I really don't know actually. I just know I hear far better then I can see, I can rely on my ears to be more accurate in doing there function then any of the other senses, I notice more things through hearing then I can through seeing. I might look at a forest and see trees and a ground, but I'll hear birds chirping, bugs moving in the ground, leaves rustleing, a low flying plane, trucks on the highway a long distance behind me, etc, etc...
I'm more sensitive to sound then anything else.