I have 2 kids who now are wonderful grownups. And I firmly believe there is a big difference between violence and "a loud pop on their behinds". First tell nice and soft, they may genuily not know what is the right behaviour. If that doesn't help - tell stronger to show that you mean it. If they hear you and understand but still go on - pop on behind is the right way to solve the problem. That is the place where little kids brain "on" switch is located. Recently one of my friends even said that till certain age human children and animals have the same psychology. Well, in a sense yes. Maybe there is some research behind this, maybe its her experience. Anyway, with the same approach I have wonderful dogs and horses. Sure, there is a distinction between animals and humans, but as regards attitudes, all are nice, kind, honest.