The latest piece of I-told-you-so was published in the journal Science and revealed ways in which humans and dogs bond with each other by looking into each other’s eyes. Japanese animal behaviourists (Nagasawa et al of Azabu University published here) found that interaction between dogs and their owners, especially by eye contact, raises levels of oxytocin in both the human and dog brains. Oxytocin is a very powerful hormone commonly referred to as the ‘love hormone’ since when we hug or kiss a loved one, the levels of oxytocin go up. And when the hormone elicits this caring behaviour, then the levels go even higher causing a looping effect. Because of this effect, it is said to play a big role in pair bonding.
Although it had already been found that oxytocin bonding occurs in other mammals, too, (interesting fact –Prairie voles, one of nature's most monogamous species, produce tons and tons of oxytocin) humans were thought to be unique in using eye contact as part of this cycle. But now it has been shown that domesticated dogs and humans share the same effect. When the research team tested hand-reared wolves (which tend to be undomesticated), they found no such effect, and wolves spent little time gazing into their owners' eyes.
The study is surprising to many who work on animal behaviour, as eye contact, especially staring or gazing, is typically viewed as threatening. However, a gaze shared between a dog and their human owner produces quite different results than one between two dogs. The team suggested that early domesticated dogs began unknowingly and unintentionally utilizing a mechanism meant for bonding a human parent with their child. Because those ancestor dogs benefited from the behaviour, the trait was passed on.
If, like us, you tend to humanize your dogs, this piece of research gets even more scary. They found that that if they 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. So your girl dog really does look at Mum or Dad more longingly! Our Sarah will never go over that piece of research.
There is a sweet little video from New Scientist on YouTube here which describes what we already knew.
A study in 2012 showed that, in humans, giving a massage also helps to raise oxytocin levels (http://www.ncbi.nlm.nih.gov/pubmed/23251939). So for the perfect double bond, giving your dog a massage and gazing lovingly into their eyes (probably not both at the same time as that could make for an awkward massage technique) the bond will be strengthened even more. We have actually noticed that often, when one of us massages Sam or Sarah, they frequently gaze at the other of us. Clever dogs! They get one oxytocin boost from the massaging Dad and another from the other Dad.