Showing posts with label Culture. Show all posts
Showing posts with label Culture. Show all posts

Tuesday, July 29, 2008

“Cultural change and biological change share the same fundamental properties of variation, selection and inheritance.” - Whitfield (2008)

“The formation of different languages and of distinct species, and the proofs that both have been developed through a gradual process, are curiously parallel” - Charles Darwin
Academically, one of my research interests is the co-evolution of genes and language. Generally, a simple observation worldwide is people who speak the same language often reproduce with each other (not always necessary but effective communication smooths the process). Based on this general observation one can assume that individuals who share a similar language will share genetic variation (see quote above).

Therefore, I was very interested in this recent feature article (view here) from PLoS Biology entitled "Across the Curious Parallel of Language and Species Evolution" by Whitfield (2008). This paper is historical in nature and starts out with Darwin (I often find if you think of a novel idea, Chucky D. thought it one hundred years ago). In an intersting parrallel I'm also wading through the first half of Janet Browne's lengthy biography, Darwin Voyaging, which is great at understanding the motivation for Darwin's love of natural history and his eventual ascendation to the thrown of biological thought. Into this Whitfield suggest evolutionary analysis will allow for a better understanding of this gene-language correlation. The author then quotes a linguist who argues that linguists may have the best case to study cultural evolution as they have the most amount of data.

Whitfield then continues to take into account similiarites between languages and genomes. First off the most important parts of a language and a genome are highly conservative but then argue that languages make huge jumps. A kind of punctuated equilibrium effect for cultural processes. He then rehashes the arguements for biological processes in brains and if there are underlying genetic correlates with different language types. Then he delves into whether or not there are parralels between culture and biology.

I think my greatest criticisms of this paper is the complete lack of an anthropological perspective (I am of course biased). Anthropology itself has long concerned itself with these questions using an evolutionary perspective. With this in mind there are a number of notable omissions within this paper. Anthropologists have been investigating the relationship between genes and language for the last 40 years at least. The father of American Anthropology, Franz Boaz, mentioned this gene-language relationship in his 1940 book Race, Language, and Culture. Early genetic work on this relationship can be traced to Cavali-Sforza and coleauges who first documented the spread of early agriculturists along with Indo-European languages. Also see Peter Bellwood's book The First Farmers for a worldwide view of this agricultural-gene-language association. In addition the article does not take into account historical linguists such as that by Joseph Greenberg, Merrit Ruhlen, Joanna Nichols, and others work into the evolution of languges.

I realize the statistical tools these individuals are using are new to quantify language differences but they are also controversial. A problem with most papers that equate cultural and biological evolution is that they assume the rate is the same. The majority of linguists believe that the deepest time one can study a language decay rate is 8,000 years. This idea is largely based on glottochronology and Joanna Nichols (1992) suggested an earlier date of around 30,000-40,000 years using a different methodology. The method that Pagel et al. (2007) use indicates a deeper time even. However, humans are a couple hundred thousand years old at best and we don't know exactly when languages show up in evolutionary history. There is good evidence that Neanderthals can speak but could Homo erectus or earlier hominins. There is also a fundamental difference between communication and language - chimps can learn language but in the wild they use elaborate communication systems to talk to each other. Is this language? even if it isn't human language.


Thursday, February 21, 2008

Natural Selection and Cultural Evolution

This is an open-access PNAS article by Rogers and Erhlich that investigates the relationship between natural selection and cultural evolution. I am an admitted skeptic when applying models of Darwinian biological evolution to culture. Generally, I feel that culture follows more of a Lamarckian Inheritance of Acquired Characteristics adaptionist model (if you are bent on applying evolution on it), where you can have rapid change within a generation. The internet is a great example of this, twenty years ago, unless you were a major nerd you wouldn't have really known about the internet. By the mid 1990s more people were starting to dial-up, then by 2000 everyone had an e-mail address, and today everyone has a high speed connection (or 50% if you read the paper) or even wireless, which wasn't even being considered twenty years ago.

However, this article makes a compelling argument for the case of cultural evolution by looking at canoes in Fiji and certain traits that disappear over time. It is worth the read.

Natural selection and cultural rates of change

Deborah S. Rogers and Paul R. Ehrlich*

Abstract
It has been claimed that a meaningful theory of cultural evolution is not possible because human beliefs and behaviors do not follow predictable patterns. However, theoretical models of cultural transmission and observations of the development of societies suggest that patterns in cultural evolution do occur. Here, we analyze whether two sets of related cultural traits, one tested against the environment and the other not, evolve at different rates in the same populations. Using functional and symbolic design features for Polynesian canoes, we show that natural selection apparently slows the evolution of functional structures, whereas symbolic designs differentiate more rapidly. This finding indicates that cultural change, like genetic evolution, can follow theoretically derived patterns.