I think you're right, Foolestroupe. Training and experience is all that's required to develop 'musical ear'. As a music teacher I've worked with hundred and hundreds of people of all ages and musical ability over the years. I have come to the conclusion that there is no such thing as 'tone deafness', unless the person is also totally deaf. Anyone whose ears function normally can hear musical tones. With time, musical training and concentrated effort/focus, the ability to distinguish between and produce "higher" or "lower" or "matching" tones on cue develops.

Years ago a middle-aged lady came to me for piano lessons. She'd taken lessons as a kid and was really down on her own musical abilities, insisting that she was tone-deaf. Testing that out, I played Middle C on the piano and asked her to sing the note she heard. She produced something around an F#, couldn't tell if she was right or wrong. Tried a few different notes, same result. Tone-deaf, right?

WRONG! I started her on a very basic ear-training program, first just practicing matching tones. I play a note, she'd sing it, I'd tell her it needed to be higher/lower, she'd try again until she matched it. WIth practice, she learned to hear the differences herself. And within a few months she could tell whether she was sharp or flat (as compared to a given tone). SHe was my very first adult student, and she taught me a lot! Studied with me for years, ended up finishing her Grade VIII Conservatory, including all those ear tests! SHe was required to identify or sing all the intervals within an octave, to play back a rather complicated little tune after she was told the key and heard it played twice (no looking, just listening). ANd she aced that part of the exam - her, the "tone-deaf" one who had "absolutely no musical talent" when she came to me (according to her, anyway). HA!

I think it's the same with 'perfect' or absolute pitch. If a toddler (aged 2 or 3) is exposed to music in the home daily, has an instrument to play on and is given a little musical training and encouragement/reinforcement, he/she learns to match tones and develops 'relative pitch' quite easily. I think that's because toddlers are at a biologically 'critical time' for learning languages -- including the language of music. Some toddlers learn these abilities VERY easily, and with time, effort and motivation/reinforcement also develop a highly accurate tonal memory.

This is what people call 'perfect pitch' - the ability to sing a note on cue without reference, to tell which note the phone rings on etc. Perfect pitch is commonly thought of as some mysterious god-given talent or gift - but it's not. It's a learned ability, and it developes when children are given effective musical training at a very early age. Haven't met a person with perfect pitch yet who didn't study music as a very, very young child! ANd that's how it 'runs in families' too - through nurture, and not just nature.

IMO and experience, of course. THe jury is still out on that, in the scientific community.