[haihaibye]

It also relies on blank slate theory - ie that all groups should perform equally, and if they don't, that's evidence enough that there is a conspiracy against them.

Perhaps a way to test the "different groups have different abilities" vs "past bias" theory, would be to find people with high IQ / historical record of accomplishment who suffered great historical discrimination and deprivation (eg Ashkenazi Jews from the holocaust, Chinese families purged in the great leap forward) and then compare their descendants test scores and job outcomes in the USA.

You could look at outcomes a generation or two afterwards and tell whether their performance was high/low ie was "reversion to high group accomplishment" or "underperformed due to present or previous oppression"

[jjeaff]

There is really no basis for any sort of theory that says underperformance of Black Americans is purely due to genetics.

Primarily because genetic diversity among Black people is too broad. In other words, if you randomly compare the genetics between two randomly selected Black people, the difference, on average, will be far greater than comparing any two randomly selected white people.

This is simply because all of humanity stems from Africa, so that is where the most diversity lies.

There are hundreds of genetic markers involved in something as comparatively simple as skin color. The genetic markers involved in something as complex as intelligence are likely orders of magnitude more complex.

You might be able to extrapolate something from certain sub-groups that branch from very narrow branches of the human diaspora, but you certainly could never, ever come up with something that made any sense to apply to the extremely broad strokes that we use to "group" people here in this melting pot we call the USA.

[haihaibye]

Nobody has ever claimed a 100% genetic basis of difference. The individual heritability of IQ is .5 to .8 for example

Sub-Saharan diversity is a real thing, eg Bantu, Nilotic, Pygmy and Bushmen are extremely diverse (African Americans are not Pygny or Bushmen so not as diverse)

But if you use cluster analysis on human genomes and ask it to divide humanity into 2 clusters, it divides humans into Sub Saharan Africans and everyone else.

The key is selection not just randomness (most variation does little or nothing) you can't say eg "Africa is the most diverse therefore it will have the best adaptations for altitude" (that would be Tibetans, courtesy of interbreeding with Denisovians)

The number of variants responsible for skin color is actually extremely small. It's why you can have such large variation between siblings.

In contrast yes intelligence is highly polygenic. However, given sufficient sample sizes you can calculate genome wide association scores and work this all out.

[vannevar]

From a policy perspective, it makes more sense to assume that past and present bias---which we know exists---is a more likely explanation than genetic inferiority (for which there is no evidence). The burden of proof is on the racial supremicists to provide support for their position, not on the government.

[haihaibye]

What's your explanation for the over-performance of the Ashkenazi and Chinese vs US whites?

(The comment you replied to)