While visiting our niece and her children over the Memorial Day weekend, I observed a familiar phenomenon. My niece has three children but there is also an older cousin Halley who lives nearby and who is often playing with Stella Blue, the oldest of my niece’s three girls. Until the baby, Willow, was born, Raven, now the middle child, was always excluded from the play of Halley and Stella Blue. Her efforts to be included in their play were simply rebuffed. Unfortunately, this has become a habit, and now Halley and Stella Blue, mother the new baby and continue to exclude Raven from their games.

Three just happens to be a bad number, sociologically speaking. At Tufts University, where I taught until I retired, we found that three students in a dorm room simply didn’t work and you had to have either two or four to avoid problems and complaints. Many other universities and boarding schools have found the same to be true.

It is also true for families with three children who are born reasonably close (within a few years) of one another. Usually two of the children partner off against the third, not unusually, the middle child. The struggle of middle children to find their identity, they are neither the oldest nor the youngest, is thus compounded by the rejection of their siblings.

The trouble with three is not just among siblings. School age children, most often girls, demonstrate the same issue. But with girlfriends, who one is in, and which one is out, keeps changing. So there sometimes appears to be a rotating third girl out. A girl, who is complaining about one girl one week, will be her best friend the next. For boys it is not so much the rule of three as it is athletic ability and game skills, rather than numbers, that determines who is in and who is out. And for boys, the exclusion is not as changeable as it is for girls.

As children get older the process of social exclusion gets extended to groups. Both boys and girls often form clubs, from which some children are excluded. This process of social exclusion has the same purpose among children are it does has for adults. Exclusion, gives the excluder a sense of superiority over the excluded. While this process of social exclusion is deplorable in adults, it can serve a useful purpose in children. This is true because in children the exclusion is often based on trivial characteristics, that most young people come to recognize as such as they mature.

It is never much fun to be excluded either from your siblings or your peers. As parents there is not a lot we can do about this other than to reassure the excluded child of his or her many positive qualities and to show them a little special care and attention. This can help to make up for, in part at least, the hurtful behavior of their siblings and/or peers.