The human brain did not spring forth de novo; the basic subcortical structures found in reptiles and amphibians survive and play a role in the operations of the human brain. (p. 100)To say that Philip Lieberman is not a fan of Steven Pinker and Noam Chomsky is a drastic understatement. A very significant portion of this book is devoted to thoroughly crushing their speculations and assumptions about a universal or innate grammar. Lieberman marshals in a mountain of evidence to show that not only is language not residing solely in Broca's and Wernicke's areas of the brain but that 'primitive', subcortical basal ganglia (the structures of our reptilian-amphibian brain) in the brain play a role in human language. Indeed, damage to the basal ganglia can cause more harm to linguistic cognition than damage to an area such as Broca's.
The Broca's-Wernicke's model of the neural bases of language is, at best, incomplete. While language often recovers after humans suffer cortical damage (perhaps reflecting the cortical plasticity noted in previous chapters), damage to subcortical circuits results in permanent language deficits. Speech, lexical access, the comprehension of meaning conveyed by sentences, and various aspects of 'high' cognition are regulated by parallel circuits that involve the basal ganglia and other subcortical structures, as well as neocortical structures. The FLS [functional language system] is a distributed network. Parallel processing occurs in neural structures traditionally associated with motor control, as well as in parts of the brain that have been associated with language, higher cognition, and perception. (p. 83)I had strong suspicions that Pinker and Chomsky were barking up the wrong tree, and Human Language and Our Reptilian Brain merely confirmed them. Unfortunately, the book is rather clinical/dry/technical/dull in style and tone and will not be read by the vast majority of those who happily and uncritically embraced Pinker's popularization of Chomsky. Hopefully, something in the future along the lines of Human Language and Our Reptilian Brain will emerge that is more readable for the masses.
Chomsky's theory seems to rest more on the back of miracles than on evolution. Lieberman brings this point home with the following.
Cognitive scientists have attempted to understand mind-brain relations using modular theories that owe more to IBM than to Charles Darwin. However, the constraints of evolutionary biology that structure the anatomy and physiology of the human brain cannot be ignored. Cognitive science must take the principles and lessons of evolutionary biology into account. (p. 159)Least the title, and my explanation so far, lead the reader to believe that language resides in the basal ganglia, I'll conclude with Leiberman's reminder from the same page as the above quote.
...the focus here on the subcortical basal ganglia must not be interpreted as a claim that either speech motor control or syntax resides in the basal ganglia. The FLS integrates activity in many parts of the human brain, including the subcortical cerebellum, thalamus, motor cortex, premotor cortex, prefrontal regions, and sensory cortex.
from the publisher:
This book is an entry into the fierce current debate among psycholinguists, neuroscientists, and evolutionary theorists about the nature and origins of human language. A prominent neuroscientist here takes up the Darwinian case, using data seldom considered by psycholinguists and neurolinguists to argue that human language--though more sophisticated than all other forms of animal communication--is not a qualitatively different ability from all forms of animal communication, does not require a quantum evolutionary leap to explain it, and is not unified in a single "language instinct."
Using clinical evidence from speech-impaired patients, functional neuroimaging, and evolutionary biology to make his case, Philip Lieberman contends that human language is not a single separate module but a functional neurological system made up of many separate abilities. Language remains as it began, Lieberman argues: a device for coping with the world. But in a blow to human narcissism, he makes the case that this most remarkable human ability is a by-product of our remote reptilian ancestors' abilities to dodge hazards, seize opportunities, and live to see another day.
Philip Lieberman is Fred M. Seed Professor of Cognitive and Linguistic Sciences and Professor of Anthropology at Brown University.
This is a thoughtful and scholarly book that is bound to expand the horizons of any. . . well-educated layperson or student who would like a brief review of this dynamic multidisciplinary field that encompasses neurology, primate studies, anthropology, psychology, and of course linguistics. --F. S. Szalay, Choice