New research conducted by psychologists at the University of Sussex, the same researchers who previously identified 17 distinct expressions used by horses, suggests that horses are capable of distinguishing between different human facial expressions.
The study’s findings, which were published in the journal Biology Letters, provide the first scientific evidence of equine ability to register human expressions of emotion.
The 28 domestic horses involved in the study, which were derived from stables in Sussex and Surrey, were shown high quality color prints of photographs of a male human expressing positive and negative emotions through facial expressions. In one photograph, he’s baring his teeth while smiling and in the other, he’s again baring his teeth but instead of smiling, he’s frowning.
When the horses were shown the photograph of the angry male for 30 seconds, the researchers observed a significant heart rate increase among the horses. Additionally, they found that the horses would adjust themselves in order to peer at the photograph through their left eye, which is a mannerism previously associated with their response to negative stimuli. According to the researchers, the left eye association is derived from the notion that the right hemisphere of their brain is home to a region that specializes in handling environments deemed threatening.
According to the prior study conducted by the U.K. researchers into equine expressions, horses have one more expression than dogs–who have 16–and four more expressions than chimpanzees, who have 13, CNN noted in a report.
University of Sussex doctoral student Amy Smith, who researches mammal vocal communication and cognition, was quoted by The Guardian as having said that what’s particularly interesting about the study “is that it shows horses have the ability to read emotions across the species barrier.”
What’s really interesting about this research is that it shows horses have the ability to read emotions across the species barrier.
“We have known for a long time that horses are a socially sophisticated species but this is the first time we have seen that they can distinguish between positive and negative human facial expressions,” she added.