Horses can remember emotional expressions that they’ve seen on human faces and adjust their subsequent behaviour accordingly, recent research has revealed. What’s more, this memory for emotions is specific to the person concerned.
Researchers, led by Professor Karen McComb from the University of Sussex and Dr Leanne Proops from the University of Portsmouth, presented domestic horses with a photograph of a happy or angry human face. Several hours later the horse saw the person in the photograph, this time bearing a neutral expression, in real life.
Observers noted which eye the horse used to look at the individual. Previous research has shown that animals tend to view negative or threatening events with their left eye. This is because threatening stimuli are processed in the right side of the brain. (Information from the left eye is processed in the right hemisphere).
The researchers found that short-term exposure to the photograph of a person's facial expression was enough to generate clear differences in subsequent responses upon meeting that individual in the flesh later the same day.
Despite the humans being in a neutral state during the live meeting, the horses' gaze direction revealed that they perceived the person more negatively if they had earlier seen them a photograph of them looking angry rather than happy.
Neither of the two humans used in the study knew which of the photographs (angry or happy) had been shown to the horse earlier in the day, to avoid any risk of behaving differently themselves.
Interestingly, the differences in reaction only applied to the person the horses had actually seen in the photograph and were not given to a different person.
Professor Karen McComb commented on the findings: "What we've found is that horses can not only read human facial expressions, but they can also remember a person's previous emotional state when they meet them later that day -- and, crucially, that they adapt their behaviour accordingly. Essentially horses have a memory for emotion."
For more details, see:
Animals Remember Previous Facial Expressions that Specific Humans Have Exhibited.
Leanne Proops, Kate Grounds, Amy Victoria Smith, Karen McComb..
Current Biology, 2018;