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Hey, don’t get all bent out of shape about it. It’s just a fact — at least according to Norwegian scientists — that older siblings tend to have IQs about 2.3 points higher than their junior sibling. Likewise, that junior sibling, should he or she have an even-more-junior sibling, is probably a bit smarter than that person. Turns out that IQ tests are mandatory for people entering the military in Norway, so statisticians had hundreds of thousands of young people’s IQ tests to sort through, and came up with this little theory (published in New Scientist). So what’s the reason? It’s not genetic, it’s social:
Older siblings might have a higher IQ because they act as surrogate parents from time to time, tutoring their younger siblings in certain situations. Another possible explanation is that parents have more time and resources to invest in their firstborn child. As a result of this, the eldest child usually has the most one-on-one time with its parents, and receives greater exposure to their sophisticated vocabulary.
They also note that second-born children whose older sibling(s) died early in childhood scored on par with other firstborn kids; on average, all were 13% more likely to be of “above-average” intelligence than their younger siblings. Now, I’m sure some of you will disagree based on personal experience, and I think I speak for everyone when I say, we’d love to hear some stories about dumb things your older brother/sister has done. Let’s see if we can turn this thing around!
When I was in school, the theory was that genetic studies indicated that firstborn children get a higher “dose” of the parents DNA, and that the parental DNA then takes about 7 yrs to replenish. So if Einstein and Madame Curie had a baby, their firstborn child would be like them, and then it woud take 7 years for them to be able to produce another “mini-me”. Any children born in-between would vary farther from the parental characteristics. It’s interesting…There are 4 children in our family, and whether this actually happened genetically or just b/c we are strange, I don’t know, but as the eldest child I am VERY much like my parents. My brother and sister born within 6 yrs are quite different. Then 10 years after me, along comes another boy, another guess what? he’s just like us in many respects, although he adopted many of MY characteristics on my parents personality type. Odd.
posted by sandra on 6-22-2007 at 7:37 am
I am the oldest of my siblings, and I certainly agree with this theory!
posted by Michelle on 6-22-2007 at 7:55 am
Many people assume I am an only child when they first meet me. Many have suspected this after knowing me for years, however, I have an older sibling. I can attest that he is smart in some ways, but completely dumb in others. I think because I was forced to be more like the elder sister, that I wind up seeming more intelligent. Whether this is true or not, doesn’t matter. To me, he’s still the kid who showers before he mows the lawn on a hot August day. He makes no sense. :)
posted by Amber on 6-22-2007 at 8:17 am
Why are half the people reporting this story failing to mention that it only studied boys? You can’t just make the leap of “Oh, it must be the same for girls, too.” That’s hardly scientific reasoning. My oldest (and therefore eldest) son is the youngest of my three children, so if I’m reading it right the study offers me no conclusions on him, nor on his sisters.
posted by Duane on 6-22-2007 at 8:19 am
I’m the middle child, and I have the highest IQ in my family.
posted by Jerrod on 6-22-2007 at 8:38 am
Some classic quotes from my older sister:
(When she was 14) “Why do you have to rotate your tires? I mean, they rotate when you drive anyway.”
(On a camping trip when she was in high school)
Mom: I’m tired. I think I’m going to go lie down in the tent and take a siesta.
Sister: What’s a siesta?
But, in all fairness I should mention that she did score one point higher than I did on the ACT.
posted by Molly on 6-22-2007 at 9:14 am
I completely agree with this theory and even more so with what Sandra had to say on the matter. I am the middle child of five and, though we’ve never taken nor compared IQ tests, it’s safe to say that mine would be the lowest. SAT scores, however, do support this theory.
My oldest brother and my younger sister are considered the brightest of the bunch. There are 7.5 years between the two of them, and only 3.5 years total between the first three kids. Being the third born, I feel like my ‘dose’ was from the bottom of the genetic barrel. The rest of us are still bright, but there’s a clear difference in how hard we had to try to get there.
*Duane-where does it say that it only studied boys? I’m sure there are girls in the Norwegian military, too.
posted by moranne on 6-22-2007 at 10:33 am
My brother has always been better at grades than I but when it comes to simple walking around sense I win. One Thanksgiving my mom let him make a pie. He had to add salt to the recipe and he had no idea how to open the container (the one with the metal spiget on top.) So he opened it with a knife and spilled salt everywhere!
posted by Rachel on 6-22-2007 at 1:13 pm
I’m an older sibling, so I’m perfectly fine with accepting this theory. I do seem to have less trouble with things like math and spelling, and I sure read faster, but I’ve done some pretty dumb things in my life. Like the time I was looking at something else and nearly walked into a telephone pole. Or the time I actually walked right into a glass door. (Although I’m SURE that it was open when we came into the store. I swear, it was. And it was a VERY clean door, in my defense.)
posted by Pointy-Hatted Geek on 6-22-2007 at 1:49 pm
I’ve always wondered why everyone thinks I’m older than my brother when he’s actually two years older than me!
posted by Jess on 6-22-2007 at 2:33 pm
I’m a first born and so is my husband.When I was studying Nature vs. Nurture, I had my husband, his younger sister(who was adopted & was 9 months younger) and myself(I’m 9 months older than he is) all take I.Q.tests. I wanted to see if there were any differences. We all scored within 4 points of each other!
Many times people of higher intelligence tend to be a little like “The Absent Minded Professor” when it comes to normal everyday common sense things.Hence the “siesta, salt & glass door” story’s My hubby forgets to lock the front door at night & turns off the light in the room when I’m still in it.
Me,I’m perfect…NOT!
I read that all of the early astronauts were either first born or only children, not only because of their smarts but because they could handle being alone for long periods of time.
My children are 19 months apart but my 10 year old daughter “mothers” my 12 year old son,they are almost like twins. She just brought home her report card today with all A’s.My son, on the other hand, just finished his first year of middle school and has ADD, they mail the report cards home, but I expect to see A’s & B’s.
posted by CropTillDawn on 6-22-2007 at 2:57 pm
I think what many people are overlooking the simple fact that it’s the role in the family the causes the intelligence boost– not a genetic inheritance.
I cared extensively for my dumb-as-a-rock little sister and autistic little brother (I have a borderline genius IQ), and all of the middle children I know who are brilliant little bastards have deadbeat older siblings who were either never around or didn’t have the baseline IQ to care for anyone or anything (including, apparently, puppies.)
I think this might be a case of parallel causation. Being saddled with complex responsibilities at an early age leads to higher IQ, but in turn, higher IQ means that you’ll be saddled with babysitting duties.
posted by Brammimonde on 6-22-2007 at 4:04 pm
My younger brother and I are a lot alike academically–we score high on tests, especially standardized ones, but slack on homework. The difference is that he started slacking and getting Cs and Ds in 5th grade; my first C wasn’t until 9th.
That might be more like study habits than intelligence as we both probably have somewhat high IQs, but still, makes me think.
posted by Courtney on 6-22-2007 at 4:08 pm
There was a lady who went to church with my family when I was little. Her Eldest son had an IQ of 72, her middle child had an IQ that qualified him for MENSA (I think it was in the mid 150s) and her youngest son was average; possibly the world’s most average person in every way. He should be contacted for focus groups.
posted by lee on 6-22-2007 at 4:57 pm
In the New Scientist article: “Petter Kristensen, at the University of Oslo in Norway, and colleagues reviewed data collected from 18- and 19-year-old men drafted into the country’s military between 1985 and 2004. These young men took intelligence tests as part of their compulsory military service.”
Just men, a little odd, eh?
posted by Ed on 6-22-2007 at 5:00 pm
I am the oldest of seven and completely agree with this theory. :)
posted by Seantal on 6-22-2007 at 7:55 pm
It’d be interesting to see some twin data on this thing.
posted by Ryan on 6-22-2007 at 8:32 pm
I read a a study that explained the effect in a different way. The first child is influenced by two adults with a (supposedly) decent grip on life. The second child is exposed to family influence that is only 2/3 adult and 1/3 somewhat clueless child. The third child is influenced only 50% by adults, and 50% by young siblings.
posted by Miss Cellania on 6-22-2007 at 8:43 pm
I can certainly believe that theory. My older sister is currently working in Nicaragua and can switch from English to Spanish so quickly and easily that you don’t even realize it at first.
I, on the other hand, have just started college and can barely remember half of what I learned in two years of Japanese.
posted by heather on 6-22-2007 at 11:54 pm
My older sister and I both seem to be highly intelligent. We lead very different lives, however, so it’d be hard to tell who’s smarter. I don’t think it matters much.
posted by Aemi on 6-23-2007 at 4:14 pm
I have read repeatedly that the oldest or only children tend to be smarter, most things I have read on this point to more time paid to the oldest sibling.
It is an interesting theory on 7 years to replenish genes, and seems to fit in my family of 3 where as the oldest I am by far the smartest (with the IQ test to back it.) The next in my family is 7 years younger and well above average, despite a reading disability. The youngest is average intelligence, but her grades blow both of us away. My boyfriend is the youngest of 5 but significantly younger than his next oldest sibling, also the smartest in his family.
posted by Sandra on 6-24-2007 at 12:26 am
I am 3 years younger than my brother and scored higher on every test we’ve had in common. He also dropped out of college after the first year, while I graduated a year early. My brother is still one of the most intelligent people I know.
Heather- As a native English speaker who speaks both Spanish and Japanese, I was wondering if you had considered that the two languages are very different. Spanish shares roots with English, uses the same alphabet, many of the same sounds and grammar structures, and has a similar thought process. Japanese has no common root, three very different writing forms, a reversed grammar structure and a very different way of thinking.
posted by Liz on 6-25-2007 at 3:26 am
although my older brother is smarter than me in a lot of ways, when it comes to some subjects or even common sense, i can evenly match him or out-smart him.
i disagree with this study 100%
posted by trouble on 6-25-2007 at 12:56 pm
I’m not technically the oldest. I’m the second of a pair of twins, but my brother and I were born first.
I’d say my (twin who is slightly older) brother is the least smart of the three of us. He’s still pretty smart, but he make stupid life choices, and he only got a B average.
I’m good at school, but I have no street smarts.
But my little sister is probably going to be the Valedictorian of her class.
I think this is because my brother and I were homeschooled for three years and my sister for five (as she is two years younger) before entering high school. When the three of us were homeschooled at the same time, Mom would always help my sister because she’s youngest and needed it most.
If my brother and I were morphed into one person, I think this study would be true. But as twins, we are but halfpeople.
(Also, the doctors put her in a warming oven type of thing when she was born, and forgot about her. I believe the term “Oh $%@!# she’s still in there?!” was used. We in my family believe that this leads to her superhuman smarts)
posted by Mary on 6-26-2007 at 3:34 am
I’m pretty sure the “seven years” rule is either ridiculous or misstated. I could see how a mother’s body might need time to recover and be optimal for another gestation (in terms of nutrients, residual hormones, or strength of the womb, etc.), but the idea that one kid gets a “higher dose” of DNA is silly since we all get a random assortment of half of our father’s DNA and half of our mother’s (except in rare cases like Down Syndrome). As for the gametes themselves, females are born with all of the eggs they will ever have, so I can’t see how their genetic composition would be impacted by recent births. Sperm are also created by splitting dad’s full DNA, so there’s no way he could give more or less of his unique DNA to one child or another. I’d love to hear some scientific explanations for this supposed seven-year rule, but I’m not buying it now.
I agree with Duane, studies with only boys may be misleading. Given the heavier babysitting demands that girls probably get, mixed families probably have different results than all boy/all girl broods.
posted by Parker on 6-26-2007 at 9:21 am
I completly agree with parker in regard to this “seven year rule” thing that was mentioned. Although I do believe genetics does play some role I’m not quite certain of, I genuinely believe intelligence is mostly nurtured. I do suppose there are some people out there with lower intelligence due to inferior genes. And also, as some people have already brought to our attention: making better grades than someone else in school is not proof you are more intelligent or more capable than they are. This could simply mean you take more pride in your academics or you have a better work ethic. There is more than one kind of intelligence; some people are quite intelligent in one area and seriously lacking in another.
posted by snuffedsenses on 7-13-2007 at 3:07 pm
I disagree with this theory. I have two older siblings and I’m the youngest. My Older brother who is the frist one, is def. smarter than me but my older sister is just so dumb. When I argue with her she just makes no sense and she dosen’t understand what i’m talkin about and says random words which does not fit in the conversation.
posted by Irene on 12-15-2008 at 11:55 pm