Operant conditioning can go two ways. You can reward or reinforce correct behaviors to extinguish the behaviors you don't want; this is called positive reinforcement. Or you can punish incorrect behaviors so that the dog complies to avoid further pain; this is called negative reinforcement.
Unfortunately, pain avoidance training presents an opportunity for abusive handlers to try to justify their mishandling of this very intelligent breed. Shepherd handlers using pain avoidance methods are often guilty of exceptionally harsh, brutal training methods, making pops on the choke chain look like routine training practice.
Both the negative- and the positive-reinforcement training methods are effective. Both methods work quickly with very similar retention rates. Negative reinforcement, however, does nothing to build the human-canine bond. The dog is not completing the tasks because he wants to please you but because he doesn't want to suffer pain. The German shepherd breed instinctually wants to please his handler. When you use negative reinforcement, you deprive the dog of this enjoyment.
As you can imagine, in competitions in which a dog's joyful, enthusiastic performance is required to pass, place, or win, the shepherd that has been trained using primarily positive reinforcements has a far better chance than the dog that is trained using pain avoidance methods.
There are a couple of words in the dog-training vernacular that you should know. A primary reinforcer is the ultimate or end reward for the dog. For your shepherd, this might be physical praise (a brisk rubbing), treats, or play (tugging on a towel or chasing a tennis ball).
Secondary or Conditioned Reinforcers
A secondary reinforcer is the signal to the shepherd that he did something correctly and that he's going to be rewarded very soon with his favorite primary reinforcer. The most commonly used secondary reinforcer is a short, verbal praise, such as “Yes!” When the shepherd hears “Yes!” he knows he performed the desired behavior correctly. Having received his favorite primary reinforcer immediately after hearing “Yes!” he has been conditioned to anticipate that the primary reinforcer is coming.
Other commonly used secondary reinforcers are a click from a clicker, a toot on a whistle, or a clucking noise. Handlers who are already holding things in their hands and those who lack confidence in their coordination will use a verbal sound or word instead of an item.
What you use as your secondary reinforcer is a matter of personal choice; it depends on your preference and the kinds of training you might be doing with your shepherd. Handlers involved in more advanced sports where complex actions are performed at a distance frequently use clickers, whistles, or other items that can be heard easily. If a shepherd is to be handled by multiple family members, a clicker is often used because it always sounds the same and is consistent no matter what the age or vocal range of the trainer.