To test a hypothesis about human-animal bonding, a study in Sweden measured the chemical responses dogs and people experienced when interacting with each other for short periods. The study was published in the journal Anthrozoos.
Ten women and their male dogs were observed interacting with each other (in pairs) for an hour, while blood samples and monitors measured their heart rates and levels of oxytocin (related to pleasure) and cortisol (related to stress) before and during the interaction. Ten other women, without dogs, were monitored for the same period. The results showed that both the women with dogs and the dogs themselves showed signs of pleasure and relaxation in ways that the women without dogs did not.
The benefits to humans of interactions with companion animals, both in general social and explicitly therapeutic settings, have been oversold largely because rigorous studies are difficult and costly. The use of physiological measures, such as the present one, is filling in the gap between hype and demonstrable effects. Oxytocin, in particular, has been found to have beneficial physiological effects. Associated with relaxation, these effects occur in both parties to the relationship: the dog being petted and the affectionate caregiver.
When my dog actively solicits stroking, pushing my arm toward her body, she is doing both of us a favor. This natural chemistry is a glue that knows no species boundaries. It implies the benefits of a companion animal in the home (including more than one nonhuman species in the home) and group housing in captive settings for individuals of the same or different species.
[The full study citation is Handlin, L., Hydbring-Sanberg, E., Ejdeback, M., Jansson, A., and Uvnas-Moberg, K. (2011). Short-term interaction between dogs and their owners: Effects on oxytocin, cortisol, insulin, and heart rate – An exploratory study. Anthrozoos, 24, 301-317.]
This research nutshell comes from Ken Shapiro at the Animals and Society Institute (ASI), an organization dedicated to policy-oriented research and human-animal studies. HRC and ASI already collaborate on multiple projects and we will work together to identify important studies for future research nutshells.