Do cats and dogs actually feel affection when you treat them right or is it really just an instinct for “more food and drink” etc?
I don’t think I’ve ever seen dogs, cats and other domestic animals smile because they’re happy and show love to their owners for treating them right.
Yeah I see memes but those are either photoshopped or snapped at the perfect moment to make it look like they’re smiling.
Neurobiologically they absolutely do. Most animals have amygdala, for starters, so they feel a lot of basic emotions. As for love, one would only need to ask whether they can do things such as produce oxytocin, recognize faces or voices, desire touch, etc.
Best answer here as it touches on inarguable facts rather than feelings. NOTE: Emotions are mainly a mammal thing, though reptiles and birds have a sort-of amygdala, not the same though.
And an interesting bit for OP: Dogs DO smile! At the least we can that we selected for more expressive facial muscles in dogs. In contrast, my pig has about zero emotional indicators, though he seems smarter than any dog I’ve met.
https://www.pnas.org/doi/10.1073/pnas.1820653116
Far more out there if you want less technical resources:
https://www.nbcnews.com/science/weird-science/dogs-faces-evolved-improve-connections-people-study-suggests-rcna22362
There has been at least one study which has shown that when a dog and their owner look into each other’s eyes, both experience a release of oxytocin. The humans experience a greater release, but the dogs receive some as well.