Indeed, all of those problems exist. However they can be more or less overcome, especially over time.
- In the first case, as with the Italians immigrating to the US, and their second generation children, per the article.
- Larger sample sizes, and lessening of socioeconomic and cultural differences should help the second case.
- The last could be assisted by better definitions of 'intelligence', or finding another, more specific field to measure.
My point is, however, that despite the improvements that could be made in this field of research, nobody will fund or perform it at least in the US.
Why? Because the brain is magic, and people who discuss physiological differences between races involving brains are racists.
1) What's the benefit of doing this research outside of curiosity? Education research is useful, yes, but studying raw intelligence to try to figure out what parts of it are genetic seems like a waste of time, unless you plan to give babies the "smart gene" in a Sci-Fi scenario.
2) I'm not sure why you're bringing up the Italian example. It shows that Italians were performing really low, but when their culture changed, the problem went away. So, it wasn't genetic. To show something comparable about the IQ gap for black people would be really hard, because Africa is poor as hell, which depresses IQ scores, and Africans living in the First World aren't a part of the majority cultures. So, you'd either have to get all black people to be rich for a generation or have them all look white somehow but keep living in a white culture in order to make a fair comparison. It's not a repeatable experiment.
Suppose you don't deliberately study "raw intelligence" but are interested in autism. There are a bunch of genes related to the manifestations of autism. You have a relatively low-functioning empathy circuit, for example. You develop obsessions with numbers, for example. This could be a malfunctioning orbitofrontal circuit (which is also dysfunctional in OCD patients).
It is not a coincidence that some people with superior memories exhibit very similar symptoms as autists, but retain most of their social ability, and there you go, innate, genetic intelligence, almost as a side effect of an impartially developed disorder.
What's the benefit of researching Viagra outside of pleasure? It was an accidental discover during heart research (IIRC).
You don't even have to be curious about discovering what genes are responsible for "superior" mental functions. That's almost like trying to solve a puzzle with the expectation that you only connect the pieces that you consciously set out to connect.
I've heard this objection before and I often wonder if the people making this argument secretly think that some races really are inferior, but that we mustn't talk about it.
Or, perhaps you are implying that such research might overturn our egalitarian, meritocratic society. Personally I have no fear about that. It's obvious that some people are born superstars in pure physical ability, and yet we all still enjoy sports and not all physical work has been dominated by one race.
And I think you can see that there would be huge benefits in learning what the non-genetic factors of intelligence are.
I've heard this objection before and I often wonder if the people making this argument secretly think that some races really are inferior, but that we mustn't talk about it."
Perhaps you should wonder if they're being sarcastic.
Take a Norwegian. Put him in a suntanning booth 5 hours a day. His skin will be dark.
Take an African. Never let him see sunlight in his life. His skin will be light.
Take an XX embryo, inject male growth hormones into the womb at the proper time, it will grow a penis.
Take the children of geniuses, have it raised by a Harlow-style "wire mother," and it'll be as dumb as a brick.
The question isn't "nature vs. nurture." It's how much of each is involved. The question about the black-white test gap is not "Are blacks born dumb?" It's "Have we already pushed everyone (black, white, visual learner, auditory learner, whatever) to the outer limits of their innate capacity?" Since the Flynn effect exists, the answer is probably, "No."
On top of that, intelligence is not a one gene, on-off thing. It's a million different things working together better or worse. That's why intelligence is distributed in a Bell curve. Anytime you have a bunch of different factors influencing things at random, a Bell curve develops, since there are more ways to randomly have a bunch of X, a medium amount of Y, but not enough Z than there are to have a bunch of all three. This means we're talking about a wide variety of genes, not just one pair of deformed genes like sickle cell anemia.
On top of all that, IQ tests are designed to measure something called "g" which is supposed to predict general ability, but the whole thing is a statistical chimera. G should be able to tell you how good you are at any other test, plus or minus a small factor of particular competency in the field, plus or minus an even smaller amount of randomness, but it doesn't actually do that. So, IQ tests basically only measure ability to take IQ tests and are vaguely correlated with other, useful abilities in the same way that height is "correlated" with the ability to drive. (Ever see a six year old who could parallel park?) See http://cscs.umich.edu/~crshalizi/weblog/523.html for a full breakdown on why "g" isn't actually a useful thing to measure.
Anyhow, there's three different problems with linking IQ and race, and none of them have anything to do with the brain being magic.