Then you run into problems of other parents since they will have their own parenting style which will affect the IQ.
I wonder if there's a big difference of the IQ in twins. If there is then the IQ difference of 3 in the article may not be all that significant.
The ideal case would be children from the same parents that lived in the same town, went to the same schools, participated in the same activities, had similar friends, and a whole list of other factors. It would also be convenient to have there be more than 2 kids to see the quantitative meaning of "older"
This may just be an indication of a first time parent spending a lot more effort on the first child or just having the resources to do so. During the early years the IQ of the first child is developed while there are fewer resources for the later children.
On the other hand, younger parents may just be starting out and have fewer resources/experience to help them raise the child.
You can also take a look at grandparents - younger parents will have a more active set of grandparents which may be contributing to this IQ boost as well.
Numerous studies have been done on siblings and twins who were raised separately. The IQ correlation between hereditary siblings is strong, that between twins is overwhelmingly strong and that between adopted siblings is almost non-existent past adolescence.
This is entirely anecdotal, but I'll jump in on this topic:
I have twin sisters (identical). Both of them are highly intelligent (go to Ivy league schools), but one has a slight "edge" on the other.
Growing up, they did everything together- the only difference between the two is that the slightly "dumber" one, I used to put down a lot more and make fun of (I got along with my other sister a little better).
It's funny how the little things you do when you're young (we have a great relationship now) can affect things when you're older.
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Also susceptible to other explanations. For instance, perhaps having a younger sibling to teach stuff to is good for your brain.
Yes, you'd really need siblings who came from the same parents, yet were separated at birth.
Then you run into problems of other parents since they will have their own parenting style which will affect the IQ.
I wonder if there's a big difference of the IQ in twins. If there is then the IQ difference of 3 in the article may not be all that significant.
The ideal case would be children from the same parents that lived in the same town, went to the same schools, participated in the same activities, had similar friends, and a whole list of other factors. It would also be convenient to have there be more than 2 kids to see the quantitative meaning of "older"
This may just be an indication of a first time parent spending a lot more effort on the first child or just having the resources to do so. During the early years the IQ of the first child is developed while there are fewer resources for the later children.
On the other hand, younger parents may just be starting out and have fewer resources/experience to help them raise the child.
You can also take a look at grandparents - younger parents will have a more active set of grandparents which may be contributing to this IQ boost as well.
Too may unknowns here but an interesting topic.
Numerous studies have been done on siblings and twins who were raised separately. The IQ correlation between hereditary siblings is strong, that between twins is overwhelmingly strong and that between adopted siblings is almost non-existent past adolescence.
http://en.wikipedia.org/wiki/Inheritance_of_intelligence#Fam...
This is entirely anecdotal, but I'll jump in on this topic:
I have twin sisters (identical). Both of them are highly intelligent (go to Ivy league schools), but one has a slight "edge" on the other.
Growing up, they did everything together- the only difference between the two is that the slightly "dumber" one, I used to put down a lot more and make fun of (I got along with my other sister a little better).
It's funny how the little things you do when you're young (we have a great relationship now) can affect things when you're older.
How sad...I also have a sister I put down, and I can't help it.