Our third son is turning 3 in about a week. He has started saying "no" when we tell him to do something, and then runs away when we try to discipline him. We have been resorting to spanking which makes him cry and elicits an "I'm sorry" but his behavior hasn't changed. In the last month, he has been doing this same behavior at school. He is put into time out at school, and we have also started taking his stuffed animal away at nap and bedtime when he behaves this way. Any suggestions about what we can do to get this behavior to stop?