Why are pianists always looking at the ceiling?

I always thought it was a kind of swanning, put on for dramatic display, and just yester­day noticed that I was doing it—alone, in a window­less practice room in the basement of Davies Hall. Just who was I trying to impress? 

Dismayed, I scanned through a video from my recital at the Phillips collec­tion and noticed I was doing it there, too. 

I have a theory (I almost always have a theory). On both occa­sions, I was trying to quickly accli­mate to unfa­mil­iar pianos (some­thing pianists have to learn to do regu­larly). Perhaps I was uncon­sciously trying to distance myself from the sound of the instru­ment, much as one would walk around differ­ent loca­tions of a hall to gauge the sound of someone else playing. 

I can’t imagine moving one’s head back­wards a foot or so actually changes the percep­tion of sound much—though maybe it does? Perhaps someone who knows more about hearing or sound percep­tion would care to comment. 

Still have no idea why a pianist’s head would move in the opposite direc­tion, though: