Dogs tap into human bonding system to get close to our hearts

Ever felt hopelessly bonded to your pooch when it stares at you lovingly? It turns out that man's best friend may have hijacked a uniquely human bonding mechanism, ensuring that we love and care for it.

Knock-on chemical and behavioural effects occur when humans bond: eye contact leads to release of the "love hormone" oxytocin, which elicits caring behaviour, and this in turn causes the release of more oxytocin. This loop has been shown to be important for human bonding, for example between mothers and their children.

Oxytocin bonding occurs in other mammals, too, but humans were thought to be unique in using eye contact as part of this cycle. "Facing others is a threatening behaviour in other animals," says Miho Nagasawa at Azabu University in Japan.

But when she and her colleagues got a bunch of dog owners to gaze into their pets' eyes, they found that oxytocin levels rose not just in the humans – but in the pooches too.