Because so many military trainers were now available, society accepted punishment as a proven method of training dogs. The idea of now training the family dog through this method caught on quickly. The door for compulsion training was opened by our society's acceptance that learning is done through punishment.
The American Kennel Club (AKC) introduced obedience training in the late 1930s in the United States, using compulsion training for competition dogs.
The release of military trainers after the Korean War (1950s) and the Police Action of Vietnam (1960s) brought about the wide use of physical punishment and choke chains.
As people began training their dogs themselves with help from new books and television in the 1970s, harsh training methods began to take a turn. Even though operant conditioning research was done in the late 1800s, it did not come into use by the masses until the 1990s, in the form of clicker training. As trainers started noticing the positive effects of this new method, they began to change their ideas. Although operant conditioning uses negative reinforcement, negative punishment, and positive punishment, the main component of this training is positive reinforcement. Using positive reinforcement training can produce greater results in a wide variety of dogs.