Don't Pressure - Don't Punish

R' Aviner -

Do not pressure a young kid under the age of six. Do not pressure him physically by having him carry things which are too heavy since he is weak, and do not pressure him emotionally, since he is also weak in this realm. If we do so, he will be placed in a stressful situation from which no benefit will come.
Do not punish him. Punishment at this age has no benefit, and on the contrary, can cause damage. The reason being is that a young child does not possess the power to properly understand the punishments. He is unable to transform them into a positive factor for building his character. Just the opposite, the punishment causes him distress and destroys his self-confidence.
Punishment is not designed to cause pain, but to serve as a medium to explain to a child: You did something wrong, you did not act correctly. If a child is sitting on the window ledge and might fall, we can act severely with him in order to teach him not to do that again, even if it causes emotional damage, since it is a life-threatening situation. But if he spills soup on the floor, dealing with him severely will not teach him to be neat.
After all, a young child does not have that much intellectual control, but is largely an emotional being. We must take this into account, and realize that there are many other ways to educate him.