Is the Oldest Sibling Really the Smartest? 

This post may contain affiliate links. Please read our disclosure policy.

Is the oldest sibling the smartest? Some researchers say yes, while others aren’t as certain. Keep reading because I’m going to tell you what the science says about the oldest child in the family.

(But first, do you have a stubborn child? Don’t let yourself get too frazzled and frustrated trying to change them. Turns out research shows that they could likely grow up to be a high-achieving adult.)

Studies Confirm - the Oldest Sibling is the Smartest

The Truth About the Oldest Sibling

Researchers have long debated whether birth order in a family had any measurable effect on where a child ended up as an adult. For some time they sort of threw up their hands and said, “Nah. This is probably all nonsense.”

In 2007 a couple of Norwegian epidemiologists decided to look again. Their research included 250,000 folks and actually showed a reliable link between IQ and birth order.

According to this study and another one done by The University of Edinburgh, first-born children “score higher than their siblings in IQ tests as early as age one.”

Why Would the Oldest Sibling Be the Smartest?

The Edinburgh researchers reported, “Although all children received the same levels of emotional support, first-born children received more support with tasks that developed thinking skills.”

They claim that parents changed their behavior after the first child.

They offered less mental stimulation to younger siblings and also took part in fewer activities such as reading with the child, crafts and playing musical instruments.”

Moms with more than one kiddo will totally understand. With a first child, parents are handed a fresh, new human and told it’s now their job to teach it what it needs to know and raise it up to be a kind, intelligent, happy adult.

We consume every book and blog post about raising children. We’re determined to get it right and someday release a fully functioning adult out into the wild.

The first-born has too many beautiful baby outfits and is held to the point that people start to joke about whether the baby will ever learn to walk. And the baby book? Baby #1 has a book that’s filled out with everything from baby’s first burp all the way to baby’s first day of school.

We follow all the rules with the first baby.

By the time baby #2 arrives, we’ve figured out that the baby books are not always right and even if they are, we’re just too darn tired to do things the same way we did with the first.

We love them the same. We’re still good parents. We definitely want to give every child the same attention we gave the first. And for the most part, we probably do fine.

But, when you start adding more kids, life gets way more hectic and parents are far more exhausted. So yeah. Maybe we let some things slide here and there. More kids equal less time.

More Facts About the Oldest Sibling

There are some other things about first-born kiddos you might want to know.

First-borns are in charge. They can be bossy and domineering because they are more often put in charge of things by parents.

First-borns believe in authority. They will often report any questionable sibling behavior to parents because the oldest child believes in rules. (Even if they don’t always believe in following them themselves.)

First-borns are perfectionists. Whether they are learning to tie their shoes, write their name, or study for an AP Bio exam in 11th grade, they want it to be perfect.

The most important thing to know about the oldest sibling.

You’ve just read about some studies and what researchers have to say. But remember, your first-born child may be the exact opposite of any example you read here.

Nothing is set in stone! That’s the most important thing.

Do you have more than one child? How do siblings get along in your house?

Leave a Review!

We LOVE hearing from you! Submit your question or comment here.

Your email address will not be published.

Your email address will not be published. Required fields are marked *

I accept the Privacy Policy

9 comments on “Is the Oldest Sibling Really the Smartest? ”

  1. Denise Arnold

    These studies sound spot on to me, of course we are talking about people and people are different and can differ from the rule. But for the most part, my three children follow suit with all the above criteria stated above. My husband is the oldest of 5 and his sister was his Irish twin, so I assume the two of them count jointly as the oldest. Their mother kept them together when they began school so that they graduated together and had the same group of friends all through HS. However, they fought all the time because they both were so stubborn and opinionated. But my husband being the more easy going of the two, would always allow her to lead any family get-together or party planning. We all called her the “boss”. I am the youngest and only girl of seven. Now here is my theory about my family. We were grouped in sections. My three oldest brothers group up very close together(about a yr apart each), and remained close most of their adult lives, the oldest of us all is definitely the smartest of us, and the second oldest would have rate 2nd. Being only a yr apart they were both so close and everything was done as one. Correction, I suppose the 3rd boy was nearly 2 yrs later after the second one. Anyway, they all three were very successful men brother #1 and brother #3 both retiring and starting up their own entrepreneurial business with their retirement funds to much success! Brother #2 unfortunately died shortly after retirement, but in the eyes of all who loved him family and friends felt he was very intelligent and skillful as a repairman in his spare time and a huge success in life.

    Son’s #4, #5, and #6, hit their teen years in the sixties and seventies during the drug and psychedelic years. They all three fell became drop outs/alcoholics/womanizers/steal drug money from my mom’s purse/spread the love and spread my seed/live on welfare/pump gas is my highest aspiration/spend time in jail is a right of passage/ lazy-do nothing-burdens-on my mother after she became a widow! So, we all backed her on kicking them out if they refused to work. One died already from AIDS, one is battling throat cancer, and had his larynx removed, the other is battling lung cancer(the two with cancer, they smoked pot and cigarettes, KOOLS and other cheap brands, all the time).

    Me, the seventh child and only girl. Well, I am told there was much rejoicing when I was born, and much disbelief as well such that family came from far distances to see that I really was indeed a girl! Anyway, by the time I became a pre-teen and teen, those “potheads” were rarely home and I had my parents all to myself. I assume when I was born and the next youngest boy was 4. The one older than him was 6. The two of them were off playing together and my mother was enjoying having a baby again so I feel I received a lot of attention. My oldest brother, the smartest one, got married just after I was born, and he and his wife took me places all my life. even after they had their own children. The second oldest married as well but moved out of state for a time during the Vietnam war while in the Air Force, the oldest went to Vietnam in the Army. Anyway, when I was 3, my mother began selling Avon as my father worked as a Brick layer and she needed to bring money in year round. She put me in the Head Start program I am sure so I had somewhere to go so she could work. I believe that helped me with that jumpstart in learning. My oldest brother is the only one of us to go to and graduate college so I wanted to imitate him. I went to college as well and was on the Dean’s list like he was and everything. But I dropped out after 2 1/2 yrs to raise a family.

    Our oldest as I have always said is just like my oldest brother, went is the only one of our kids to finish and get a 4 yr degree so far. The other 2 have some college. Our youngest our daughter, in most ways is like me, she is a stay-at-home and a work from home. She has an amazing creative side and is talented musically and vocally. Intelligence is a subjective thing. Some look at intelligence as book knowledge, some a combo of book and common sense. I am of the belief it is of the latter, the combination of the two. Our second son I always thought he was a dream come true as far as academically until we got to middle school, lol. This poor boy, is the most unorganized kid ever, and in middle school you have got to figure out how to be organized and keep your schedule. Some things happened and we homeschooled him as well and he ended up becoming the most self disciplined, responsible, easy to teach student you could dream of, so sometimes a person is born with an ability to learn quickly like our second son, but have other abilities come more slowly.

    1. Dolly Sweeney

      Thank you Denise for your family story. I see so many similarities to my father’s family. He was oldest of 11. And with my 5 children. I once (as a teacher’s aide) attended a workshop on family order. We were seated according to our birth order: only, oldest, older of 2, younger of 2, middle, and baby. We were told to complete a questionnaire as a group. At my table (oldest), many of us reached for the form, but I got it (I am also the oldest of 40 grandchildren!) At the baby table, they talked about the questions, but NOBODY completed the form. It was an eye opener since most of us were oldest and onlies. And most of our students were babies!

  2. I am the eldest in my group of siblings.  Arguably, I am the most stubborn, rule following, opinionated and successful.  Natural for me to take charge in a situation with a group solving a problem and natural for me to dictate what my siblings should do.

    My eldest daughter is very much the same.  Stubborn, Opinionated, leader, go getter, high achiever, perfectionist and successful.  

    Found my daughters baby books to be exactly as stated. 1st one complete, 2nd lots of blanks.

    1. Mary Sanchez

      I’m the first-born and relate to some of this….especially as it pertains to my parents. But I’m not the bossy one and not the one striving to be the best, that’s my sister – the second born. I went further in school than my sibs and held managerial positions but I’m not the Type A that my sister is.

  3. Christine Caron

    What about the 3rd or youngest.  I’m the 3rd and I’m also the youngest.  You don’t give info on them.
    We are always left out. 

  4. Connie Cooke

    Right on! My first son (I have two “boys” – grown way up!) has a really high IQ. He was reading at 4, telling time (on a real clock) at 3 1/2. Early on, he loved books and would come out with as many as he could carry for me to read to him. He had an impressive vocabulary. He would, and does, learn everything there is to know about a subject he’s interested in. He loves music, sang in the college choir, now sings with a caroling group, and loves going to the theater, although not really wanting to be in a play. He was pretty quiet as a child. In high school, he took “computer science” in 10th grade and absolutely ate it up. This was before PCs and cell phones. His teacher was a retired college professor. This changed his life. At 50, he is now a senior software engineer and doing very well.

    On the other hand, #2 son was the happy-go-lucky, always smiling kid. Everyone he meets is his friend. When it came time to read to the boys, he’d sit for one or two books, but then had bigger fish to fry! He had very little interest in school except for the social part. His teachers would say he was a joy to have in class but his mind seemed to be elsewhere. He enjoyed performing. In high school, our biggest blessing was our car insurance, because he had to maintain a B average to keep his insurance, and he had to drive quite a ways to school. We never verbally compared them to each other. He got through college, thanks to his music classes. He performed in local theater a lot, and went to New York and Florida to perform also. At 48, he now is married with two boys (who also fit the profile!) and is a high school music/drama/stage tech teacher, loved by his students and fellow teachers. So, yes, the birth order profile fits well!

  5. Jason L Petersen

    I have to ask, are you the oldest sibling in your family? Inquiring minds wish to know!

  6. They fight awful and love astoundingly. Just turned 5 and almost 3, we have not had them from birth. They are grandsons, so after 3 of my own, this article hardly applies. My youngest is 25. We have had the boys since 2 and 7 months, part time and full time last 7 months.  This is it for them. We are still picking up pieces, and will forever as their dad died 2 weeks ago. My son. The older boy is extremely protective of his baby brother but also rats him out. The younger has 2 speeds:  full speed ahead and off. Older is smart, younger is really smart. I think they are here just in time or still with time. 

Scroll to Top