Earlier this summer, my daughter began reading the Harry Potter series. Like most kids who discover these amazing books, she was instantly drawn to both the plot and the characters. As a result, she now spends most of her imaginary play in the role of Hermione Granger uttering "Oculus Reparus!"
But no sooner had she completed Chapter One of Harry Potter and The Philosopher's Stone, my son (who read all seven of the books -- more than once -- two summers earlier) promptly turned around and read the entire series back to back. While I'm sure that her enthusiasm for these stories reminded him of how much he enjoyed them himself, I'm fairly certain that there was also an element of sibling rivalry at play.
It's not the first time that I've witnessed this sort of dynamic between my kids. And there's a wealth of literature out there backing up the idea that sibling relationships are vitally important in shaping who we are and how we behave.
Still, I find that I can't read enough about the precise ways in which sibling dynamics (or the lack thereof) affect our development into adulthood.
To wit, here are five recent findings about siblings:
1. Close sibling relationships are good for your health. At least, so says a Harvard University study showing that being close to one's siblings at college age was a crucial determinant of emotional well-being at 65. I'd read about this study a couple of years ago when it came out. What I hadn't realized is that the purported benefits of close sibling relationships extend not only to mental health, but to physical health as well. According to relationship researcher Mark Morman of Baylor University, siblings who maintain close relationships in adulthood are less at risk for depression and they maintain lower heart rates as well.
2. But only one third of siblings remain close into adulthood. According to scholars in Europe, another third remain relatively close. And while few adult siblings sever ties completely, about 33 percent drift apart entirely, sometimes describing their relationship as distant or rivalrous. (Earlier studies based in the United States offer more favorable percentages.)
3. Despite sharing similar genes, sibling personalities often differ. This is perhaps not all that surprising, given that in an environment of limited resources (read: parental attention and affection), you would expect siblings to differentiate themselves in order to get noticed. Still, siblings who share the same gene pool do tend to resemble one another markedly both physically and intellectually. And yet, their personalities diverge 80% of the time.
4. The effects of maternal favoritism persist into adulthood. According to one recent study in the United States, recollections of maternal favoritism in childhood were more important than perceptions of current favoritism in predicting tension among adult siblings, regardless of age. And children of mothers who favor or reject one child are also more likely to suffer depressive symptoms as middle-aged adults. (Whether and how this extends to paternal favoritism strikes me as an avenue ripe for research.)
5. Being an only child confers some real benefits. There's a lot of talk these days about the importance of birth order in shaping personality. I also feel like I keep reading essays by only children who want to give their own children siblings, whether to shoulder the burden of caring for an ailing parent or to relieve the burden of being the only one left when one parent dies. But despite the bad rap being an only child sometimes gets, new research suggests that only children tend to exceed other kids in terms of academic accomplishments, sophistication, vocabulary, and even social skills. Precisely because they have to learn skills outside the home -- whether at school or day care and the like, they tend to have a greater ability to make and maintain friends and to resolve conflict. Hmmm. Wouldn't have expected that.