Dogs trained using aversive stimuli, which involve punishments for incorrect behavior, show evidence of higher stress levels compared to dogs trained with reward-based methods, according to a study published on December 16 2020 in the open-access journal PLOS ONE by Ana Catarina Vieira de Castro from the Universidade do Porto, Portugal, and colleagues.
The researchers observed the behavior of 92 companion dogs from 7 dog training schools in Portugal that use either aversive methods (which use mainly aversive stimuli), reward methods (which focus on rewarding desired behaviours), and mixed methods (which combine the use of both rewards and aversive stimuli). They filmed training sessions and tested saliva samples for the stress-related hormone cortisol. Dogs trained using aversive and mixed methods displayed more stress-related behaviors, such as crouching and yelping, and showed greater increases in cortisol levels after training than dogs trained with rewards.
The authors also conducted a cognitive bias test in an unfamiliar location outside of the dog’s usual training environment with 79 of the dogs, to measure their underlying emotional state. They found that dogs from schools using aversive methods responded more pessimistically to ambiguous situations compared with dogs receiving mixed- or reward-based training.
Previous survey-based studies and anecdotal evidence has suggested that punishment-based training techniques may reduce animal welfare, but the authors state that this study is the first systematic investigation of how different training methods influence welfare both during training and in other contexts. They say that these results suggest that aversive training techniques may compromise animal welfare, especially when used at high frequency.
The authors add: “This is the first large scale study of companion dogs in a real training setting, using the types of training methods typically applied in dog training schools and data collected by the research team. The results suggest that the use of aversive training methods, especially in high proportions, should be avoided because of their negative impact on dog welfare.”
Source: Science Daily
Journal reference: Ana Catarina Vieira de Castro, Danielle Fuchs, Gabriela Munhoz Morello, Stefania Pastur, Liliana de Sousa, I. Anna S. Olsson. Does training method matter? Evidence for the negative impact of aversive-based methods on companion dog welfare. PLOS ONE, 2020; 15 (12): e0225023 DOI: 10.1371/journal.pone.0225023
DoggyMom.com 
I wonder about how much anxiety in dogs can traced to the use of punishment in training. I have seen an experienced owner/ trainer use an ecollar with a dog rescued from a dog fighting ring and I respect his training and care of the dog but I have also seen people use them to try and fix behaviour issues quickly and it is a lazy, selfish thing to do. In the case of the rescued dog it has meant that she seemed to become a more content, confident and less likely to become aggressive with other dogs. In a way the decision to use such a method was based on saving the dog and it was a last resort. I know the owner spent weeks just preparing her for using such a collar. I wish access to these collars were restricted to only experienced and certified trainers. Sorry I do not want to justify the use of these collars but I have seen circumstances where the correct use has helped save a dog’s life. I guess because I have had close involvement with the kind of dogs who do end up in rescues and often end up with behavioural issues I have remained open minded but correction and punishment usually only makes matters worse.
I have had people suggest I use one with my super intense girl, who does have a mind of her own. I am proud of what we achieve training wise with positive only training. The only correction we have ever used is the use of a martingale collar when training and it has seemed to work as a guide in training. Ada is a confident, happy dog in virtually any situation, she may never be a star at obedience but I know that when she is obedient it is because she trusts me and works with me. I also know that in the wrong hands she could have been a very different dog. I have worked with older dogs that have had huge issues with anxiety which I believe has largely been the result of inappropriate treatment.
I sometimes wish you had to get a licence and pass a test before owning a dog.