Identity and development

Jealousy plays a huge part in their fights and tiffs, but arguing also has another function: it allows each child to express his identity alongside his siblings' separate identities. So if they cry, blame each other, call each other names, shout what they want, express their anger and unhappiness, they're making themselves heard and letting everyone know they exist.  

Arguments also allow kids to test their limits, learn to live alongside each other and learn that if you hurt or insult someone you're likely to get hurt yourself. 

If you watch animals' behaviour you'll see that in a group of siblings, the youngest spend a lot of time playing but also fighting, testing the strength they'll need when they get older and finding their place in the circle of life. Children do this just as much, but in a different way. And arguing and fighting is important for their development - as long as the parents set rules and limits...