When it comes to the interaction between species, few critters are as good at connecting with each other as humans and dogs.
Dogs are more skillful than wolves and chimpanzees at using human social communicative behaviours. A new study from researchers in Japan show that dogs are able to use mutual gaze as a communication tool and they learned how to do that from humans through domestication.
The scientists now know that gazing behaviour from dogs, but not wolves, increased urinary oxytocin concentrations in owners, which consequently facilitated owners’ affiliation and increased oxytocin concentration in dogs.
Further, nasally administered oxytocin increased gazing behavior in dogs, which in turn increased urinary oxytocin concentrations in owners.
These findings support the existence of an interspecies oxytocin-mediated positive loop facilitated and modulated by gazing, which may have supported the coevolution of human-dog bonding by engaging common modes of communicating social attachment.
Humans bond emotionally as we gaze into each other’s eyes—a process mediated by the hormone oxytocin. Stare into someone’s eyes and if there is a connection the hormone is released. Ocytocin is sometimes called the “love hormone” because when released, it creates attentive, caring behviour–what some have called the maternal instinct. The more the feeling is there, the more ocytocin is released and the cycle repeats itself.
Dogs have learned how to use what was once only shared between humans to ensure that we love them as much as we do. We know that oxytocin bonding occurs between other mammals. Critterfiles.com wrote last year about how when chimpanzees share meals together they release more oxytocin.
Researchers at the University of Japan had dog owners and their dogs gaze into each other’s eyes. What they found was that oxytocin levels rose both in the dogs and in humans.
Wolves, on the other hand, were also tested. These were the domesticated ones that have been hand-reared. And when wolves gazed into their owners’ eyes, no rise in oxytocin was detected.
They then sprayed either oxytocin or a placebo into 27 dogs’ noses, in a randomised experiment. Female dogs that received the hormone spent more time staring longingly at their owners, and oxytocin levels also rose in those people.
The conclusion? Gazing into a dog’s eyes or when dog’s gaze into people’s eyes, a positive loop is created.
Now dog owners know with certainty. Your dogs really love you–and really want you to give them a cookie.
http://www.sciencemag.org/content/348/6232/333.full
