Battle Zone: The Playroom
What's Going On: There's no question that your toddler knows knocking down his sister's tower is going to get a reaction. "At this age, your child realizes that he has the power to make an impact -- both positive and negative," says Sank. So a little excitement is probably just what he was looking to create -- especially if he felt left out or bored.
Four-year-olds know they're supposed to use words instead of hitting. And they probably abide by that rule on a playdate or in preschool, but the family room is a different story altogether. "Home is a comfort zone, and kids naturally fall apart in ways they never would at a friend's house or in school," says Anthony E. Wolf, author of "Mom, Jason's Breathing on Me!" The Solution to Sibling Bickering. Add to the mix a brother or sister -- the one person who's always going to be around no matter what -- and you have the perfect storm.
Keeping the Peace: Forget about playing judge and jury. "Each child needs to hear your house rules reiterated," says Wolf. Say to your older kid, "I know that you're upset, but we never hit; you have to use words to let us know how you feel." To your toddler, you might say, "If you want to play with your sister, you can't knock down her buildings." Let them both know that if they can't get along you're going to separate them. "That might be the biggest motivator of all -- in the end, they'll probably behave because they want to keep playing together," says Wolf.