We can tell without moving the head, though moving it helps to pinpoint the location. The shape of the ears and the head and how they attenuate different frequencies coming from different directions plays into it. Don't tell me you can't tell if someone is shouting your name from directly behind you. You won't have time to turn your head but you'll know.
Last Edit: Sept 29, 2018 9:37:43 GMT -5 by Hiromant