The first evidence that the hormone oxytocin has a direct effect on the social interactions of dogs with dogs and their owners has been shown by researchers in Japan. Teresa Romero from the University of Tokyo in Tokyo, Japan and colleagues are the first to demonstrate a social aspect of oxytocin that is extraneous to sexual behavior or parenting behaviors. The research was published in the June 9, 2014, edition of the journal Proceedings of the National Academy of Sciences.
The researchers examined the effect of oxytocin by spraying dogs with a mist containing the hormone applied through the dog’s noses. A saline solution served as a placebo. The dogs that received oxytocin were observed to initiate and maintain social encounters with other dogs faster and longer than dogs that received saline. Dogs that received oxytocin also initiated interactions with their owners more readily even though the owners had been instructed to ignore the dog.
The scientists measured the blood and urine levels of oxytocin before and after the dogs received oxytocin. The sampling was done at five minute intervals for 90 minutes. The effect of external oxytocin was almost immediate and increased to a maximum at 15 minutes after the external oxytocin was introduced to each dog. This time frame correlates well with the time frame of maximal interaction between the dogs and other dogs and with the dog’s owners.
Dogs that had an initial high level of oxytocin in their blood were observed to be more social with other dogs and humans at a faster rate. Dogs with lower natural levels of oxytocin responded slower. The introduction of an external oxytocin stimulus produced higher levels of production of natural oxytocin in all dogs. This is the first research that shows that oxytocin has a behavioral effect on animals that are social beyond parenting or sexual behaviors. The effect can be extrapolated to humans.