Do long-lasting cultural habits suggest genetic causes?

 

In the Boston Review has Philip Cohen reviewed Wade’s “A Troublesome Inheritance” in a piece entitled “Don’t Trouble Yourself”. A couple of points caught my attention. In the last paragraph of his section entitled “Descent into Racism” (this may give you a flavour of the mood) Cohen writes:

Obviously, Wade offers no evidence to support his genetic story of Africa’s poverty because none exists. In the absence of evidence, Wade resorts to homicide statistics. Most countries in sub-Saharan Africa have higher homicide rates than the rich countries, which he calls “a difference that does not prove but surely allows room for a genetic contribution to greater violence in the less developed world.” This contradicts the basic logic of science. As the biologist H. Allen Orr points out in his devastating review, the existence of a difference is not evidence for any one cause of that difference.

Here is the relevant section from Orr: “But if the issue is whether people differ innately in a behavioral trait, a material line of evidence cannot be that people differ in the trait. They may easily differ for other reasons. (Do differences in currency have a genetic basis? After all, there are differences in currency!)”

The argument is true as far as it goes. By leaving out intelligence differences Wade has weakened his explanation of economic differences. However, the currency analogy is interesting. A long established currency would be evidence in favour of something which led to restraint in financial matters for generation after generation. That the name of the British currency is still the “pound” is trivial compared to the fact that it is the world’s oldest currency still in use. So, either solely cultural, or genetic and cultural forces have maintained this store of value since Anglo-Saxon times. The “culture only” explanation is interesting, because it suggests that a habit, once established, will continue, like motion in frictionless space.  This is not entirely silly: culture is a collection of habits, and a habit may persist simply because no-one can be bothered to change it (like calling the currency “the pound”). There are still little roads in the City of London which reproduce paths up from the river landing piers. Now that everyone has built their houses it would be tedious to destroy that street pattern. Worse, it would lead to the loss of some good pubs, for whose customers in the late evening the zigzag nature of the thoroughfare is so well suited.

However, that behavioural inertia would suggest that colonial practices should have stuck in Africa. The railroads should still be there, and all the heavy equipment, all well maintained. Why did that not often happen in Africa? Why did not the African and Indian peoples build on these cultural traditions to make sure there citizens travelled in the carriages, and not on the carriages? Why did Malaysia, post liberation, do better than Kenya, which was predicted at the time to be the likely winner?

So, a difference between genetic groups does not of itself prove a genetic cause, though of course it suggests it, rather in the way that finding health and lifespan difference between social classes suggests that status and resources are part of the cause of the observed differences in life outcomes.

It seems the key attraction of culture as an explanation of behaviour is that it is like mercury, flowing everywhere, adapting to everything, and moving on without leaving a mark. Culture accounts for a people not changing, for a people changing a bit, and then for not changing again.

Although I am not in the prediction business, I wonder what the culture-only protagonists would predict for North Korea? It certainly seems a very different country from South Korea. As Jayman has noted, it may not be a full genetic match, because we do not have genomic data from North Korea. On the basis of the East German experience, if the two countries were to be unified today I predict it would take one generation for the North Koreans to almost catch up with the South Koreans in terms of enterprise and innovation. Specifically, that after 25 years the new generation in the North will be very much like the next generation in the South. All this assumes that the South, as seems likely, supports the North for about 25-40 years. So although the main effect will be over in a generation, this implies that residual effects last two generations. So perhaps we have to say that cultural effects can be reversed in two generations and genetic effects somewhat changed if you implement very strong selection for 16-24 generations.

Is there any state of the world the culture-only hypothesis denies?