ok but caudate activation isn't love, it's anticipation of reward. we could be the reward. that doesn't mean they love us the way the question implies
Fair. And the definition of "love" is doing a lot of work in this question. If we mean attachment and preference for proximity, there's solid evidence. If we mean something phenomenologically richer, that's a much harder claim to make from imaging data.
I have thought about this every single day for 8 years and I still don't know. My dog looks at me like I'm the sun. But she also looks at a piece of cheese like I'm the sun. I genuinely cannot tell the difference.
The oxytocin loop between dogs and humans is real. Mutual gaze increases oxytocin in both species. That co-evolved over thousands of years of domestication. That's not manipulation, that's genuine social bonding.
There's actually good neuroscience on this. Gregory Berns' fMRI work with awake dogs found the caudate nucleus activates to owner scent more strongly than to food scent in many dogs. That's the reward anticipation region. It's not conclusive but it's not nothing.