Thursday, October 14, 2010

Culture Evolves Slowly, Falls Apart Quickly

Found via Farnam Street.

Societies come together slowly, but can fall apart quickly, say researchers who applied the tools of evolutionary biologists to an anthropological debate.

Using archaeological records and linguistic analyses rather than fossils and genes, they created an evolutionary tree of political forms once found in Pacific islands.

The study, published October 13 in Nature, was intended to illuminate an issue of contention among archaeologists, anthropologists and historians: whether societies become more complex in incremental steps or sudden bursts, and whether they dissolve in similar fashion.

Over 84 societies in this tree, Currie and Mace overlaid what’s known from archaeological records of their social structure, which underwent “spectacular political differentiation to give rise to examples of the entire range of political organization,” wrote Collapse author Jared Diamond in an accompanying commentary.

When they compared the resulting tree to trees generated by computational models of different anthropological narratives — linear and stepwise, varied and lurching — the researchers found a close match to the linear. Political complexity indeed grew slowly, bit by bit, with no sudden jumps from bands to chiefdoms or tribes to states.

“Political evolution, like biological evolution, tends to proceed through small steps rather than through major jumps in ‘design space,’” wrote Mace and Currie.

However, purely forward-marching models didn’t fit the data. There was evidence of societies marching backwards as well, and this didn’t follow the same step-by-step path. Societies could collapse.

The study will undoubtedly be criticized, especially for its rough categorization of subtle political differences into four hierarchical categories, wrote Diamond. But what’s most important is that the techniques of evolutionary biologists can be applied to anthropology.

Most anthropologists interpret the past “by narrative accounts of individual cases, less often by narrative comparisons of selected cases, and infrequently by comprehensive narrative surveys,” Diamond wrote. “My first reaction to Currie and colleagues’ paper was one of surprise: why hadn’t we used their method before, because it is so obviously superior?”

According to Diamond, cultural phylogenies might be devised for societies in southern and central Africa, which have highly diverse languages and rich political histories.

Analyzing political evolution in Europe and central Asia, where most languages have gone extinct and cultures have long intermingled, is “the grand challenge,” he said.


Related book: Collapse: How Societies Choose to Fail or Succeed

Related book review: The Vanishing