Some of what’s swirling in my mind after reading Hive Mind:

1. At the individual level, IQ is much more highly correlated with job performance than income.  So while national IQ has a bigger effect on national income than personal IQ does on personal income, it’s less clear that national IQ has a bigger effect on national productivity than personal IQ does on personal productivity. 

How could income and productivity two diverge?  Imperfect information could arguably do the trick, but a stronger story is that egalitarian norms compress pay within countries, but not between countries.  This needn’t make Garett’s mechanisms irrelevant, but it would imply that what he calls the “IQ paradox” is markedly smaller than it looks.

2. Quite a few economists, most notably Hanushek, emphasize the social benefits of raising academic test scores.  Garett’s IQ-centric story is far more credible.  It’s easy to see how an across-the-board increase in intellectual prowess would have far-reaching social benefits.  It’s much harder to see how better math skills would have such effects.  After all, most people already use far less math on the job than they learned in school. 

3. Garett reviews a lot of evidence on the determinants of the global IQ gap, but as far as I can tell never references what seems like the most probative evidence: IQ studies of transnational adoptees.  This especially relevant for Third World IQ.  How much of the IQ gap reflects Third World deprivation?  Just compare the IQs of adoptees born in the Third World to the IQs of their non-adopted biological siblings.  True, this understates the environmental effect because even adoptees endure a subpar Third World prenatal environment, but it’s still a compelling lower bound.

When I asked Garett about this, he assured me that such research exists.  But nothing great pops up on Google Scholar.  So what are the best studies, and what do they conclude?

4. I can easily imagine Hive Mind inspiring a wave of IQ NIMBYism.  I can also imagine it reinvigorating Soviet-style emigration restrictions to fight “brain drain.”  This doesn’t mean Garett’s wrong, any more than nuclear war would invalidate Einstein’s theory of relativity.  But it’s a sobering thought – and Garett doesn’t seem sobered by it.

5. While Garett shies away from moral judgment, he could easily filter his results for an array of moral perspectives: utilitarian, nationalist, Kaldor-Hicks efficiency, egalitarian, etc.  Even for the nationalist, this is more complicated than it sounds: If Congo’s national IQ rises by 10 points, the beneficiaries including Congo’s trading partners as well as Congo itself.  But if the book’s worth writing, this complicated question is worth tackling.  I’ve discussed these ideas with Garett for years and read his book carefully.  But if you asked me, “What would a cosmopolitan Jonesian think?,” my answer remains hazy at best.

6. Some of Garett’s mechanisms – like the political effects of IQ – seem like genuine externalities.  Others – like the effects of IQ on savings – don’t.  In terms of standard welfare economics, how does Garett classify each of his channels?  Inquiring minds want to know.

7. The last question comes from my three-year-old daughter: “Is it a bee book?”  Well? 🙂

Bonus Question: Whenever I see growth regressions, I routinely ask, “What happens if you weight by population?”  1.3B high-IQ, low-income Chinese seem like they could be a big fly in the ointment.  Are they?