Penny Lane always makes me think of playing the violin in school. Right down to the smell of the rosin, and the impending sense of doom and humiliation.

I think you can just listen to music in isolation, in and of itself: have the music remind you of nothing but how much you like that piece of music. But it's hard to divorce it from the when and where of listening, and if you're the type of person to replay (which surely defines pretty much everyone) then that becomes the soundtrack to something else. I'm sort of boggled that anyone needed to research this.

Oh, and REM's Monster album = Sonic the Hedgehog. The underwater levels. :D