Using rewards to reinforce behaviors that are desirable to adults not only misses inherent developmental realities that are beyond the child’s control, it erodes trust between the child and the adult.

Let’s start with the developmental aspect of things.
This is actually very simple: child brains are different from adult brains, in that they are not fully developed. The part that is still developing is the part that is responsible for, among other things, self-control.

When we expect a 4-year-old or even a 7- or 10-year-old to control their own behavior – especially in heightened emotional situations like birthday gift disappointment or sibling fights – we are asking them to do something they are developmentally incapable of doing.

It’s like asking a 2-year-old to tie her shoes. You know a 2-year-old does not have the physical dexterity and hand-eye coordination to tie her own shoes, so you’d never ask her to do it, and you certainly wouldn’t get angry or punish her if you asked her to and she didn’t perform. 

But a reward is not a punishment…I don’t see the problem.

A reward becomes a punishment when it is withheld.

If you get a sticker for cleaning your room, it’s a punishment to NOT get a sticker when you don’t clean your room.