>ABSTRACT:
> Recent biomedical research shows that roughly three-quarters of
> cognitive abilities are attributable to genetics and family
> environment.
A heritability statistic does not allow the attribution of cognitive abilities of any one person to genetics, family environment or some other factor. It's estimate of how much *variance in a population* can be attributed to genetics. What heritability is a measure of is oft misunderstood, including by econometricians who are trying to critique the Bell Curve (e.g. Goldberger). There is a clear explanation of this in Lewontin's radio lectures printed as *Biology as Ideology*, so it is rather surprising that this mistake is made over and over. For further developments, see Stephen Rose's Lifelines; Ned Block's contribution to the new edition of Ashley Montagu, ed. Race and IQ; John Vandermeer's *reconstrucing biology*
>This paper presents a theory of growth in which
> human capital is determined by inheritable factors and family
> size. The distribution of income is shown to affect the number
> of births, with greater inequality raising the fertility rate
> and reducing output growth in the transitional dynamics. If
> human or physical stocks are sufficiently low, the model shows
> that an economy can be caught in a fertility-caused poverty
> trap, while countries with more resources will converge to a
> balanced growth path where the average rate of transmission of
> human capital from parents to children determines the long-run
> rate of output growth.
It's not Murray-like to invoke the inequality of income as the effective cause of any social problem, including a fertility caused poverty trap. I don't have time to return to Debraj Ray's textbook Development Economics to remind myself of the basics of a fertility caused poverty trap (which shouldn't be confused with the eugenic spectre of differential reproduction) or read Frank Furedi's book on population and development. Ray describes the workings of a trap without reference to the human capital attributes of the population.
By the way, there are some very interesting passages in Marx's Theories of Surplus Value and Capital where he analogizes the inter-generational transmission of skills to the inheritance of variation in Darwinian theory (Marx seemed however quite unaware of the grave problems in Darwin's ideas about inheritance, including his theory of pangenesis). Yet perhaps Marx hit in some rough, broad way on the meme/gene analogy before either concept had been developed!
don't have access to my books right now.
kelley, we should indeed talk about the theory of human capital. Just picked up Michael Perelman's latest book Class Struggle in the Information Age in which he critically discusses the Becker/Schultz theory.
yours, rakesh
ps Henry, thank you for the articles on the exploding Kashmiri crisis. I shudder.