It’s pretty apparent that dog owners love their pets, but do dogs have the equivalent of love for their owners? Or do dogs just respond to someone who treats them well?
Dogs will of course respond well to those who treat them well, but so will humans. But you’re obviously asking a more complex question, and yes, there is a lot more to it than that.
The human-dog relationship is deep and complex, and dogs know and sense far more than we give them credit for. Whether a dog can know “love” in human terms is perhaps not the right question, but they form attachments and loyalties that can be profoundly deep and enduring for as long as they live. It’s been said – and from personal experience I believe it – that the Bernese Mountain Dog bonds with its human companion for life. I don’t think this is atypical, but merely more obvious and extreme than other breeds.
There have actually been some scientific tests done in attempts to prove whether or not dogs feel affection. The conclusion seems to be “yes”, based on the release of the hormone oxytocin. Here is one article that briefly discusses the conclusions drawn from those studies (as well as looks at how our cats might feel about us): Dog affection
Similarly, this article reviews some studies done on dog brains (using MRIs) that also seem to support that dogs feel affection towards their humans. It also covers some other studies, including behavioral ones, that support dog affection. Article
IOW, science is coming up with more and more evidence that dogs do feel affection for their humans.
While I’m not an expert, dogs clearly seem to bond with their humans over random people who many play with them or even feed them. My dog enjoys playing with other dogs and so taking him to a kennel owned by a friend when we go away really isn’t a burden for him. But you can bet that as soon as we get back he will leave his dog friends and run out into our car expecting us to take him ‘home’. He always does that with us, and I’ve never seem him do it with anyone else. He’s been with us since he was a puppy. We feed him, take care of him and provide him with lots of affection and a warm place to sleep at night. When he wakes up in the morning he knows we will be there to greet him, and we know he will be there to greet us. It’s a mutually beneficial relationship that we seem to have exclusively with each other. At least for now.
I think my dogs love me.
Also, my dog really loves a lot of my friends, but not all of them, and it has nothing to do with them feeding the dog, or even paying a lot of attention to the dog, or even how I feel about that particular person. (At least one of these people is not really a worthy person. I like the person despite all shortcomings, and so does my dog.)
I think my first dog loved her previous owner (first eight years of her life) more than she loved me, and that them giving her up kind of broke her heart, but I do think she liked me.
All my other dogs I have had since they were puppies, and I’m pretty sure they liked me a lot–best of all.
I’m also pretty sure my first cat loved me. I don’t think I want to know about the others, though. Even though I do treat them pretty well.
Dogs are pack animals, and they do have an instinct of loyalty to/care for other members of the pack, and particular instincts with regard to the animal identified as pack leader. Whether this can be termed “affection” is, I suppose, debatable but, yeah, why not? And I think that there’s evidence that in domesticated dogs these instincts transfer to the human family/human owner.
I agree that the terminology can be debated ad nauseum, but I think it is pretty clear that dogs have a very strong affinity to those they accept as their “pack.” My dog is happiest when both his Mommy and Daddy are home, and is never quite as happy when only one of us is around.
(I can only assume that he is even less happy when neither of us is around, but I can’t testify to it because nobody is there to observe it)
Here is a weird thing. My dog and my cat do not get along particularly well. They don’t fight, usually. Every now and then they play, but they have all different ideas of what play means so that doesn’t usually work out.
A couple of months ago the cat had to go to the vet, and he had to stay there overnight. When I brought him home, the dog rejoiced. He acted just almost as happy as if another family member had been away for a bit and then returned. Maybe not quite as delighted as one of my friends that he likes showing up, or the kid getting home from camp, but still, happy. Surprised the hell out of all of us. Especially, I think, the cat.
So apparently he accepts the cat as a pack member. And I think he misses the other cat, too. (Saha, 1997-2014, now buried in the rose garden.)
We have a house/pet sitter who spoils our dogs rotten when we go away for a week.
When we return, it’s kind of scary how happy the dogs are.
When I lived with my mom and dad, they had their dog and I had dog of my own. While both dogs loved all of us, each one seemed to know who they belonged to. Their dog seemed more bonded to them and mine was bonded more me.
Have you ever watched videos of dogs greeting their owners returning from military service?
When I get home from work each day, my little dog appears so happy to see me that she can barely stand up (she’s a young dog but appears literally overwhelmed with excitement to see me).
I am the ‘big dog’ in the house (that is to say that I’m fairly sure I have established myself as the pack leader in the eyes of the dog - and I have done this by behaving sort of like a ‘big dog’ - when the ‘little dog’ misbehaves, I firmly (but gently) pin her down by the neck, get in her face and put on a growly voice to say “I’m the big dog. You’re the little dog. Got that?”) - it’s hard to say whether she’s acting out of genuine affection or if it’s just submissive behaviour to the established pack leader.
I guess it eventually comes down to the ‘philosophical zombie’ question. I can’t tell what’s going on, if anything, in the head of another human, let alone a dog, but it makes sense to assume certain things.
As to the original question: undoubtedly. There’s a reason why dog loyalty is lauded as much as it is.
Re: Dogs being pack animals.
I recall reading an article, though the particular link for the citation escapes me, that described the way dogs vs. wolves made pack decision. Wolves had the the rigid hierarchy. Dogs… well, dogs went with whichever dog had most friends/was most popular at the time. It would be nice if people stopped equating dogs to tame wolves. They diverged from a common ancestor literally tens of thousands of years ago, and are vastly different, behavior-wise.
Again, anyone who’s seen/experienced a dog’s joyous reunion with its owner(s) after a period of absence would never have doubt on this question.
I sometimes see belittling references to dogs having an automatic attachment to whoever raises them, as though this was a disqualifying factor. The same is largely true of humans.
I love this one experiment video I saw. A piece of meat was put under a low ledge, where the animal could see it, but not get it out. Wolves would try and try and try and try and never give up trying to get it. Dogs would try a couple times, then look up at the humans for help.
Who’s the smart doggie? Yes, you are!
Dogs are expert tool users, and we’re their tools. 
IMHO, animals (including humans) do most or all of their thinking on an emotional level. Basically “gut checks” for most interactions. We humans have an extra special level of cognition and communication that interacts with our emotions, giving us more complex emotions. And of course we have opportunities to be very rational and analytic, essentially trying to rise above our emotional thinking. Mostly I believe we think semi-rationally. With dogs, it’s way toward the emotional side of the spectrum.
In short, my answer to the OP is that dogs mostly only have love* (and hate and fear and desire and …) bouncing around in their brains.
*Love meaning like, have positive feelings for, have loyalty for, etc. Without human complications.
Our newly adopted dog is blind. I find it ironic that I am his seeing-eye Human.
He’s the most “attached” dog I’ve even had - he wants to be as close as possible to me all the time. Just being in the same room isn’t good enough - he wants to be touching me. I don’t know if it’s “love,” but if I’m downstairs, he whines until my wife lets him down so he can be with me, even though she’s available for human companionship.
If anyone wants a smile and tear here’s a video of dogs greeting their returning owners. That certainly looks like more than just another person who feeds me.