Horse Brain, Human Brain. Janet Jones
Читать онлайн книгу.
it begins to decay. Breed makes a difference, too. Horses with long convex faces, like Standardbreds and Thoroughbreds, have better acuity than horses with short concave faces, like Arabians.
Focus
The human eye is superb at focusing on one detail of a scene. Muscles holding the flexible lens of the eye pull it into a more convex shape to focus on objects close up. You can feel these muscles working if you hold a finger up in front of your eyes. Focus on the finger then look past it (without moving your eyes) to a distant object. Go back and forth, getting the feel of the ciliary muscles that flex your lens. This ability—called accommodation—allows us to inspect objects while working on them with our hands. Humans excel at visual accommodation.
Horses do not. Their ciliary muscles are too weak to pull the lens into a more convex shape for greater focus (fig. 3.2). So when you hold something near your horse’s face—a bridle or clippers—he can smell it but will have great trouble focusing his eyes on it. To show your horse something new, hold it near his nose for a good sniff or on his shoulder where he can feel it with his excellent sense of touch. If it must be seen, hold it out in the air several feet away, and wait a bit. What little focus horses can achieve happens slowly. That’s why sudden movements near their bodies can surprise them.
3.2 Like the human eye, the equine eye contains a pupil, iris, ciliary muscle, and lens. However, it is a bit more compressed, or flatter, in shape than the human eyeball.
Range of Vision
Ask a child to describe a horse’s eyes. One of the first things the child will mention is that they are very large and set on the sides of the head, unlike small human eyes that point forward. This simple observation generates profound differences in the ways humans and horses see. Eye position affects visual range, peripheral motion detection, and depth perception. Equine eyes can even move independently to scan one side of the world more intently than the other.
Human sight is accurate enough to decode tiny marks on a page, but only for a very small slice of the view. While reading, a few words in your central vision are truly clear; the rest are blurred. Stretch your arm out to the side, holding something like a pencil vertically in your hand. Look straight ahead. You won’t see the pencil in this position. 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 pencil 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 (figs. 3.3 A & B).
By contrast, if we held a pencil straight out from the side of a horse’s head, it would be almost in the center of his vision. With eyes on the sides of his head, he catches a 340-degree view, almost four times greater than the range we see. Imagine what would happen if we humans had four times more vision to process every second of the day. We’d be edgy, too!
The horse’s visual range stretches from the outside of the nose all the way around to an imaginary line extending back from the hip. The last few degrees of angle near the hind legs and hips permit only very poor vision. When leading or riding your horse, the vehicle that you cannot see approaching from behind your shoulder is within his line of sight, but it’s not too clear. It’s coming toward him, often at a rate faster than he is moving. Green horses see this as a chase, and every fiber of their being says that the way to survive a chase is to run. Now!
3.3 A Human range of view is about 90 degrees, so the rider in this drawing only sees someone moving hay near a wheelbarrow.
3.3 B Equine range of view is about 340 degrees, so the horse sees everything except the bird behind him.
Working with the Side View
One of the most common mistakes made with nervous horses is to thwart their side view. Humans can’t see it, so we forget it’s there. We lead horses through narrow passages forgetting that the walls completely block their primary lines of sight—then we wonder why the horse is skittish.
Because it’s best for our forward-facing eyes, humans assume that the frontal view is also best for the horse. Some equestrian websites even advise this position. Let’s return to Hawkeye, a lovely appendix hunter shown by an excellent equitation student who was new to me. We were working in the indoor arena when Hawkeye skirted the sliver of light that I told you about. At first, I just watched.
The rider was annoyed. In keeping with standard technique, she pushed Hawkeye straight toward the sliver of light on the sand that already scared the bejeebers out of her. She tried to make Hawkeye stand still and stare at the sliver head on, eyes bugged out like tennis balls. The horse danced back and forth, trying to turn to the side, and each time the rider cued her back to center. These demands—which good riders carry out every day—provide a perfect example of riding against the equine brain.
How so? Well, let’s think it through.
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 she considers a threat.
Without radically moving their heads, horses can’t see much below the level of their eyes, and they see nothing under their noses. So, as Hawkeye reluctantly approaches the light-snake, it vanishes from her line of sight. This makes it all the more frightening.
Standing still concentrates a horse’s fear rather than alleviating it. Frightened horses need to move; that’s what their brains are telling them to do.
Each time 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 the frontal stance where equine vision is worst.
We might scoff at a big horse who is afraid of a sliver of sunlight or an evil paper cup—but fear is in the eye of the beholder. When was the last time you felt good about a big hairy tarantula running through your hair?
Hawkeye refused to obey the frontal commands, and by now the rider was very frustrated. At such moments, it’s tempting to dismount and drive to the nearest ice cream store for solace. But that only teaches a horse that shying buys her a nice safe stall for some couch time. Because the horse was afraid but not terrified of the light-snake, I asked the rider to remain mounted and distract the horse with a task that moved her away from the threat. Yes, this sounds like “letting her get away with it,” but work with me for a minute here.
The best technique is to ride to any distance the horse considers safe, with the object in view (fig. 3.4). Trot back and forth in a series of loops that place the object most frequently at the horse’s side. Focus on pace, relaxation, and inward bend; ignore whatever’s scary—don’t even glance at it. When the horse settles at that distance, gradually enlarge the loops, maintaining the distance that keeps him tranquil. Ride a foot or so closer to the object each time you go by. When the horse passes it calmly, even from a distance, stroke his neck and speak kindly but keep moving. We want the horse to believe that the task is to form loops with an inward bend—period. If he skirts the fright-sight at some point, decrease the loop to make the task easier. Move closer when the horse is ready, not when you are ready.
3.4 When the horse is frightened of something, like a sliver of light on arena sand, avoid a frontal approach. Instead, work gradually back and forth from the sides with a distracting task until the horse settles. This method accommodates equine vision instead of expecting the horse to adopt human frontal vision.
A simple lesson like this might take 1 minute or 100, two days or two months. Don’t push or punish fear. If the horse needs a 50-foot berth to negotiate an object calmly,