So, that seems to say that differences factually do exist in IQ results, but there's disagreement on how to explain them. And that Watson has jumped to the most offensive and biased possible explanation?
There are a number of plausible environmental explanations ... for example, questions on IQ tests having cultural biases.
There's also a problem with grouping individuals into races. What happens when a certain race has a higher IQ in the US than in another country? What about mixed races? How do we group them?
> The racial groups studied in the United States and Europe are not necessarily representative samples for populations in other parts of the world. Cultural differences may also factor in IQ test performance and outcomes. Therefore, results in the United States and Europe do not necessarily correlate to results in other populations.
> Most people have an ancestry from different geographic regions, particularly African Americans typically have ancestors from both Africa and Europe, with, on average, 20% of their genome inherited from European ancestors. If racial IQ gaps have a partially genetic basis, one might expect blacks with a higher degree of European ancestry to score higher on IQ tests than blacks with less European ancestry, because the genes inherited from European ancestors would likely include some genes with a positive effect on IQ. Geneticist Alan Templeton has argued that an experiment based on the Mendelian "common garden" design where specimens with different hybrid compositions are subjected to the same environmental influences, would be the only way to definitively show a causal relation between genes and IQ. Summarizing the findings of admixture studies, he concludes that it has shown no significant correlation between any cognitive and the degree of African or European ancestry.
"Since the beginning of IQ testing around the time of World War I there have been observed differences between average scores of different population groups, but there has been no agreement about whether this is mainly due to environmental and cultural factors, or mainly due to some genetic factor, or even if the dichotomy between environmental and genetic factors is the most effectual approach to the debate."
So that appears to confirm -- the differences in IQ test scores do exist, but there is disagreement on how to explain the differences.
Watson's claims exceed what the evidence supports, in that he claims the differences are genetic, but the evidence is incapable of telling us whether that is the case or not.
I just realized another way that Watson's claims exceed the evidence.
He said, "I'm worried about Africa because our policies assume their IQ is the same as ours" (paraphrase, not an exact quote).
To base "worry" about a section of the world on differences in IQ tests relies on the assumption that IQ is a major determinant in how a section of the world fares.
In other words, even if you accept that we have evidence of IQ differences, we have no evidence measuring moral differences, community/social differences, ambition levels, etc.
So his comment doesn't reflect careful, nuanced thought. For someone who usually does think carefully, it's not unreasonable to think the lack of careful thought here is driven by a desire to confirm a pre-existing bias (such as the bias that whites are superior).
There are a number of plausible environmental explanations ... for example, questions on IQ tests having cultural biases.