Birth Order and Personality: What Does It Mean?

Studies from the past three years show that birth order determines IQ and our personality traits. If this is so, then how do sibling rivalries shake out in stepfamilies when birth order becomes an issue?
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I have one sibling. He's about a year and a half younger than me. When we were younger, I was the dominant older sister. Pierced his ear. Made him eat goop. As we've gotten older, the roles between us have shifted. We give each other advice. We listen to each other. He is my equal now and we rarely fall into those old roles. (Okay, I know more than he does, I do, I do, na-na-na-boo-boo.).

Jeffrey Kluger's new book, The Sibling Effect: What the Bonds Among Brothers and Sisters Reveal About Us, and a whole lot of research on siblings, show that our birth orders do have more weight in our lives than, say, horoscopes. Says Kluger in an interview on NPR's Leonard Lopate show:


"There's a certain amount of lock in... You can't change history, you can't change the present things like birth order patterns... those things are fairly well fixed up to a point, when people get out of the house and once you get out of the house that history stays with you, sort of like a programming...

...And it is essentially, very broadly, true that firstborns will be the most successful. They will be the ones who earn the most. They will be the ones who are most loyal to the family, most driven to achieve in traditional ways.

They will also be the tallest, even if it's only by a few centimeters, and they tend to have higher IQs by about three points over the second-born."

Am I the tallest? No. Earn more? No. The smartest? No. But our smarts are different. My brother is more street smart. Me, more book smart. Does that put us in a mold? Maybe so.

What I find most interesting about this isn't really about my role in my family with my brother, but the role that I had during the time my father was remarried and I gained two new people in my family: a stepmother and a stepsister. Stepsister (let's call her Wanda because, why not?) was two years older and was an only child. Wanda lived with my father (I lived with my mother) and I visited there every other weekend.

This was a problem for a few reasons.

1. Wanda had always been the one and only focus in her family. She now had to share focus.

2. Wanda didn't know that I was the older sister. Age took back seat to birth order. She didn't get to boss around my little brother. I did. She didn't get to boss me around because in my mind, I was the head sibling in charge.

3. I wasn't the middle child. And as everyone knows, the middle child is stuck in birth order hell. The middle child isn't the safe older one. Or the racy baby. You're in purgatory as the middle child, and since I had always been in charge of the sibling dynamic, my childhood self couldn't control those urges to break free of that middle child syndrome. Wanda, if you're reading this, don't blame me! Blame the 12 year old me!

4. Wanda got to live with my father, and for this I was (albeit unconsciously) jealous.

If we had better help transitioning to our roles, maybe I would have enjoyed having an "older" sister. In truth, there was one year when we were first blended where I looked up to her. She was a great artist. A confident girl. But once the power struggles between she and I began, they could never really be repaired.

Studies from the past three years show that birth order determines IQ and our personality traits. If this is so, then how do sibling rivalries shake out in stepfamilies when birth order becomes an issue? What about blended families? My daughter is the baby of the family. My son is the oldest. That's in OUR house. My son is an only child in his father's house because his father doesn't have any other children, right? Or am I wrong? I know Jake is connected to his sister outside of our house--it's not that she stops existing when he's away from her--but the dynamic is entirely different. At his father's, he doesn't have to share. He can have more adult conversations because there's not another child in the house demanding we get down to toddler level.

Look, I'm not saying any of this is good or bad. I'm simply fascinated by it--and more, I'm interested in how it forms us as a person for the rest of our lives. If children in blended families have both siblings, steps, halves, etc. then their birth order changes... constantly?

Thoughts?

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