On a Big Bang Theory episode (sec 56) Leonard is talking over the phone and everyone wonders who's the person on the other side, afterward Sheldon claims:
This should be fairly easy to deduce. He’s holding the phone to his
left ear. Ears do not cross hemispheres, so he’s using the analytical
rather than the emotional side of the brain, suggesting that he has no
personal relationship with the caller.
Is there any correlation between the ear you choose to hold the phone and the person on the other side of the line?