Researchers based at the University of Sussex (U.K.) took photographs of male human faces (why male is uncertain) and showed them to various horses. The photographs showed clearly either a human face that was “happy” or displaying “anger.” The reactions of the horses to the portraits was recorded.
The researchers concluded that the horses reacted in different ways according to the emotional state of the person in the photograph and the reaction to the angry looking person was a negative one. In total, 28 horses were ‘surveyed.’ With each of the angry faces, each horse looked at the photo through their left eye. The lead researcher, Amy Smith, told BBC News: “The right hemisphere is specialized for processing negative stimuli”, this because mammals tend to process information collected from the left eye through the right brain hemisphere.
As well as viewing the eye, heart monitors were fitted to the horses and a noticeable variation to the heart beat was recorded when the horse looked at a photograph of an angry face.
From this, the researchers conclude that the process of domestication of horses has led to horses being able to interpret and react to strongly expressed human emotions. Similar inferences about domestication and reactions to human facial expressions has been shown with dogs.
Exactly when the the domestication of the horse occurred is a matter of scientific debate. The area where this first happened is thought to be the land that now forms part of modern-day Ukraine, southwest Russia and west Kazakhstan.
The study is published in the research journal Biology Letters, and the work is headed “Functionally relevant responses to human facial expressions of emotion in the domestic horse (Equus caballus).”
In related horse news, Digital Journal recently profiled a riding school where horses riding classes are offered to people of all ages and abilities, including special classes for those with a disability.
