Scientists from the University of Sussex and Portsmouth have been examining whether horses are able to remember and understand human facial expressions. The University of Sussex has previously put together a directory of horse facial expressions and carried out another study where they found that equines are able to read human emotions, as can dogs. This study was published in Current Biology. The abstract is available to read and subscribers can log in to read the full study.
The team wanted to discover whether horses are able to remember facial expressions they had seen, and whether they used their prior knowledge to guide how they chose to interact with people, whether those people had been previously seen smiling or looking angry.
This small study involved 11 horses, who were each shown a large photo of a human with one of two facial expressions - smiling or looking angry - for two minutes. After 3-6 hours, the horses were brought face-to-face with the individuals in the photos. When they met the horses, the humans showed a neutral expression on their faces. The humans in the study were not told whether the horse had seen a photo of them looking angry or smiling.
The scientists found that those horses who had previously seen an angry-looking photo of the human that they met spent longer looking at them through their left eye than the horses who had seen their human smiling in the photo. Previous studies have shown that the left eye is used to send information to the brain when there is a possible threat as that is where danger is processed. These horses also seemed to find meeting the human face-to-face, stressful, showing coping behaviours such as scratching and sniffing the floor.
Horses who had been shown a smiling photo of the human they met, spent more time looking at them through their right eye, which connects with the left hemisphere of the brain, an area which offers positive reactions.
The scientists wanted to check whether the horses were reacting to a different person, so showed new horses photos of angry or happy people. A few hours later, the horses met the other participant. The people were treated the same way, regardless of which photo the horses had been shown.
The scientists concluded that the horses were able to remember facial expressions of particular humans, even though they had seen them for only a short while on a photograph. They also concluded that the horses were able to remember and use the information that they had gathered on the human’s emotional state.
The scientists pointed out that this experiment did not show whether horses are able to read the expressions of other species as well - dogs have a similar amount of facial expressions as humans and horses, and use them to communicate. The team hypothesised that perhaps horses were particularly attuned to human interaction because they have been domesticated for such a long time. This ability of the horse has been linked to their need for social interaction because they prefer to live in groups rather than alone.
Proops, L., Grounds, K., Smith A.V., McComb, K., Animals Remember Previous Facial Expressions that Specific Humans have Exhibited, Current Biology, Vol: 28, Issue 9, p1428 - 1432, May 2018