Cats, she pointed out, simply don’t have the facial muscles to make the variety of expressions a dog (or human) can. So when we look at a cat staring at us impassively, it looks like a psychopath who cannot feel or show emotion. But that’s just its face. Cats communicate not with facial expressions but through the positions of their ears and tails. Their emotional lives can seem inscrutable—and even nonexistent—until you spend a lot of time getting to know one.
Dogs, on the other hand, have learned to mimic humans. They do that thing where they pull their mouths back into something resembling a smile. They hang their heads in a way that looks super guilty. Just as humans have shaped the physical appearance of dogs, we’ve bred them to be extremely attuned to human social cues. Dogs that repeatedly raise their brows to make cute puppy faces are more likely to be adopted out of shelters.