Tales of hearts given and not returned are as old as time itself, and but tales of non-reciprocal interspecies love are perhaps less common. The unrequited love between Bella and Jacob aside, there exists a sizable group of non-fictional people who find love with non-human animals: dog owners.

You love your dog. Does your dog love you back? Is the love that an owner feels for her dog reciprocated? That's the question that a group of Swedish and Danish researchers wanted to answer.

Dogs are highly attuned to human social cues. They don't just enjoy a symbiotic relationship with us; they are our social partners. So if an owner has a positive view of her relationship with her dog, perhaps a higher frequency of positive interactions will occur between the two, leading the dog to reciprocally perceive a close relationship with its owner. At least, that's the hypothesis.

Twenty dog-owner pairs participated in the study. The humans each completed a questionnaire called the Monash Dog Owner Relationship Scale (MDORS) which was designed to evaluate the strength of the relationship from the perspective of the owner. The MDORS contains 28 items which are divided into three sub-scales. The first assesses the nature of the dog-owner interactions ("How often do you hug your dog?"), the second reflects the emotional closeness that the owner feels towards his or her dog ("I wish my dog and I never had to be apart"), and the third concerns the perceived investment required to care for a dog ("My dog costs too much money").

The dogs were thrust into a modified version of the Ainsworth "Strange Situation" procedure, a clever experiment originally designed to measure the strength of human parent-child relationships. Since it measures both proximity-seeking behavior and assesses the sense of security the owner's presence might provide the dog, and since the owner-dog relationship has often been compared by analogy to the parent-child relationship, the strange situation has been increasingly used quite effectively to understand the human-canine bond. Indeed, it's not such a strange comparison to make. Owners who reported stronger relationships with their dogs also had more oxytocin in their urine.

The doggy version of the strange situation begins with the owner sitting in a chair ignoring her dog. After a few minutes, a stranger comes into the room and, ignoring the dog, talks to the owner. The stranger attempts to play with the dog, and then the owner quietly leaves the room. The stranger continues to engage the dog in play, and then leaves the room, leaving the dog alone. The owner returns, greets the dog, and begins ignoring it again. The stranger returns, greets the dog, and ignores it as well. Finally, the owner leaves a second time.

When conducted with human toddlers, the slightly distressing nature of the strange situation - being left alone, having to engage with a stranger - activates an innate, adaptive system that motivates the child to seek the proximity of their caregiver. By carefully observing the child and weighing his comfort-seeking behaviors against his more independent exploration behaviors, researchers can determine whether or not the child is "securely attached" to mom or to dad.

The researchers found, predictably, that dogs were more likely to initiate physical contact with their owners if their owners' self reports reflected a high level of interaction with their dogs. And owners who reported a high level of interaction with their dogs had dogs who were less likely to play independently. In a human toddler, we might say that the lack of independent exploration reflects some form of insecure attachment but for dogs it probably represents a consequence of positive reinforcement for interacting with their owners.

A more complete understanding of dog-owner relationships comes from looking not at the dog or owner in isolation, but as a unit. This study marks one of the first attempts to scientifically probe the relationship between dogs' perception of their bond with their owners, and owners' perceptions of their bond with their dogs.

And here's the bad news for all those dog lovers who are just certain that Fluffy loves them back. There was no correlation between the "perceived emotional closeness" subscale of the MDORS questionnaire and the dogs' behavior in the strange situation. The researchers put it bluntly, writing, "there was no evidence to support the view that because a person has a strong emotional bond to their dog, their dog is similarly attached to them."

Jacob loved Bella, but Bella chose Edward. As with paranormal teenage romance novels, so too with life. You can not simply love a dog so much that it will be forced to love you back.

Rehn T., Lindholm U., Keeling L. & Forkman B. (2013). I like my dog, does my dog like me?, Applied Animal Behaviour Science, DOI: 10.1016/j.applanim.2013.10.008