When youngsters come to Meredith Manor, one of the first things I show them is a big ball of string. Now if I asked them to sit down right then and there and eat that whole ball of string, they'd find that pretty gross. But if they started at the end, which is actually the beginning, and they swallowed a very little bit at a time--very methodically, very logically, very calmly--ultimately they would finish it. Then they'd say, "Well, look at me! I swallowed that whole ball of string!" Training a horse is identical to swallowing a ball of string, both from the trainer's perspective and from the horse's viewpoint.
One of the most common ways people get in trouble training horses is that they ask their horse to take too big a bite of string at one time. When you're working with a baby horse, each thing you teach him must be taught as one little word, one little bit of language, that you'll eventually put together to hold a conversation.
A horse cannot make a connection between two things with more than two degrees of separation. The first degree away from what he already knows should be something he "feel." For example, heeding him up into the corner of an arena makes him feel like he's going to get trapped. The second degree can be a little more arbitrary--the trainer turns her primary line as they reach the corner and creates an opening that the horse can move into. So he turns. Once the horse is changing his direction in response to a change in direction of the handler's primary line, the trainer can build on that understanding to teach different sizes and shapes of turns. And so on. That means if you're trying to teach him something new that's more than two steps away from something he already understands, he's not really going to get it. If you get too far away from what he already knows, you're asking him to bite off too much string.
Some people do manage to teach a horse something that's unrelated to what he already knows. By repeating a cue and rewarding the horse's successful guesses, you can put a cue or signal on him so that when you do a particular thing, he'll give you a particular response. You can also do this by associating something the horse already understands with a particular signal. But a cue or signal only produces a preconditioned amount of an activity. You won't be able to change the speed, direction or intensity of the response. You can ask for the activity but you can't moderate it. You've got a trick horse but you haven't got a trained horse.
Some trainers ask a horse to bite off more string than he can chew because they confuse cause and effect. Just being able to cause a horse to do something is not the same as training him in a way that each thing he learns becomes the basis for another step. You are not developing any understanding that you can build on to teach him other things.
For example, taking a horse in a round pen and chasing him around then jumping in front of him or yelling or flipping a rope so he whirls around and changes direction may make someone look like they're in control of the horse. But they are not creating a feeling of a shape that the horse can understand so that he'll give you that shape again when you create that feeling again but under different circumstances in a different place.
When people chase a horse in a round pen, he tends to motorcycle around, leaning to the inside and counterbalancing himself by sticking his head to the outside. It's a great way to teach a horse to fall down. And that's not the shape you want him to remember and give you again when you start riding him on a circle.
Used properly, a round pen can help a horse begin to understand how to work in a corridor of aids on a circle. For example, as his training progresses, we eventually want our horse to carry his head just a little to the inside of a circle for different reasons. So if we're heeding a horse around in a circle on a lead rope using a round pen as one side of our corridor of aids, we're already asking him to carry his head a little to the inside and creating a feel for that circle shape we want.
Later, when we introduce seat bone pressures and leg pressures and bit pressures to create a feel for that same circle shape, we can go back to the round pen and use part of an already familiar corridor of aids he felt as a specific shape in groundwork to help the horse move one or two degrees to an understanding of the new aids under saddle.
Since aids can be moderated, you can use them to create new levels of understanding in something the horse already knows. For example, once the horse feels a particular corridor of aids as a canter shape, you can use one or more of those aids to moderate things like the length of his strides or the number of strides he takes within a particular time frame. If you've only taught the horse to canter by kicking his shoulder, he'll canter. But he'll only do it at a particular speed, a particular length of stride or whatever else you've told him to do when you put that signal on him. Now you've got a trick horse.
Real training is about building a horse-logical language made up of corridors of pressures the horse can feel as specific physical shapes. If you've taught those shapes using aids, you can modify the aids to modify the shapes. Now you can play any horse game you want.