The use of even mild punishments in training can make dogs more stressed and more pessimistic compared to dogs who are trained with positive reinforcement-based methods. That’s an important conclusion of a study by Ana Catarina Vieira de Castro of Porto, Portugal and her colleagues. They recently published Does training method matter? Evidence for the negative impact of aversive-based methods on companion dog welfare.
The importance of this study is that it addresses a common question: If dogs can learn from both positive training methods and from those that use punishment, does the choice of method matter? The recent research offers a compelling answer to this question because the effects of training methods extend far beyond the actual skills learned.
To compare the effects on dogs trained with different techniques, researchers recruited 92 dogs—42 dogs from three training centers that used play and treats to encourage desirable behavior and 50 dogs from four training centers that trained by yelling, leash jerks and forcing dogs into positions such as sitting. Videotapes of training sessions revealed that the dogs who were punished and forced into behavior showed more signs of stress during training then dogs who were trained with positive methods. The behaviors compared included standard measure of stress such as lip licking, yawning and panting.
Dogs who were trained with aversive methods were also more frequently in an overall tense state than dogs trained positively. Aversive training methods were associated with more yelping, crouching, and lying on the side or back. Additionally, the dogs receiving punishment during training had higher levels of cortisol (a common measure of stress) than they did at home. The dogs trained positively showed no differences in cortisol levels compared to when they were at home.
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In another part of the study, researchers found that the effects on the dogs extended beyond the training session and had an effect on their general outlook on life. Specifically, the dogs who experienced punishment during training were more pessimistic than the dogs who did not. To study that aspect of the dogs’ experience, researchers investigated how 79 of these dogs responded to the potential of a food reward. The dogs were taught that bowls on one side of a room had sausage while bowls on the other side of the room were empty. Then, researchers placed bowls in locations between the two spots and measured how quick each dog was to approach the bowl with unknown contents. Optimistic dogs raced right over the bowl while pessimistic dogs approached more slowly. The more punishment dogs had faced, the more pessimistic they were.
Previous work on the effects of aversive methods have focused on shock collars and working dogs. Though such studies concluded that positive punishment is damaging to dogs, this new study addressed more mild forms of aversives such as yelling and jerking on the leash, and was done on family dogs. That’s important because many people who would never dream of training their dogs with shock collars (which have been banned in some countries) are nevertheless using negative consequences to train their dogs. This study supports the idea that dogs are harmed even with the use of less extreme methods, and offers compelling evidence that the use of punishment in training is a problem for canine welfare.