Summary: Using aversive stimuli and punishments to train dogs leads to increased stress and anxiety in the animals.
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 publishing December 16 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.”
Funding: The current research study was supported by FCT – Fundação Portuguesa para a Ciência e Tecnologia (Fellowship SFRH/BPD/111509/2015) and UFAW – Universities Federation for Animal Welfare (Grant 14-16/17), with grants awarded to ACVC. SP was supported by PIPOL – Regione Friuli Venezia Giulia. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. FCT – Fundação Portuguesa para a Ciência e Tecnologia: https://www.fct.pt/index.phtml.pt UFAW – Universities Federation for Animal Welfare: https://www.ufaw.org.uk/.
Does training method matter? Evidence for the negative impact of aversive-based methods on companion dog welfare
Dog training methods range broadly from those using mostly positive punishment and negative reinforcement (aversive-based) to those using primarily positive reinforcement (reward-based). Although aversive-based training has been strongly criticized for negatively affecting dog welfare, there is no comprehensive research focusing on companion dogs and mainstream techniques, and most studies rely on owner-reported assessment of training methods and dog behavior. The aim of the present study was to evaluate the effects of aversive- and reward-based training methods on companion dog welfare within and outside the training context. Ninety-two companion dogs were recruited from three reward-based schools (Group Reward, n = 42), and from four aversive-based schools, two using low proportions of aversive-based methods (Group Mixed, n = 22) and two using high proportions of aversive-based methods (Group Aversive, n = 28). For evaluating welfare during training, dogs were video recorded for three sessions and six saliva samples were collected, three at home (baseline levels) and three after training (post-training levels). Video recordings were used to examine the frequency of stress-related behaviors (e.g., lip lick, yawn) and the overall behavioral state of the dog (e.g., tense, relaxed), and saliva samples were analyzed for cortisol concentration. For evaluating welfare outside the training context, dogs participated in a cognitive bias task. Results showed that dogs from Group Aversive displayed more stress-related behaviors, were more frequently in tense and low behavioral states and panted more during training, and exhibited higher post-training increases in cortisol levels than dogs from Group Reward. Additionally, dogs from Group Aversive were more ‘pessimistic’ in the cognitive bias task than dogs from Group Reward. Dogs from Group Mixed displayed more stress-related behaviors, were more frequently in tense states and panted more during training than dogs from Group Reward. Finally, although Groups Mixed and Aversive did not differ in their performance in the cognitive bias task nor in cortisol levels, the former displayed more stress-related behaviors and was more frequently in tense and low behavioral states. These findings indicate that aversive-based training methods, especially if used in high proportions, compromise the welfare of companion dogs both within and outside the training context.