“We like things that remind us of us,” Delgado told me. “We like smiling. We like dogs doing what we tell them. We like that they attend to us very quickly. They make a lot of eye contact.”

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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.

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A common charge against cats is that they do not care about their owners as anything more than a source of wet food. In studies of pet-owner relationships, scientists have found that dogs are more “attached” to owners. These studies frequently rely on protocol called the Ainsworth Strange Situation, in which the pet explores an unfamiliar environment alone, with its owner, or with a stranger. Dogs are more at ease with their owners rather than with strangers. Cats can’t seem to care less about the human there.

Maybe this says something about pet-owner attachment, but Delgado noted that dogs are used to their owners taking them to new places. Cats are territorial, and they might only leave the house to go to the vet, so what looks like indifference to their owners might just be overwhelming anxiety about a new, strange environment. Plus, the Ainsworth Strange Situation was developed by Mary Ainsworth to study parents and infants—another example of us judging cats on human rather than cat terms.

Also, not all cats. There are terrifying cats, but there are also cats who just want to snuggle all day. Delgado was taking her cat on a walk when I called her. Evans has a lovely ginger tomcat, who definitely is not a psychopath and who definitely was not the inspiration for her latest research.

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The survey, Evans hopes, is just the first step in devising a way to measure psychopathy in cats. She’d like to eventually study cats in their natural habitat—their house—so as not to rely on the word of their owners. The ultimate goal of the research is to devise a test for shelters so they can better match cats with owners. Whether it’s fair to call a cat a psychopath, we naturally do it, and it affects how well new owners and their cats will get along.