42 of 44 people found the following review helpful:
5.0 out of 5 stars
Explore the brain/language relation, July 28, 2000
Three reasons to read "The Symbolic Species". 1) Deacon describes how neuroscience is finally producing results that deal with the issue of how brains make human language possible. 2) Deacon presents a theory of brain/language co-evolution that stresses the importance of behavioral innovations that alter the human environment leading to subsequent genetic adaptation. 3) Deacon explores ways by which Philosophy of Language can be refined by incorporation of results from the scientific study of human language.
This three-fold enterprise depends on the neuroscience results discussed in Part Two of "The Symbolic Species". For example, Figure 7.8 draws our attention to the idea that prefrontal cortex is disproportionately large in the human brain. Deacon suggests that changes in the relative sizes of brain regions during human evolution is a mechanism for adaptations that allow humans to better perform language tasks. Figure 8.3 pictorially illustrates an evolutionary trend in anatomical connections towards more direct cerebral cortex control over the motor neurons that are involved in vocalizations. These examples illustrate the fact that Deacon's theory of brain/language co-evolution is heavily dependent on comparative studies of brain anatomy. Deacon tries to convince us that the major anatomical changes during human brain evolution are the precise types of changes in an ape brain that would facilitate human language behavior. According to Deacon's theory, early humans started using language as a social innovation and then the human brain changed so as to make it easier to use human language. The fact that human social interactions are a huge part of the human environment guarantees that there has to be some truth in Deacon's theory, but is it just part of a larger story?
A specific issue that Deacon touches on is the fact that non-human apes are able to learn the basics of human language simply by being exposed to a social environment where human language is being used. Why do non-human apes learn the basics of language rapidly and then stop developing more sophisticated language behavior just at the developmental stage where human children are taking off with a huge vocabulary and increasingly complex syntax? The best that Deacon's theory can suggest is that humans, unlike chimps, have had 2 million years of language use and subsequent brain evolution in response to selective pressure for larger brain regions that aid in symbolic thought. I agree that it would be astounding if certain brain regions such as the adult human prefrontal cortex is not more useful for human language tasks than is the chimp prefrontal cortex, but is this really the most important thing we need to know about the relationship between brains and language?
Is there another way of looking at the difference between human and chimp brains? One that might better inform us about the functional differences between human and chimp brains that give humans superior language skills? Deacon mentions an alternative in Chapter 6, "...the rate of human brain maturation...is prolonged compared to other primates..." In fact, most human brain growth happens after birth while most chimp brain growth happens before birth. What does this have to do with language behavior?
Perhaps everything. Why DO humans have big brains? Even though Deacon correctly points out the fact that, in the case of brains, bigger does not mean better, his whole theory ends up depending on the idea that by making some brain regions bigger, you get an ape that is better at learning human language. Deacon tries to gloss over this contradiction by assuring us that his theory is really making use of a powerful mechanism for evolving a more language-competent brain, the mechanism of "parcellation", which he claims can mechanistically explain data such as those given in Figure 8.3. Can parcellation really do all the explanatory work that his theory demands or is there a need for additional mechanisms?
Why DO humans have big brains? What if big human brains are just a side effect of some other more important aspect of brain physiology? What if larger human brain size is just a side effect of evolutionary selection for prolonged synaptic plasticity during human childhood? Maybe if we could alter a few genes in bonobos so as to prolong postnatal brain growth in certain bonobo brain regions like the anterior cingulate cortex, just maybe we would give bonobos a longer window for developing sophisticated language skills.
There is a whole tradition within neuroscience that started with behavioral studies of associative learning and led to studies of the cellular and molecular mechanisms of learning and memory. This branch of neuroscience research is almost completely ignored by Deacon. We have to wonder if Deacon's focus on neuroanatomy has provided him with a limited data set which paints his theory of brain/language co-evolution into a corner.
So my advice is that people who are interested in language should read Deacon's book, but recognize the limitations of his perspective. In the next few decades the rest of the story of how brains make human language behavior possible will come rolling in. Deacon has provided us with a working model of how to apply this hard-won knowledge of the brain to our understanding of human language, but Deacon's is just an early pass at this kind of empirically-anchored theoretical neurolingustics. Much more is yet to come. Even scientists should heed Wittgenstein's warning not to be too quick to formulate grand theories of language while so much data remains to be collected.
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27 of 29 people found the following review helpful:
4.0 out of 5 stars
Great, February 21, 2003
This review is from: The Symbolic Species: The Co-evolution of Language and the Brain (Paperback)
This is ambitious stuff. Deacon wants to explain the origins of language, underlying neural dynamics, explain symbolic reference and to show why Chomsky is wrong on his ideas on language. The result is a highly readable and complex text that somehow Deacon manages to maintain coherent. Many interesting ideas and insights can be found in the pages of this book. However it is not at all clear to me to what extent all of this is groundbreaking stuff. For example, darwinian processes in neural dynamics and development are not new ideas, as Deacon admits. Edelman, Calvin, Changeaux all got there first. The role Deacon gives to the prefrontal cortex is not new either. His explanation of symbolic reference as a collection of indexical and iconical relationships, and further symbo-symbolical higher orther relationships, is philosophically questionable to say the least. Why would symbolic abilities arise out of adding levels of non-symbolic relationships, in the way Deacon proposes?. Surely, symbolic abilities must depend on non symbolic mechanisms at some level, but it is not clear at which.
But Deacon also has moments of genius. His attack on Chomskian innate universal grammar frameworks is brilliant. Language evolved to adapt to the cognitive abilities of humans and therefore it seems it is learned too easilly. It is not that children have a grammar module, but that their general modules are enough when most of the adaptive work was done by language itself by evolving. Deacon also shows why grammars are not things that can become innate in the first place too. They cannot be invariant enough for selection to work on the brain to aquire them. Deacon also shows what did happen in the brain for there to be language. The relationship between brain-size and cognitive ability is more complex than we thought, and Deacon shows us why and how.
Also quite good is Deacons explanation of why language evolved in the first place. It evolved as a means to deal witht he changing social and sexual organization of hominid groups, that started to form pair-bonding while being foragers. Language acted as the glue that kept these dynamics stable.
This is very good stuff, and it is bold and plausible. Deacon did not solve the mystery of intentionality or language, but his insights might show the way towards doing exactly this. There are few other books on language and the brain as thought provoking as this one.
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42 of 48 people found the following review helpful:
5.0 out of 5 stars
architectural structure of arguments, March 7, 2000
Reading only one or two pages into this book already makes it clear that this is a work by an exceptionally well informed and disciplined writer; and reading to the end does not disappoint at any time. This is a tightly argued serious scientific thesis by a professor of biological anthropology with an encyclopedic knowledge of linguistics, neurophysiology, neuroanatomy and human evolution. It is an original work in which Deacon sets out his arguments and marshals the evidence for a comprehensive theory in a methodical and structured way. It is not for the faint hearted, and reading it demands careful attention to the tightly written dense structured prose; it is not repetitive and the logical structure of the arguments is architectural, so that careful reading and a good memory are essential. Useful diagrammatic illustrations help to make some of the concepts easier to grasp. The effort is worth every moment. Deacon's conclusions have consequences for philosophy and theory of mind no less than for the central area of linguistics and the evolution of human intelligence. This book has done more to shape and to consolidate my knowledge of who we as a "symbolic species" are than any other I have read in this decade. Strongly recommended.
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