Dear Mr. Dad: On weekends my buddy comes over with his 1-year old son. My boy just turned two and has started acting aggressively towards the baby, even hitting him. How can I help them get along?

A: Hopefully your friend isn’t taking your son’s inhospitality personally, because it has nothing to do with him or his baby. As unpleasant as it can be for the people around them, aggressive behavior is very common for toddlers. It’s a normal developmental stage. He’s learning about cause and effect (Hmm. If I poke that little kid, he cries. What would happen if I pulled his hair?) That, however, doesn’t make the aggressive behavior okay. And you need to do whatever you can to stop it.

Here are some strategies that can help.

  • Figure out why. Chances are, your son is upset because he feels your buddy’s baby is intruding on his turf, playing with his toys, and stealing your attention (and he’s probably right on all counts). Unfortunately, at two, his verbal skills aren’t polished enough for him to actually explain what he’s thinking. So if he’s worried that the baby will steal his toys, he may skip the “tell-dad” stage and go straight to the hitting stage.
  • Set expectations. Give your son some notice that you’ll be having guests, and remind him that he needs to treat them with respect (no hitting, biting, etc.). If he doesn’t want to share his toys, let him stow a few favorites where the baby won’t find them. Warn him that hitting will get him sent to his room or could result in losing a toy for while–another important lesson in cause and effect. Also, give him an alternative way to express his anger: giving himself a time out, or using words to say “you’re making me really mad!”
  • Control yourself. When your son behaves inappropriately, pay attention to how you respond. Yelling at him will probably reinforce the bad behavior. And saying things like, “Don’t hit him or I’ll hit you!”—or worse, actually hitting him—demonstrates that it’s okay for big people to hit littler ones.
  • Keep it short. Skip the long-winded explanations, or well-meaning questions like, “How would you feel if Teddy hit you?” He doesn’t have the cognitive ability to put himself in someone else’s shoes. Instead, follow through immediately on the warnings you gave him earlier.
  • Pay attention. Respond quickly every time your son acts aggressively–don’t wait until he’s been doing it for five minutes and then announce, “That’s enough!” And be consistent in whatever consequences you use. Having a toddler requires your constant supervision and involvement. Leaving both kids in the other room while you and your buddy watch Sports Center , is a recipe for disaster.
  • Say sorry. Make your son apologize every time, even if he doesn’t seem to mean it. Get the words down first—the empathy will follow.
  • Have alternatives. Is your son getting enough physical activity every day? He should be out running himself ragged for at least an hour every day. Pent-up energy can turn into aggression.

Reward positive behavior. Go out of your way to catch him being good. Tell him you’re proud of the way he shared his toys and used his words instead of hitting. An occasional treat after the fact, isn’t a bad thing. But don’t bribe him.
Know when to get help. If none of this helps your son curb his aggressiveness, talk with your pediatrician. It may be time to call in the pros.