When our two grown-up sons were in elementary school, my wife and I despaired of their ever getting along. Bickering, insults, mutual recrimination and, at times, physical altercations were the order of the day. The seemingly incessant squabbling went on for years. Our older son in particular appeared determined to make his brother’s life utterly miserable.

We made the same two mistakes many other parents fall into when they see their kids at odds with one another. First, we projected our children’s behaviour into the future, believing that these patterns would inevitably persist unless we nipped the fraternal hostility in the bud. Second, we focused on the behaviours, attempting to root them out by means of cajoling, lecturing, threats and, finally, punishments. We were triggered into acting in ways we later regretted. It’s in the nature of sibling conflict to bring out the deepest anxieties and least adaptive responses in the parent.

If the Bible is a guide, sibling conflict is as old as mankind. Of the very first two human beings born of a mother, the older killed the younger. The Cain-Abel story, says a philosophical character in John Steinbeck’s great novel East of Eden, “is the best-known story in the world because it is everybody’s story. I think it is the symbol story of the human soul.” Steinbeck points at the essence of sibling rivalry– the resentment of having to share parental love and attention with an unwelcome intruder and, ultimately, the fear of being rejected in favour of another. “The greatest terror a child can have,” he writes, “is that he is not loved, and rejection is the hell he fears. And with rejection comes anger, and with anger some kind of crime in revenge…”

When parents respond to sibling conflict with their own anger, they reinforce in a child’s mind the fear that she is being rejected. The usual measures to stop the behaviour, such as punishments and time-outs, have the same effect. When we punish a child for something that is not deliberate but is impulsive and arises from her insecurity and her immaturity, we confirm the fundamental anxiety that caused the behaviour in the first place. The behaviour is a symptom — what makes a difference is to address the underlying dynamics.

It is natural for an older child to feel threatened by the arrival of a sibling and to experience intense jealousy. No matter how well cherished, few children can know or sense that parental love is infinite and therefore not divisible, that love given to a brother or sister does not diminish the love available. So the first way to deal with sibling rivalry is to anticipate it. When we expect something and understand it, we are less likely to be triggered into negative reactions.

“Adapting to the existence of a sibling is one of life’s most important challenges,” developmental psychologist Gordon Neufeld says. “The child must be helped to come to terms with the futility of possessing mommy or sending the sibling back to whence he came. So many kids never come to terms with having to share the world. The failure to adapt to the existence of a sibling leads to incessant conflict and selfishness.”

Adaptation occurs when a child gets the futility of wishing that reality should be other than how it is. It does not arise from intellectual understanding or from acquiescence with parental demands. Adaptation means a child going from frustration to futility, from “mad to sad.” The parent’s role is often to help a child find his sadness and tears over a situation that cannot be changed. Instead of reacting to behaviours or trying to jolly a child out of feelings of sadness or anger or even hatred, the parent comes alongside and puts into words the emotions behind a child’s actions.

Rather than focusing on the hostile interaction between children, we should pay attention to each child’s internal experience. “You were very angry with your brother today. You became upset. You wanted to hit.” We achieve two goals: We convey to the child that we understand and accept her feelings, and we model for her a way of expressing them in words without the need for hostile acting-out. This way, the parent never has to take sides, to take on the role of cop, judge or jail warden.

It is helpful when a new sibling takes up a parent’s time to enlist the help of the extended family and adult friends who can provide the older child with nurturing, loving contact. And parents can evoke the nurturing, caretaking instincts of the older child by endearing the younger one to him: “Your sister just loves you. She is so lucky to have you as an older brother.” A sibling who feels valued is less likely to be competitive.

Not all sibling conflict represents sibling rivalry. Immaturity is one cause and, if all goes well, a self-correcting one. It is also common for a child to take out her frustrations on a more vulnerable object, the sibling. Parents here should identify what frustrates their child rather than, once more, attempt to change the behaviour.

Finally, some children seek to make it with their peers by rejecting their own siblings. We often noticed that our elder son’s attitude toward his brother was worse when peers were around. Immature children will try to connect with each other by excluding or shaming a third. In this case, the solution is for the parents to provide loving energy to the offending child, thereby diminishing his need for acceptance by peers.

It’s a mistake, when kids are constantly squabbling, to leave them to “work it out for themselves.” They are too immature to do so. What is required is our presence and our loving intervention. Nor, on the other hand, should we assume that the absence of sibling conflict is always a good thing. Kids, just like adults, may be “getting along” for the wrong reasons — one may dominate the other, or they may both fear the parents.

When sibling conflict is present, parents need not despair. “It’s actually a great opportunity,” Dr. Neufeld says. “Instead of futile admonitions like ‘Be nice, don’t be mean,’ we parents can model reason, boundaries, problem-solving and compassion.”

Above all, we convey the message that our love for our children is not conditional, it does not evaporate when they displease us. More than anything, that’s what soothes the anxieties that fuel sibling hostility.

I am happy to report that our two adult sons, after some ups and downs and much soul-searching, have developed a respectful and loving brotherly relationship.