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Dogs may be man's best friend, but it's hard to tell if the feeling is mutual. It's tough to figure out what's going on in anyone's head, let alone a species that can't talk.

But there are techniques researchers use to look for emotions in animals, and studies suggest that dogs do form deep emotional bonds with people. And their ability to do that might be why they became our best friends in the first place. Dogs certainly do things that seem loving, and not just when they snuggle up to you on the couch for some extra pets.

Research suggests that your dog has your back, for example, and will snub those who snub you. And if it seems like your pup tries to console you when you're sad, that might not be your imagination. In studies, they do seem to display empathetic concern, like nuzzling a person when they're sobbing, or becoming anxious at the sound of an infant crying.

Dogs are also able to distinguish among human emotions by smell alone because how we feel changes the chemicals in our sweat. So even if you're putting on a brave face, they probably still know you're sad. But none of that is love, per se.

To find evidence for emotions, researchers have looked to see if dogs exhibit the same physiological responses we do when we feel things. For example, a 2015 study used fMRI, which monitors brain activity based on blood flow, to look at how 12 dogs reacted to the smell of themselves, people they knew, strangers, and familiar and unfamiliar dogs. The scent of people they knew activated an area of the brain that the other smells didn't: the caudate nucleus, the same part of the brain's reward system that activates when we humans look at pictures of people we love.

Other lines of research have looked at oxytocin levels. Oxytocin is sometimes called the ‘love hormone,' which is a major oversimplification of how it affects your body and brain, but it does seem to play a big part in creating and maintaining emotional bonds. And when you interact with people you love— like when you hold your baby, or flirt with your partner— the levels of oxytocin in your blood and saliva jump.

Studies have found that there's a similar rise when you play with your dog, for both you and them, and that just gazing into each other's eyes can be enough to cause a mutual spike. But that doesn't necessarily mean that your dog loves you— or that you love your dog. Psychologists are quick to note that it's impossible to prove emotions with physiological tests.

Even with people, blood tests don't equal feelings. You can ask if someone loves you, but there's no lab result that can tell you if they mean it when they say yes. So a lot of our understanding of dogs' emotions comes from the same techniques used in studies on emotions in humans— especially humans that can't convey their feelings verbally, like babies.

Psychologists study infant attachment by looking for certain key behaviors: things like seeking physical closeness with their caregivers, becoming more adventurous when they're nearby, and being distressed when they're separated. And multiple studies have found that the bond between dogs and their owners is super similar to the bond between children and their caregivers. For example, both babies and dogs have done Strange Situation Procedure tests, where you watch them while they're left in a room either alone, with a stranger, with their parent or owner, or with some other combination of people.

And while both babies and dogs seek physical closeness with their person, they also tend to display more independence by exploring or reacting more positively to strangers when their caregiver is around. That's probably because their caregiver acts as a safe base of support, giving them the security they need to take risks. Both babies and dogs also tend to get distraught when their person leaves and seek comfort from them when they return, suggesting they're a kind of “safe haven” that reduces stress.

Studies like these have even revealed different attachment styles in dogs, similar to what's been described for how people bond with their parents. It makes sense that babies and dogs have similar types of bonds with those that raise them. Dogs are a social species, too, and when they're young, they rely entirely on whomever cares for them to survive.

Scientists think that in humans, that reliance is part of why we form such strong social bonds. So it wouldn't be too surprising if dogs have similar psychological pathways to reinforce their own social bonds. And some researchers think their ability to form these bonds especially across species, is a big part of why they ended up being our companions.

They connect with us in a way we find meaningful. So, the science does suggest that your dog is deeply attached to you. But attachment doesn't necessarily translate to love.

Psychologists still debate whether love can be measured, if non-human animals are cognitively capable of feeling it, or even what love really is. Science can tell you that certain chemicals spike when your dog interacts with you, and show the strength of their attachment. But whether that really means your dog loves you is a question science can't fully answer.

You'll just have to look into those big round eyes, scratch an ear, and decide for yourself. SciShow Psych is a production of Complexly, which brings you over a dozen channels, like The Financial Diet. Here's Chelsea, from TFD to talk more about it. -If you want to learn more about how to be a person in the world and make the tough parts of adulthood not so scary, you should check out The Financial Diet, on of SciShow Psych's sister channels.

We talk about money—everything from how to save it, to how to spend it, to what to do when you owe a lot of it— because even though you don't want to think about money, life is so much better when you know how to handle it. So check out The Financial Diet at the link in the description. See you there! [OUTRO♪].