I think this has more to do with evolution. One can determine which direction that they want to project their voice, but cannot determine from which direction sound will come from.
Not to be an ass, but this has been my response to this statement since 1968.
Whether evolution is true or not, it's just a phrase that seems to make sense. If everybody listened twice as much as they spoke it's almost a given we'd see less heat and more light. Well, it's probably a given for some.