Just finished a quick nine holes and had my usual vodka grapefruit at the nineteenth hole. There are several TV's playing that ring the bar with the sound off on most. Watched an interview across the bar trying to concentrate on the left half of face of Geoff Shackleford, a very bright, good looking, articulate, young commentator and his right eyebrow kept jumping out at me. In trying to concentrate on the left half face my peripheral attention often notices more movement on the right not displayed on the left. Geoff's right eyebrow seems to raise earlier, more often and higher than the left. Most of the time the left eyebrow seems to be recruited based on his emphasis, later than the right, and dropped quicker.
From my perspective he is communicating with his right side of face and the left reflects what the right is doing when the stimulus is enough.
I have no real opinion on the range finders.