The Co-Evolution of Language
And the Brain
By Terrence W. Deacon
Norton. 527 pp. $29.95

Go to Chapter One

The Growth of the Little Gray Cells

By Robin Lakoff
Sunday, November 23, 1997; Page X06
The Washington Post

Among the properties that distinguish human beings from other creatures is our propensity for asking the question "What distinguishes human beings from other creatures?" And among the answers frequently given to that question are: language and our big brains. Where do these come from, and which came first? Typical modern conclusions are that the brain developed first, permitting our complex linguistic behavior; that human language is quantitatively, not qualitatively, different from animal communication; and that our linguistic capacities are "innate," pre-programmed from conception rather than learned by rote.

In his new book, The Symbolic Species: The Co-Evolution of Language and the Brain, Terrence W. Deacon, associate professor of biological anthropology at Boston University, reexamines these questions and offers thought-provoking and controversial answers. He argues that the growth of the brain did not precede and permit the evolution of language. Rather, as the book's subtitle suggests, Deacon believes that the brain and language co-evolved: An increase in the size of the brain's prefrontal cortex permitted the development of symbolic capacity, even as the complex linguistic structures deriving from that capacity "selected," in the Darwinian sense, a brain that had a large enough prefrontal cortex to make use of this novel form of communication. As Deacon puts it, "The major structural and functional innovations that make human brains capable of unprecedented mental feats evolved in response to the use of something as abstract and virtual as the power of words."

In Deacon's view, human language capacity is, on the one hand, just a small step from primate communicative behavior; some primates have large vocabularies and relatively abstract ways of expressing information. On the other hand, human linguistic communication has taken a giant leap beyond any nonhuman system in that it uses symbolic reference: Our rules of grammar are symbolic, as are the categories (e.g. nouns) that they incorporate. The vocabularies of all human languages encode abstract ideas. Mere increases in the numbers of words available in a primate communicative system, or longer strings of words, would not make them equivalent to human languages.

But our language ability did not arise out of nothing. Furthermore, it is not an isolated component of the brain: The capacities we use to speak are applied elsewhere in our cognitive strategies. In these two respects, Deacon takes sharp issue with MIT linguist Noam Chomsky's idea of a "language acquisition device" (LAD), a module somewhere in the mind (and/or brain) that is innate, present at birth in all humans but without analogs in the brains of other creatures, and specialized for language alone.

While Deacon acknowledges that language capacity, or competence, is in some sense innate -- "children enter the world predisposed to learn human languages" -- he takes issue with Chomsky's use of the term innate, which he (somewhat eccentrically) understands as involving "an ability to perform certain language tasks as though they had previously been learned" (italics his). But Chomsky means by "innateness" essentially what Deacon does: that we possess at birth a mental template that allows us to decode the utterances we hear around us as infants, and to derive our grammars from those observations. We have not "learned" anything before we are exposed to it in the first years of life.

This controversy mirrors the current debate between nature and nurture. How many of our predispositions are we genetically born with, and how many do we learn from our environment? Chomsky's emphasis on "innateness" supports the position that most aspects of human behavior are genetic and not readily changed; Deacon's position cedes more influence to postnatal environment. Likewise, Deacon's version fits more readily into modern theories of evolution in seeing connections between human and animal communication; Chomsky's autonomous and unique LAD is difficult to account for in a Darwinian framework.

Deacon's controversial ideas merit wide attention, but the format of the book may discourage all but the most dogged readers. It's a problem familiar to authors who attempt to bring the complex ideas of science to a nonprofessional public. The style sometimes bogs down in convoluted syntax; technical terms are introduced without being clearly defined (for instance, "kernel sentence," "eukaryotic," "encephalization"). More seriously, the lay reader is often overwhelmed: What should be summarized briefly, or even omitted, is dealt with in excruciating detail.

At the same time, if I had to choose between dumbed-down popularizations in which each sentence is a paragraph and smartened-up ones that require some slogging through, I would unequivocally choose the latter. If you're willing to struggle in order to be introduced to important and provocative ideas, you should read The Symbolic Species.

Robin Lakoff, professor of linguistics at the University of California at Berkeley, is the author of "Talking Power."

© Copyright 1997 The Washington Post Company

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