Quote Originally Posted by Parallel Pain
It's hard enough to train humans, who can be manipulated by peer-pressure, religion, order, or threats to run headlong into a wall. I don't think it's possible to train horses, who are motivated only by instinct and their own survival, to do the same. I mean maybe if we can tell them "do it or I'll put a bullet through your head" but we don't speak horse.

Anyways this is how the infantry square works. It's so compact it gives the men some courage, and even if they do want to run they can't. As the formation remains intact, to the horse the rows and rows of men look like a wall, so they either refuse to charge or shy away before impact. It's the same for line formation as long as the men don't start running or bolting.

Horses during charge, if it is properly performed, are acting like during stampede, and this is affecting the way they react. Stampeeding horses do not care what is in front of them, but are running in a way where main group is running, ignoring men, diches or other obstacles.

This means that one horse will never charge line of men, but a big group may do this. But they will only do this if none of the horsemen will freak out and turn before impact. If even one person would break from charge, then whole charge will be destroyed.
This obviously means that a lot is in the mind of those who are charging. If the horsemen were ready to sacrifice they will perform much better and will actually take less losses, as only they are able to charge efectively.