> The thing that's intriguing to me is the sudden onset of a compulsion to do one particular thing.
The article suggests something different than a compulsion, something like a sudden awareness of music (or art or whatever) that the person didn't have before.
For example, I have a kind of involuntary hobby of cataloging 3rd inversion seventh chords in music. Tchaikovsky likes to use them in descending chromatic sequences. Brian Wilson has a funny one in "God Only Knows" where the bass idiosyncratically resolves up. Etc.
I didn't have an obsession to learn about harmony and then catalog what I learned in the music I hear. I had an awareness of harmony before I took music lessons, then I learned the notation and went, "Oh, that's what it's called."
I think that's one of the most frustrating parts of learning something that's really new to you. Suppose I had no initial awareness of harmony and tried to learn to identify those 3rd inversion seventh chords by obsessively cataloging them. Perhaps I do some work studying pop and classical music, and after lots of effort I come up with the Tchaikovsky and Beach Boys examples. Then some musician with an awareness of harmony walks in and starts effortlessly adding more: there's one arpeggiated when Link falls in a hole in Ocarina of Time, in the theme to Back to the Future, a famous one in the transition of the last movement of Beethoven's Fifth, a string of them in a chromatic sequence in the Shepherd's Tune from Wagner's Tristan und Isolde, etc. "Oh, and isn't the verse of Tom Petty's 'Here Come's My Girl' just a famous alternation between a triad and a 3rd inversion seventh chord built on the first scale degree of a Lydian scale?" In that case I would start to wonder whether I really want to continue with my project.
Of course one can actually learn and improve that awareness with enough practice. But it requires perseverance to keep at it in the face of people who naturally have those same abilities (and often don't seem to value them).