Researchers have found that the muscles of domesticated dogs have evolved to make their eyes look bigger, and more expressive. This muscle, called the levator anguli oculi medialis (LAOM) muscle, is not present in wolves and only appears in dogs over the last 33,000 years! Humans also have the LAOM muscle. So, its possible that because of domestication, dogs have evolved so that they can communicate with us.
Now, go ask if your dog wants a treat!