Horse-and-human teams perform complex manoeuvres in competitions of all sorts. Together, we can gallop up to obstacles standing 8 feet (2.4 metres) high, leave the ground, and fly blind – neither party able to see over the top until after the leap has been initiated. Adopting a flatter trajectory with greater speed, horse and human sail over broad jumps up to 27 feet (more than 8 metres) long. We run as one at speeds of 44 miles per hour (nearly 70 km/h), the fastest velocity any land mammal carrying a rider can achieve. …
That’s the opening of Janet Jones’ essay in Aeon, “Becoming a Centaur.” Jones has been a neuroscience professor and a stable owner, so she brings a beautifully doubled perspective to the topic, reminding me of Adam’s Task by Vicki Hearne, a 1986 book about training (mostly) horses and dogs from the perspective of a philosopher and poet who extensively studied animal training as well as doing it professionallly. But Hearne’s perspective was only secondarily scientific; Jones is steeped in numbers and fascinating explanations:
No one disputes the athleticism fuelling these triumphs, but few people comprehend the mutual cross-species interaction that is required to accomplish them. The average horse weighs 1,200 pounds (more than 540 kg), makes instantaneous movements, and can become hysterical in a heartbeat. Even the strongest human is unable to force a horse to do anything she doesn’t want to do.
Jones cannot get over her wonder that humans and horses aren’t enemies, and she describes quite lyrically how the connection works:
In mounted teams, horses, with prey brains, and humans, with predator brains, share largely invisible signals via mutual body language. These signals are received and transmitted through peripheral nerves leading to each party’s spinal cord. Upon arrival in each brain, they are interpreted, and a learned response is generated. It, too, is transmitted through the spinal cord and nerves. This collaborative neural action forms a feedback loop, allowing communication from brain to brain in real time. Such conversations allow horse and human to achieve their immediate goals in athletic performance and everyday life. In a very real sense, each species’ mind is extended beyond its own skin into the mind of another, with physical interaction becoming a kind of neural dance.
Jones provides a wealth of scientific detail–the differences between horse and human eyes, different communications with the brain cortexes, the art and science of subtle signals (inward pressure from a rider’s left calf tells the horse to move sidewise to the right). But the part that feels, well, miraculous, is the brain-to-brain communication:
Specifically, neural signals from the horse’s eyes carry the shape of an object to his brain. Those signals are transferred to the rider’s brain by a well-established route: equine receptor cells in the retina lead to equine detector cells in the visual cortex, which elicits an equine motor reaction that is then sensed by the rider’s human body. From there, the horse’s neural signals are transmitted up the rider’s spinal cord to the rider’s brain, and a perceptual communication loop is born. The rider’s brain can now respond neurally to something it is incapable of seeing, by borrowing the horse’s superior range of vision.
These brain-to-brain transfers are mutual, so the learning equine brain should also be able to borrow the rider’s vision, with its superior depth perception and focal acuity.
And if that weren’t enough, Jones goes on to speculate that humans may be able to transmit executive function (the ability to form expectations, make a plan, and carry out that plan) to horses, whose brains don’t operate on that level. This is unproven, but Jones gives some examples of why she believes that scientific study might find evidence.
I have effectively never been on the back of a horse, beyond a few childhood forays in those very controlled pony ride attractions. So I can only faintly comprehend the sensations Jones describes. If you’re a rider, I suspect this article will have an even stronger impact–meanwhile, I’m just going to spend some time revelling in the magic relationship between horses and humans–and the science driving the magic.
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