Sunday, 10 February 2013

Razib Khan on how culture evolves

Thumbs up from me for Razib Khan for his recent posts dinging most cultural-anthropology here and here.

Anthropologists have turned into one of the main forces standing between humanity and a proper science of culture.

Also, thumbs up for knowing enough to understand that culture evolves. However, I have to ding Razib for this:

an understanding of evolution or genetics is not necessary to gain a first order understanding of the nature of the phenomenon of human culture, but cognition is
It's just a daft thing to say. I would compare it to saying that evolution or genetics is not necessary for a first order understanding of the nature of animals, but organic chemistry is. That sort of thing isn't very meaningful or helpful.

Culture evolves. That's just as important to understanding culture as it is to understanding animals and plants. The "first order understanding" business is weasel words.

Razib also gets "dinged" from me for saying:

Of course the rules of science don’t necessarily apply to history
Er, history is about facts and facts are the domain of science. Of course the "rules of science" apply!

...and "dinged" again for saying:

In sexual organisms genetic inheritance is symmetric (the autosomal genome has equal contributions from both parents), and exclusively vertical (parents to offspring). In contrast cultural inheritance can be asymmetric (i.e., one inherits by and large the culture of one parent) and horizontal (one inherits the culture of one’s peers). [...] This regular and systematic inter-quasi-generational horizontal transmission illustrates flexibility of cultural transmission which has few parallels in biological genetics.
Razib is drawing an unhelpful comparision. Memes are not much like autosomal genes, but they are a lot like genes in microbes and parasites.

The claim that horizontal transmission in cultural evolution has few parallels in "biological genetics" seems simply wrong: microbes and viruses are transmitted horizontally between humans whenever they touch each other, breathe in each other's vicinity or eat anything.

The whole "Why culture is chunky and genes are creamy" thesis seems very dubious to me. Razib has picked a trait for which there's little variation (skin colour) and compared it with a cultural trait for which there's a lot of variation (language type). However comparing a cultural trait for which there's little variation (e.g. which side of the road you drive on) with a genetic trait which has a lot of variation (e.g. what skin viruses you have) would have led to the opposite conclusion. All Razib's example shows is that all human DNA has a fairly recent common ancestor, while many cultural traits evolve rapidly and diversify quickly - due to the short generation times of memes. However, that isn't really news and doesn't lead to grand generalizations about the relationship between memes and genes. There are plenty of genes that have short generation times and evolve rapidly too - they just aren't human genes.

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