The Role of Oxytocin in the Dog–Owner Relationship

Abstract

Simple SummaryA number of studies have shown that when dogs and humans interact with each other in a positive way (for example cuddling) both partners exhibit a surge in oxytocin, a hormone which has been linked to positive emotional states. It is not clear however, if this increase in oxytocin occurs between any dog and human or whether this is more specific to the dog–owner bond. In this study we measured oxytocin levels in dogs and humans before and after they interacted with their closely bonded partner (dog–owner dyads) and with a partner they were familiar with but with whom they did not have a close bond. Based on previous literature we predicted that dogs and owners would show an increase in oxytocin after a positive social interaction, and that this increase would be higher when the dog and owner were interacting with each other than when the interaction occurred with a partner that was just ‘familiar’. In fact, overall we did not find an increase in either, dogs’ or humans’ oxytocin level, although there was a lot of variability in the response. We discuss various reasons why our results are not in line with other studies.AbstractOxytocin (OT) is involved in multiple social bonds, from attachment between parents and offspring to “friendships”. Dogs are an interesting species in which to investigate the link between the oxytocinergic system and social bonds since they establish preferential bonds with their own species but also with humans. Studies have shown that the oxytocinergic system may be involved in the regulation of such inter-specific relationships, with both dogs and their owners showing an increase in OT levels following socio-positive interactions. However, no direct comparison has been made in dogs’ OT reactivity following a social interaction with the owner vs. a familiar (but not bonded) person, so it is unclear whether relationship type mediates OT release during socio-positive interactions or whether the interaction per se is sufficient. Here we investigated OT reactivity in both dogs and owners, following a socio-positive interaction with each other or a familiar partner. Results showed neither the familiarity with the partner, nor the type of interaction affected OT reactivity (as measured in urine) in either dogs or owners. Given the recent mixed results on the role of oxytocin in dog-human interactions, we suggest there is a need for greater standardization of methodologies, an assessment of overall results taking into account ‘publication bias’ issues, and further studies investigating the role of relationship quality and interaction type on OT release.

Variability in Human-Animal Interaction Research

“…Other studies have found that dogs' variation in their oxytocin receptor gene is related to certain breeds of dogs' social behavior when greeting unfamiliar people ( 77 , 78 ) as well as dogs' attachment behaviors directed to their owners ( 50 ). As the oxytocin pathway has been discussed as a potential mechanism underlying positive human-dog interactions ( 79 , 80 ), these individual differences across dogs may be important for understanding variability across studies.…”

Dogs Supporting Human Health and Well-Being: A Biopsychosocial Approach

“…Oxytocin not only buffers the stress response and cortisol secretion ( 68 ) but is also involved emotion, trust, and bonding ( 69 ). The oxytocin system has been hypothesized to be a primary mechanistic pathway involved in human-dog interactions ( 70 ). Positive dog-owner interactions including stroking, petting, and talking have been shown to result in increased oxytocin levels in both dog owners and dogs, which has been related to the strength of the owner-dog relationship ( 71 ) and dog-human affiliative behaviors ( 72 , 73 ).…”

Effects of Stroking on Salivary Oxytocin and Cortisol in Guide Dogs: Preliminary Results

“…In dogs, OXT has become a biomarker commonly investigated in behavioral and neuroendocrinological research, but, in contrast to the investigation on serotoninergic system, commonly associated with aggressive behavior [19], the oxytocinergic system has been frequently linked to sociopositive human-dog interaction [20]. Actually, the behavioral effects of oxytocin in dogs are mainly based on three macro-areas: the effect of human-dog social interaction on peripheral oxytocin levels, the associations between the polymorphisms in oxytocin receptor gene and social behavior, and the effect of exogenous oxytocin administration on dogs' social behavior [21].…”