That's bull, there's a good number of kids out there who were never smacked when they were a kid, and they know if they do wrong they get punished and the difference between right and wrong. Usually people who smack kids do it because they don't know how to discipline a child correctly, hitting and yelling 'don't do that' is something that would work with dogs, but kids need to be taught why they can't do that. If a kid runs out into the road, and the parent smacks the kid, what's the kid learnt? Don't do that again. Where as if a kid runs out in the middle of the street and gets shouted at initially, then the parents explain why you can't do that. Which'll have more effect?