You Two Are Related? How Siblings Can Be So Different

As a mother, pediatrician, and sister, I recognize all too well how different siblings can be. One brother might be a bookworm, the other a jock. One sister an optimist, the other a cynic.

Like me, you probably wonder how people from the same genes and the same environment can end up being so different.

 

oranges and apples

In the 1980s, Robert Plomin, a psychologist specializing in twin studies and behavior genetics, discovered something interesting (as summarized by Alix Spiegel in the article Siblings Share Genes, But Rarely Personalities). In regards to physical characteristics and intelligence, siblings were fairly similar. But when it came to personality, they were more like strangers. In fact, their personalities were similar “only about twenty percent of the time.”

That finding prompted the scientific community to ask:

How can children raised in the same family have such different personalities?

According to Spiegel’s article, three theories surfaced:

1) Divergence:

Given human nature, children compete with each other for their parents’ attention. As a result, if one child excels in academics, another might choose sports, hoping to stand out to his or her parents.

2) Environment:

Though on the outside it appears children in the same family share the same environment, they really don’t. Because kids differ in age, they’ll experience family events differently, particularly difficult events like divorce or death. For example, a mother’s cancer diagnosis will have different effects on a five-year-old than a twelve-year-old, and as such, each child will have different needs. The parents will then treat each child differently based on these needs. This in turn molds different personalities.

3) Exaggeration:

Children in the same family are often compared to each other, and their differences, even if minor, might be exaggerated. For example, “Oh, she’s the talkative one.” Or, “he’s the trickster.” Before long a label is born, reinforcing the trait and perhaps even escalating it over time.

Surely other variables mold our personalities, including neurochemical factors, but I suspect these theories hold some truth.

Carrie and Jo with fruit

So what got me started down this road of contemplation? My sister, a talented singer and songwriter, has recently branched out with her new band, ADHD. As I looked through the group’s page on Reverbnation and watched and listened to my extroverted sister sing and dance with a beer bottle in her hand, I thought, “Holy cow, how can we be so different?”

And then I thought, “Holy cow, my sister is really talented!”

My favorite song she wrote is “Suffocate” (the first one listed under songs). When I heard it, I couldn’t stop singing it.

But of course, as an introvert, only in the privacy of my own home…

Carrie and Jo (2)

Are you and your siblings different?

Related Articles:

Commentary: Why are children in the same family so different? Non-shared environment three decades later

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Rubin4Carrie Rubin is the author of The Seneca Scourgea medical thriller. For full bio, click here.   

 

244 Responses to “You Two Are Related? How Siblings Can Be So Different”

  1. N. E. White

    I have two sisters and two brothers (five in total). We are all very different. And I think we came out all very different, but as you said, labels were applied early and stuck and, for better or worse, shaped our lives.

    Like

    • Carrie Rubin

      Yes, I was always the quiet one and the bookworm. I still am. Unless I’m comfortable with you and we’re one-on-one. Then I’ll talk your ear off. 🙂

      Liked by 1 person

  2. Kate Johnston

    I have 5 brothers and 1 sister, and, yes, we all have different personalities, yet we share a lot of things in common, too.

    I have always held the belief that we are born with a preset personality, and that personality is shaped by relationships and experiences. To me, this explains why siblings can all be so different despite having the same parents and being raised essentially the same way. I know that with my two kids, their personalities were noticeably different even in infancy. One was a snuggler; one wasn’t. I think as parents we might pick up on those kinds of cues, consciously or not, and go from there.

    I have also noticed that siblings’ relationships can be different with different members of the family, for instance, two siblings might be more competitive when their dad is around, but not so much when their mom is around.

    Interesting post!

    Liked by 1 person

    • Carrie Rubin

      I agree. I think much of personality is innate. There are certainly infant personality types, and they manifest quite early. Then environment tweaks and adds to it even more. In fact, I suppose it would be more surprising if siblings ended up alike! But those differences are what keep life interesting, I guess. And family gatherings… 😉

      Liked by 2 people

  3. El Guapo

    I have two older sisters.
    It’s often hard to tell that any of us are from the same family.

    Off to check out your sister’s music!

    Like

  4. Vanessa-Jane Chapman

    I’m just on my lunch break at work at the moment (my lunch breaks tend to consist of not leaving my desk, but just doing some personal things on the computer instead, which I’m sure you’ll tell me is not good for me!), so I can’t really listen to the music right now, although I did hear your sister on a clip once you posted on facebook so I saw how good she was. I will endeavour to remember to come back to that link later when I’m on a computer at home to listen! I’m very different from my siblings, but then we have different fathers, plus I never lived with them, so it’s hardly surprising! I notice a lot of difference between my two kids though – a certain amount must be what they’re born with, but I can certainly understand that point about the environment which appears the same is actually different over time, and how those subtle differences can be exaggerated by labelling!

    Like

    • Carrie Rubin

      My sister and I actually have different fathers, too, but I never use the term half-sister. I’ve never cared for the term, and I never see her like that anyway. So I guess I can’t blame all our differences on environment. 🙂

      As for working at your desk through lunch, that’s something I know all too well. But introverts prefer that, don’t they?…

      Thanks for stopping by, Vanessa. I know you’re in a bit of a blogging overload, so it’s nice of you to visit. Hope your Friday is good!

      Liked by 2 people

  5. emma

    The biggest difference for my sister and I (3-1/2 year difference in ages) is what we remember about the chaos and abuse in our family. It’s nice for me that she believes what I’ve told her about our childhood, even if she doesn’t remember all of it, and even though she’s found a way to develop a relationship with our mom, something I’ve never been able or willing to do.

    Like

    • Carrie Rubin

      Certainly the presence of abuse will mold personality, and each child will experience the environment differently given their age, just as you and your sister did. So sorry to hear that was the case for you. No child should have to experience that.

      Like

      • emma

        I’m just glad children have someone like you to go to, Carrie. In my day, no one talked about anything.

        Like

  6. Gwen Stephens

    Even though you’re different, it’s interesting to note that you’re both artists in your own way. I’m sure you marvel at the differences in your two boys. We do it with our kids, too.

    Like

    • Carrie Rubin

      Oh yes, my sons are very different from each other. They like to joke they came from different fathers (which they didn’t!). Teenage boy humor…

      Like

  7. acflory

    Very impressed! But the talent gene merely chose a different path to express itself. 😀

    Like

    • Carrie Rubin

      Thank you for the kind words. We do indeed have different interests, but we also have a lot of fun together. 🙂

      Like

  8. Angie Mc

    Reblogged this on Angie Mc's Reblog Love and commented:
    Insightful post. Helpful to understand sibling relationships. Carrie asks, “HOW CAN CHILDREN RAISED IN THE SAME FAMILY HAVE SUCH DIFFERENT PERSONALITIES?”

    Like

  9. Honie Briggs

    That song is awesome. You and your sister have talent. Wow, good genes! Funny, I’ve been studying genetics this semester in my anthropology class. Very interesting stuff. Five siblings in my family. Sometimes it is hard to believe we have the same parents.

    Like

    • Carrie Rubin

      My teen sons are very different, too, and as such, they like to tease each other they come from different fathers (which I assure you they don’t!).

      Thanks for checking out my sister’s music and for your kind words. I’m quite proud of her. 🙂

      Liked by 1 person

  10. pegoleg

    Very interesting. Treating kids differently because of their differences begets treating kids differently because of their differences begets….it’s a chicken/egg sort of thing.

    I’ve often thought if I could put my 2 kids in a bag and shake them up they could share their strengths (and mitigate their tiny, tiny weaknesses.)

    Sounds like you and your sister, however different, make a lovely fruit salad together.

    Like

    • Carrie Rubin

      It is kind of like the chicken/egg thing. Then you toss those genes in with it, and all bets are off. Luckily, even when sibs are different (like my sis and me), they can still get along and have fun (like my sis and me). Well, hopefully they can.

      Like

  11. Kourtney Heintz

    Very cool post. I’m an only child so I can’t really weigh in on this one. But I know lots of siblings who are nothing alike and I always wondered why. Thanks for answering that question!

    Like

    • Carrie Rubin

      Recent studies have suggested only children are better adjusted than those of us with siblings, so you have that to take solace in. 🙂

      Like

      • Kourtney Heintz

        I’m definitely very solitary. And I tend to be my own island. But I can be territorial with what is mine. 🙂 But I’ll take that better adjusted and wrap it around my shoulders.

        Like

  12. benzeknees

    I have only a sister & yes we are very different! We were both raised in an abusive home. My way to cope – hide, be very quiet, don’t make waves, bury myself in books. Her way to cope – be defiant, dare them to hit you. After a short time of hearing her get so many lickin’s I stepped in to try to save my little sister from herself. I hid her disobedience, I took the blame sometimes because it was easier to be hit than listen to her cry. I let her bully me because she knew I would never “tell on her.”
    Now we are adults, we have become much more the same – we are both damaged by what took place in our childhood home, we are both chronically depressed, we both experience severe panic attacks & bouts of PTSD. I turned away from my parents to help myself heal, my sister turned to our parents to carry her through hospitalizations & long periods of inability to care for herself.
    My sister & I are estranged – we are just too toxic to each other for a relationship.

    Like

    • Carrie Rubin

      So sorry to hear you had such a difficult and damaging upbringing. Certainly that can invoke personality traits all on its own. It’s interesting how you and your sister chose such different ways to cope. Our coping mechanisms are probably innate in us, but hopefully through things like therapy, we can learn others, too.

      Sometimes we have to distance ourselves from toxic people, even if they’re family members. Our sanity demands it.

      Thanks for your sharing your story.

      Like

  13. raeme67

    I have 9 siblings. Although I see some similarities, with ten kids how could you not? But, we are all different in many ways as well. I do see a vast difference between my son and daughter.

    Like

    • Carrie Rubin

      That’s right–you come from a huge family. How difficult it must’ve been for your parents to find one-on-one time with each of you. It’s difficult enough with two!

      Like

  14. Roy McCarthy

    But both talented creatively Carrie. I had twin brothers eight years younger, totally different. One quiet, withdrawn and thoughtful the other a sporting ‘jock’ (in your Ameri-speak 🙂 ) They spent little time together once adults but, when the quiet one died it had, and continues to have, a devastating effect on the other.

    Like

    • Carrie Rubin

      Oh, I imagine so. I’m so sorry to hear that. I can’t imagine the emptiness he must feel after losing his twin. And you, too, on losing your brother.

      Liked by 1 person

    • Carrie Rubin

      And it’s terribly uncomfortable too. All moist and sticky. And every now and then a seed goes up the nose.

      Like

          • Bruce Thiesen

            Perhaps they can skip all the intermediate steps and just give us a combination of a melon and apple. Meapple, or Melpple, or such. The important thing is that we just need something new and we need it now. The public is bored. There’s no more time to waste on these archaic fruits.

            Like

  15. Daniel Nest

    Whoa. That was a nice song. Your sister rocks!

    And I’m a bit disappointed that there isn’t a fourth theory explaining the differences: What if one sibling is a Virgo and the other is Pisces? It’s as if astrology is suddenly not a real science or something!

    My brother is 10 years older, so I kind of always took it for granted that we’re quite different with such an age gap between us. There are some interesting theories.

    Like

    • Daniel Nest

      I was meant to write “these are some interesting theories.”

      Damn…I’m the nitpicker of the family. I bet my brother would never return to correct his post like this.

      Like

      • Carrie Rubin

        Ha, maybe not, but I know I would. So yes, here’s to the Type-A-ers of the world.

        By the way, I meant to ask if chapter three of “Nano” is in the works?

        Like

        • Daniel Nest

          I wish I could say it was, but it’s put on hold for now. We have some (good) changes coming up at home, so I probably won’t have the chance to dive into it properly for a while. Thanks for checking up, though! I do intend to write more again one day…

          Like

    • Carrie Rubin

      You’re right. We should never discount the science of astrology. Or the advice of fortune cookies. And of course, those tea leaves need to be taken into account. P-values, sample sizes, and confidence intervals? Nonsense!

      Thanks for checking out my sister’s song. I’m pretty proud of her. 🙂

      Liked by 1 person

  16. Jay

    We’re very different, but it’s the small things that other people notice, expressions mostly, or a stubborn streak. We all look pretty different too. Once a woman told me and my youngest sister that she knew we were sisters because of our hair colour (which came out of a bottle in both cases). Another woman grilled us about our mother’s promiscuity becasue she was sure we must all have different fathers ( gee thanks!)
    Now that we have a new generation in the family, this one all boys (so far) we see it a bit differently. Easier to see similarties when they’re young but so fun to watch personalities develop.

    Like

    • Carrie Rubin

      It is, isn’t it? It’s been fun watching my sons come into their own. They’re very different from each other too, and they like to tease each other that they’re from different fathers as well (which they’re not!). Teenage boy humor…

      Thanks for reading and commenting!

      Like

  17. Silver in the Barn

    Fascinating topic. I listened to a DNA expert on NPR who explained that genes are like phone numbers (over-simplifying here). Yes, siblings are comprised of the same DNA but in each child it is reshuffled, he says, just like all the various permutations of phone numbers comprised of the same numerals. Made sense to me when I consider how very different my four siblings are from me – born within seven years of one another with the same parents and we are all quite distinct personalities. I am the only introvert, strangely enough.

    Like

    • Carrie Rubin

      Yes, those genes can manifest in very different ways. Combine that with the home environment, and it’s easy to see why siblings can end up so different. I suppose what ultimately matters though is how well they get along. 🙂

      Like

  18. PAMO

    Your sister is EXTREMELY talented! (As are you Carrie!)

    I’m the youngest in my family and think all the studies you’ve listed make perfect sense. 🙂

    Like

    • Carrie Rubin

      So Pam’s the baby of the family, hmm? That must be why you’re so sweet. 🙂

      Thanks for the kind words and for listening to my sissy’s music. Sorry your comment went to moderation. Not sure why that happened. WordPress can be weird sometimes.

      Liked by 1 person

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