Did you know that horses have facial expressions? Research has shown that their surprisingly nuanced ability to show (for example) alarm, surprise or sadness means that they’re not quite as expressive as humans, but are more adept in this sense than chimpanzees.
A new study does an about-face, so to speak. A team from the Universities of Sussex and Portsmouth wanted to know what horses thought about our very own facial expressions – and it turns out that not only can they remember them, but if you’ve been a bit of a grump, they’ll remember it in the future.
“A wide range of animal species are also capable of discriminating the emotions of others through facial expressions,” the authors of the Current Biology study note, including dogs, chimpanzees, and even pandas.
There’s some pre-existing evidence suggesting that horses can too, but as the researchers explain, “it is not known whether animals can form lasting memories of specific individuals simply by observing subtle emotional expressions that they exhibit on their faces.”
In order to find out, they presented a series of domestic horses with photographs of an angry or happy human face. (It’s worth checking out the surreal photographs of these interactions, by the way, which makes it look like the person is being held hostage by an equine captor.)
They then waited for a few hours, before bringing the horse over to meet the human featured in said images – this time, with a neutral facial expression – who didn’t know which photograph had been used in order to prevent accidental bias. At the same time, horses were also taken to meet another human whose face they hadn’t seen in the photographs.
Now, previous work seems to suggest that a variety of animals view events associated with negative outcomes through their left eye, whose visual information is processed in the right hemisphere of the brain. As it happens, this hemisphere specializes in processing information regarding threats and dangers.
During this new experiment, then, the team paid attention to which eye the horse focused its gaze with, while also monitoring any displacement (stress-generated) behaviors, heart rate, and approach or avoidance patterns. All things considered, they found that not only do horses understand what these two distinct facial expressions mean, but they remember who made them and behaved accordingly.
Horses, already known for being socially intelligent, clearly have a capacity for emotional memory too. Excitingly, it’s not clear why horses seem to possess this ability.
One possibility is that it’s innate, and apart from their own species’ faces, this also applies to humans. “Alternatively, the ability could have specifically evolved during the process of domestication or may be learned during a lifetime of experience with people,” the researchers add.