There's another piece in the New York Times today about how birth order and family dynamics might play a role in "intelligence" (as measured by IQ -- an imperfect measure at best). This is a follow up to their earlier story about research reported in Science and Intelligence that claims, based on research on male Norwegian conscripts, that "social rank" in a family accounts for a "small but significant" difference in IQ scores. (Zuska reminds us of the dangers of drawing too strong conclusions from limited data.)
Today's Times piece seems to be a round-up of anecdata of the sort that readers would find engaging as they quaff their coffee. However, I think the anecdata suggest ways that the system under study is complicated.
Possibly important factors identified in the story today include:
- Parental and family expectations on children -- where the firstborn is often tagged as the most responsible or serious kid and younger kids are often tagged as goof-offs, free spirits, or what have you. If the kid buys the label, it can be something of a self-fulfilling prophecy.
- The cognitive boost elder siblings may get from "tutoring" younger siblings -- because, as any TA can tell you, you understand X much better when you can explain X to someone else.
- How much time and attention the kids get from the parents -- suggesting that the real braniac should be the "only" child.
No doubt all of these can play a role. But surely other factors might as well.
One important factor might be where one's parents are coming from -- what sorts of familial and cultural assumptions they grew up with themselves, and the extent to which they have embraced or challenged those assumptions. In particular, familial attitudes about gender might make a big difference. They could certainly play a role in what kinds of toys, books, and activities are part of each child's early environment. Later, they might make a difference in what kinds of courses a kid signs up for or avoids in school, and how parents (and teachers and guidance counselors) respond to the grades a kid brings back in these courses. (The classic example, from my youth, was the documented tendency of guidance counselors to look at a middling grade, like B-, in algebra and, for a boy, say, "Hey, pay more attention in the next math course!" while telling a girl with the same grade in the same course, "Gosh, honey, you should probably repeat the course.")
There are some families -- still -- where the parents decide that spending money on higher education for daughters is frivolous (while for sons, of course, it's a responsibility). Sometimes this attitude pushes the daughters to give up on higher education. Other times, it prompts the daughters to bust their butts to achieve in school, line up scholarships, and show their parents just how wrong they were.
In my own immediate family, I am the eldest of four children and the only daughter. When my mom went back to school when I was eleven, that made me the instant babysitter for my brothers (unpaid, of course). You cannot believe the incentive this gave me, greater with each passing year, to get really good grades so I could go to college far away. (This was the "moving out" scenario in which my parents could be expected to subsidize my not living under their roof.) For my youngest brother, there surely wasn't the same "Get me out of this cacophony!" incentive, but avoiding boredom seems like it could also be motivating.
One of the things I always notice in stories like this is that parents are assumed to be relatively constant in the familial environment. In real life, that's not a great assumption. Parents can have careers that go through different cycles of engaging and draining, which can influence the time they have to spend on active parenting and the energy and mood they bring to interactions with their kids. Changes in health, relationships with partners, relationships with their own parents, career changes and geographical moves -- all of these play a role in the dynamics of family interactions. Each can effect what kids learn and how kids see themselves and their interactions with the larger world.
And, especially in American society where parents are bombarded with messages that they should do X, Y, and Z to enrich their children's learning environment, enhance their intelligence, and give them every advantage they need from the womb onward to secure a top-flight education and well-paying job, I can't help but wonder: Is this kind of research going to be the source of more parental anxiety? Will it be used as a cudgel to blame parents who don't work out how to treat their third child in a way that makes up for the "disadvantage" their birth order is likely to have on their IQ?
Providing your kids with a good environment while their growing up is important, but surely there's more to successful parenting (and even to helping your kids become educated persons) than just maximizing their IQ.
Ya know, it would be much more fun to make comments about intelligence and birth order if I knew my little sister was reading this... :)
I do want to make a completely unrelated comment on:
The cognitive boost elder siblings may get from "tutoring" younger siblings -- because, as any TA can tell you, you understand X much better when you can explain X to someone else.
This is one of the ideas behind "Peer Instruction." At least as described and implemented by physicist Eric Mazur (who's done some physics education research), this involves students interacting with each other as they work out the answers to questions. The reasoning behind the method is two-fold. First, the student who "gets" it is closer to the student who doesn't than the professor, and may be able to explain it in a way that will be more accessible and useful to the second student than the professor. Second, the student doing the explaining learns it better for exactly the reason you describe.
I want to teach upper-division quantum mechanics sometime so I can understand it better!
-Rob
Come on, get real. Does anyone think that three points difference is that important? Statistical difference may not be the same as functional difference. In a world in which we do different things in different ways, three IQ points cannot make or break ones life.
I'll go for the only child being more brainy.
Come on, get real. Does anyone think that three points difference is that important?
Good point.
It *is* true that the uncertainty on the mean of the distribution will be *far* less than the uncertainty on each data point, statistically speaking. But one of Janet's points is that the *systematic* errors here are way larger than any difference they've detected.
But, yeah, 3 IQ points? Most college students drink more than that away!
-Rob
The guys that did this study need to take my course in Tests and Measurements again. Three points is WELL within the standard deviation of most measures. Also, what is the standard error of the measures they were using? Didn't hear about that either. The lay public needs to get off its duff and start asking questions. Of course, three points do not make any sense as being "significant." Once again, we have a study that comes out and the news medias will run with it without asking simple, obvious questions. There are MANY factors that can explain a simple three point difference on any test. When I saw the figures the papers were reporting on the "significant differences" between these IQ scores, I thought someone was kidding. People: start asking questions.
Does anyone think that three points difference is that important? Statistical difference may not be the same as functional difference. In a world in which we do different things in different ways, three IQ points cannot make or break ones life.
yes, three points is important. imagine a world in which every family has two children, and the distribution of IQ scores is shifted down 3 points (1/5th of a standard deviation) in the second child (that is, the first children have a distribution centered around 100 and the second children have a distribution centered around 97). Of all the individuals with IQs of 120 or above (about college level), 60% will be first-borns. That's not trivial. If any profession requires IQ at that level or above, first-borns will be vastly overrepresented. it's not trivial.
on the individual level, you might be right, but in the aggregate there's a non-trivial effect.
And yet I got all the athleticism and good looks in the family, which, come to think of it, isn't all that much.
I, too, am an oldest child who was responsible for watching her three younger siblings and I also wanted to get as far away as possible as soon as I left high school. This more than anything drove me to do well in school which I thought would increase my chances of going to school out of state. When I left, the next oldest had to take over my responsibilities. He, too, worked very hard in order to go to college and graduate school. My two youngest siblings, not so much. Was it simply that my brother and I wanted to get away from our responsibilities that we did so well? Was it that we were seen as the overachievers and therefore the younger sibs tried to differentiate themselves in other ways? Or maybe it had something to do with how the younger siblings were treated by teachers who had already taught their two older siblings? Who knows.
To me, if this is a real effect (and as many people have pointed out, it's hard to believe that three points is that significant), the really interesting question is why? Why are oldest children "smarter" (as based on IQ tests)? What is it about being an oldest child that makes a difference?
It's interesting but still I wonder why, what is the underlying factors of these statistics. It may go to the heart of some of the fallacies about IQ tests themselves and the misconceptions of what they actually measure.
Personally, it is pretty clear to me individual families will vary quite far from this conclusion and other factors can totally wash out whatever these effects are. I come from a family of five children now in our 40's and 50's, all of us considered smart and accomplished. I am the fourth child in the family and was always labeled the braniac of the family. I was the best at math and science, my interests were in that direction from an early age. Still the others are no slouches. The oldest, who has turned into a natural leader and big overachiever, was also rule bender as a teenager that made our parents a loosen up a bit for the rest of us. She went on to be a successful in business. The second child was successful in her own right as a geologist after being a bit of wild child. The third child was definitely a wild child but also very smart and excelled verbally and went on to study law and is now successful lawyer and businessman. I as the fourth child was perhaps the most voracious reader and certainly the more introverted child and the one with the highest IQ test score though my parents with never tell me exactly how far north of 140 it was because they did not want us fixating on such scores as a measure of our potential. I was also the only lefty of the siblings. I scored very high on engineering, math, and science aptitude tests. I received the Ph.D. in science. The fifth child, the baby, has gone to establish herself in her own right and achieve in world of marketing and sales after getting business degrees. I did tutor her in math and biology when we were kids. We all learned to play musical instruments as children, though I am the only one that still plays. We all participated in competitive athletics as children both solo (we were all swimmers) and team sports.