Dear John Rosemond: Our 7-year-old son and 32-month-old daughter squabble with each other constantly, mostly over taking and playing with each other?s toys.

The problem is our daughter, really. She will hit, scream and throw things when she is angry. She wants to be in her brother?s room, to do whatever he is doing, and he will not close his door. He?s not rough with her, but we know he deliberately aggravates her. We have tried time outs and separating them. With this sort of age gap, is there some way of stopping the almost constant uproar?

Dear Reader: Yes, there is. When sibling conflict involves a 2-year-old and an older child, any attempt to aim corrective discipline at the toddler is going to fall flat on its face. As I say in ?Making the Terrible Twos Terrific!,? this age child is often impervious to discipline.

Holding both children equally responsible for the problem isn?t going to work until the younger child is at least 3, so until then the only effective thing to do is to make the older child COMPLETELY responsible for the problem. That may seem unfair, but the fact is that an older child ought to be able to prevent the problem from happening. In this case, the fact that your son enjoys aggravating his younger sister further justifies holding him responsible.

The solution is obvious and simple: your son closes and if necessary locks his door. That accomplishes two things: first, it establishes a physical boundary between himself and his sister; second, she is forced to begin learning to entertain herself.

Allow one outburst a day. The second outburst means your son?s not accepting his responsibility for the problem. As a result, he goes to bed an hour early, and every subsequent outburst shaves an additional 30 minutes off his bedtime. I just bet that will be sufficient motivation for him to keep his door closed.

Dear John Rosemond: My 16-year-old son refuses to wear his glasses. For the past two years, I have offered to get him contact lenses for his birthday, but he has refused. He will be driving soon, so I told him that if he didn?t wear his new glasses, which are less than a month old, he would have to reimburse me for them. He says he hates them and wants contacts. Furthermore, he is willing to pay for them himself out of his savings. Should I let him get the contacts or should I make him pay me for the glasses first?

Dear Reader: Under the circumstances, which are that he has had ample opportunity to accept your offer to pay for contacts, he should most definitely reimburse you for the last pair of glasses you bought him before he is allowed to purchase contacts for himself, and he most definitely should shoulder this responsibility. And don?t let him drive until he does.

John Rosemond is a family psychologist in North Carolina. Questions of general interest may be sent to him at P.O. Box 4124, Gastonia, NC 28054 and at http://www.rosemond.com. ? 2011, The Charlotte Observer