The study of the nature and
development of the largely unique linguistic abilities of the human species has
been a long standing enterprise for many generations of scientists and
non-scientists alike.  Notwithstanding the enduring attention that this topic
has generated, its study has yet to yield a comprehensive framework capable of
explaining not only how these abilities have come about, but also how they are
exercised by the brain of contemporary human beings.  In Toward an
Evolutionary Biology of Language, Philip Lieberman argues that a fresh
understanding of humans’ ability to produce and comprehend speech can be
derived from the study of the complex physical machinery that allows for the
production and comprehension of speech sounds in real-time social
interactions. 

At a fundamental level, Lieberman’s
approach is to focus on the interplay between the physical aspects of the
machinery and its multi-layered functioning. His attention is devoted to
performing meticulous and scientifically grounded comparisons between the
communication devices and abilities of humans and those of non-human animals. 
As most scientifically grounded and successful research enterprises that place
seemingly self-contained experimental findings into a bigger picture, Lieberman’s
approach is guided by a solid theoretical framework.  This is not to say that
the author is blinded by his choice of the evolutionary biology framework based
on the work of Charles Darwin to the point of discarding facts that do not fit
with it.  On the contrary, this framework is used rather skillfully to
entertain some captivating and creative ideas about the evolution of the human
capacity to communicate by means of speech sounds. It follows that the author
is not kept hostage to the multitude of research findings that originate from
dissimilar areas of scientific inquiry such as genetics and linguistics. On the
contrary, Lieberman organizes and describes such findings artfully giving
readers enough information to evaluate the extent to which his explanations are
empirically grounded.

Every time Lieberman goes beyond
the evidence to venture an interpretation of the facts uncovered by one of his
carefully sequenced descriptions of scientific investigations, he makes it easy
for readers to demarcate ”facts” and ”conjectures”.  This is a challenging
task because of the nature of the ”facts” that he discusses in the book, from
contemporary evidence (such as the fine-grained differences in the
communication devices of existing human and non-human animals), to
archeological evidence (such as the differences in the devices of existing
animals and of their ancestors, both human and non-human). Undoubtedly, as he
moves away from contemporary evidence, the chances of entertaining conjectural
lines of thought increase exponentially. Nevertheless, the author’s transparent
style and modesty of exposition ensure that the chances of readers mistaking ”facts”
for ”conjectures” remain slim.

Obviously, there are other
attractive aspects to Lieberman’s book that are noteworthy. Most of all, this
is a book that tells a story about how a methodological approach that
incorporates different knowledge domains into a scientific area of inquiry can
yield a cohesive bundle of findings and a challenging new way of looking at
them.  Superficially, the book appears to concentrate on, and be limited to,
language and its origin.  However, in it, language is portrayed as an ability
that has flourished on the larger platform of human cognition. Thus, cognitive
functioning and its neurological substrates aid Lieberman in his attempts at
understanding the linguistic abilities of the human species.

By means of this methodological
approach, Lieberman devotes his attention to the nature of the biological bases
of human language and relies on evidence and conjectures about its evolution to
put forward an organized attempt to confute the modular view of linguistic
abilities widespread among many prominent cognitive scientists.  He agrees that
human beings are biologically determined to learn and use language. However, he
thinks that scholars of cognitive sciences (mostly linguists) are guilty of
having ignored the findings of biology and its main theoretical framework, and
of having limited their intellectual enterprises to some ”unique” features of
human speech (those pertaining to syntax and the lexicon) while widely ignoring
others (those pertaining to the voluntary nature of human speech and to its
spectacularly fast speed of transmission relative to other forms of
communication). 

Even if not all the pieces fit the
image that the author proposes (mostly because of incomplete or unclear
findings), the evidence is compelling that the variety of human linguistic
abilities, including syntactic, semantic, lexical, and phonological/phonetic
processing, depends on the coordinated functioning of many areas of the human
brain. Lieberman’s reasoning relies on the idea that the brain and other
physical devices such as a species-specific tongue and supra-laryngeal vocal
tract are, at their core, evolutionary adaptations.  Under this general idea
falls Lieberman’s more specific claim that in the course of human evolution
physical structures that were originally devoted to motor control have been
modified to function as speech processing centers.  Although his claim that
there is no genetically transmitted innate knowledge of syntax seems to
logically and elegantly be derived from the biological and behavioral evidence
that he forcefully presents, the same evidence does not seem to, by itself,
confute the possibility of a language module.  It rather outlines the
possibility of a language ”device” that relies on the working of several,
empirically separable areas of the brain whose general functional properties
may be those of other devices (e.g., neurological areas devoted to motor
activities).  The fact that some brain mechanisms devoted to syntactic
processing have antecedents outside the domain of language simply reinforces
the idea of neurological mechanisms that have optimized their functioning by
evolving into apparatuses that perform specialized functions.  Of course, this
line of reasoning may require a conceptual reframing of the notion of ”linguistic
module”, perhaps resulting from a shift in focus from syntax to other equally
fascinating properties of human speech (e.g., its speed of processing and its
voluntary nature).  

On the whole, Lieberman’s book is a
captivating read for a wide-ranging audience, from seasoned scholars of
cognitive science, who will find the author’s claims grounds for serious
examination, to undergraduate and graduate students interested in cognitive
science who will find his writing instructive and (perhaps) worthy of a career
in the area.  It is a book that combines detailed evidence with big-picture
ideas and that reminds us all that the study of language is far from being
completed.  The hope is that Lieberman and other equally serious scientists
will continue to challenge existing theoretical frameworks so as to approach
the possibility of a time when our understanding of human linguistic abilities,
involving both perception and production, is less uncertain.  

© 2006 Maura
Pilotti

Maura Pilotti,
Ph.D., Department of Psychology, Dowling College, New York.

Categories: Psychology