The findings, published this week in Science, come from British evolutionary theorists Mark Pagel and Quentin Atkinson, the authors of an influential 2006 Science paper on the intermittently rapid evolution of life.
Whether evolution occurs in an intermittent or steady — punctuated or gradual — fashion is a matter of fierce debate among biologists. In 2006, Pagel and Atkinson crunched DNA from 125 organismal trees and calculated that some 22 percent of all genetic differences were rooted in moments of sudden change.
Twenty-two percent may not seem a large number, but in genetic terms it’s immense, especially given that the changes occurred in a few blinks of a geological eye. Their findings were greeted as powerful evidence in favor of punctuated evolution.
Not content with that, Pagel and Atkinson wondered if languages might follow similar rules.
"It’s an interest of mine to treat language as a discrete evolving system, like genes," Pagel told Science. "We’ve been pretty successful in reconstructing phylogenies of language groups on the basis of vocabulary genes, just as one might use genes to reconstruct the family tree of species."
Applying the same statistical methodology to the world’s tongues, they found that between 10 and 30 percent of all words arose during language splitting events.
"We think that the bursts of change we have identified have historically arisen from a group wishing to establish a distinct identity," wrote Pagel in an email. "Bursts may also arise from
‘founder effects’ such as when a small group which may have idiosyncracies eventually gives rise to a new language."
Does this mean evolution might be some kind of universal law that we just happened to notice in animals first? That it operates the same way in different systems, like gravity or the laws of thermodynamics? I called Pagel and asked. Here’s our conversation.
We’re working on the idea that specieation is an unappreciated special time in evolution, and we want to emphasize that we don’t think there’s anything mysterious going on; all the usual Darwinian and evolutionary mechanisms apply, but there’s good reason to think they get speeded up at the time of speciation.
Frequently it’s the case when a new species is formed that it’s moving into a new niche. So it rapidly adapts and evolves to a new niche; once it’s reached that new optimum, it can settle down and slow down its rate of evolution. You imagine terrestrial mamals taking to the water to become seals and dolphins …. at first, there a strong selection to get streamlined body shape; and once that was achieved, they didn’t have to do any more.
Then with languages, we sort of have to draw analogies. We think that language splitting events may be a special time in the evolution of a language; the example I give of Noah Webster [who started his eponymous dictionary to split American from British English.] His intentions captures what might be general feature of language evolution. Human groups try to establish a distinct identity; you can paint yourself a different color or build a new kind of boat … or you change your language. And as you use it, you remind yourself that you’re different.
But is it the exact same set of laws governing both?
It’s really just that in both cases you have a system — in one case genetic, and another cultural — and those systems are moving to a new peak. Adapting to to new environment for genes, for languages moving to achieve some other aim. And it’s been useful in human evolution to have tightly knit groups of people … you can imagine that [changing their language] is one of the things they do. They come up with ways, perhaps unwittingly, to remind themselves what group they’re in.
We want to be careful not to force things into the same box. But at the process level, the level of genes adapting … if we think it’s important for our well-being to be in these groups, then culture, like a species, moves … to a point which enhances their well-being. I wouldn’t want to go any deeper than that, in the sense that there’s a lot of contoversy about whether cultural evolution analgous to genetic
— and i think the power of the idea is in this process level. That’s what’s driving it, the well-being of the actors in both case.
Or, a slightly different answer: at the statistical level, we use the same statistical methodology in both cases. The phenomena looks the same for biological species and for languages on phylogenetic trees of languages. So at that level, yeah — we have two systems based on the same analysis strategies. But I don’t think that there’s an underlying process.
Does the loss of languages parallel the loss of biodiversity?
It’s a very good analogy. In fact, I think it would be very easy — I did it 10 years ago — to show that the loss of linguistic diversity makes the loss of biological diversity seem tiny. The proportion of our languages that we’re losing each year is far greater than the total proportion of the species.
The question is whether linguistic diversity is important in the same way we think genetic diversity is. It matters to the people who speak it, but does it matter except in a deeper psychological sense? We’re all so attached to the language we speak, we think it’s a horrible thing to lose; but it’s less clear that we’re losing anything deeper than that, such as a way of thought. Personally, I doubt it. Though I have said in print that languages structure our mind, I don’t htink that people who speak a New Guinean or Native American language think fundamentally differently than me; and you or I could have been brought up in one of those cultures, and we’d be much like we are now.
Could languages give rise to group behaviors — in the sense that you or I might not be different, but if 1,000 English speakers had been raised to think something else, they might do something different as a group?
We have to be careful not to equate language with culture, even though
I do — it’s convenient. It’s probably true that French people think slightly different than Germans or Italians, but those are probably habits of mind that aren’t tightly linked to language. There are certain metaphors, certain subtle connotative meanings that differ across language — when you and I think of ship, we’re probably too young, but if we were older, they were referred to as "she." Do people around the world think of ships as women? Maybe it’s an Anglo-Saxon hangup. There could be things like that associated with language.
What about variation in language as an inoculant, preventing dangerous ideas from spreading too rapidly?
I don’t know. It could be. If you had a lot of different speakers, different languages, that could slow down the spread of ideas — but I don’t think that’s anything that co-evolved with languages. I don’t think languages evolved to slow the spread of ideas.
It is the Babel myth — in the sense that God struck everybody down and the gave people these different languages so they couldn’t make the
Tower of Babel … so I guess that’s an old theme. But I don’t think that has anything to do with the evolution of language. Language is about communicating.
Languages Evolve in Punctuational Bursts [Science]
Images: American Heritage Dictionary; Douglas Adams’ Babel Fish; and Pieter Brueghel.
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