Gazing deeply into your dog’s eyes unleashes chemical attraction

View the videos

Dogs and people have true chemistry. When staring deeply into each other’s eyes, each species experiences a rush of the cuddle-chemical oxytocin.

In an experiment, people shared long mutual gazes with their beloved dogs, sometimes lasting more than a minute. Afterward, concentrations of oxytocin that the dogs released in their urine at least doubled from pretest levels, researchers in Japan report in the April 17 Science.  And dosing dogs with extra oxytocin lengthened the time that some dogs stared into their owners’ eyes.

Earlier work found an oxytocin rush in people, too, as they melted into the deep gaze of their dogs. The new results demonstrate the existence of a return swoop of this emotional feedback loop: A comparable canine oxytocin rush leads to even more gazing between humans and their pets.

Other studies have linked oxytocin surges with lingering eye-to-eye communing between human moms and babies. And oxytocin shows up in the chemistry of social bonding — parent to offspring or mate to mate — in a variety of other species. Dogs therefore might have won their place in the hearts of humankind by co-opting the physiology of human bonding, says coauthor Miho Nagasawa of Azabu University in Sagamihara, Japan. 

For this study, 28 dogs, a mix of breeds and sexes, and their human companions participated in the basic gaze test. Researchers instructed the people to sit in a chair and watch their dog. They could return gazes or nuzzles but not romp. (Physical play could confuse the oxytocin results.)

Nine of the dogs and their people fell into prolonged bouts of looking into each other’s eyes; the others just gazed briefly at their owners in between restlessly walking around, trying to play, and flopping on the floor. Neither the quick-gazer dogs nor their humans showed much change in oxytocin concentrations, so the researchers concluded that eye-lock duration matters. Five hand-raised wolves tested with their people didn’t share lingering looks at all. These pairs also did not experience oxytocin surges.  

In a second test, researchers squirted oxytocin up the noses of dogs, and added two human strangers to the room along with the dog’s familiar owner. Female dogs paid more attention to their owners than to the strangers, and tended to extend their soulful gazes. Thus natural upticks in oxytocin can intensify dog gazing, which in turn pushes the dog owners toward more gazing and emotional melting. Cross-species gazes feed on themselves, building a social bond that probably evolved during domestication, the researchers conclude.

Other dog researchers welcome the simultaneous information on both sides of dog and human encounters. But how mutual gazing might have fit in to the domestication of dogs, separating them from their wolfish ancestors, isn’t so clear, the scientists say.  

The study doesn’t say what might happen if wolves actually had looked into the eyes of their owners, notes Clive Wynne of Arizona State University in Tempe. And the socialization of the dogs and wolves in the study wasn’t comparable, making it difficult to draw broad conclusions, says Zsófia Virányi of the University of Vienna’s Clever Dog Lab and Wolf Science Center. Dogs and wolves with similar lives can perform similarly in tests of such skills as following human gazes or interpreting human gestures.