This kind of training usually stems from the trainer having a high level of anxiety or not having enough knowledge to be trying to train animals. Blood sugar problems and over-caffeination of the trainer can also interfere with the trainers cognitive abilities. This kind of training always leads to conflict between the trainer and animal.
Behavior: Standing with head in front of chest.
Antecedents: Trainer is standing in front of the horse, wearing her treat bag on the right side of her body. She is bridging using a clicker. It is summer.
Consequences: The trainer clicks twice but it does not seem connected to any particular behavior. The second time, the trainer lures the horse to put its nose on the bag and clicks when the horse reaches for the food.
Summary: MAJOR ERROR!!! Nothing good can come of this.
It is imperative for a trainer to have an idea of what the behavior should look like in order to reinforce a correct approximation. It is also imperative for a trainer to understand that the horse will acquire bad behaviors as rapidly as good behaviors and avoid rewarding random actions including nosing into the trainers space. If your horse acquires unwanted behaviors, you need to figure out when you trained the animal to do that.