The Surprising Ways That Siblings Shape Our Lives

 Susan Dominus, NY Times -   When we think about the forces that shape us, we inevitably turn to parents. The parent-child relationship is the basis of probably half a millennium’s worth of psychoanalytic conversation and intellectual discourse; parenting books are perennial best sellers, with advice that fluctuates as often as the health advice on what to eat or drink and how much. Their whiplashing instructions don’t stop many parents from reading them, and who can blame those mothers and fathers: Children are baffling, variable, not that verbal — and parents also know that if they get it wrong, their kids will blame them for just about everything.

And yet researchers, after analyzing thousands of twin studies, have come to the conclusion that the shared environment — the environment that siblings have in common, which includes parents — seems to do precious little to make fraternal twins particularly alike in many ways. They can be exposed to the same rules of oboe practice, dinnertime rituals, punishments, family values and parental harmony or discord, and none of it really matters in many key regards — siblings’ personalities may very well end up as different as those of any two strangers on the street. No one would argue that parenting doesn’t matter; it’s just that the choices so many loving parents agonize over — whether to co-sleep or not, whether to enforce the rules rigidly or sometimes let them go — don’t matter nearly as much as we imagine they do. Nor does that mean that genes are all-powerful; it’s just that nurture comprises so much more than parenting — the environmental effects a child is exposed to are vast, and include (just to start) the media they consume and the friends and teachers in whose company they spend most of the day.

And then there are siblings. “I think the influence of siblings on each other is an area in psychology that has not nearly received the attention it deserves,” says Lisa Damour, a psychologist and author who writes about adolescence. “When we look at child development, our main frameworks have been around the influence of parents on children, and that’s the established tradition that we’ve had a hard time moving past.”  More