MIT: No easy answers in evolution of human language
David Chandler, MIT News Office
February 17, 2008
The evolution of human speech was far more complex than is implied by
some recent attempts to link it to a specific gene, says Robert Berwick,
professor of computational linguistics at MIT.
Berwick will describe his ideas about language in a session at the annual
meeting of the American Association for the Advancement of Science on
Sunday, Feb. 17. The session is called "Mind of a Toolmaker," and
explores the use of evolutionary research in understanding human abilities.
Some researchers in recent years have speculated that mutations in a
gene called Foxp2 might have played a fundamental role in the evolution of
human language. That was based on research showing that the gene
seems to be connected to language ability because some mutations to that
gene produce specific impairments to language use, and because our
closest living relatives, the chimpanzees, lack both these gene mutations
and the capacity for language. But the claim that the gene mutation is
directly connected to the development of language is very unlikely to be
right, says Berwick, who holds appointments in MIT's Department of
Electrical Engineering and Computer Science and Department of Brain and
"This kind of straightforward connection is just not the way organisms are
put together," he says. When it comes to something as complex as
language, "one would be hard-pressed to come up with an example less
amenable to evolutionary study." And the specific Foxp2 connection is
based on a whole chain of events, each of which is speculative, so there's
little chance of the whole story being right.
"It's so chaotic, it's like weather forecasting," he says. "The noise
overwhelms the signal."
Rather, language is almost certainly the result of a far more complex and subtle interplay among a variety of factors, Berwick says, and it may never
be possible to connect it to specific genetic changes. "There are some
things in science that are very interesting, but that we're never going to be
able to find out about," he says. "It's a sort of romantic view some people
have, that anything interesting can be understood."
Even defining something as complicated as language in a precise way is
daunting, as ongoing disputes over the significance of language
experiments with apes, parrots and dolphins have made clear. Berwick
says, "If you can't define what it is, why study it from an evolutionary point
It's more likely, Berwick says, that the role of the Foxp2 gene in language is
somehow peripheral to the capacity for language itself. He compares it to a
printer in a computer system--it's part of the overall system, but it's not
fundamental. Berwick thinks a more productive approach to studying the
evolution of language is to examine it in terms of deeper, internal
In his own research, Berwick has compared the structure of languages with
the structure of bird songs, and has found interesting connections that may
lead to a better understanding of some aspects of language.
Both bird songs and all human languages seem to share some underlying
characteristics related to their metrical structure, Berwick says. There's an
underlying sing-song beat that is pronounced in poetry, music and in the
songs of birds that may reveal a fundamental aspect of how our brains
process language. Future research could probe this link further, even
looking at possible connections between other specific genes, in both birds
and humans, that might be connected to this sense of metrical structure.
Ultimately, the important thing is to understand that language is, at bottom,
something that takes place inside the human mind and is independent of
any particular sound, sight or motion. The same internal mental
construction could be expressed through verbal speech, through writing or
through sign language without changing its basic nature, Berwick says. "It's
not about this external thing you hear," he says. "It's about the
representation inside your head."