So people with perfect pitch often complain about headaches when, say, a choir starts to lose pitch. This is because they can hear how the pitches sung by the choir have drifted away from the pitches notated on in the part they are reading from. That knowledge can apparently be quite distracting.<p>However, I have <i>never</i> heard a student with perfect pitch complain or even inquire about internal inconsistencies in tuning that would lead to comma drift. E.g., "Hey, I was practicing singing C-G-D-A-E-C and I ended up slightly off from the C I started with. What gives?" I've never heard of a student stumbling upon anything like this <i>independent of</i> reading a text about the problems of tuning systems.