Toddler hitting older brother

[Logan's mommy]

Ds2 (20 months) hits and pulls ds1's (9) hair anytime they're both in the same area for more than 20 seconds. I don't know what to do to get him to stop, I feel terrible because the only place ds1 gets any real peace is when he's in his room and that's not really fair to him. HELP! How do you curb the hitting behavior in your toddler?

[PluggingAway]

Gosh, that's a tough one. My 18 month old sometimes will hit or pull my 4yo hair. We model "gentle touch" to the 18 month old and give DS1 sympathy. We then change the scenery (leave the room, engage in a new activity, etc.) and hover to be proactive to intercept any future assaults. We tell DS1 that DS2 is still "learning the rules" which he seems to really appreciate. *Knock on wood* this approach has seemed to work very well.