How your horse’s vision differs from yours
See that sliver of light on the sand, shining through a gap in the roof of the indoor arena? Every time she goes past, Hawkeye arches her neck and skirts the boundary as if it’s a rattlesnake. The sliver changes in size and shape with the sun’s movement, and the mare seems to see each tiny difference as a brand-new snake. When a concurrent sound erupts—say, the sound of a grain of sand sliding—she leaps sideways.
These are normal behaviors that reflect the way a horse’s visual systems are hardwired into his brain. We can teach horses to overcome them, but we can’t make them go away. Nor can we make a horse see the way we do. How we respond to his fear depends partly on our own vision, which determines our expectations of what horses see.
Since the 1960s, cognitive psychologists have shown that we construct sight using information from our eyes combined with knowledge in our brains. Things can go wrong at either end—the eye or the brain. A person whose eyes become blind still sees images and dreams. One whose eyes are intact but whose visual cortex is damaged often sees lights and shadows but can’t make sense of them. In rare cases, people who are completely brain-blind can grasp a coffee cup set in front of them or navigate around objects, responding to the physical world even though they cannot consciously see it. This ability, called “blindsight,” isn’t limited to humans; cortically blind animals can do it, too.
Occasionally, a smidgen of visual cortex is impaired so specifically that its owner—having otherwise normal sight—suddenly cannot see color, shape or perhaps movement. Imagine trying to cross a busy street with eyes that function normally but a brain that can’t perceive motion. Cars travelling 60 miles an hour become a series of still images stopped along the road. At the next glance, they’re still stopped, but in different locations.
Neuroscientist Gerald Edelman said it best: “Every perception is a creation.” The trouble is that horses create their perceptions in ways that are very different from ours. Visual information travels from the eye to the brain in both species, of course. But the human brain sends back six times as much neural information in the opposite direction, transmitting messages to the sensory relay station that captures incoming views. This wiring is infrastructure for perceptual interpretation: the effect of knowledge being melded with the eye’s pictures of the outside world. So, who’s more objective in seeing reality, you or your horse? Hate to break the news, but it’s probably your horse. His brain is less prone to illusions and assumptions than yours is.
Equine vision is different from human vision in almost every way—acuity, range, eye contact and detection of peripheral motion, just for starters. If you want to shape your horse’s performance and gain his trust, you need to understand how his vision differs from yours. You can then use that understanding to develop training techniques that work with the horse’s visual system instead of against it.
A DIFFERENT FOCUS
Horses often give the impression of superb vision. Walking in an open field as a bird flicks a wing in the distance, a horse may raise his head, point his ears, flare his nostrils and widen his eyes. This impressive display of intelligence and sensitivity is sometimes called the “look of eagles.” But it stems from how equine vision works. Focusing on the bird’s location, the horse is trying to improve his view by raising his head and enlarging his eyes. He pricks his ears because he cannot see stationary details well. His nostrils expand to enhance his excellent sense of smell.
Equine eyes are eight times larger than human eyes; in fact, they are larger than those of any other land mammal. But a horse’s acuity—the ability to discriminate fine detail while focusing on something in the center of the visual field—is considerably worse than ours. Reading is a great example of acuity. Right now, your eyes are picking up tiny differences in the black marks on a page. You can see the difference between an “e” and a “c,” for example.
By convention, normal human acuity is 20/20. What a normal person sees from a distance of 20 feet is the same as what you see from a distance of 20 feet. Meaningless, right? The numbers don’t tell us much until we use them for comparison. A typical horse’s acuity is about 20/30. Details we can see from a distance of 30 feet, he can only see from 20 feet. A horse has to be 50 percent closer to see the same details. Ah, that means something!
A 50 percent deficiency is enough for any rider to consider. Imagine what a horse sees when you ride him to a jump. For you, it’s clear, sharp and bright. You’d be mighty nervous if it looked fuzzy and faded. But equestrians are often startled to see photographs constructed to show what a jump looks like to a horse. Even in sunshine, the horse’s view of a jump is blurry, hazy, dim, flat, vague … all the adjectives you’d rather not ponder as you’re galloping 30 feet per second toward a big oxer that could ruin your day.
Individual horses, like people, differ in acuity. About 23 percent of horses are nearsighted, which means they do not see details clearly until they get close to an object; 43 percent of horses are farsighted, able to make out details only as they get farther from an object. It stands to reason that slightly far-sighted horses will excel in disciplines like jumping where the ability to home in on fine points from a distance fuels their athleticism.
Acuity also changes with age, as anyone who has reached age 50 can verify, because the eye’s lens loses flexibility over time. The best acuity in horses occurs around age 7. Prior to that it is not fully developed, and thereafter it begins to decay. Horses with long convex noses, like many Standardbreds and Thoroughbreds, have better acuity than do horses with short concave noses, like Arabians.
POINTS OF VIEW
The most obvious features of a horse’s eyes are their size and placement on the sides of the head. Human eyes are comparatively smaller and point forward. The position of the eyes on the face accounts for profound differences in the ways people and horses see, dictating visual range, peripheral motion detection and depth perception. A horse’s vision is determined by 5 million years of equine evolution. Trendy tie-downs and personality assessments won’t change that—we have to accept how horses see the world and work with it.
Human sight is accurate enough to decode tiny marks on a page, but only for a small slice of the view. When you read, only two or three words in your central vision are truly clear; the rest are blurred. Stretch your arm full length to your side, holding up your index finger. Look straight ahead. You won’t see the finger. You can’t even see your arm. Now move your arm slowly in a wide outstretched semi-circle toward the front, keeping your eyes focused on a distant point in front of you. No cheating! The finger remains invisible until it reaches almost a 45-degree angle. Human vision is limited to roughly 45 degrees on either side of our noses, for a total of about 90 degrees.
By contrast, if your horse could hold his hind hoof straight out to his side, it would be almost in the center of his vision. Because his eyes are on the sides of his head, he has a 350-degree view, almost four times greater than the range we see. Think of how dependent we are on sight, how important it is to us. Now imagine we had four times that much vision to process every second of the day. We’d be edgy, too!
The horse’s visual range stretches from the end of his nose all the way around to an imaginary line extending straight back from his hip. The Attack Tractor that you cannot see approaching from behind your shoulder is well within his line of sight. It’s coming toward him, maybe at a rate faster than he is moving. Some horses see this as a chase, and every fiber of their evolutionary being says that the way to survive a chase is to run. Now. The balloon bobbing at the side of the arena is the equivalent of a ball soaring straight toward a horse’s face. If that balloon is yellow, it will be especially bright to equine eyes. No wonder he shies and bolts.
The horse sees a broad band of the world to the sides and back of his body, but it is narrow. His vision is poor above and below the level of his eyes. Sights directly to the horse’s side but on the ground or in the air are difficult to see unless he cocks his head. Equine vision also creates blind spots. A horse cannot see a person standing directly in back of him. Surprised from behind, even the sweetest horse can kick in almost any direction. That’s where that tenet of good horsemanship—approaching the hindquarters from the shoulder—comes from. You want to make sure he knows you’re there.
A second blind spot exists in front of the horse’s face, from his eye level to the ground below his nose and out to about six feet. A hand suddenly raised will appear to him to come from nowhere. He cannot see the grass he grazes on, the bit he accepts, the fingers that stroke his muzzle. He uses the whiskers around his mouth to sense these objects. A horse whose whiskers are shaved is at a sensory disadvantage.
One of the most common mistakes people make when dealing with nervous horses is to thwart their side view. The rider, with forward facing eyes, assumes that positioning a horse for a frontal view is best for all. Some equestrian websites even advise this position. The rider pushes Hawkeye straight toward the sliver of light on the sand that already scares the bejeebers out of her, then tries to make her stand still and stare at it head on, eyes bugged out like tennis balls. These demands defy the functioning of a horse’s brain.
Why? First, from the front, human eyes can see an object clearly, but a horse’s wide-set eyes cannot. All Hawkeye knows is that her rider is upset, forcing her forward to a place that she considers threatening. Second, as she reluctantly approaches, the light-snake vanishes from Hawkeye’s line of sight, which of course makes it all the more frightening. Third, standing still concentrates the horse’s fear rather than alleviating it. Fourth, when Hawkeye cocks her head and pivots to the side for a better view, her rider pulls on one rein and presses with the opposite leg, pushing her back to a stance where equine vision is worst.
Fear is in the eye of the beholder. We might think it silly that Hawkeye is afraid of flapping plastic or a paper cup … but how would you feel about having a big, hairy tarantula running through your hair?
Let’s give Hawkeye a break. Start with some groundwork. Try leading her toward that sliver of light, but if she balks, don’t push. Allow her to move in circles or loops at the closest distance she considers safe. Then use some vicarious learning: Let Hawkeye watch a familiar human friend walk to the object, stand next to it and speak calmly. She will recognize the voice. Stroke her neck and encourage her to approach. A step or two more than she wants equals success. Offer praise and stop for the day.
If this technique fails, have your friend bring a known, preferably herd-dominant horse to the object. (Verify ahead of time that this horse is unafraid.) Speak slowly in a low pitch and stroke your horse’s neck while she watches her buddy survive the terror. If this also fails, move out of sight of the object and put your horse to work on a completely unrelated task. Tomorrow, start building her trust using objects that she considers less frightening. Eventually, you will be able to return to the original fright-sight and try again.
When your horse is relaxed while viewing the threat, even if only from a distance, walk her back and forth past the object before requesting a head-on approach. When she is willing to advance face-first, encourage her to stretch her neck down and forward for a good sniff. Stroke her neck, speak calmly and let her sniff the object. She’ll probably jump a couple of times—that’s OK, I’d jump too if you asked me to sniff a tarantula. Touch the hazard so your hand makes a soft noise against it; this will allow the horse to learn more through her excellent hearing. Gently roll or push the object around as the horse becomes accustomed.
Now, let’s suppose the fright-sight appears while you are riding. It’s tempting to call it a day and drive to the nearest ice cream store for solace. But that only teaches Hawkeye that when she shies, you will take her to her comfy stall. Instead, remain mounted and distract her with a task that moves her away from the threat. Yes, this feels like “letting her get away with it,” but it’s only one step of a larger process. Try riding to a distance the horse considers safe, with the object in view. Trot back and forth in a way that places the object most frequently at the horse’s side. Focus on pace, relaxation and inward bend; ignore whatever scares her.
When Hawkeye is calm, quietly enlarge the loops, maintaining any distance that allows her to remain tranquil. Then ride a foot or so closer to the object each time you go by. When she passes it calmly, even from a distance, stroke her neck and speak kindly. If she skirts it, decrease the loop next time to make it easier for her. Move closer when she is ready, not when you are ready.
A simple lesson might take one minute or 100, two days or two months. Try not to push or punish fear. If the horse needs a 50-foot berth to negotiate an object calmly, give it to her. The priority is her mental composure, not her physical distance from the scary view. Tomorrow you can set the goal for composure at 45 feet. If you’re rushed or annoyed start the lessons another day. Forcing a horse is a good way to destroy her trust in you, frighten her all the more, and wake up with Nurse Ratched by your bed.
PREDATOR AND PREY
Beautiful wide-set equine eyes reflect the evolutionary needs of prey. We hate to think of ourselves as predators, but our forward-facing eyes tell every horse the truth. Prey animals identify predators by smell and sight—including their view of eye position. One look at a human face, and the evolutionary equine brain knows we are predators.
Because horses see us as natural predators, human eye contact has a warning effect. Next time your little gangster needs a reprimand, add some stink-eye to your verbal reminder. It’s the human equivalent of an alpha mare’s flattened ear. (If you can flatten your ear, that would be even better. Let me know how that goes, OK?) If your horse moves too quickly on a longe line or in a round pen, try looking down, watching and listening to his feet surreptitiously to stay safe. If he frets when entering a trailer, ask onlookers to go away. Hard to catch? Look to the side, or slowly walk backward toward the horse while speaking quietly.
Evolution has also equipped horses to be highly aware of peripheral motion. To move in for a kill, predators need sharp sight in central areas of the visual field. Prey animals, on the other hand, don’t often need to know what they have seen. They only need to know that they have seen. In other words, horses must notice peripheral motion immediately, regardless of what it is, so they can leave the scene at high speed before a potential predator begins to approach. When needed, equine eyes can even move independently to scan one side of their world more intently than the other.
The human brain takes half a second to process each glance at the world and determine what it has seen—shape, color, size, distance, importance and so on. Half a second of processing is out of the question for a horse in the wild: He needs to notice a tiny movement in the bushes and step on the gas. Every millisecond of delay could mean death. If the movement turns out to be a bicycle instead of a lion, that’s OK. Nothing is lost by running from a bicycle.
The horse’s natural reliance on peripheral motion detection dictates his need to shy or bolt—and otherwise “misbehave”—while ridden. Help him out by sharpening your peripheral senses. Try to become more aware of objects behind and to the sides of your eye, putting your ears, nose and cognitive experience to work. If a horse is full of corn in an area where he is normally calm, investigate. Chances are good that he notices something you do not and is trying to tell you about it.
Acuity, range, eye contact and peripheral motion detection—in all these ways the horse’s vision differs from a person’s. Keeping these differences in mind will help you to communicate more effectively with your horse and train him in ways that accommodate his senses. In the meantime, keep your eyes open for those light-snakes on the sand.
About the author: Janet L. Jones earned her PhD in cognitive science, the study of the human mind and brain. She won UCLA’s dissertation award for her research on brain processes. Now professor emerita, she has taught the psychology and neuroscience of memory, language, perception and thought for 23 years and is the author of three books. She has competed in Western, English, reining, hunter and jumper classes in five states and uses the principles of dressage with every horse. Jones currently owns a 17.1 hand off-the-track Thoroughbred who makes every day interesting. Readers can reach her at [email protected]
This article first appeared in EQUUS issue #461.
Don’t miss out! With the free weekly EQUUS newsletter, you’ll get the latest horse health information delivered right to your in basket! If you’re not already receiving the EQUUS newsletter, click here to sign up. It’s *free*!