While communicating, people tend to direct their gazes to the face (particularly eyes) of people. Why don't rather we look at their neck or just their chest or even their hair while communicating with people? What are we looking for?
A sign, a hint about that person's thoughts. Obviously that is the case ,but on the other hand, I think there is something more about that. Take those movie scenes in which people's head cut off their shoulder and they are still alive. I think the whole body doesn't seem human to me, whereas the head seems definitely so. Is it just a stable reference point that we've picked after centuries, or is it a native property specialized for a certain purpose of human kind?