If you could not automatically identify the color red, but instead could only tell whether one color was redder than another you'd have the visual equivalent of relative pitch. It would not necessarily be true that you could learn to identify red without being given another reference color to compare it to. So I don't think there's any reason why perfect pitch HAS to be something you can learn. On the other hand, I have read that if you work at it you can improve your ability to identify pitches without context.Here's the wikipedia article https://en.wikipedia.org/wiki/Absolute_pitch
technically, this has to be possible... because it's not like people are born already knowing what "C" sounds like. They have to learn what "C" sounds like by listening to music and forming connections with the note each pitch corresponds to in our system of music. In other words, perfect pitch is a form of memory... people remember what the pitch of a note sounds like, so when they hear that pitch later, they can identify the note. So can't you "learn" perfect pitch by memorizing sounds? Is it really a "god-given talent"?
No. I have great relative pitch, but the reference is not stable. I can sing my lowest note, call that an F, and get within a quarter tone of correct. But that is nothing like perfect pitch where the brain just knows. I can hold the pitch we have decided on for a couple of hours, but after the rehearsal is over I have to start over. I've been at music for 55 years, if this perfect pitch talent was going to happen it would have by now. I'm just now learning to name intervals when I hear them on a recording, to try to play by ear, so it is possible to learn in one's sixties. Just not the perfect pitch talent.
What will develop perfect pitch (even in adults) is to always play in a perfectly tuned instrument. (that makes sense , does it not?)I believe that in this respect digital pianos are a very good idea since they are always tuned. Most of my practice is done on a digital piano (otherwise the neighbours would kill me), and since I got one, and started using it with regularity instead of th enoraml piano, I developed perfect pitch. (I always had excellent relative pitch). To the point where if I play on a piano that is relatively out of tune (that is, the piano is properly tuned but not to A=440) I start making amazing mistakes because what I am playing does not correpsond to the sound I am producing.
I'm not certain what kind of pitch I have. If I hear any note on the piano (except perhaps at the extreme higher and lower ends) I can tell what note it is without relating it to another note. I can also do this with the cello, and to a certain degree the guitar. So if I hear a note on the piano, played as a single note with no other reference, I know what that note is immediately. I can't tell what a note is if sung or played on any other instrument which I find interesting because the piano is my main instrument, cello is my second and I play the guitar a little for fun. So basically, it must be the length of time I have spent playing these instruments which allows me to just 'know' what the notes are when they are played.This obviously isn't perfect pitch, and it's not relative pitch so I don't really know why I know the notes on these few instruments. It seems to me that I must have learnt them through playing the sounds so often. This must mean that pitch is something which can be memorised.