The Power of Discourse: Associations between Trainers’ Speech and the Responses of Socialized Wolves and Dogs to Training

SIMPLE SUMMARY: In a previous study, we found that Positive Reinforcement Training promoted relaxation in wolves and dogs. Here, we investigate aspects of the trainers’ voices possibly involved in this effect. Dogs’ great interest in high-pitched, intense speech has already been reported, but whether and how wolves respond similarly/differently to voice characteristics has never been studied. We analyzed 270 training sessions with nine mixed-breed dogs and nine wolves. We grouped human speech into three categories: nice, neutral, and reprehensive, and analyzed how their duration and their acoustic characteristics within training sessions were associated with animals’ behavior and physiology. The longer the duration of nice speech during a session, the more often tail wagging was observed in both subspecies, while the opposite was found for reprehensive speech. The duration of reprehensive speech was also associated with a decrease in correct responses in dogs and with retreating in wolves, while a longer use of nice speech was associated with animals being next to the trainer for longer within a session. Sessions with a higher average pitch was more often associated to changes in dog behavior, while wolf behavior changes were more often associated to low intonations. Our results suggest that a friendly voice during training supports performance and positive emotional responses in wolves and dogs. The different response towards the pitch between the subspecies may be related to the domestication process, which selected, in dogs, characteristics that facilitate interaction with humans. ABSTRACT: In a previous study, we found that Positive Reinforcement Training reduced cortisol of wolves and dogs; however, this effect varied across trainer–animal dyads. Here we investigate whether and how the trainers’ use of speech may contribute to this effect. Dogs’ great interest in high-pitched, intense speech (also known as Dog Directed Speech) has already been reported, but whether and how wolves respond similarly/differently to voice characteristics has never been studied before. We analyzed 270 training sessions, conducted by five trainers, with nine mixed-breed dogs and nine wolves, all human-socialized. Through Generalized Linear Mixed Models, we analyzed the effects of (a) three speech categories (nice, neutral, reprehensive) and laugh; and (b) acoustic characteristics of trainers’ voices on animals’ responses (correct responses, latency, orientation, time at less than 1 m, non-training behaviors, tail position/movements, cortisol variation). In both subspecies, tail wagging occurred more often in sessions with longer durations of nice speech, and less often in sessions with reprehensive speech. For dogs, the duration of reprehensive speech within a session was also negatively related to correct responses. For wolves, retreat time was associated with more reprehensive speech, whereas duration of nice speech was positively associated with time spent within one meter from the trainer. In addition, most dog behavioral responses were associated with higher average intonations within sessions, while wolf responses were correlated with lower intonations within sessions. We did not find any effects of the variables considered on cortisol variation. Our study highlights the relevance of voice tone and speech in a training context on animals’ performances and emotional reactions.