Hormonal Synchronization of Cortisol Levels and Emotional Contagion Between Human Owners and Agility Dog

Research has produced evidence of affective empathy between humans and pet dogs, indicating that dogs can respond to human emotions through an unconscious process. Based on previous literature, one of the mechanisms for emotional contagion is likely chemosensory cues. The present study examines emotional contagion (transference of emotional state between individuals) with human owners and agility dogs. Methodology involved measuring cortisol levels of both humans and dogs at agility competitions, a canine sport where handlers guide dogs through an obstacle course. In a home environment researchers also exposed dogs to sweat samples obtained from owners during the competition and collected subsequent cortisol responses from the dogs as an estimate of stress levels. Dogs also completed memory tasks requiring them to recall the location of a hidden object. Behavioral and physiological responses were measured in A) a pretrial condition (no sample presented), B) a control condition (after dogs were exposed samples obtained from owners during nonstressful activity), and C) after the dogs were exposed to the owners' experimental samples (collected during agility competition). Results from the first phase of the study indicated that humans' cortisol levels were predictive of dogs' cortisol levels in neutered male dogs. In the second part of the study, it was shown that dogs that had better synchronization with their owners at the agility competition experienced increases in heart rate in the experimental condition while dogs who had not previously synchronized with their owners did not. Cortisol responses again seemed to be mediated by sex with females experiencing decreases in cortisol during the experimental condition and males experiencing increases in cortisol. Task performance as assessed by latency provided no conclusive evidence of cognitive repercussions for the observed physiological responses with no differences between the control and experimental conditions. Overall this research provides evidence of synchronization but emphasizes the importance of sex differences and within group variability (potentially explained by attachment-related measures) among dogs and suggests a need for more comprehensive hormone analysis.