Yesterday I did another bit of twitter back and forth with someone with a strong belief that there strong biological differences between ethnic groups - a particular focus being intelligence - and I just want to lay out why I spend time on this on twitter
(As followers will know, I've been on this for a while, with @aylwyn_scally, @AdamRutherford and @JenniferRaff as a group who we bounce ideas off and discuss)
The first thing is to realise that I don't believe I will "win over" many - perhaps any - of the people who talk on twitter about this. The reason why I engage is to open up the arguments which I think are often more broadly held but not discussed.
I think the following (wrong) position is commonplace:
Ethnicity is mainly genetic. Physical + mental traits have varying levels of genetics; lots (height) to some (intelligence). Therefore part of the reason why ethnic groups have different education outcomes is genetic.
Ethnicity is mainly genetic. Physical + mental traits have varying levels of genetics; lots (height) to some (intelligence). Therefore part of the reason why ethnic groups have different education outcomes is genetic.
People often will add that this "part reason" is small vs societal differences, but explains the lack of progression to the highest levels of some ethnic groups, and couple this whole statement with a strong "equality under the law" and individuals have to be treated the same.
So - what is wrong with this position? Oddly enough the main things which are wrong is not what people expect - that genetic variation is a substantial component to the variation in intelligence measures / educational attainment. The genetics of intelligence measures are robust.
Rather there are two things which wrong. The first is rather fundamental - many things can be genetic but not correlated to each other - your hair colour and intelligence measures for example, or your height and your chance of getting colon cancer
So - saying two things have a genetic component in no way says that by tracking one thing (whatever the genetics is that goes into ethnic group determination) helps predict another thing (in this case measures of intelligence)
This is because the genome is a very big place, and sex shuffles randomly across it. It's complex to explain in detail; think of it as if there are ~300,000 independent parts of the genome. Each parent passes on a pretty perfect shuffle between half of each of their parents.
The second thing is that despite many people being pretty confident of their own ethnic group assignment (though not all!) and often confident about making snap assessments of other people (eg "Afro-Caribbean") ethnic groups labels are in fact a long way off genetics.
There is a lot to unpick here. Ethnicity is often defined by a mixture of physical characteristics (skin colour is a big part, but there is more than that) and cultural aspects, in particular language, dress and mannerisms.
Skin colour is not so much of the genome; in the 300,000 odd places in the genome it is at most 3,000 odd places (and that's being generous). Facial features, height etc might take you to up to 30,000 or so - most of the genome is not in the genetics of physical ethnicity traits
This is most obviously recognisable in "mixed race" families, where it is often the case that children will have a big variation in skin colour and other attributes.
But the "formation" of ethnic groups is also due to complex mixing of people's - both in terms of genetics and culture. Some have been recent, but some old and many we haven't traced out yet.
For example, "Europeans" is a mix of three quite distinct groups : stone age hunter-gatherers, Anatolian farmers + Steppe pastoralists. Part of the population of Anatolian farmers migrated as well down the east coast of Africa, contributing genetics and likely farming culture
Another massive migration was from Spain to central and south America, with the harsh Conquistador group having a large genetic and cultural stamp in combination with different native american people - this broad grouping leads to the Hispanic ethnic group
Another obvious case is trans-atlantic slavery giving rise to a mixture of different genetic and cultural components from mainly from west africa plus European genetics and culture and then, in particular in the Caribbean, south Asian due to indentured servants
The *norm* for humans is to partly migrate and mix at the scale of genetic timescales - human population geneticists expect to see more and more detail as we sequence more living humans and in particular more ancient bones
The "ethnicity" concepts are laid on top of this complex genetic mixing a culturally driven way - the labels are not good proxies for genetics and can never really be because genetics is far messier and far more independent areas
Because of this, although the physical aspects of ethnicity have a genetic component, ethnicity is just not a good proxy to genetics. For starters it is just one label for this complex thing but also is just a big mess underneath
Some skeptics - and people who hold hard onto the sense of racial differences - might agree with all of this but then say "but there are still *some* level of genetic differences between ethnic groups" and this "must contribute even if it is just a little bit"
So - there are genetic differences between people, yes, and formally any grouping of people measured at good enough precision on anything will show differences, but this is true for *any* arbitrary grouping.
I might as well characterise people across the world by the Premier League football club they support, and then measure height, educational attainment, colon cancer genetics..., and there will be differences. But that difference would be arbitrary by classification.
Critically it would not be very useful for me to ask everyone on applications to tick "which Premier League football club do you support" with a "prefer not to say" box, and then use that inform decisions. Far better to ... assess people directly.
Are ethnic group labels as arbitrary as Premier League football clubs? It's probably a close run thing (for a variety of reasons, Premier League club support is weirdly hetreogenous worldwide). Both though are not *useful* proxies.
Furthermore, due to the endless mixing of humans (it is really a constant thing), the arbitrary groupings over 50 years ago will just morph into arbitrary groupings now and in the future. Hence "Cape Coloured" and "Black British in Liverpool".
That the genetics of intelligence is genomewide, not obviously recently selected and that ethnicity labels are crude, broad groupings across complex human history means genetics has a low - if any - contribution to between ethnic group educational differences.
