At the beginning of the year, I asked the undergrads in my Animal Behavior class what they hoped to learn this semester. We discussed that Animal Behavior would cover the hows and whys of the entire animal kingdom, but they returned to their real question: "Sure, the bee waggle dance sounds cool, but does my dog love me?"
I'm no stranger to this question, and probably neither are you. When it comes to dog love, two camps emerge: those who pose the question, and those wondering why anyone would bother asking the most obvious question on the planet. "Of course dogs love us!" scream the commenters in any article discussing dog love.
Today is Valentine's Day. Hallmark holiday or no, today is the day we exchange heart-shaped objects at an excessive rate and discuss matters of the heart. If there's any day where it's okay to talk about dog love, today is that day. Do dogs love us, and how would we know?
Looking at you
Dog love is all the rage nowadays, and oxytocin (the supposed "love hormone") is a big part of the conversation. Studies find that touch and physical interaction between dogs and people can increase levels in both parties, as does gaze between dogs and their owners (but don't go staring down random dogs, please. It's about gaze with a known dog).
But oxytocin is not straightforward. For example, administering oxytocin to female dogs led to an increase in gaze toward their owner, but not so in male dogs. Another study found that variations in the oxytocin receptor gene were associated with differences in dog behavior toward people, but not always in the same direction: the same allele was associated with higher friendliness scores in one breed but lower friendliness scores in another. While oxytocin could be part of the discussion, it's definitely not the only answer. Instead, I put my money on behavior.
Dogs are attached
Not by way of a leash or super duper Velcro. Since 1998, we've known that dogs show attachment behaviors towards their owners in a way that's similar to what's observed between infants and their mothers.
Infants do not treat all people the same (unless you're this child confusing his father with the father's identical twin). Attachment bonds describe an enduring close relationship between two individuals, offering a sense of safety and security. It's particularly relevant for individuals who rely on others for survival.
The Strange Situation Test developed by Mary Ainsworth in the 1970s identified behavioral underpinnings of attachment relationships (here's a video of her test in action). In the test, an infant is brought into a new place and experiences mild distress when separated from the mother. Attachment theory suggests that under these conditions, infants will respond preferentially toward mothers but not strangers, indicating their affectional bond.
When brought to a new place and separated from their mothers, infants seek more contact with their mother than a stranger when reunited, and they show signs of safety and security when in their mother's presence as opposed to that of a stranger. Infants are also more likely to investigate new objects when with their mother is present, suggesting that the mother provides a base of security from which the infant can explore the world beyond.
Numerous studies have since put companion dogs and their owners through a modified version of the Strange Situation Test. Time and again dogs turn out to be right on par with human infants, seeking more contact with owners than strangers, being more anxious when their owner is gone, and settling more when the owner returns than a stranger. Like infants, dogs are more likely to investigate novelty when their owner is present (an interesting phenomenon I cover here).
Give your dog the choice of you and someone else, and you're going to win.
Dogs at a shelter also show attachment behavior toward a newly assigned "owner" compared with a stranger. So did guide dogs who, before settling in with their blind owner, lived with a puppy walker and trainer. The study of attachment behavior in guide dogs concludes, "that repeated bond breaking is not detrimental to forming attachment later in life." Adopt an older dog, and she will love the heck out of you.
What does this all add up to? How do we even define 'Love'? Of Merriam Webster's nine, yes nine, full definitions of love, I'm drawn to 1a. "strong affection for another arising out of kinship or personal ties." While dogs don't use so many words, there's ample indication that they could fit the bill on this one. And for those who I claim to love, I’d probably smack on a similar definition.
My little dog Brandy never participated in a modified version of the Strange Situation Test, and I know nothing about her oxytocin levels after we gazed into each others' eyes before bed. She passed long before I ever heard of such studies. But do I think she loved me? Isn't it obvious there's only one answer?
Want more? Check out these open access articles:
Payne et al. (2015) Current perspectives on attachment and bonding in the dog–human dyad. Psychology Research and Behavior Management.
Rehn et al. (2013) Evaluating the Strange Situation Procedure (SSP) to Assess the Bond between Dogs and Humans. PLOS One.
Ainsworth & Bell (1970) Attachment, Exploration, and Separation: Illustrated by the Behavior of One-Year-Olds in a Strange Situation. Child Development.
Kis et al. (2004) Oxytocin Receptor Gene Polymorphisms Are Associated with Human Directed Social Behavior in Dogs
Nagasawa et al. (2015) Oxytocin-gaze positive loop and the coevolution of human-dog bonds. Science.
Palmer & Custance (2008) A counterbalanced version of Ainsworth's Strange Situation Procedure reveals secure-base effects in dog–human relationships. Applied Animal Behaviour Science.
Topál et al. (1998) Attachment behavior in dogs (Canis familiaris): A new application of Ainsworth's (1969) Strange Situation Test. Journal of Comparative Psychology.
Valsecchi et al. (2001) Development of the attachment bond in guide dogs. Applied Animal Behaviour Science.
Image: Happy lil' Luke! via m01229, Flicker creative commons.