(from article) But twin and adoption research focuses on questions that are much more relevant for parents: how your child will turn out if you switch to another parenting style.
Yeesh, not another one of these flawed conclusions drawn from likely flawed research. The main conclusion one can draw from the study cited, if that article is accurate, is that increasing one's own vocabulary can have a negligible long-term effect on your child's vocabulary, not that switching to another "parenting style" will have negligible effects-- and certainly not that switching to different educational strategies will have negligible effects. These types of studies are often used to "support" a wide range of questionable assertions, such as that the environment has a negligible lasting effect no matter what, that training/education has only a negligible effect on IQ, that only people with a certain IQ should go to college
, etc.
Since, as Caplan explains, intelligence is highly heritable, it is especially important for smart people to have lots of children.
Intelligence certainly is highly heritable, and more intelligence is more better.
I agree with you that more intelligent people should have more children than they do now; there may actually be a tendency for the opposite to be true. I don't have any cites ready to hand, but again IIRC lower economic status -> more children, and lower education -> more children as well, likely a secondary phenomenon due to the link between economic status and education. This phenomenon makes sense to me, as it increases the likelihood a family / bloodline will survive, especially in very impoverished regions with abysmal health care, and may increase the financial stability of a family as well.
If there is anything to the notion that highly intelligent people are more likely to be successful and achieve higher education levels, then it may well be true that highly intelligent people have fewer children on average than less intelligent people. And I don't see how that's a good thing, though it is understandable: higher education can take so much time and money that one's personal life is given secondary status for a while, at least enough to impact child-rearing plans.
