Do dogs actually feel guilt?
The guilty look is real, but the evidence suggests it is not guilt. What dogs display is appeasement behaviour, a response to human cues rather than to their own past actions.
The key experimental finding is that the look appears based on the owner's demeanour rather than on whether the dog actually did anything. In studies where owners were misled about whether their dog had disobeyed, dogs showed more guilty-looking behaviour when scolded, regardless of what they had done, and innocent dogs who were scolded looked guiltiest of all.
The behaviours involved are the recognisable ones: lowered posture, averted gaze, flattened ears, tucked tail, lip licking, showing the belly. These are conflict-avoidance signals whose function is to defuse perceived threat from a social superior. The dog is reading you in the moment, not reflecting on the bin it emptied two hours ago.
This matters for training, which is why it is worth knowing rather than being a pedantic distinction. Telling a dog off after the fact does not connect the correction to the behaviour, because the association window is very short. What it does teach is that your return is unpredictable and sometimes unpleasant, which can produce anxiety and more of the appeasement display, reinforcing the owner's belief that the dog knows.
Dogs clearly experience primary emotions such as fear, excitement and affection. Whether they experience secondary emotions like guilt, which require a sense of self and of having violated a standard, is not established.
The practical alternative is management: prevent the opportunity, and reward the behaviour you want when it happens.