I've had some of the closest relationships in my life with dogs and cats — some of whom I grew up with and some I met as adults. While some might scoff or laugh at the phrasing or emotional content of the previous sentence, it doesn't change the way I feel, and I'm not afraid to admit it (in fact, my relationships with those animals are at the heart of my vegetarianism; I realized at an early age that if I couldn't eat my dog or cat because I knew them, I couldn't eat a cow or pig because I didn't.) 

A growing number of people are unafraid of expressing strong feelings and attachments with animals in their lives — and even make careers writing about them. An increasing body of scientific evidence lends credence to the emotional connections we have with our pets too: The latest, published in the journal PLOS One, examined what happens in the brains of women when they see their kids and their dogs (turns out, similar things). 

The study included a group of 16 women who had a child who was 2 to 10 years old and a dog that had been with the family for at least two years. After visiting the subjects' homes, filling out a questionnaire about the relationship with the child and the animal, and taking pictures, the mothers were then invited into a neuroimaging lab. There, they used a functional magnetic resonance imaging (fMRI) machine, which looks at blood flow and oxygen levels in the brain to determine what part of the brain is activated. While in the fMRI machine, they showed the women images of their child and their dog, as well as pictures of other unknown children and other dogs. 

"Several previous studies have found that levels of neurohormones like oxytocin — which is involved in pair-bonding and maternal attachment — rise after interaction with pets, and new brain imaging technologies are helping us begin to understand the neurobiological basis of the relationship, which is exciting," said Lori Palley, DVM, of the Massachusetts General Hospital Center for Comparative Medicine and co-lead author of the report

In this study, brain regions associated with emotion, reward, affiliation, visual processing and social interaction showed more activity if subjects saw their own kid or dog — and the fusiform gyrus, (part of the brain's temporal lobe that is involved in facial recognition) showed a stronger response to images of the subject's dogs. But the substantia nigra/ventral tegmental area (SNi/VTA) — known to be important when it comes to bonds — was activated only in response to images of a participant’s child.  

“Although this is a small study that may not apply to other individuals, the results suggest there is a common brain network important for pair-bond formation and maintenance that is activated when mothers viewed images of either their child or their dog,” said Luke Stoeckel, PhD, MGH Department of Psychiatry and co-lead author of the PLOS One report. 

Further research is necessary to replicate these results and the next step would be to look at a larger, more diverse sample of subjects, to see if similar results are seen in other groups of people, like fathers, parents of adopted kids, and women without children — as well as in pet-owner bonds with other species. Dogs, especially, have co-evolved with human beings for over 30,000 years (and cats for at least 10,000 years). There could be cultural variables as well. For example, what about people who dislike dogs, cats and other animals? 

We'll have to wait to find out. Until then, don't feel bad about getting or making your pets Halloween costumes or holiday gifts, and enjoy that special bond with them — it's the real deal. 

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Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.

Does the human brain see pets as children?
New research looks at the neurobiological basis of both kinds of relationships.