[extropy-chat] FWD (SK) Darwin Meets Chomsky

[Terry W. Colvin]

http://www.the-scientist.com/
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research Volume 18 | Issue 24 | 16 | Dec. 20, 2004 Darwin Meets Chomsky 
Scientists converge in a multidisciplinary approach to understanding human 
language | By Nick Atkinson Reproduced with permission of Punch Ltd. Darwin 
saw parallels between the evolution of species and of languages

Charles Darwin spotted it. In The Descent of Man, he wrote: "The formation 
of different languages and of distinct species and the proofs that both 
have developed through a gradual process are clearly the same." He'd been 
struck by ideas that William Jones had advanced 50 years earlier, that the 
similarities between languages as disparate as Sanskrit, Latin, and Old 
Persian, suggest a common historical ancestry.

These foundations for an entirely new field of research were largely 
ignored for almost a century. Language wasn't recognized as a heritable 
trait, subject to processes of natural selection. Instead, studies of 
biological and language evolution followed different trajectories, evidence 
of which is still reflected in the departmental structure of most 
universities. The divide is finally being bridged, even if a common 
terminology has taken a while to establish.

"It's important to make the distinction between historical linguistics, how 
a language changes over time, and studies of the evolution of language in 
humans," says Partha Niyogi at the University of Chicago. He is one of a 
flotilla of scientists from diverse backgrounds who are currently charting 
new waters in language evolution research. Previously intractable problems, 
such as how meaningful language first emerges from a more primitive 
signaling system, are now being addressed with newly combined theories and 
methodologies.

INNATE GRAMMAR Groundbreaking work by Noam Chomsky laid the foundations for 
this type of language research, of trying to understand how human language 
is possible at all. Why, for example, do children all over the world, 
regardless of their backgrounds, arrive at roughly the same set of rules 
governing the way they communicate? Natalia Komarova, at the University of 
California, Irvine, says that such questions are important.

"Every child faces an enormously complex task while mastering her native 
language. Without formal instruction, she has to figure out all the rules 
of underlying grammar." Komarova points out that this goal must be achieved 
using only a limited set of sentences, those actually heard, from the 
infinite number of possibilities. "In fact," she says, "if you're 
completely open-minded it's mathematically impossible to guess the correct 
rule."

Somehow, though, children do manage this impressive feat, overcoming what 
is known as the paradox of language acquisition. Chomsky's revolutionary 
insight was in postulating an innate universal grammar, which helps 
children navigate the infinite realm of choice. Komarova and others, such 
as Harvard University's Martin Nowak, are beginning to explore the 
evolutionary origins of the universal grammar by drawing on some of the 
tools that evolutionary biologists have been developing over the last few 
decades.

Nowak says that the complexity of the problem has hampered progress. "To 
study [language] from an evolutionary standpoint requires detailed 
knowledge of several fields." His own work lies at the center of a rapidly 
growing literature that uses evolutionary biological tools to yield insight 
into some of the basic questions on language evolution.1,2

Nowak points to limitations of current methodologies. "Most traditional 
linguistic models have assumed that one party is the teacher and the other 
is the student. However, that's not the case in real life," he says, 
referring to recent studies of a newly emerging sign language in a 
Nicaraguan deaf community, whose evolution through successive cohorts of 
children has been closely followed.3 "Children appear to learn from their 
peers; they arrive at a consensus by which they communicate effectively." 
This research supports Chomsky's theory of an innate grammar and provides 
valuable field data on how new languages evolve, but it greatly increases 
the complexity of the models theoreticians must now develop. Fortunately, a 
precedent already exists. Courtesy of Claude Bramble HELLO, HELLO?  Can 
linguistics shed light on animal communication, such as alarm calling in 
vervet monkeys? (shown above) If so, animal models might in turn help us 
undestand human language.

EVOLUTION TACTICS At its simplest level, language can be viewed as a 
sequence of signals between speaker and listener. This is where methods 
lifted from evolutionary biology come into play. The late John Maynard 
Smith championed the adoption of game theory,4 which revolutionized 
ethology during the 1970s and 1980s. Game theory is now applied to a 
diverse range of research questions, enabling the study of frequency 
dependence: population-dynamic situations in which an individual's best 
response depends on what others are doing.

Niyogi, who recently collaborated with Komarova and Nowak,1 says such a 
conceptual shift is essential. Traditional linguistic approaches can't 
really tackle more realistic scenarios, such as how a group of children 
might learn from a more fluid set of teachers, including both peers and a 
wider, age-structured group, he says. "Linguists are going to have to come 
to terms with the fact that we need a more sophisticated, population-based 
setting."

Another tantalizing possibility is to define the limits of the universal 
grammar. An overly intricate grammar would take too long to learn, as too 
many examples would be needed to test the validity of each linguistic rule. 
After all, humans have only a limited time for learning language before 
they reach adulthood. "This is really where linguistics meets evolutionary 
biology," says Komarova. "There is a selection pressure to make universal 
grammar smaller and easier to learn." An ultracompact grammar isn't 
necessarily the most efficient, though. Larger grammar pools increase 
flexibility, making it possible to express more complex ideas and thus 
facilitate innovation.

Cognitive scientist Gary Marcus, at New York University, is interested in 
the origins of the human mind.5 He emphasizes the complexity of the task 
ahead and the need for new, more flexible approaches. "It's easy to view 
language as the product of natural selection, but we shouldn't see it as a 
single trait shaped by a single selection pressure," he says. Instead, we 
need to see it as a mixture of cognitive mechanisms, some old and some new, 
each of which might be subject to numerous differing, even competing, 
selection pressures.

MORE THAN A GAME Simon Kirby, reader in the evolution of language and 
cognition at the University of Edinburgh, says that the cross-disciplinary 
approach has helped dismantle the dogma that all languages are equal. "One 
of the main contributions coming from the evolutionary biology side is that 
languages improve qualitatively," he says, "so a language can become more 
efficient at conveying information as it evolves.

The flow of ideas between disciplines isn't all one-way traffic. Theories 
of learning are vital for any attempt to understand human language. "When 
the story is finally told about how language has evolved, learning theory 
will play a central role," says Niyogi. He argues that both the linguistics 
and computer science communities, which together are responsible for the 
major developments in learning theory, share the view that its role hasn't 
been sufficiently incorporated into evolutionary models. "You can't simply 
collapse 50 years of language research into a single parameter, call it "P" 
and say it's analogous to cultural transmission."

Not all the findings from ethological game-theory studies necessarily map 
onto linguistics research. Language is a consensus between speakers and 
listeners. In other biological systems, mutualisms are often kept honest 
because both partners are continually attempting to exploit one other. But 
Harvard University's Steve Pinker says that the cooperative nature of 
language is the most likely factor driving its evolution.

"I don't think that language could have evolved primarily as a technique of 
manipulation," he says. Most animal signals are clear-cut examples of 
manipulation, in which signalers and receivers exert selective pressure to 
produce more effective means of exploitation and resistance, respectively. 
Pinker draws a distinction between these types of interactions, such as 
mating calls, and the complexity of language, which requires a huge 
investment by the listener simply to decode the information. Why, Pinker 
asks, would the listener bother to do this if only to be manipulated as a 
result?

Nevertheless, it's clear that many of the other central evolutionary 
concepts, such as kin selection, are vital to language. "Human interactions 
are not entirely antagonistic. There are kin, spouses, and reciprocators, 
where the relationship is largely (albeit not completely) nonzero-sum and 
positive," says Pinker, drawing attention to the fact that often both 
parties can benefit through successful communication. "I think the 
cooperative story has to be basically right. Lying and manipulation are a 
parasitic overlay."

LANGUAGE FRUIT FLY Comparing animal signals, morphologic structures, 
genetic systems, and learning processes across species has paid dividends, 
according to Tecumseh Fitch at the University of St. Andrews' School of 
Psychology in Scotland. "Many historical linguistics methods can be 
successfully applied to nonhuman systems," says Fitch. "Bird and whale-song 
dialects show geographic variation and changes through time, just like 
human language does." This raises the possibility of using other animal 
species, what Niyogi calls a "language fruit fly," to better understand 
human speech.

Clearly these are exciting times for language research. And there's no 
shortage of raw materials, says Kirby. "We have an embarrassment of data. 
Language is going on all the time, all around us."

References
1. MA Nowak et al,  "Computational and evolutionary aspects of language," 
Nature 2002,  417: 611-7. [PubMed Abstract][Publisher Full Text]

2. WG Mitchener, MA Nowak  "Chaos and language," Proc Roy Soc Lond B 
2004,  271: 701-4. [Publisher Full Text]

3. A Senghas et al,  "Children creating core properties of language: 
evidence from an emerging sign language in Nicaragua," Science 305: 
1779-82. [Publisher Full Text]  Sept. 17, 2004

4. JM Smith  Evolution and the Theory of Games Cambridge University Press 
1982.,

5. G Marcus  The Birth of the Mind: How a Tiny Number of Genes Creates the 
Complexities of Human Thought New York: Basic Books 2004.,


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"Only a zit on the wart on the heinie of progress." Copyright 1992, Frank Rice


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