By Jackie Bellamy-Zions, Equine Guelph 

Ever wondered if ponies can interpret human emotions through facial expressions? While humans may instinctively avoid someone with a furrowed brow, how well do horses understand our feelings? A recent study by Dr. Katrina Merkies, an associate professor and researcher at the University of Guelph, set out to answer this intriguing question. Dr. Merkies and her team conducted an experiment involving 20 lesson ponies and a group of skilled actors to determine whether ponies could distinguish between happy, sad, angry, and neutral human facial expressions.

While previous research has used flashcards to explore this concept, this study is the first to observe how horses react to real, in-person facial expressions. The results offer valuable insight into equine emotional recognition.

Dr. Merkies explains, “In terms of behaviour generally, the right brain processes emotions and particularly negative stimuli, whereas the left brain is more related to social interactions and learned behaviour.” This distinction between the right and left hemispheres of the brain plays a key role in how horses process human emotions.

Understanding how horses perceive human emotions also requires a closer look at their vision. Unlike humans, horses have monocular vision—each eye sees a separate image, and the visual information from each eye is carried via the optic nerve to be processed by the opposite side of the brain. The left eye sends information to the right brain, and the right eye sends information to the left brain. This unique setup, with minimal binocular vision, means that horses rely on the separate processing of each eye to interpret what they see.

After initial clicker training took place with the ponies so they would be likely to approach the human actors, two actors presented expressions of happiness, sadness, anger, and neutrality. 

As hypothesised, the angry and sad faces resulted in the ponies looking at the actors more often with their left eye first. The left eye glance corresponds with the right brain, which is in charge of processing negative stimuli. Conversely, the ponies more often looked at the joyous expression with their right eye, and interestingly the neutral facial expression came up with a 50/50 reaction! 

The ponies also exhibited more licking and chewing with neutral faces, and they focused their ears more on the actor and stood farther away from joyous or sad expressions. Another action noted in the study included heart rate, which was not affected by any of the facial expressions presented. 

“I think it’s important to note that although the horses did respond to the different facial expressions and they clearly distinguish between them, that doesn’t necessarily mean that they understand what we’re feeling or that they feel what we feel,” says Merkies. “They may respond more to an angry face but that doesn’t mean that they feel your anger and that there are other things taken into consideration, like the way that you move your body and what else is happening in the environment.”    

Merkies sums up, “Many different cues factor into how a horse will respond in any moment, but understanding our facial expression is important to social interactions. It’s interesting that facial expressions are highly conserved across species, so even though we can have very different physiognomy (we look very different) — for example, a mouse compared to a horse, compared to a human — facial expressions are fairly similar, which is very interesting and very helpful because if you can understand the facial expression from another being or another species, then you can know how to respond appropriately.” 

To see the research paper, visit Can Ponies (Equus Caballus) Distinguish Human Facial Expressions? published Sept 7, 2022.

Related: Use of Tools by Horses

Published with the kind permission of Equine Guelph.

Main Photo: iStock/Tsmorton