SCIENTISTS have decoded the special chemistry between humans and dogs, discovering that the so-called “love hormone” also works on man’s best friend.
Japanese researchers have found that dogs sprayed with oxytocin become more affectionate, with both each other and humans.
The findings suggest that the effects of oxytocin — known as the “monogamy hormone”, “cuddle chemical” and “trust-me drug”, among other nicknames — are not limited to members of the same species, let alone intimate couples.
Oxytocin may be the key neurological ingredient in the close social bonds that exist “beyond immediate reproductive interest”, the researchers report today in the journal Proceedings of the National Academy of Sciences.
Oxytocin has been at the centre of research into the biology of love. It is released during sex, and high levels of the hormone have been measured in new couples. Oxytocin production is also stimulated by labour and breastfeeding, and synthetic versions are used to induce birth and reduce post-natal bleeding.
Scientists suspect it plays a broader role in social behaviour by contributing to relaxation, trust and psychological stability, with some researchers investigating it as a treatment for autism and schizophrenia. The latest study goes further, suggesting it is the neurological underpinning of “cooperative associations between individuals from different species”.
The researchers say oxytocin triggers social behaviour which stimulates the brain to produce more oxytocin — a “positive feedback loop” which may explain how the special bond between humans and dogs evolved in the first place.
“That positive feedback … facilitates repeated interactions with individuals with whom positive interactions have already occurred,” they say.
The findings could explain how the bond between people and dogs became entrenched after wolves were domesticated up to 33,000 years ago, producing one of the few animals “able to establish close bonding and attachment with people”.
“Our findings suggest that oxytocin might be an important mechanism that allowed the evolution of enduring cooperative bonds between related and unrelated individuals,” the report says.