In 2009 my colleagues and I published evidence that birth order influences whom we choose as friends and spouses. Firstborns are more likely to associate with firstborns, middle-borns with middle-borns, last-borns with last-borns, and only children with only children. Because we were able to show the effect independent of family size, the finding is unlikely to be an artifact of class or ethnicity. The result is exactly what we should expect if birth order affects personality. Despite the adage that opposites attract, people tend to resemble their spouses in terms of personality. If spouses correlate on personality, and personality correlates with birth order, spouses should correlate on birth order.
Thus, the evidence seems to be shifting back in favor of our common intuition that our position in our family somehow affects who we become. The details, however, remain vague. The Norwegian study shows a slight effect on intelligence. The relationship study shows that oldest, middle, youngest and only children differ in some way yet gives no indication as to how. Moreover, although these effects are reasonably sized by the standards of research, they are small enough that it would not make any sense to organize college admissions or dating pools around birth order, much less NASA applicants.
Still, I expect people—myself included—will continue to try to make sense of the world through the prism of birth order. It’s fine for scientists to say “more study is needed,” but we must find love, gain self-knowledge and parent children now. In that sense, a great deal about who we are and how we think can be learned reading those shelves of birth order–related self-help books, even if the actual content is not yet—or will never be—experimentally confirmed.
Note this story was originally published with the title "Ruled by Birth Order?"
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58 Comments
Add CommentSo families with many children are favoring "quantity over quality" so to speak?
Reply | Report Abuse | Link to thisAlso adds a dimension to the Chinese one-child policy.
This is complete nonsense and the fact that crap like this continues to be published is alarming.
Reply | Report Abuse | Link to this@yawhey, sure you didn't forget an "n" in your name? just from experience i can tell you there are fundamental differences in the personality and behaviors of folks with different birth orders, if you can't see that, well...i just don't know.
Reply | Report Abuse | Link to this@yawhey, sure you didn't forget an "n" in your name? just from experience i can tell you there are fundamental differences in the personality and behaviors of folks with different birth orders, if you can't see that, well...i just don't know.
Reply | Report Abuse | Link to thisI guess whether one is happy to accept the study on siblings intelligence depends on where you came in the pecking order. Plus, I'd be interested to know if any studies have been made on effects of gender re this issue.
Reply | Report Abuse | Link to thisJane (first born, two younger brothers....)
none of this birth order stuff rings even remotely true for myself and my family - we are opposite the assumptions in virtually all respects. it looks like a modernized form of astrology from here...
Reply | Report Abuse | Link to thisThere has to be differences as parents tend to become more and more relaxed and comfortable ie: less paranoid concerning their children as they have more. I have 2 older sisters (I'm a boy), and for one, I definitely have a higher IQ than either of them. Secondly, I resemble my eldest sister in terms of personality, but the middle child sister is just... ugh. She's whines and has a lot of paranoia/stress (she had IBS for a while from stress). I'm sure there's some importance to order of birth but it's not genetic.
Reply | Report Abuse | Link to thisdah.... the readers comments seems to indicate that they are born very low in the birth order ranking.
Reply | Report Abuse | Link to thisCan't they avoid stick to to ME, ME, ME.... that leads to poor statistical inference.
@javogh
Reply | Report Abuse | Link to thisYou still must factor for people's psychological profile being influenced by accepting these 'facts' about themselves.
Even if you don't believe in Taurus, if the subject self-identifies as a Taurus, they'll display related traits.
dah.... the readers comments seems to indicate that they are born very low in the birth order ranking.
Reply | Report Abuse | Link to thisCan't they avoid stick to to ME, ME, ME.... that leads to poor statistical inference.
I was surprtsed that the author didn't mention Frank Sulloway's "Born to Rebel", which took a Darwinian approach to birth order and its relation to political radicalism.
Reply | Report Abuse | Link to thisI am surprised that the author didn't mention Frank Sulloway's "Born to Rebel," which examined birth order and political radicalism in teerms of evolutionary psychology.
Reply | Report Abuse | Link to thisWhile not denying birth order as an influential factor in determining many aspects of personality, studies of a selected population have limited value. Scandinavian countries and Japan, for examples, have relatively homogenous social characteristics that can affect outcome. Selecting a population suffering from pervasive hunger would surely affect outcome, as would a population such as Louisiana residents for those children born before and after the hurricane. This report offered no convincing new evidence.
Reply | Report Abuse | Link to thisReading the comments, I wonder whether they have actually read the article, eg "Moreover, although these effects are reasonably sized by the standards of research, they are small enough that it would not make any sense to organize college admissions or dating pools around birth order, much less NASA applicants."
Reply | Report Abuse | Link to thisI'm sure we all had an uncle, who drank a bottle of booze and smoked 50 cigarettes a day, and lived to be 95, but we all know ( I hope) that doesn't prove, that it's healthy to do it.
I can calmy bask in the certainty of being by far the most intelligent, though the last of three sons, I have been married twice, to a single child and a firstborn, etc., but that is neither here nor there.
Statistics apply to a great number of incidents, but not in any significant way, to individuals. And, as some Monthy Python film stated, we are all individualas, except the guy who shouted, "I'm not"
Well, I rather AM a statistical anomaly here! I was the only child of an unmarried couple, and given up as an infasnt for adoption. The wonderful home I was adopted into had already adopted another son. So my big brother (in all but genetic relations) would be in the "first" position, and I would be in the "second"... or would we?
Reply | Report Abuse | Link to thiswe have two from a first marriage and two from our current marriage--how do two sets of kids sharing one birth parent figure into this?
Reply | Report Abuse | Link to thisThe author of this article falls into a bad trap at the end. He admits that "I expect peoplemyself includedwill continue to try to make sense of the world through the prism of birth order.", yet he also clearly states that, at best, there is a "a small but reliable negative correlation" in one study in one country. So for an individual to generalise the traits of a single person encountered based on birth order strikes me as about as helpful as using their star sign. The probability may be ever so slightly better, but certainly not enough to make sensible conclusions, as is basically just stereotyping.
Reply | Report Abuse | Link to thisIt would be advisable to disclose the methodology used in this study.
Reply | Report Abuse | Link to thisso i'm number 8 and all this since -no-sciesne- no- sience stuf confuzes me.
Reply | Report Abuse | Link to thisIf the base assumption is that parental resources/attention affect the intelligence of the child then this study is inadmissible for anyone who is not Norwegian. This is a sample of a homogeneous population with a distinct culture. Behavioral assumptions, i.e. parenting style, cannot be extended to a larger group. The study doesn't speak to the larger population at all.
Reply | Report Abuse | Link to thisLike any statistics you can interpret them to either prove or disprove your argument depending on what slant you put on them. For instance I bought a product that said it was 97% fat free - that meens it has 3 % pure fat in it - Yuk.
Reply | Report Abuse | Link to thisAs a CO/GP I had the hunch that two factors may influence the observed disparities: first born get more attention, care and a more stimulating environment, as they are the only ones,at least for a while, and also each delivery depletes the iron, vitamins and minerals stores of pregnant woman, a factor also shown to influence development. Thank's God this issue is extremely eeasy to fix
Reply | Report Abuse | Link to thisThis is shocking to read:
Reply | Report Abuse | Link to this"For example, wealthier, better-educated parents typically have fewer children."
It's the opposite. If you're wealthy, you have more children than average, not fewer. First you have more resources. Secondly, fertility is a health issue. Poor women have fewer children on average, less than 2 as it happens.
Actually, the quote specifically lists wealth AND education as factors in the number of children had. One of the basic things taught in my Economic Development class was that better-educated folks tend to have aspirations that are more career oriented, thus child-bearing becoming a lower priority.
Reply | Report Abuse | Link to thisAs for less educated, poorer folk, statistics show that they are less aware of the advantages of contraceptives and/or have less than optimal judgement when engaging in child-bearing activities, thus unplanned parenthood becomes a common event. It has nothing to do with pre-planned intentions.
All in all, just compare child birth rates in developed and 3rd world countries. You'll see that the findings support the quote you found so shocking.
" But two studies from the past three years finally found measurable effects"
Reply | Report Abuse | Link to thisTranslation: We didn't like the results, so we just kept massaging and massaging the studies until we got one we liked and then declare IT to be the accurate study.
The factor that appears to me to be ignored in addressing this question is the most important and obvious. What no one seems to address is that humans are primates and our familial conduct is governed by the same social forces as other primate societies. Families are little societies, cults :-) really, and there is a predictable dominance hierarchy among siblings as more children are introduced. Older children are the bigger, stronger, more world-wise and therefore tend to be more alpha members of that society for good or bad.
Reply | Report Abuse | Link to thisChildren model how the world works and how to cope with it based on what they learn from their parents. Younger siblings do the same but they also model the world based on what they learn from their siblings, like distorted echos of their parental example. By way of example if a parent governs the "tribe" abusively you would expect the older, larger, stronger siblings tend to visit this same behavior to govern the younger, weaker ones. This is the classic genesis of a bully for example, visiting the abuse they suffered on the more vulnerable. At the same time if the parent governs and nurtures the younger siblings make likewise get to much of this, the "baby of the family" condition. The younger may be more likely to be followers, more indulged or more abused depending on a particular family dynamic.
I would hypothesize that the larger the family the more pronounced the effect, with older children tending to de facto take over more of the parenting modeling role to the younger children.
While these may be poor examples they are just to illustrate why you would expect to find a tendency to different personalities based on birth order: as children they adapted their behavior to cope with their station. It is no great mystery, the above dynamic appears clear to me to be the most probable cause of it.
A couple of further predictions from the family-as-a-society theory. Older siblings would tend to have more initiative or be more responsible because they grew up 'governing,' they would tend to more self-assured or even narcissistic because they were raised with 'underling' siblings as minions.
Reply | Report Abuse | Link to thisIn fact I believe many of the problems between adult siblings result from an inability to recognize and replace this childhood relationship with a more adult coequal relationship, perhaps with an older sibling expecting unreasonable control or a younger sibling expecting unreasonable support.
Are you sure about this? Here in Asia first born are way smarter than their siblings. I am a first born and I have an IQ of 132, my middle born sibling has an IQ of a near moron state, 79, whereas out youngest has a normal IQ. And unfortunately I have more "Last Born Child" friends and my youngest siblings has more "First Born" friends, contradicting the statement above.
Reply | Report Abuse | Link to thisThe authors of this study seem to have been born in lower birth order it looks from the way they handle statistics!
Reply | Report Abuse | Link to thisOn the contrary, it looks as if the authors this study seem to be born lower down the birth order from the way they handle statistics! Yes, smaller families enable parents to provide better education and better quality of life to siblings! But, I have seen in many many large Indian families, the younger children more sharp, inquisitive and knowledgeable! The advent of information and knowledge era and the way Indians handle the same stand testimony to this fact!Sample size being so small, such conclusions are not expected to be reflecting the true picture around the world!
Reply | Report Abuse | Link to thisThe evidence for birth order effects is very weak. You would have to control for so many other factors that are undoubtedly much more important: prenatal nutrition, how much stress the mother is under, family economics, childhood trauma or diseases, education and social class, basic genetic differences. The correlation you are getting may have more to do with the questions you are asking than the actual fact of birth order. Perhaps we should ask how children born at different times in their parents lives are treated differently. There are also the studies that show that children born late in their parents lives are prone to more mental conditions such as autism and other disorders possibly linked to accumulated genetic damage. Then there is the issue of gene silencing, and even the fact that mothers carry cells from their babies in their blood possibly for years after they are born. There are so many confounding factors, I doubt that anyone can lift this idea out of the realm of folk wisdom. It might have more truth than some doubletalk nonsense like astrology, but it would be incredibly difficult to prove that the actual order of birth had anything to do with the differences observed between siblings. If I had to rate my 8 sibs on intelligence for example, ranked by birth order I would put it 9,10,5,7,8,9,6,9 which would be pretty much random distribution. Further, in our case family size clearly had little to do with intelligence, as the entire family with the exception of one is clearly well above average intelligence, and that one shows signs of possible birth trauma, which would probably be pretty random too. So all in all, I think this person needs a different thesis project, as I would never give them a degree based on this one... muddled thinking throughout! C-
Reply | Report Abuse | Link to thisMax Power , I think your off the cuff analysis may have some merit, in that the large family is indeed like a little troop of chimps. With our family, the older parented the younger. How good a job did we do? The younger kids certainly never lacked for attention. Plus many of the toys and other resources given to the older kids were hand-me-downs, and enriched the lives of the younger ones. One effect was also the availability of a "protector" at school for the younger ones protecting them from bullies, and even helping them with school work. Still there were also the expectations imposed by parents and teachers on the younger wanting them to measure up to the older, and at the same time benefit from learning from the older's mistakes, and the increased experience of the parents. Now if we list again the number of children that each sib had by birth order, we get: 1,2,1,1,3,0,1,0 . Does this say any thing other than nobody was interested in having 8 children? Still, I think it was a fine way to grow up, especially since we moved so often, and lacked the extended family a child raised in a village would have. I still think actual birth order would be found to be meaningless if you corrected for all these other confounding factors, like the things I mentioned, like if your older sibs were supportive or abusive. In our family's case our income and status continued to rise as my parents had more kids, and my father continued to increase his experience and moved to ever higher and better paid positions. Possibly because the demands of the larger family made him work harder. This would have a very different outcome if the main breadwinner was stuck in a dead end, and maybe both partners had to work, and the income was static, then each child would see a smaller share of resources based on birth order, until the older sibs could start working and add to the family income, or at least take off on their own, which also happened to our family. More so, in our family, the older sibs had to pay their own college expenses, while the younger sibs got help, because as the older ones left, there were more resources for them. This would lead you to think there would be lower scores in the middle, because these kids didn't benefit from first born status, nor did they get the benefit of being at the end and having all the family's resources to assist them as they moved into adulthood. We were a good strong middle income family with adequate nutrition and health care. How this would have played at the lower income levels I don't know.
Reply | Report Abuse | Link to thisBirth order probably does have an effect of some kind, but we simply don't know enough to make a call.
Reply | Report Abuse | Link to thisI will say that I'm the youngest of 3 and believe myself to have the highest I.Q., whatever that means. So that contradicts, but again nothing is written in stone.
Also, in high school, out of my group of 10 friends, 7 were the youngest, one was the oldest, one was the middle child, and one was an only child. 7/10 is pretty significant.
I also wouldn't reject the hypothesis that the youngest siblings are most likely to engage in risky behavior, with the oldest probably being the least likely.
I think the astrology metaphor might be apt, though -- it's all just a fictional narrative that influences our self-perceptions.
I have read studies that large families tend to be more abusive as well. I do not think we should give per child tax credits in light of this information.
Reply | Report Abuse | Link to thisMy sister married a 1st born. I married a middle child like myself, my brother the youngest married the youngest of 7. I find most first born seem to be type A personality's. My sister MUST be right or there WILL be blood!(Think Hillery Clinton!)., On the other hand her husband is also a type A personality, But he is more like Bill Clinton-Obama a charmer, but do NOT stand in the way .
Reply | Report Abuse | Link to thisMe I am the middle child as is my Husband, we both have whats called the Amiable type personality,But I am bit more imp even at age 47.
I was a stay at home mom , until our only child married last year, Now I a Pyro, I make Jewelry with a Torch and Glass!. My husband , Interestingly enough he is a freelance Corporate Trainer ,he also is a Training Coach.
My brother is a lovable sort ,His nick name is "Homer" His wife is also sweet and a bit silly like my brother.
I think of the first born as the "Perfect DO BEE" child. My parents were very strict on her and expected her to make A's They also made her responsible for my actions, which was not fair by any means, harder still ,when you have a younger sister who has undiagnosed IMPULSIVE HYperactive ADHD. Unfortunately for both of us, I made her life a living hell, as I didn't know the meaning of the word NO. So my sister endured the wrath of my parents and in return, my face took the wrath of my sisters beatings ( gives a whole new meaning to there will be blood now doesn't it?!)
I became the space cadet , the one that was always going to the hospital because "I didn't notice the dog that tore open my face was foaming at the mouth had Rabies
Nor did I take note that the old lumber pile I jumped on from the roof, had 3 inch nails ,FINELY took note of the 3 inch nails that came out the other side of BOTH hands and one foot, and my severed right ear! That was BEFORE age 5!
MY Much younger brother (by 6 years) became my parents pride and joy and basically their pet. He became the life of the party, class clown.I love the critter , I also love to find ways to scare him. How easy he forgets! Last year we were walking outside. He said he liked I was now his BIG, little sister ,and he was NOW the BIG lil brother, The 6 foot 5 BIG little bro forgot his place He Didn't see my hand ,until it was too late. Big lil 5 foot 4 sis took his hand ,she was now hugging on a LIVE Electric Cow fence, making Lil bro scream like a little girlie man, while shouting YOUR THE BIG SISTER YOU ARE the BIG SIS..LET ME GO!( I still Snicker at that, it WAS worth the shock.!
I think that looking at a family as a troop of monkeys society at least shows that there are identifiable inherent social forces of dominance, subservience, responsibility, privilege, protection, etc. that operate within any family according to birth order, like any primate society. Factor in the immature understandings of the (parents are alpha) "beta, delta, gamma" 'co-parenting' older siblings and you have reproducible effects. The coping mechanisms of a sibling of a given birth order could be shaped by these forces in a predictable way.
Reply | Report Abuse | Link to thisTherefore the effect of birth order are not necessarily like astrology or other hokum, these effects are real.
We can call this the Malcom-In-The-Middle effect.
There may also be something to the genetic deterioration of aging parents as they give birth to the younger children too.
the only logical thing that comes to my mind is that usually parents put more effort into the first born child so naturally he come out to be smarter than his siblings. But anyways, there are exceptions to this first born IQ theory and you find a lot of them everyday. However I would extend my congratulations to SA for shedding some light to an interesting topic. Thanks SA :)
Reply | Report Abuse | Link to thisfirst borns might be more control oriented, but later borns are more likely to reject any type of control imposed on them.
Reply | Report Abuse | Link to thisAlso, The fact thet the authors are first borns make the article biased.
Reply | Report Abuse | Link to thisI happen to agree about the birth orders,...,I come from a family of 7 siblings and WOW, you could sit down with us, talk with us, and definitely tell our birth order just by some controlled, documented methods.
Reply | Report Abuse | Link to thisI cannot believe, from the comments, that the readers are intelligent readers of Scientific American.
Reply | Report Abuse | Link to thisI come from a family that had 3 boys. I am the first born and I know I'm smarter than my 2 younger Brothers. I married my Wife who is a first born in her family, my middle Brother (second born) married his Wife, a second born in her family. My youngest Brother (3rd born) married his wife who happens to be the 3rd born in her family. I always felt my parents favored my youngest Brother (he got more than I did) however when I asked my Father about this later in life, giving him examples that I had observed growning up, he did admit that it was true, but explained that by the time my youngest Brother came along that my Father was better off finacially and could afford more things. This made sense at the time, but not when I was a kid. With my first Wife I had three children, the first born was a girl and was the smartest of the three. The second born was a girl and was a royal pain in the ass, as was my second born Brother. The third born was a boy and like my third born Brother was not too bad.
Reply | Report Abuse | Link to thisI had one child with my Wife of the past 33 years and this only child is by far smarter than anyone of us. She graduated with honors with a Bachelor's degree in Spanish. Has a good job much earlier than any of us ever did and will start on her Master's Degree this Fall also in Spanish.
I am a firm believer in birth order and it's effects on personality, intelligence and anything else in life. I know this is true because I'm first born and the smartest of the group along with my only child who is as smart as I am...
Respectfully,
First Born
I'm wondering what affect parental age has in the IQ of later born children. If things like chromosomal abnormalities are not controlled, you could see a small effect.
Reply | Report Abuse | Link to thisI think @bubblewrap74 has a point. The more offspring one has, naturally, the older one is and is therefore more likely for genetic health to be affected. Could a similar correlation be found on two child families whose children were born many years apart?
Reply | Report Abuse | Link to thisSomething to think about.
And so the puzzles still remains unsolved.
Reply | Report Abuse | Link to thisHad a bit of difficulty registering here so I could post comment. (Perhaps because I am second-born?)
Reply | Report Abuse | Link to thisAnyway comment may appear twice because of this difficulty. Comment is: And so the puzzle still remains unsolved.
As a youngest child, I initially got angry at the implications of this article- that I, merely by being the youngest child am less intelligent than my elder siblings. I also believe in the power of belief, and that if you tell parents and children that they're youngest is less intelligent then the probably will be.
Reply | Report Abuse | Link to thisBut there is flaw in the logic that youngest children are "less intelligent" due to birth order is that it implies that older siblings are actually more intelligent when merely they perform better on IQ tests.
Additionally, this article fails to include any information on how intelligence is being tested in the studies, and what the actual differences are in scores between the different groups, and the methodology for administering the tests.
Regardless, the only conclusion I feel is possible from these studies might be that oldest kids perform better on intelligence tests. Maybe those older kids simply perform better on IQ tests because of an eagerness to please adults, when the younger kids are just not as interested in making adults happy.
I certainly hope that Steven Pinker is not held in too high a regard when it comes to child-rearing advice. He seems to imply that most of one's personality is genetic, thus justifying abdicating parental responsibility. That reminds me of BF Skinner who raised his daughter in an experimental manner. No one doubts the influence of genetics on personality, but the details are far from clear. When infants can die from lack of physical contact with human, environmental influences cannot be underestimated.
Reply | Report Abuse | Link to thisAlbert Einstein said Everything should be made as simple as possible, but not simpler. That dictum has been ignored by those dealing with Birth Order. When Birth Order is made too simple as in oldest, middle and youngest child, it becomes useless dealing in generalities rather than specifics in personality. May I suggest how Birth Order can be made a little less simple so that it is much more effective in understanding personality? How about five Birth Order personalities Only, First, Second, Third and Fourth Born with repeat cycles in large families? It is more complex but still as simple as possible. You can find it at www.birthorderplus.com.
Reply | Report Abuse | Link to thisRudolph Drykers had a lot to say about birth order in the 1970s, too much to summarize. I could not find references to him in Google. He was an Adlerian but grounded in practical family counseling. Does anyone know how to get his stuff?
Reply | Report Abuse | Link to thisThe name is spelled Rudolph Dreikurs.
Reply | Report Abuse | Link to thisCliff, Thanks! That explains the search problem. In the early 1970s he gave a course at UVM (Vermont) that was videotaped by our guidance counselor and shown to a small group of faculty members at our high school. I remember some of the information on birth order. It was good stuff. The 10 hours of tapes are long gone.
Reply | Report Abuse | Link to thisThis is absolutely ridiculous. It can be easily explained by something touched on earlier in the article: Because lower IQ families tend to have larger families, and approximately 50 percent of IQ is an environmental factor, then a person in a larger family will on average have a lower IQ, first or last. It is absolute nonsense that birth order matters.
Reply | Report Abuse | Link to thisThis is quite a ridiculous study. It can be easily explained by the fact that people with lower IQ's will tend to have more children, who will inherit their genes and grow up in a "low IQ environment," resulting in a lower IQ themselves; be it the first kid or the last. Statistically speaking then, this correlation makes a whole lot of sense. This team's report is absolute nonsense.
Reply | Report Abuse | Link to thisI'm the oldest of three, and i believe it may play a small role in shaping who you become, but not a significant one. My brother is 5 years younger than me, and my sister, 10 years younger. I noticed once my brother was born that my parents didn't have as much time to spend with each child, and their patience also diminished. By the time my sister was growing up, i noticed my parents were completely lacking in energy, patience and they didn't have time to do anything with us anymore.I know it played a role in how advanced i was going into school compared to my siblings, but it was only a head start, they caught up, it just took more time for them as they didn't have a patient mom of one doting on them. As for personality, who knows, everything you've experienced plays a role in who you are today, and i think it would be very hard to pin it all down to something as simple as birth order or your sun and ascending signs...
Reply | Report Abuse | Link to thisThanks for the info. Just to be added, analyzing your personality through name on http://seremonia.co.cc/tools/visio-persona . Simple & worth to try :)
Reply | Report Abuse | Link to thisCheck out this article with birth rate stats (and there are many other similar articles with similiar stats. Most of the poorest countries in the world have more children. The richer more educated countries with higher per capita income have fewer children.
Reply | Report Abuse | Link to thisQuality not quantity.
pg 6: http://www.prb.org/pdf11/2011population-data-sheet_eng.pdf
The article doesn't say whether parental age was corrected for in the study that linked IQ to birth order. I believe that genetic quality decreases over time.
Reply | Report Abuse | Link to thisAs to the person who knows from their own experience that the effect of birth order are obvious......that's why we have science. A lot of things that seem obvious to us, are not there at all.