Religion would seem to be the clear choice of smart people in this hypothetical example, but there would still be a positive correlation between IQ and atheism. The correlation exists not because smart people have necessarily rejected religion, but because religion is the “default” position for most of our society.
This same principle works in places where the default and iconoclastic beliefs are reversed. Japan, for example, has no tradition of monotheistic religion, but the few Japanese Christians tend to be much more educated than non-Christians in Japan. By the logic of someone who wants to read a lot into the Stankov study, Christianity must be the wave of the future, perhaps even the one true faith! But, of course, the vast majority of educated Japanese are not Christians. Just as with atheism in the West, the correctness of Christianity cannot be inferred from the traits of the minority who subscribe to it in Japan.
On the specific issue Richwine is right, Christianity is associated with higher socioeconomic status vis-a-vis non-Christianity across much of East Asia. You can go look in the WVS or Statistics Singapore. Though I do have to note that only in South Korea does there seem to be a positive correlation between theism and socioeconomic status (e.g., in Singapore those with no religion and Christians both have high SES and tend to be concentrated among young professional class Chinese, those with lower SES tend to be Muslims [Malays] and followers of Chinese folk religions). Additionally, in Taiwan, South Korea and Singapore it seems that Buddhism has reworked itself to mimic the aspects of Christianity which made it more appealing to middle-class professionals. This is a classic case of a new equilibrium being attained after the initial outside cultural “shock” of Christianity. Finally, in Japan Christians are basically a rounding error (a few percent at most), so the example of Korea, where they are 1/3 of the population is of more relevance.
But I was struck by a general implication from Richwine’s model. Two premises:
1) Elites, cognitive or otherwise, tend to deviate from the “default” norms of society for various reasons (it could be signalling costly behavior to show that they are “above” conventional considerations and such).
2) Eventually, the masses often emulate in the elites in subsequent generations.
The inference would be that cultural cycles should exhibit a pattern where the masses serve as lagging indicators of elite sensibilities. Once the masses start attempting to “catch up,” of course the elites have moved on. Empirically implausible? I’ll let readers dissect it.