Let me start by saying that this article is not meant to supply a moral judgment as to the humane or inhumane nature of positive punishment, it is only meant to explain what it is, how it works and how it can have unexpected side effects.
In terms of psychology of the dog and how it pertains to training, positive punishment means something is added to make a behavior decrease. Sounds pretty simple but there are many variables including the emotional makeup of the dog, the intensity of the punishment, level of reinforcer for bad behavior and how well timed the punishment is. In the simplest form, in order for a punishment to be effective, it must be well timed and be stronger than the level of reinforcement the dog feels when performing the undesirable behavior. If the punishment is ill timed or not strong enough, the dog will continue the same behavior. Examples of positive punishment are leash yanks, yelling at the dog, hitting the dog, shocking the dog with a collar, etc.
Many fully positive reinforcement trainers will say that positive punishment does not work. This is not true, positive punishment works quite well, even when delivered by a plant. Anyone who has had a run in with stinging nettles, poison oak, poison ivy or any number of thorned or spiked plants can attest to the power of positive punishment.
With positive punishment, timing has to be impeccable, otherwise the dog may associate the punishment to something unintended. In human terms, lets say you had never seen a bee before and were stung by one, if the pain was immediate, you would easily connect the pain to the bee and avoid them in the future. If instead, you didn’t feel anything immediately, but seconds later when the bee was long gone, you felt a stinging sensation just as you brushed against a bush, how likely would you be to connect the sensation to the bee? How likely would you be to connect it to the bush? Without prior knowledge of the insect, you would be much more likely to connect the punishment to the bush rather than the bee. Your behavior toward the bee would be unchanged; however, you would probably immediately develop a fear towards any and all bushes of similar appearance.
There are also emotional considerations. Dogs are individuals and as such, react to things on different levels. Some dogs accept mild to moderate positive punishment with little to no negative affects while others can be deeply damaged by it. You must be able to temper the level of your punishment not only to the reinforcement level of the unwanted behavior, but also to the emotional strength and temperament of the dog.
The first picture in this article gives a very clear indication of the effects positive punishment can have when administered harshly and by someone uneducated in techniques and ramifications. This woman is poised to strike her dog who is cowering in the corner. Though we have no idea the context of this punishment, we can make an educated guess that since this is a puppy, it has to do with soiling in the house. This punishment is ill timed since it is well after the fact and is absolutely not going to stop the soiling in the house, in fact, it can have a completely opposite affect where the dog soils more out of anxiety or fear. At best this punishment will teach the dog not to soil in front of the owner, at worst, it will teach the dog distrust or fear the owner. This association can create a timid, fearful, extremely submissive or even aggressively defensive dog when in the owner’s presence, especially if the owner is in this posture. Further, it can create a dog that will react in the same manner to anyone that attains anything even similar to this posture, such as someone getting ready to throw a ball.
Positive punishment is an extremely powerful tool of learning which is much more complex than the normal dog owner realizes. There are multiple schools of thought as to its positive and negative aspects. This article only scratches the surface and I suggest before you decide to use any level of positive punishment in training your dog, you educate yourself on all aspects involved in using it.