Inner voice
Two different results of psychological research say: with the use of reward you get what you wanted, and with the use of punishment you do not. So, if you want your child to change his behavior, "give him a present" whenever he does something good; if you punish him for doing something undesirable, all that will happen is that he will start hiding from you what he did. Second, if one has "intrinsic motivation" for doing an activity and begins to receive too much praise or gifts as a reward ("extrinsic motivation"), this can begin to diminish or even completely destroy that initial enjoyment and desire to do something.