>>11134636I don't know about blacks, but it has definitely been shown that environmental and social factors can also affect IQ significantly among people that are of the same "race", depending on how you define it. For instance, if you accept that middle easterns and north africans are caucasian, as most scientists do, you can see a 1 SD gap between them and europeans. Lynn has also noticed that people from those regions scored 1 SD lower on IQ tests on entry to the US, in other words around 85 IQ, same as blacks. But second and third generation immigrants from those regions ended up with higher IQ averages, very close or in some cases higher than the national average. That is one example of a gap between two groups of the same race.
You can see a similar gap between asians such as japanese and filipino or native americans. Both are classified under mongoloid, and both are close to each other in a similar way of ME/NA people and europeans. Once again, there is a 1 SD gap between countries like japan or china and other ones like the philippines or laos. Although in both cases, the groups are closely related to each other, they have very different IQs, on par with blacks, even though they are genetically very far from them. In the case of ME/NA immigrants, it has also been shown that their IQ gap tends to decrease or completely go away by lynn itself.
Why does the black and white IQ gap still persist? I don't know, but to say environmental factors cannot cause such a wide gap is not true, as it has been seen from ethnic groups under the same race classification having wide IQ differences.
The IQ gap between blacks and whites are also lower in other countries western countries such as the UK
