I'm at the same APEE meetings in Nassau that Arnold's at and I saw another paper presented by Garett Jones. It was titled "A Political Coase Theorem for the Intelligent." It was on how high-IQ pairs in experimental games do significantly better on trust and cooperation. He then reasoned from that to higher IQ creating more solutions to cooperation problems and, therefore, creating more economic growth.
He pointed out a number of times in his presentation that, given how many variables researchers had studied in trying to understand differences in cooperation in experiments, adding IQ to the mix should have been done in the 1960s. It shouldn't have had to wait 40 years.
One implication for countries that want more growth, he said, is to get higher-IQ immigrants. In Q&A, I asked him if he was suggesting something like Canada's immigration rules that seem to put a higher weight on IQ indirectly or whether he would be happy with a Bryan Caplan solution that would allow pretty much anyone in who wanted to come. In the latter case, I noted, maybe self-selection takes care of the problem: maybe the people who come here, even without a government selection device, self-select and so maybe we end up with higher IQ people anyway. Garett seemed to lean to the former and said that one thing the government could so is, when an immigrant got a Ph.D., "staple a green card to it." That sure would have saved me a huge amount of hassle and uncertainty with the INS in the 1970s.