I hear all the time people saying "Oh, I know my dog knows they are wrong, they look guilty." They couldn't be farther from the truth!Seriously, that is a complete falsehood, that like many other things gets passed down from person to person without any real evidence or experience based knowledge to support it.
People are constantly putting human emotions onto dogs. It's wrong. It leads to unhealthy dog/human relationships. It results in dogs behaving in undesirable ways. It leads to dogs being taken to shelters and possibly put down. See where I'm going with this? The more we understand about the true nature of dogs, the easier it is to get along with and communicate with them. That leads to less dogs being abandoned and euthanized. I'm all about the dogs, I just put up with the humans.
Guilt is one of those human things thrown onto dogs. In reality, it is simply the dog displaying submissive physical cues to let you know that it is clearly reading your aggressive/tense/agitated/dominant cues. Yup, all those things are what your body gives off in the most subtle ways. Tension is expressed in our bodies like a neon sign even if we have no idea it is happening. That ache you get in the back of your neck when traffic gets bad, thats a physical response to a stressful stimulus, and guess what? Your dog can pick up on all of that.
You walk in the house, see the trash strewn about and you instantly get tense. When your dog sees you they read that tension loud and clear, subsequently showing a submissive response. It's not "guilt," it's submission. But don't take my word for it. Finally I came across an article in a science journal backing this concept up with actual experimental evidence.
Check it out at the end of my entry on my personal blog. It's worth learning about.