Here are some recent results, from Sandra Black, Paul Devereux, and Kjell Salvanes.
More able parents tend to have more able children. While few would
question the validity of this statement, there is little large-scale
evidence on the intergenerational transmission of IQ scores. Using a
larger and more comprehensive dataset than previous work, we are able
to estimate the intergenerational correlation in IQ scores, examining
not just average correlations but also how this relationship varies for
different subpopulations. We find that there is substantial
intergenerational transmission of IQ scores; an increase in father’s IQ
at age 18 of 10% is associated with a 3.2% increase in son’s IQ at the
same age. This relationship holds true no matter how we break the data.
This effect is much larger than our estimated elasticity of
intergenerational transmission of income of approximately .2.
Here are ungated versions, or here. Note that a) this is based on Norwegian data, b) income elasticity declines with birth order, c) intergenerational IQ elasticities are broadly the same across different levels of education for the father, d) the sample size is much larger than usual, and e) the author caution against assuming this is entirely a genetic effect; in another study large family size lowers IQ for instance, adjusting for parental IQ.
This is exactly the kind of research we need in order to justify eugenics. I have heard that higher IQ people tend to have less children in modern times than lower IQ people. And if larger family size makes the offspring less capable, than we are pioneering interesting times. It is also quite unfavorable to research a parent’s effect on their children because most of the “bad” in a child can be attributed to the parents, and very little of the good seems to transfer over. Therefore, I’d like to see vast research in this field, as it will help curb population growth.
I presume this data is from IQ tests given to male military conscripts in Norway? It would be interesting to see what the impact of higher IQs among mothers is. The combined effect of fathers’ and mothers’ IQs on sons would presumably raise the intergenerational transmission of IQ above the 32%, but not double it due to the effect of assortative mating already being seen in the father’s influence. Perhaps the effect of both parents would be around 50% rather than the 32% seen for fathers. That would imply that parents who average 130 IQs would tend to have children who regress toward the mean (of 100) and wind up averaging around 115. That level of regression toward the mean seems plausible, fitting both previous studies and what you see around you in families you know.
“in another study large family size lowers IQ”
It would be more accurate to say that lower IQ is associated with larger family sizes.
> It would be more accurate to say that lower
> IQ is associated with larger family sizes.
No, because you left out the key part: “adjusting for parental IQ”. That is, given a fixed parental IQ, larger families tend to have children with lower IQ according this study.
租車|傢俱|抓æ¼
it is interesting
Did I see this kind article before?
Comments on this entry are closed.