That's an interesting point by Meself above. Playing by ear is what (some) children do if you give them an instrument, just as they will copy adult speech patterns. Later they may learn to read music, and will (in our culture) very likely learn to read text, but the listening, speaking and playing-by-ear skills are more natural and best acquired early.

I think it may well be the case that the adults who simply can't play anything without written music have not had enough opportunity to play by ear when young. They may even have been discouraged from listening, when their music teacher said, "Play what's written down, not what you want!" So they never learned to trust their ears.

You never hear anyone say they can't sing unless they see the music written down - they'll learn both the words and the tunes of songs by listening, because almost every child is encouraged to to this early in life.

So, if this is the case, being able to read music does not hinder people from learning to play by ear, it's just that this is the first and only method they have ever learned to use. With singing, those who learn later to sing from written music are still capable of remembering songs and singing them by heart, because this was learned early.

Those of us who are lucky enough to have both skills are not in any way disadvantaged by having some musical literacy, any more than people who can read and write are disadvantaged when it comes to speech. But I'm sure it's a lot to do with the opportunities encountered in the early years.

Marje