When an older child is mean or teases a younger child, often, we scold the older child. "You are older. Why do you do that to your little brother or your little sister?" What we are forgetting is that the older child is actually more vulnerable than the younger child. We worry that the younger child feels left out and doesn't know as much, we cater to the younger child. What we really need to keep in mind, is that the older child needs more from us when there is a little one, not less. After all, the older child is the one who is used to having a mommy and daddy all to himself or herself. Then all of a sudden, this bundle of joy comes and takes that attention away from the kid. It is normal that the child is going to take out his jealousy or the feeling that they need more attention, out on the younger sibling. When the younger sibling acts that way, you want to do two things. One is you want to re-direct that older sibling to have a positive impact on the younger child. Two, you want to keep in your mind that this older child feels less than, in some way. Empty. Needs more contact and connection. Provide it, and you'll see that they will behave better.