We all know that look. When you walk in on your dog with this expression, you just know they did something they weren't supposed to do. Luckily, they're cute, so we don't mind seeing these guilty faces.
According to dog cognition scientist Dr. Alexandra Horowitz, this fear is a real thing. She asserts this in her 2009 study "Disambiguating the 'guilty look': salient prompts to a familiar dog behavior." Apparently, the idea of guilt is something we misattribute based off our own perception.
Don't feel bad for the misunderstanding. In a recent interview, Dr. Horowitz said, "I look at a dog showing the guilty look and it feels guilty to me. It does! We're kind of wired to see it this way, so it's nobody's fault."
So what went into the study that proved all this? According to the paper,
"Trials varied the opportunity for dogs to disobey an owner's command to not eat a desirable treat while the owner was out of the room, and varied the owners' knowledge of what their dogs did in their absence. The results revealed no difference in behaviors associated with the guilty look. By contrast, more such behaviors were seen in trials when owners scolded their dogs. The effect of scolding was more pronounced when the dogs were obedient, not disobedient."
To summarize, the dogs reacted primarily to consequences. This represents fear, as opposed to a recognition of misdeeds. This isn't to say dogs don't have a conscience, but the results show their emotions are a bit more primal.
"It seems unlikely that they have the same types of thinking about thinking that we do, because of their really different brains, but in most ways dogs brains are more similar to ours than dissimilar. There is some work showing that some animals are planning for the future and remember specific episodes in the past. With dogs, there's not as much evidence yet. Which isn't to say that they don't, but it's to say that it's really hard to design experiments around it."
"They're not remembering it in language. They don't talk about it. Do they think about it, when they're lying on the couch waiting for you to get home? We don't know. We would love to know that, but we don't know."
"When you adopted your dog, and suddenly you're living with a dog, within a week we have opinions about the dog's personality, what they're like and what they're thinking. It's a way to try to predict what's gonna happen next with an organism that we don't really know. So we use the language of human explanation, and we just put it on the dog."