To communicate with a horse, you might employ reins, bits, lead ropes, halters, bridles, spurs, or riding crops, but you might want to start with your posture. Before getting on to a horse, how you behave on the ground can send signals to the animal, such as if you’re a dominant member of the herd or not. Horse owners have been employing these ideas for a long time, but since horses are known to glean information about people from a variety of sources, researchers wanted to know just how much of a role posture played on its own. When a horse reacts to a human’s presence, is it responding to the human’s posture, stern gaze or the smell of apples coming from a jacket pocket?
To try to isolate the role of human posture, researchers had to come up with an experiment that could account for all the other stimuli a horse looks for. To do this, 30 domestic horses were fed a treat by two women of similar height and build, wearing matching outfits to normalize their appearance as much as possible. The women had never met the horses before, and they they even covered the lower part of their face with a neck warmer to avoid sending unintentional cues with facial expressions. After the initial introduction to the two doppelgangers, the women moved to different parts of the arena to test the horse’s sensitivity to body language.
Looking solely at stature
With all these controls in place, the experimental condition was the posture the women adopted after being “introduced” to the horse. Instead of a matching “neutral” posture, one woman stood up straight, with her arms straight and legs about shoulder-width apart. Her counterpart bent her knees slightly, hunching forward with her hands angled over her abdomen, almost like a person trying to stay warm on a cold day. As expected, over the course of four trials each, the horses were much more likely to approach the woman adopting the submissive posture.
Confirming the importance of posture in human-equine relations may help settle one question, but it naturally raises others. Horses communicate with each other in many ways, such as flattening their ears to show a degree of hostility, which obviously don’t carry over to human anatomy. Likewise, human arm placement isn’t commonly seen in lower-ranked members of a horse herd, so it seems that horses are willing to translate our bodies into a meaningful message. Hopefully further studies, possibly with untamed, or at least unbroken, horses can find out more about when horses learned to read a human’s body language.
Source: Horses can read our body language even when they don't know us by University of Sussex, Science Daily