When you look at it, your brain is in a series of complex change: gazing makes your brain secrets a large amount of oxytocin that makes you get closer. At the same time, the oxytocin in its brain is increasing, making the same impact…
“It”I mention here is dog. Journal“Science”has published a study in recent year, that points out that gazing behavior between owners and dogs produce a positive feedback of oxytocin secretion, which makes dogs become human’s best friends. Wolves, who rarely engage in eye contact with their human handlers, seem resistant to this effect. Hence, oxytocin not only become the connection of people’s love, but also produce the love over species.
What is oxytocin?
In 1906, the renowned British physiologist Sir Henry H Dale discovered a type of hormone facilitating uterine contractions. He named it “oxytocin”. In 1909, the clinical potential of Dale’s seminal findings on oxytocin was realized by the celebrated British obstetrician and gynecologist William Blair Bell. Bell claimed that oxytocin could not only rapidly facilitated uterine contractions to assist in fetal delivery, but also prevented postpartum hemorrhage, and provided considerable relief for male and female patients suffering from severe constipation. In the early 1950s, American biochemist Vincent du Vigneaud identified the nine-amino acid sequence of oxytocin, and synthesized this polypeptide hormone for the first time. This work represented the first characterization and synthesis of a neuropeptide and resulted in a Nobel Prize in Chemistry for du Vigneaud in 1955. (More details about oxytocin in http://jop.sagepub.com/content/27/3/231.full)
Oxytocin is normally produced by the paraventricular nucleus of the hypothalamus and released by the posterior pituitary. Both male and female can secrete oxytocin. After releasing, a part of oxytocin reaches periphery tissue through blood circulation, and the rest passing hemato encephalic barrier, enters the central nervous system and functions as a neurotransmitter.
Oxytocin’s functions
Oxytocin influence several aspects of individual behaviors. The studies in early stage mostly focus on its impact of maternal behavior. A study shows that there is a positive correlation between oxytocin throughout pregnancy and maternal-fetal attachment. In other words, if mother has high levels of oxytocin, she would do more intimate behaviors, such as hug. Besides this, oxytocin affects couple relationship. Because the couples who absorb oxytocin have less conflicts and more positive communications. Additionally, previous studies have shown oxytocin increases trust among people.
It is very interesting that oxytocin can also affect some animals. 
Microtus ochrogaster release oxytocin that stimulates dopamine during mating, so they can maintain monogamy. However, microtus montanus, which has similar genes with microtus orhrogaster, doesn’t release oxytocin and dopamine, so this species maintains group marriage.
Then we go back to the study at Azabu University in Sagamihara, Japan, which was published in “Science”. The result finds that gazing from pet dogs made high levels of oxytocin contents in owner’s urine samples, and vice versa. Therefore, the relationship between owners and pet dogs becomes closer and closer. This positive feedback loop, he says, may have played a critical role in dog domestication. In this study, the dogs were males and females, spayed, neutered and intact. The breeds included Golden retrievers, standard poodles, miniature Dachshunds, miniature Schnauzers, a Jack Russell Terrier, and two mixed breed. So the samples are very representative. And I think the conclusion is convincing.
So that human and dogs become good friend is not a coincidence. What’s more, in my opinion, my dog is as my “fur baby”, do you?
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