Rating: 
Summary: How special are symbols?
Review: The following is based mostly on others' discussions of The Symbolic Species, so I may have missed arguments/explanations from the book itself.The author argues that symbolic references are what separates human language from that of other animals. In the third chapter, he defines a symbolic relationship as one that is neither iconic (based on formal similarity) nor indexical (based on contiguity in space/time). Instead, a symbolic relationship is a connection between two or more indices: the relationship between "A" and "B" reminds one of the relationship between "B" and "C", rather than just "A", "B" and "C" refering to one another separately. A word, then, can be a symbol because its relationship to the external world can be affected by the word(s) with which it co-occurs in speech (in other words, there is a connection between connections). I may not be correctly understanding Deacon's use of "symbol"; it was not so easy for me to see what it meant. Deacon also says, I think, that symbolic connections damage, or can damage, the ability to implement lower-level connections: use of the word "fire" can cause one to think of related words/concepts, rather than respond to the immediate presence of a fire. If I have understood Deacon's definition of "symbol", then, in neurological terms, symbolic relationships should correspond, to some extent, to a hierarchy of connections between neurons, reflecting, maybe among other things, the connections between lower-order indexical relationships. Deacon says in ch. 9 that the well-connected prefrontal cortex is involved in constructing "the distributed mnemonic [reviewer defines "mnemonic" as "memory-related"] architecture that supports symbolic reference", but that it does not have much to do with "the storage or retrieval of symbols" (both ch.9). If I understand him here, he is saying that, once prefrontal connections have been used in the creation of symbolic relationships, they are left free to create new ones rather than devoted to any specific ones. I do not know that i agree with Deacon, overall, though i thought he may haved done well to focus on learning -- e.g. the chimpanzee experiment in ch.4 -- rather than less empirical concepts of cognition. Still, _The Symbolic Species_ is best read with an eye out for subjective statements (in ch.13, I think he claims that only humans can experience conflicting emotions) and with the understanding that he may not always adequately define the "symbols" he discusses.
Rating:
Summary: Great
Review: 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.
Rating: 
Summary: Explore the brain/language relation
Review: 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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