Dogs know when they don't know
DogStudies lab... have shown that dogs possess some "metacognitive" abilities -- specifically, they are aware of when they do not have enough information to solve a problem and will actively seek more information... a test in which a reward (food/toy) is placed by one researcher behind one of the two fences while another researcher held the dog. They found that the dogs looked through gaps in the fences significantly more often when they had not seen where the reward was hidden.
Amusingly, looking through the gaps didn't help sometimes.
The researchers theorize that... the dogs get so excited about finding the reward, that they cannot stop themselves from approaching the closest fence even when they have seen that the reward is probably not there.