Adult Siblings Can Make Our Lives Healthier And Happier

Katherine Streeter for NPR

This article was originally published on NPR.org.

We’ll have a total of just 10 at our Thanksgiving this year, with the biggest absence being that of my mother, who died in March at the age of 92. Our 2-year-old granddaughter and her parents won’t be there, either, nor will my nephew and his 6-month-old son, so we’ll have no children around to temper the loss. Instead, we’ll have to get our yuks from the antics of our daughter’s 90-pound dog, Huxley.

There will still be relatives aplenty, though, and luckily I love them all. But in a way the one I know best is the middle-aged man across the table whose blue eyes look just like mine: my younger brother Paul.

Paul and I irritated each other when we were kids; I would take bites out of his precisely made sandwiches in just the spot I knew he didn’t want me to, and he would hang around the living room telling jokes when he knew I wanted to be alone with the boy on the couch.

But as adults we’ve always had each other’s backs, especially when it came to dealing with our mother’s health crises, which became more frequent in her final years. Paul was the first person I wanted to talk to when there was something that worried me about Mom; I knew he’d be worried, too. He was the one I called when Mom didn’t answer her phone the morning she had died in her sleep.

There’s probably a biological explanation for the intensity of the sibling bond. Siblings share half their genes, which evolutionary biologists say should be motivation enough for mutual devotion. “I would lay down my life,” British biologist J.B.S. Haldane once said, applying the arithmetic of kin selection, “for two brothers or eight cousins.” Siblings are a crucial part of a child’s development, too, teaching one another socialization skills and the rules of dominance and hierarchy, all part of the eternal struggle for parental resources.

When psychologists study siblings, they usually study children, emphasizing sibling rivalry and the fact that brothers and sisters refine their social maneuvering skills on one another. The adult sibling relationship has only sporadically been the subject of attention. Yet we’re tethered to our brothers and sisters as adults far longer than we are as children; our sibling relationships, in fact, are the longest-lasting family ties we have.

Most such relationships are close — two-thirds of people in one large study said a brother or sister was one of their best friends. One thing that can scuttle closeness in adulthood is a parent who played favorites in childhood; this sense of resentment can last a lifetime.

A study by Jill Suitor, a sociologist at Purdue University, and her colleagues polled 274 families with 708 adult children (ages 23 to 68) in 2009 and found that the majority had good feelings toward their siblings. Most didn’t remember much favoritism when they were kids, but those who did reported feeling less loved and cared for by their siblings. It didn’t matter whether they felt themselves to be the favored or the unfavored child. The simple perception of parental favoritism was enough to undermine their relationship.

That’s one thing Paul and I have going for us: We’re pretty sure our parents treated us the same when we were growing up. Yet we’re very different people. Paul is gregarious while I’m shy, funny while I’m not, a terrific amateur saxophonist while I can’t read music or carry a tune. This isn’t unusual. In families with more than one child, every sibling seems to get a label in contrast to every other sibling.

So if your kid sister is the queen bee in any social gathering, you might get labeled “the quiet one” even if you’re not especially quiet, just quiet in comparison. And if you’re a bright child who always gets good grades, you might not get much credit for that if your big brother is a brilliant child with straight A’s. There’s only room for one “smart one” per family — you’ll have to come up with something else. (I was smart, but Paul was smarter; I ended up being the “good one.”)

The very presence of siblings in the household can be an education. When a new baby is born, writes Purdue psychologist Victor Cicirelli in the 1995 book Sibling Relationships Across the Life Span, “the older sibling gains in social skills in interacting with the younger” and “the younger sibling gains cognitively by imitating the older.”

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