This is were the horse wants to be with you rather than being with his horsey friends. Have you watched horses out in the fields playing? One horse is the dominate horse, telling others to move out of the way, or go there or do this. Once you start developing a communication system and using the seven games you will become the leader. Once you have mastered the games, and have done them on horseback, (always start on the ground)you will have gained the dominance role. The first part of gaining leadership of having the horse respect you. Soon you will have a greater understanding of how horses think and feel about situations.
Horses have a split brain, meaning that one side in the prey animal side, and the other is the thinking side. The right side is the prey, while the left is his thinking side. Say that a horse is afraid of a plastic bag, their instinction would be to run (right side). But if one has the proper leadership techniques, than the horse will start to think about the situation ahead and use his left side of his brain.