New Study Shows Horses' Left Eye Determines Threats

Over the years there's been a number of studies showing that horses can interpret human expressions. However new research actually demonstrates that horse can remember human emotions.

The latest study was conducted by researchers at the universities of Sussex and Portsmouth and was published in the journal Current Biology.

Socially Intelligent Animals

"We know that horses are socially intelligent animals, but this is the first time any mammal has been shown to have this particular ability," Portsmouth research Leanne Proops said. "What's very striking is that this happened after just briefly viewing a photograph of the person with a particular emotional expression — they did not have a strongly positive or negative experience with this person."

Strong Memory

Karen McComb, a professor at the University of Sussex, said in a news release, "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 behavior accordingly."

Left eye senses threats . . .

The researchers arose at this conclusion after a series of experiments where they showed domestic horses photographs of humans with either a happy or angry human facial expression.

Later, when showing the horses the same people in the new photographs making neutral expressions, the researchers observed the eye movements of the horses.

This experiment determined that the horses saw those who had been photographed with angry faces to be more threatening. And they made this determination with left eye. concluding it's the left eye that is more prone to picking up threatening signals.

The reaction to angry facial expressions was particularly clearer with the left eye. There was a quicker increase in the horse's heart rate, which led the team to conclude it was the left eye that was more prone to picking up threatening signals.

It's important to note that those being photographed did not know which photographs the horses had seen before, which was done to eliminate the risk factor of the humans behaving differently in the later photo shoots.

Dogs look at angry human faces with the left eye too. The reasoning is that the brain’s right hemisphere – where information from the left eye is recorded and interpreted - is specialized for dealing with scary or threatening stimuli. But the horse research has taken this type of research into a new arena.

McComb, said “Horses may have adopted an ancestral ability for reading emotional cues in other horses to respond appropriately to human facial expressions during their co-evolution. Alternatively, individual horses may have learned to interpret human expressions during their own lifetime.”

The fact the equine species can read the facial expressions of another species, such as humans is a pretty big deal, and one to follow as time goes on. I'll be doing so. Please let me know if any of my readers have similar interests?

Primary Source Current Biology