> Notes separated by octaves are like higher and lower versions of the same note. I don't know if this is an in-born ability or a cultural one, but I can say t

> Notes separated by octaves are like higher and lower versions of the same note. I don't know if this is an in-born ability or a cultural one, but I can say that I (for one) don't have any perceptual sense of "sameness" in an octave. To me, two keys with the same letter-name on a piano make two different notes, just like any other interval (though I'm not saying that the different intervals don't sound different). This may be a form of amusia, but I enjoy music, sing to myself, recognize melodies, and find the dissonant Happy Birthday in your link unpleasant (all of which contrasts strongly with the forms of amusia I've read about); on the other hand a lot of the things that people say about music don't mean much to me, except that in some cases I have a mathematical understanding which I can't really connect to a perception.