Yet at least in the case of those of African ancestry don't seem to ever catch up. Those of East Asian ancestry don't seem to ever drop to European levels either. It makes perfect sense that lower exposure to parasites and better nutrition will boost IQs for quite some time. Since stupid people generally earn less, this means their children get to enjoy fewer of the benefits of a good envrionment.
Remember even Lynn, Jensen, ect., the scientists favouring the hereditarian hypothesis consider a 50-50 split between genetic and environmental factors to best match their data. Their opponents claim it is nearly all envrionment.
I'm pretty much certain Askenazi Jews are smarter than gentile Europeans because of genetics. I'm also very certain that East Asians are smarter than Europeans because of genetics. The IQs of these groups have been measured in environments that appear to be as optimal as we can make them.
I'm not so sure where South Asian and Middle Eastern IQs would lie under 1st world conditions but if I had to make a guess I'd say the difference in intelligence is probably comparable to the difference between Europeans and Asians, putting their average somewhere in the mid 90s.
I'm also unsure how much of this low IQ is just the result of inbreeding, which is something "easily" fixed. It seems very plausible that the European vs. Middle Eastern gap can entirely be explained by different levels of inbreeding.
African IQs until quite recently seemed very firmly and robustly one standard deviation (15 points) below the European average, but there's recently been some strange educational achievement data from the UK, which suggests the difference may be as low as half a standard deviation. Low 90s quite honestly seems a stretch considering all the other data though, so my best estimate is in the 80s. Which also happens to be about right considering educational attainment of second generation immigrants elsewhere in Europe and African Americans.
During a recent discussion with komponisto about why my fellow LWers are so interested in the Amanda Knox case, his answers made me realize that I had been asking the wrong question. After all, feeling interest or even outrage after seeing a possible case of injustice seems quite natural, so perhaps a better question to ask is why am I so uninterested in the case.
Reflecting upon that, it appears that I've been doing something like Eliezer's "Shut Up and Multiply", except in reverse. Both of us noticed the obvious craziness of scope insensitivity and tried to make our emotions work more rationally. But whereas he decided to multiply his concern for individuals human beings by the population size to an enormous concern for humanity as a whole, I did the opposite. I noticed that my concern for humanity is limited, and therefore decided that it's crazy to care much about random individuals that I happen to come across. (Although I probably haven't consciously thought about it in this way until now.)
The weird thing is that both of these emotional self-modification strategies seem to have worked, at least to a great extent. Eliezer has devoted his life to improving the lot of humanity, and I've managed to pass up news and discussions about Amanda Knox without a second thought. It can't be the case that both of these ways to change how our emotions work are the right thing to do, but the apparent symmetry between them seems hard to break.
What ethical principles can we use to decide between "Shut Up and Multiply" and "Shut Up and Divide"? Why should we derive our values from our native emotional responses to seeing individual suffering, and not from the equally human paucity of response at seeing large portions of humanity suffer in aggregate? Or should we just keep our scope insensitivity, like our boredom?
And an interesting meta-question arises here as well: how much of what we think our values are, is actually the result of not thinking things through, and not realizing the implications and symmetries that exist? And if many of our values are just the result of cognitive errors or limitations, have we lived with them long enough that they've become an essential part of us?