The Bonding Hormone
Dogs carry the illustrious title of Man’s Best Friend. This has been the case for hundreds of years, but why? And do they really deserve such a highly regarded label.
Is the relationship we have with our pet dogs really a special mutual bond? Many believe that it is just a simple, practical codependency that was created thousands of years ago and stuck.
The Science of It
For decades science has dismissed dogs as being unworthy of valuable study, however, that is now changing. With the recognition of the extraordinary bond that exists between dogs and humans, science is finally asking why are dogs so advanced at reading human emotions. What makes them so attuned to us in a way that no other animal is, not even chimpanzees?
Studies being carried out have found that when we interact with our canine pals, especially mutual eye gazing and touch, we activate a hormone. This hormonal response is the same chemical that is released when we bond with our human offspring.
Professor Kerstin Uvnäs Moberg at Swedish University of Agricultural Sciences studies the hormone Oxytocin and the positive feelings it produces. This bio-chemical strengthens the process of attachment that makes a bond so much more than just simply liking.
When a mother breastfeeds and stares into the eyes of her baby, the baby’s oxytocin levels rise. As the baby feeds and stares back the mother releases oxytocin in response. This positive feedback loop creates a strong emotional bond between mother and child.
The belief is that this same process is at work when we pet, play and gaze into the eyes of our pet dogs.
So the Scientists started studies...
Professor Moberg ran experiments measuring oxytocin levels before and after petting. He saw oxytocin levels in both the dogs and their human owners increase during this time. A graph showing the peaks in the oxytocin levels was similar to that of a mother and her newborn baby during breastfeeding.
Animal Behaviourist, Takefumi Kikusui at Azabu University in Sagamihara, Japan and his lab specifically study the effect of oxytocin in humans and another species. Oxytocin is a hormone that plays a powerful role not only in the bonding process, but is also been heavily linked to trust.
Kikusui and his team led a study involving experiments with both dogs and wolves. Around 30 dogs and their owners were involved in the study. Kikusui himself was one of the participants with his two standard poodles. The researchers were even able to find people raising wolves as pets and reached out to ask if they would contribute to the research.
To conduct the experiment the scientists took urine samples from both the dogs, wolves and their owners both before and after 30 minutes of interaction.
What the studies revealed...
The interactions varied between the pairs. The scientists observed rough play, petting, mind stimulation, talking and varying levels of eye contact. Although, the owners with wolves had little-to-no eye contact. Unsurprisingly really, as it is often interpreted as hostility in the wild.
Interestingly, they found that those making the most eye contact saw levels of oxytocin increase the highest. Those with barely any mutual eye gazing were at the lower end of the scale. These results can help explain why dogs are so tightly connected to us.
Domesticated dogs have learnt that eye contact in particular seems to provide information on a human’s readiness to communicate. They tend, in a home environment, to be more willing to look into our eyes in a way they that they would not do with each other, or any other animal.
As we know that Oxytocin is released with eye contact. This behaviour also adds to that increased level of a chemical that strengthens bonding. Dogs have evolved to look at our eyes in a way that is not yet seen or proven with any other species.
A remarkable evolution
To add to this remarkable disparity in eye contact, dogs also seem to have what is known as Left Gaze Bias. This is a way of reading facial expressions, that as far as we know only humans display signs of. The theory is that our emotions are more accurately represented by on the right side of our face. People will instinctively nearly always look to the left first.
Daniel Mills is the UK's first Professor of Veterinary Behavioural Medicine based at the University of Lincoln, UK. He demonstrated this in a study by projecting images onto a screen and recording each dogs eye responses. The images varied between human faces, the faces of dogs and inanimate objects.
When the recordings were played back in slow motion it was clear to see that when each dog saw a human face their eyes instinctively looked to the left. When each dog was shown either a face of a dog or an everyday object their response were random. Sometimes they looked away entirely.
This experiment shows the level at which dogs are attuned to our facial expression and more importantly the amount of communication and emotion that we express with our eyes.
When you combine these two impressive idiosyncrasies it becomes clearly as to why and how dogs have become Man’s Best Friend.