Jennifer Wathan of the University of Sussex said that their study is the first to examine a potential cue to attention that humans do not have: the ears and they have found that in horses their ear position was also a crucial visual signal that other horses respond to. In fact, horses need to see the detailed facial features of both eyes and ears before they use another horse's head direction to guide them.
The researchers' observations show that horses rely on the head orientation of their peers to locate food. However, that ability to read each other's interest level is disrupted when parts of the face-the eyes and ears-are covered up with masks. The ability to correctly judge attention also varied depending on the identity of the horse pictured, suggesting that individual facial features may be important.
The study was published in the Cell Press journal Current Biology.