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IQ and birth order
buzzed, B&W
hairylunch
So, apparently, my IQ is probably about 3 points higher than my younger brothers . . . interestingly, the study concluded it wasn't biological, but something about the environment, or nurture wins out over nature. "Some studies find that both the older and younger siblings tend to describe the first-born as more disciplined, responsible, a better student." In my family, that's probably true. I'm a bit more uptight than my brother.
This kind of experimentation might explain evidence that younger siblings often live more adventurous lives than eldest siblings. They are more likely to participate in dangerous sports than eldest children and more likely to travel to exotic places, studies find. They tend to be less conventional in general than first-borns, and some of the most provocative and influential figures in science spent their childhoods in the shadow of an older brother or sister (or two or three or four).
One could argue this is apparent in my family as well, with my brother having a unique sense of fashion, and being much more the world traveller than I am.
It's also interesting that there are two versions of the article on the NY Times site. They're both by the same author, and appear to be different revisions of the same text. Compare Study Say Eldest Children Have Higher I.Q.s with Research Finds Firstborns Gain the Higher I.Q..

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What's the confidence interval? 3 points sounds like noise. The rest of it sounds like anecdotal or self reporting evidence.

They had a sample size of over 240,000 males, "including some 64,000 pairs of brothers."

I'm not sure what the confidence interval would have been. If we assume two samples of 64k and using a one-tail t-test, the standard error is going to be pretty small. Assuming the standard deviation for IQ is 15 points, we've got the sqrt[(15^2+15^2)/64,000], or ~.08. t = (Difference in the means)/~.08. For a sample of 64k at the 95% confidence interval, we need a t value of 1.645, and 3.291 for the 99.95%. That would correspond to differences of .137937 or .275959 in the means to say one is greater than the other.

I don't remember my stats well enough to determine the actual difference between the two? The example above would just say that A is greater than B, w/o getting the 3 point gap . . .

In any case, considering the study was published in Science, and the charged nature of the topic, I'm sure they'd have made sure the stats were valid.

I think the other conclusions were all from other studies as well, not anecdotal or self-reporting.

In any case, I'm surprised those were your crititques, rather than the silliness of me applying a population study to an individual case.

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