, if any, and then how to improve on your next guess.  Every time I heard a note anywhere in the music building, I would set my mind to work 'calculating' what it was.  I had a few music student friends test me on the piano, exclaiming that 'perfection' was my goal.  One told me that I would probably ever get it perfect, but they all noted my progress and seemed both interested and impressed by it.

Starting with just one octave and lots and lots of drilling, I reached the point where I could identify any note from C4 to B4 with a note being played at about one note per 4-5 seconds, with about 80-90% accuracy.  Pushing myself, I expanded to two octaves, then three, then the whole piano, then having the notes being played faster and faster.  While I was doing this, I participated in the UC San Francisco study and played various other games on the internet.  At first, I failed to qualify as having Absolute Pitch in the UCSF study, but after more training and a few more attempts, I finally made it.  When I found ProLobe and AP Avenue (linked above), I was able to push my skills even further.  I discovered that the only way to stretch your skills was to challenge yourself with something much harder.  It seemed similar in nature to visualization in chess.  At first, you start off with the ability to visualize a certain number of moves ahead.  In order to improve, you have to push yourself to see just a little bit further, which mentally is quite taxing.  Also, you have to constantly reinforce what you can do over and over in addition to this stretching.  By playing a game that included the whole piano with muddy low notes, ringing high notes, and multiple notes being played at once, identifying just one note being played on my own instrument became a trivial thing.

So now I sit with a very useful skill that can no doubt be developed even further.  I am happy with my progress so far.  Once I reached a certain level around the end of Summer 2013, I lost interested in pushing it even further for the time being, because I had already invested dozens if not hundreds of hours drilling these skills.  For the entirety of Fall 2013, my skills were functionally equivalent to AP and everyone seemed to notice this.  Just being involved in music and working with it in my head (which I do as a music student anyway) was more than sufficient for keeping it fresh, and of course I would keep listening to my CD of tunes every so often.

I am presenting this story to anyone else who may have the same inkling that I did to engage in this nerdy quest.  I have come to the end of this journey with a few broad conclusions:

The method that worked for me is what I believe is referred to broadly as Melody Triggers, and I've seen it discussed elsewhere on the internet as a learning method that some have tried and used with success, others without.  The idea is that a note that you hear triggers a melody in your mind which is tied to a certain note, tipping you off as to what note it is.  It is dependent on having a good long-term pitch memory and relative pitch skills already, as well as the concentration and focus to work with music in your mind.

I believe there are four broad levels of pitch awareness:
    • Tone Deaf - This represents the inability or difficulty of telling the difference between pitch classes.  In other words, someone who hears and E has trouble telling it from a D, even with them played within a short time window.  Most likely their long-term pitch and short-term pitch memory are weak and they are struggle to hear or analyze music in their mind.  There are a variety of levels within this category.  Being totally tone deaf is probably quite rare, whereas the kind of tone deafness just below Relative Pitch is more common.  I've noticed that some people possess only certain kinds of tone deafness - in other words, they are able to sing a note correctly, but unable to hear it or mirror it internally.  Or perhaps they can hear it or mirror it internally, but struggle to hear themselves singing it.  Others may know all of the scale degrees but mix them up in their mind, so have perfect intonation but sing the wrong part or the wrong note for the context.
    • Relative Pitch - This represents the level of many untrained individuals who are habitual music listeners or have had a significant exposure, as well as your average musical and musically trained individual.  Relative Pitch means you are able to distinguish between all 12 tones in relationship to one another, particularly in the Major and Minor scales.  The short-term pitch memory of these individuals is often quite accurate and functionally equivalent to perfect, however their long-term pitch memory is often less reliable.  Like those with Absolute Pitch, individuals with relative pitch possess a degree of internal music making and mental practice, although they are usually not confident that they are in the correct key!
    • Absolute Pitch - This represents the level of individuals who are either very musical innately (fortunately), have had a high degree of musical exposure and training while young, or both.  Functionally, it means having a pitch memory and recognition that is accurate enough to perceive music internally and externally to the key in which it was originally heard.  In other words, it mostly represents a highly accurate pitch memory.  Absolute Pitch possessors are individuals with great pitch memories or good ones with Relative Pitch who have undergone training, and they use this memory to work with notes.  Absolute Pitch is characterized by a high degree of mental practice and internal music making - in fact, it may be a prerequisite for most individuals who possess this skill to continue mental practice or else their skill will wane and deteriorate.
    • Perfect Pitch - It appears some special individuals have even more extraordinary and solid reinforcement of their perception of musical tones.  It is unclear to what degree this is the result of early musical training during the critical early years of life or the product of unusual musical abilities, but their perception of tones is as much linguistically based as memory based and can therefore be even more accurate and confident in their answer than with a skill based purely on memory.  Also, a condition exists called Synesthesia whereby certain individuals can associate colors, sensations, and other experiences with aural stimulus such as pitches.  This can give them 100% accuracy and confidence in their pitch awareness, and someone with this condition perhaps constitutes the classic or old-fashioned case of 'Perfect Pitch'.    It is also double-sided, as individuals with this trait report irritation and even physiological reactions to music that is out of tune.
It is my conclusion that many, if not most, individuals with Relative Pitch have the ability to develop functionally equivalent Absolute Pitch or "psuedo-absolute pitch" with a great deal of practice and training, and the motivation to sustain it with constant practice.  However, I cannot be confident that all individuals with RP would be able to do this.  It is merely my hope and belief, substantiated in part by my own experience, but far from proven.  In my own case I was clearly working with a good pitch memory already.  Perhaps individuals with very unreliable long-term pitch memories may not already have the tools to use the Melody Triggers method, but this does not preclude them possibly training their pitch memory to the point that they could (see below.)  For individuals with Relative Pitch and above average or good long-term pitch memories that aren't quite all the way there, I believe the way is open for them to acquire AP with these methods.  For individuals who have been very pitch deprived and / or are tone deaf, it may be possible for them to acquire Relative Pitch skills, but whether they can take the next step and acquire Absolute Pitch is highly uncertain, especially as adults.  Possible, perhaps, for the exceptionally dedicated and obsessed?

As all I am saying so far applies to adult learners, the news is even more optimistic for those who are young or young adults.  While the difficulty of such studies as an adult are undeniable, the younger one is, the more plastic and 'sponge-like' your brain is generally, especially within the age range of 0-12 years old.  I would speculate along with C.C. Chang that the vast majority of individuals with vigorous musical training at this age should be able to develop Absolute Pitch.  This is founded on the following observation he has made, which is chromatic scale is a human invention - there is nothing innate about it.  It must be learned.  To the criticism that there are individuals with early musical training who do not develop it, I am now very curious to know what methods were used and what theory those methods were informed by.  Teaching a human being to recognize musical tones as a kind of language, and strengthening their musical memory through constant exposure to perfectly-tuned instruments, are the methods called for.  What methods are currently being used?  Are they proper, efficient, and effective?  Are they standardized?  These questions demand answers.  Perhaps a scientifically informed Absolute Pitch course for young children could be developed and taught universally in studies to further test whether this ability is really off limits to anyone.

I would go further and say that second, while to some extent the strength of one's pitch memory (as with any memory) is surely genetically determined, this is true for all memory.  It's also true that all memories that we know of can be improved with practice and training,  even as an adult.  Why should pitch memory be any different?  The rest of pitch memory is surely determined by the degree to one's exposure to music (and therefore pitches) over one's life - i.e., nature.  The higher degree of exposure, the more 'in tune' your brain and pitch memory will be.  It should really be that simple, and to assert otherwise I think is a more extraordinary claim.  Therefore, because the particular method I use is founded on memory and memory training, it should be accessible to everyone as a possible avenue, although of course success for every individual is not guaranteed, especially as an adult learner.  If one's long-term pitch memory is not consistently reliable enough, then the key would be to train this memory - perhaps separate focused methods are called for here, supplementing the ones I've already discussed that worked for myself.

Third, all human beings are born with the capacity to recognize intonation (a critical component of comprehending language) and with some degree of pitch memory (everyone gets a tune stuck in their head, show me one who doesn't!) - we all have the hardware that makes these methods theoretically possible.  If we can all learn a language and learn how to interpret meaning from the inflection of one's voice, we should all be able to associate a letter with a particular pitch sensation because language already does this.  This suggests why speakers of tone languages have vastly higher incidences of perfect pitch.  As a reminder, adults are more than capable of learning a new language - even a tone language. 

Fourth, there is a large prejudice and misconception in our society about the nature of Perfect Pitch and it being a nature and not nurture trait, which only hinders the confidence and the persistence of those who seek to acquire it.  I argue that the evidence to show it is entirely innate is highly dubious - there are self-reported instances everywhere of individuals acquiring it, including myself.  I have a critique in particular to level at the UCSF study based on my experience.  It is worth putting in bold text for its importance.

Because a very reliable pitch memory, instead of just an average one, is required for functionally equivalent Absolute Pitch, this is the reason I speculate why the distribution curve in the UCSF is so one-sided.  It's not that there aren't many gradients on the road to Absolute Pitch - it's just that if your pitch memory is around one whole tone off for example, it's not quite good enough for the functional skill, even though it's still way ahead of someone who is tone deaf.  In the UCSF survey you will both appear to have around the same level of competence at pitch awareness, when this is clearly not the case in reality.  Arguably, an individual who is only around a whole-tone off with some training could have the accuracy necessary for functionally equivalent Absolute Pitch. It may be that there are no recorded instances of 'true Absolute Pitch' being developed in an adult, yet 'psuedo-absolute pitch' is allowed for and recognized.  Perhaps 'true Absolute Pitch' in this case is referring more to Synethesia which was discussed earlier as an unusual condition and not a requirement for AP.  I struggle to see a difference otherwise, and if they are functionally equivalent, I'm sure no one who makes use of their functionally equivalent skill would care what it is called.  Far greater clarity in the real difference between 'psuedo AP' and 'real AP' is required on the part of the literature and I hope my experience and other self-reported success stories can help clarify the true nature of Absolute Pitch.

In the end, there is one final point to be made, and that is the nature of learning such things as an adult versus a child.  It is indeed true that once we are already an adult, these things become much more challenging, and success cannot be guaranteed.  However, for anyone who is already musically inclined and involved in music, I would not hesitate in giving it a try if you are motivated and willing!  I would also recommend the method of Melody Triggers if you are already good at distinguishing pitches, but you might want to start with Chroma methods first if you have difficulty distinguishing between the 7 diatonic and 5 chromatic tones of a scale.  

If you are an adult you have a challenge ahead of you, which is why I believe all children should be taught the musical alphabet at an early age.  Early exposure is critical to learning anything but persistence at any age will be rewarded.