Razib Khan One-stop-shopping for all of my content

May 5, 2011

Why the Amazon Rainforest is species rich

Filed under: Amazon Rainforest,Amazonia,Diversity,Ecology,Environment,Speciation — Razib Khan @ 3:08 pm

A monkey frog

The Pith: The Amazon Rainforest has a lot of species because it’s been around for a very long time.

I really don’t know much about ecology, alas. So my understanding of evolution framed in its proper ecological context is a touch on the coarse side. When I say I don’t know much about ecology, I mean that I lack a thick network of descriptive detail. So that means that I have some rather simple models in my head, which upon closer inspection turn out to be false in many specific instances. That’s what you get for relying on theory. Today I ran into a paper which presented me with some mildly surprising results.

The question: why is the Amazon Rainforest characterized by such a diversity of species? If you’d asked me that question 1 hour ago I would have said that it was a matter of physics. That is, the physical parameters of a high but consistent rainfall and temperature regime. This means the basic energetic inputs into the biome is high, and its consistency allows the organisms to plan their life schedule efficiently, maximizing the inputs. All ...

April 21, 2011

The Court Jester and the averaging fallacy

The Pith:Climatic and biological evolutionary pressures on an ecosystem complement at different scales. Neither is “dominant,” as that framing is not even wrong.

Yesterday I alluded to the Court Jester hypothesis of evolutionary change, which is often contrasted with the Red Queen hypothesis. The main embarrassment for me as a person who fancies himself a fan of evolutionary process is that I hadn’t ever heard of the Court Jester Hypothesis before yesterday. Therefore I went back to the paper which outlined many of the basic ideas of the model in 2001, Distinguishing the effects of the Red queen and Court Jester on Miocene mammal evolution in the northern Rocky Mountains. To be fair, the hypothesis itself is a tightening of a range of ideas which were long in the air. I did know, for example, about the Turnover-pulse hypothesis. These are all a set of models which emphasize the abiotic selective pressures on life forms, as opposed to the biotic ones. An abiotic pressure would be something like the Younger Dryas cold snap. A biotic pressure might be an exotic invasive species spreading through the ...

July 15, 2010

Linguistic diversity = poverty

Filed under: Culture,Diversity,Economic Growth,Economics,Language,Norms,Values — Razib Khan @ 3:05 pm

In yesterday’s link dump I expressed some dismissive attitudes toward the idea that loss of linguistic diversity, or more precisely the extinction of rare languages, was a major tragedy. Concretely, many languages are going extinct today as the older generation of last native speakers is dying. This is an issue that is embedded in a set of norms, values which you hold to be ends, so I thought I could be a little clearer as to what I’m getting at. I think there are real reasons outside of short-term hedonic utility why people would want to preserve their own linguistic tradition, and that is because I am no longer a total individualist when it comes to human identity. I have much more sympathy for the French who wish to preserve French against the loss of their linguistic identity against the expansion of English than I had a few years ago.

Language is history and memory. When the last speaker of English dies, or, when English is transmuted to such an extent that it is no longer English as we today understand it, our perception of the past and historical memory, our understanding of ourselves, will change. There is a qualitative difference when Shakespeare becomes as unintelligible as Beowulf. Though I tend to lean toward the proposition that all languages are a means toward the same ends, communication, I agree that there are subtleties of nuance and meaning which are lost in translation when it comes to works of literature and other aspects of collective memory. Those shadings are the sort of diversity which gives intangible aesthetic coloring to the world. A world where everyone spoke the same language would lose a great deal of color, and I acknowledge that.

But we need to look at the other side of the ledger. First, we’re not talking about the extinction of English, French, or Cantonese. We’re talking about the extinction of languages with a few thousand to a dozen or so speakers.  The distribution of languages and the number of speakers they have follows a power law trend, the vast majority of languages have very few speakers, and these are the ones which are going extinct. We are then losing communal identity, a thousand oral Shakespeare’s are turning into Beowulf’s and Epic of Gilgamesh’s, specific stories which have to be reduced to their universal human elements because a living native speaking community is gone. Let me acknowledge that there is some tragedy here. But this ignores the costs to those who do not speak world languages with a high level of fluency. The cost of collective color and diversity may be their individual poverty (i.e., we who speak world languages gain, but incur no costs).

Over the arc of human history individuals and communities have shifted toward languages with more numerous following. Sometimes, as in the case of the marginalization of the dialects of France for standard French in the 19th century, there was a top-down push. In other cases there needed to be no top-down push, because people want to integrate themselves into networks of trade, communication and participate in the family of nations on equal footing. Losing the languages of your ancestors means that your ancestors are made to disappear, their memory fades, and is replaced by other fictive ancestors. Modern Arabs outside of Arabia will often acknowledge that they are the products of Arabization (this is most obvious in the case of regions like Egypt or Mesopotamia which have long and glorious historical traditions pre-dating Islam). But they also in particular circumstances conceive of themselves as descendants of Ishmael, because they are Arab. A similar sort of substitution occurs when peoples change religions. The early medieval European monarchies, such as the Merovingians and the House of Wessex, traced their ancestry to German pagan gods. Later European dynasties tended to establish fictive ties to the House of David.

But letting one’s ancestors die also means that one can live with other human beings, and participate clearly and with a high level of fluency. You may object that this does not entail monolingualism. And certainly it does not, but over the generations there will be a shift toward a dominant language if there is economic, social and cultural integration. The way we can preserve local traditions and languages in the face of the homogenizing power of languages and cultures of greater scope is to put up extremely high barriers to interaction. The Amish have preserved their German dialect and religious traditions, but only through opting out of the mainstream to an extreme extent (and the Amish are bilingual too).

On a deeper cognitive level some readers point out that there are hints that the Sapir-Whorf hypothesis may be correct. This is still not a strong enough reason for the perpetuation of linguistic traditions which are not widely subscribed. Humans have a finite amount of time in their lives, and the choices they make may not be perfectly rational, but quite often in the aggregate they are. When it comes to some aspects of cultural diversity, such as dress and religion, the importance we place on these traits is imbued by aspects of human psychology. Not so with language. Communication is of direct utilitarian importance.

Now that I’ve addressed, at least minimally, the tensions on the macro and micro level when it comes to linguistic preference, I want to address the aggregate gains to linguistic uniformity. My family is from Bangladesh, which had a “language movement”, which served as the seeds for the creation of that nation from a united Pakistan. Though there was a racial and religious component to the conflict I don’t think it would have matured and ripened to outright civil war without the linguistic difference. Language binds us to our ancestors, and to our peers, but also can separate us from others. A common language may not only be useful in a macroeconomic context, reducing transaction costs and allowing for more frictionless flow of information, but it also removes one major dimension of intergroup conflict.

So if only everyone spoke the same language there would be peace and prosperity? Perhaps not. Recently I have been convinced that it is best to have an oligopoly of languages so that “group-think” doesn’t impact the whole world in the same way. I’m basically repeating Jared Diamond’s argument in Guns, Germs, and Steel, as to why Europe was more cultural creative in the early modern period than China. Institutional barriers can allow for more experimentation, and prevent “irrational herds” from taking the whole system into dead-ends. Another way to think of it is portfolio diversity. Though linguistic diversity will introduce frictions to communication, on the margins some friction is useful to prevent memetic contagion which might occur due to positive feedback loops.

Below I present my model in graphical form. One the X axis is a diversity index. Imagine it goes from 1 to 0. 1 is the state where everyone speaks a different language, and 0 is the one where everyone speaks the same language. A state of high linguistic diversity converges upon 1, and one of low diversity upon 0. I believe that as linguistic diversity decreases one gains economies of scale, but there are diminishing returns. And, beyond a certain point I suspect that there are decreases to utility because of the systematic problem of irrational herds. I didn’t put a scale on the X axis because I don’t have a really clear sense of when we’re hitting the point of negative returns on homogeneity, though I don’t think we’re there yet.


Note: My confidence in the hypothesis that there are negative returns at some point is modest at best, and I have a high level of uncertainty as to its validity. But, I have a high confidence about the shape of the left side of the chart below, that very high linguistic diversity is not conducive to economic growth, social cooperation, and amity more generally scaled beyond the tribe.

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