Anything will distract him and when it does, he's gone. He's out to lunch. You see people distracting their horse with badly applied aid pressures all the time. They only use one aid or pressure too loudly out of all the aids it takes to communicate an understandable shape to the horse. That distracts the horse from the all the other aids that could give him a clue about what to do and he misses the meaning of the communication.
Bits are the biggest problem here.
When you communicate horse logically using methodically applied directional pressures that shape rather than attack the horse, you are training, not breaking. Training involves developing rhythm and relaxation through repetition. Punishment has no place in a training program. Punish yourself, not the horse. All rights reserved.