Toward an Evolutionary Biology of Language

In this forcefully argued book, the leading evolutionary theorist of language draws on evidence from evolutionary biology, genetics, physical anthropology, anatomy, and neuroscience, to provide a framework for studying the evolution of human language and cognition.

Philip Lieberman argues forcibly that the widely influential theories of language's development, advanced by Chomskian linguists and cognitive scientists, especially those that postulate a single dedicated language "module," "organ," or "instinct," are inconsistent with principles and findings of evolutionary biology and neuroscience. He argues that the human neural system in its totality is the basis for the human language ability, for it requires the coordination of neural circuits that regulate motor control with memory and higher cognitive functions. Pointing out that articulate speech is a remarkably efficient means of conveying information, Lieberman also highlights the adaptive significance of the human tongue.

Fully human language involves the species-specific anatomy of speech, together with the neural capacity for thought and movement. In Lieberman's iconoclastic Darwinian view, the human language ability is the confluence of a succession of separate evolutionary developments, jury-rigged by natural selection to work together for an evolutionarily unique ability.

Evolution is opportunistic and has a "historic" logic of its own making. Existing structures and systems are adapted to serve new ends, often maintaining their original functions as well. Once a new behavior is in place, natural selection may then modify a structure to enhance that aspect of life; but some, or all, of the demands of the starting point may persist. …the brain mechanisms that yield human syntax ability also have evolutionary antecedents outside the domain of language. The subcortical basal ganglia structures of the human brain that are critical elements of the neural systems that allow us to comprehend the meaning or to form a sentence also continue to support neural circuits that regulate motor control as well as aspects of cognition, mood, and much else. The evolutionary record of the changes that yielded human language is evident in the morphology and physiology of the brain and body; disputes concerning the evolution of language follow from different readings of the text.
Uncertainty arises because the text has become obscured; the species who possessed intermediate stage of language are extinct…. Nonetheless, the situation is not hopeless…the present anatomy and physiology of the human brain and body reveal its evolutionary history, which, in turn, provides insights on the nature of the biologic bases of human cognition, language, and other aspects of human behavior.

—from Chapter 1

Joseph T. Devlin - Science

Discussions of language tend to start from the assumption that it is a uniquely human trait without antecedent in the animal kingdom. Toward an Evolutionary Biology of Language forcefully challenges this assumption. Lieberman brings together a wide range of evidence from comparative anatomy, physiology, neurobiology, genetics, neuropsychology, and linguistics to illuminate the protolinguistic abilities in other species.

Philip Lieberman is Fred M. Seed Professor of Cognitive and Linguistic Sciences and Professor of Anthropology at Brown University.