We shower them with affection and provide all their necessities. They love and protect us in return--even run to our side when we call and cuddle on command.
This strong bond between dogs and humans has existed for more than 10,000 years. But exactly how, and why, did the human-canine connection evolve to become so close? A new study from Australia suggests a clue to the answer could be oxytocin, the so-called love hormone, found to increase trust in humans and help mothers and babies bond.
"This study tells us that the neuropeptide oxytocin is involved in the ability of dogs to use human social cues such as pointing, to their advantage i.e. to find hidden food," Jessica Oliva, a graduate student in biology at Monash University in Melbourne and the study's lead author, told The Huffington Post in an email. "It is likely that this inter-species bonding and inter-species communication go hand-in-hand, thanks to oxytocin."
Got that? Oxytocin, which is released in the brain in response to intimate contact like petting or cuddling, may help dogs pay closer attention to humans -- and thus enhance their relationship with us.
The oxytocin oomph. For the study, 62 male and female pet dogs were encouraged via hand signals to find a food treat hidden in one of two bowls. The dogs were tested twice--once after being given a nasal spray of oxytocin and again after given an inactive nasal spray containing just salt water. Each dog was then rated on his/her ability to follow the cues to get the treat.
What did the researchers find? The dogs performed better after receiving the oxytocin, and the performance boost persisted for up to 15 days after the oxytocin was given. The fact that dogs did better after receiving a squirt of oxytocin suggests that the hormone enhances their ability to attend to human social cues. That suggests that oxytocin played a key role in the domestication of dogs--which outperform wolves in their ability to respond to human social cues.
The bonding brain. What do other scientists make of the study? Dr. Paul Zak, a professor of neurology at Loma Linda University in California, told ABC News that the findings were interesting but said he hoped the researchers would look at receptors in the dogs' brain and measure the actual oxytocin levels in their system.
After all, oxytocin "is one of the many signals in the brain that motivates social behaviors," he said. "The brain is much more complicated than one chemical."
The study was published in the February 2015 edition of the journal Animal Cognition.
For more on the untold story of dogs' domestication, check out the "Talk Nerdy To Me" video below.