Whenever the conversation turns toward the effect of various types of dog training methods on a pet dog’s behavior there seems to be a line drawn between two venues, one being “positive dog training” involving rewards of food and play; the other being “discipline-based training” which uses slip collars, leash tugs and other physical enforcement to produce compliance.  Actually, there are four methods used to teach dogs the kinds of behaviors that we desire they learn.  The first method is call “positive reinforcement” with the word “reinforcement” referring to anything that will increase the likelihood that the behavior will be repeated by the dog.  The term “positive” refers to giving the dog something he desires, like food.  The second method, “negative reinforcement” refers to taking away something unwanted or annoying such as pulling up on the leash causing a choke chain to tighten and pushing down on the dog’s hindquarters while telling him to sit.  The negative reinforcement results when the dog sits to relieve the pressure around his neck and lower back.  The next two methods involve punishment that reduces the likelihood that the behavior will be repeated by the dog.  If a dog does something we don’t want him to do, “positive punishment” is taking something the dog wants away from him.  While positive dog training is based on positive reinforcement, discipline-based training uses negative reinforcement and positive punishment combined.
Around the mid-1940’s, most dog training was discipline-based due to training models from military dog trainers but over time, positive dog training came to dominate the canine training scene.  However, over the past few years, discipline-based training has begun to gain in popularity due to high profile dog trainers like Cesar Millan.
Two French researchers wanted to test the effect of the two training styles by collecting data based on observation rather than changes in blood chemistry, heart rate or other invasive procedures.  After attending a number of dog training classes to observe the training procedures used, they selected one class which used positive dog training methods exclusively and contrasted it with another, mostly negative reinforcement dog training class.  There were 24 dogs’ trained using positive training and 26 using discipline-based methods and each dog and owner pair was tested on familiar exercises such as heeling and sitting on command.  The researchers measured the amount of stress the dogs showed when performing these learned exercises; behaviors associated with stress such as mouth licking, yawning, scratching, sniffing, shivering, whining, low posture, attempts to run away, and avoiding eye contact with their handler.
The results:  65% of discipline-based trained dogs showed at least one such sign compared to 8% in positive trained dogs, yawning – 23% discipline trained, 0% positive trained, and low posture – 46% discipline, 8% positive.  As for having a tendency to avoid eye contact, (avoid looking at things that make them uncomfortable), 38% of the discipline trained dogs looked at their owners face compared to 88% of the positively trained dogs.
This is a small study but it is one more to suggest that using punishment and negative reinforcement can produce harmful and unwanted emotional changes in dogs.