I don’t know. I intended the model to be descriptive of a driver of economic progress (which is explicitly noted to be one of the likely many) rather than predictive. It lacks some modern features, such as changing survival rates and capital accumulation, that are required to explore the important future issues. It is my intention to explore them at some point – probably post-PhD. Another interesting related question would be the selection pressure for conspicuous consumption today - although I am always hesitate to draw conclusions about modern selection pressure. I am willing, however, to draw some policy implications. If economic growth is at least partially driven by conspicuous consumption – be that through the innovation involved in producing goods for consumption or in earning the income to obtain them – then policies intended to curtail conspicuous consumption may have negative side effects. I believe that, on net, a consumption tax would be preferable to an income tax. However, the analysis of whether a consumption tax is implemented should include the trade-offs suggested by the model. One area that I am willing to make predictions is concerning the Galor-Moav paper I referenced above. If Galor and Moav’s proposal that a genetically mediated preference between quality and quantity drove the Industrial Revolution is true, then the modern growth state is vulnerable to strongly quantity preferring types who put all of their effort into reproduction. My paper explores that possibility.

Status is competed for in many dimensions - and women have reasons to seek it. Conspicuous consumption by a male includes making resources available for their wife or partner to waste.

@expeedee and @Phil75231 Libertarianism does not require security to be sacrificed. Individuals are protected from harm by others. If you are worried that humans are not basically good, would you want to give them coercive power through government?

Twin studies suggest that since the demographic transition, heritability of fertility has been well above zero. Some people respond to the socioeconomic shocks differently to others.

On the first question, human capital is dependent on the level of education, which increases human capital, and technological progress, which decreases it. Technological progress decreases human capital as it makes the education received redundant - e.g. you learn to use one form of software and it is then superseded. At lower levels of human capital, there are higher returns to education. Hence, human capital eroding technological progress increases the returns to education and the incentive to invest in it. I should note that this is an assumption of the model rather than a result of the model. On the second, the quantity-preferring types need more incentive to invest than the quality-preferring types. As technological progress speeds up, the incentive increases (as indicated by my first answer) and the incentive becomes large enough that the quantity-preferring types respond to it through educating their children. (and sorry for the long time for a response - I've been on the road for the last week)

Morstern, I tend to agree that the introduction of contraception makes the relationship between quantity and education more complex than the model suggests. As for IQ, that is one of the elements in my mind when I talk of inherent quality. arosko, in many ways, this model is simply taking the r-K selection model of biology and putting it into an economic context. Although I'm not particularly familiar with the research, my understanding is that r-K selection theory can be (and has been) applied at all scales.

TGGP, I wasn't aware of that literature on noise, so thanks for the link. If all the remaining variation is noise, my expectation will be wrong (as I wasn't including random variation in my definition of non-shared environment). However, its not time to give up looking yet!

@Nador, thanks for your comment. I agree that correlation is not transitive, but I consider that the assumption of transitivity is reasonable for the ballpark purpose of the exercise. On your second point, the estimate in step 3 needs to be adjusted by step 2 as there are two parents. Step 2 is whole genotype correlation.

@ben g, to call it an error is to overstate the case. Obviously, heritability of a trait can change significantly from generation to generation, which would make any intergenerational calculations an error. But heritability can also remain relatively consistent (making certain assumptions about the environment and selection pressures) and can be useful in examining intergenerational change, as is often done in quantitative genetics. Bowles and Gintis's implicit assumption of a constant environment and heritability is fair given the purpose of their paper (and I tend to think it is also a broadly accurate assumption). Over the time covered by the generations of interest, there has been a relatively consistent correlation between income and IQ and parent and child IQ, and consistently high heritability of IQ in the populations of interest. As the paper shows, the specific heritability calculations are not the most significant factor in obtaining the result - it is the magnitude of the income-IQ correlation (or income-other genetic factors correlation) that tends to limit the degree to which IQ and genetic factors can be used to explain the strong correlation between parent and child income.

The evidence would suggest that IQ is more important than socio-economic status. From Herrnstein and Murray's The Bell Curve:

The second broad implication is that parental SES is important but not decisive. In terms of this figure, a student with very well-placed parents, in the top 2 percent of the socioeconomic scale, had only a 40 percent chance of getting a college degree if he had only average intelligence. A student with parents of only average SES - lower middle class, probably without college degrees themselves - who is himself in the top 2 percent of 1Q had more than a 75 percent chance of getting a degree. Once again, the common stereotype of the talented-but-disadvantaged- youth-denied-educational-opportunity does not seem to exist in significant numbers any longer. Only seven-tenths of 1 percent of whites in the NLSY were both "prime college material" (IQs of 1 15 or above) and markedly disadvantaged in their socioeconomic background (in the bottom quartile on the SES index). Among this tiny group, it is true that fewer than half (46 percent) got college degrees. Those who did not, despite having high IQs, may be seen as youths who suffered from having a disadvantaged background. But recall that this group consists of only four-tenths of 1 percent of all white youths. A category of worthy white young persons denied a college education because of circumstances surely exists to some degree, but of such small size that it does not constitute a public policy problem. What about another stereotype, the untalented child of rich parents who gets shepherded through to a degree? Almost 5 percent of white youths had below-average 1Qs (under 100) and parents in the top quartile of socioeconomic status. Of those, only 12 percent had gotten college degrees, representing just six-tenths of 1 percent of white youths. Judging from these data, the common assertion that privileged white parents can make sure their children do well in school, no matter what, may be exaggerated.

Or this:

For example, imagine a white person born in 1961 who came from an unusually deprived socioeconomic background: parents who worked at the most menial of jobs, often unemployed, neither of whom had a high school education (a description of what it means to have a socioeconomic status index score in the 2d centile on socioeconomic class). If that person has an IQ of 100 - nothing special, just the national average - the chance of falling below a poverty-level income in 1989 was 11 percent. It is not zero, and it is not as small as the risk of poverty for someone from a less punishing environment, but in many ways this is an astonishing statement of progress. Conversely, suppose that the person comes from the 2d centile in IQ but his parents were average in socioeconomic status which means that his parents worked at skilled jobs, had at least finished high school, and had an average income. Despite coming from that solid background,
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