Any adults assume that an infant or young toddler “knows better” because he looks ashamed when he is scolded.  Looking ashamed shows only that the child understands that he has earned your disapproval, not that he has done something wrong.  You may also notice that he may look proud when praised for doing something right.  This is because he knows that he is approved of for that behavior at that moment.  It will take patience, repetition, and lots of practice before he can understand that rules are the same over time and apply to many situations.  Oh, you mean I still can’t push the buttons on the radio, just like yesterday (or five minutes ago)?