I've seen that people are quite good at tracking the gaze of others for mating purposes. Who is looking at whom and how they are looking is all quite interesting and informative.
it's probably very very important evolutionary to know if the lion is looking at you or the gazelle 5 meters to the left. (and also very frustration-inducing for people who have strabismus)
how so? if you are talking about males, it doesnt matter who the females are looking, the strongest male will fight or dominate the other males and get the females anyway. If it is females, well the females dont really need to compete for male attention. a look from a potential predator on the other hand is an immediate and lethal threat.
