COMPARISONS OF THEORIES ON THE ORIGIN OF LANGUAGE: LANGUAGE ON THE BRAIN
“Darmok and Jalad at Tanagra. Sokath, his eyes uncovered!”
Apart from linguistic historians, researchers from other fields are also hungry for revelations; Artificial Intelligence researchers are eager to see how to apply it in cases of complex dynamical systems and in imbuing artifacts with the capacity to learn language; Developmental psychologists and neurophysicians would have new perspectives on problems like William’s syndrome and be able to better diagnose and predict the neurological effects of strokes. This essay explores theories on the origins of language put forward in Derek Bickerton’s Language & Species and Terrence Deacon’s Symbolic Species with specific regard to differences in the approach to Chomsky’s Language Acquisition Device (LAD), the species language barrier, and whether an intermediate language existed between protolanguage and language.
A supporter of Chomsky’s theory of the existence of a LAD in the brain that allows humans to use language, Bickerton refers to language as “a system of representation” and as an “evolutionary adaptation of a particular species” (46). Developing Chomsky’s idea further, Bickerton describes a Secondary Representational System (SRS) latent in any creature whose primary system is developed enough to analyze its environment and categorize sensory input. Essentially syntax and grammar, SRS is also noted as being latent but possibly unusable if the SRS is not equipped with an extensive vocabulary of terms acting as a referential index for the categories into which analyzed sensory input is fit into. E.g., a two dollar coin would be like a vocabulary term, and the croissants or other arbitrary baked goods it could buy would be the category. Bickerton continues to explain that animals without language can and have been trained to use their hypothetical SRS to exhibit some form of protolanguage, but are not be able to use it to as significant an extent as humans do, as they lack an extensive vocabulary.
Deacon agrees in respect to language being an evolved aspect and extends upon Bickerton’s idea, saying that “language is not merely a mode of communication, it is also the outward expression of an unusual mode of thought―– symbolic representation.” (22). Deacon disagrees with Bickerton’s approach of having the LAD or SRS be the basis of research in regards to the origin of language, as he suggests that a system of symbolic representation develops through the “internalizing the symbolic process that underlies language.” (22) Deacon states that the “hopeful monster” theory of humans having a LAD is appealing because it provides: i) a clear discontinuity between the language abilities of human and non-humans (only people have LADs, so only people have language); ii) a systematic interdependent set of grammatical rules (allowing legacy research on grammar to be used means that researchers have something to already go by); iii) presumes universal features of language structure (a unifying theory of language structure would be very nice to accept and use); and iv) explains the ease of language acquisition for children under the age of two despite being exposed to a relatively small vocabulary as well as having little grammatical correction from their parents (36).
For Deacon, this list of reasons to support the LAD theory suggests that there is something missing; that the LAD concept effectively acts as a placeholder for a yet to be explained concept and he questions if it could have evolved through natural selection. Additionally, the trouble with looking for evidence that the LAD exists is that researchers would be looking for something that explains the source of language competence during development, and not initial language origin itself – it does not help explain why the present human brain configuration was favored in respect to language, “how incremental and partial versions were also functional, and how structures present in nonhuman brains changed to have it” (38-39).
With respect to Bickerton’s SRS idea, Deacon approaches it by noting that if only humans use language due to the evolution of a specialized language device, which in turn is enabled by a highly complex language comprised of grammar, syntax and a vast vocabulary; then surely animals that do not use language as we do must still be using a simplified version of language. But according to present research using the accepted linguistic definition of language, there are no simple languages present in nature. Replying to those who argue that animal calls and gestures are a form of language, Deacon notes that “treating animal calls and gestures as subsets of ‘language’ reverses the sequence of evolutionary precedence and inverts their functional independence” and that “nonlanguage” communication is self-sufficient and needs no support from language to help acquire or interpret it (53). Deacon explains that the division between an animal’s usage of an indexical reference system works on the basis that a call or gesture references (i.e. means) a concept; a word or symbolic reference works on a similar basis, but also provides the ability to reference abstract concepts like non-immediate time and space as well as thought. Consequently, symbolic reference allows for thinking and talking about situations like perspective-reversal (what it is to be in another’s shoes), which has been experimentally shown to be extremely difficult to do even by ancestrally-close primates. (Deacon 419). Therefore, this is where Deacon draws his conclusion as to why animals do not naturally employ language; in essense, call reference is not the same as word reference. Bickerton has similar beliefs (although based on his focus on grammar and syntax), but determines that in regard to why animals do not naturally employ language is mostly a matter of it being simply too complex for animals to wield.
Returning to the idea that there are no simple languages that have been yet found in nature (implying that most, if not all animal protolanguage-like communication is a complex ordeal), Deacon proposes that the capacity for full-on human language might not to be a complexity problem, but possibly one of symbolic reference. With this idea in hand, Deacon then suggests that grammatical rules and categories are symbolic products and that syntax is “just physical regularity” used to encode symbolic operations (44). If the development of language complexity is secondary to the cognitive adaptation to symbolic reference, this idea inverts the evolutionary cause and effect path of Bickerton’s SRS: language develops its own neurological facilities in order to incrementally advance itself. This suggests that simple languages that did not use symbolic reference had to exist in pre-human society at some point and that the human brain was re-organized and optimized to allow for language built on the concept of symbolic reference to be easily acquired.
Bickerton disagrees over the idea of an interlanguage, citing a variety of reasons why language could not have evolved gradually, including a lack of archaeological evidence and that an interlanguage would require “the acquisition of properties that are in direct conflict with the principles of human language.” (178-179) Bickerton continues in his refusal of an interlanguage:
If human languages were acquired in the way that computer languages are acquired, that is, by conscious and deliberate learning, such a “detour” on the road to language might be harder to rule out. But there is every reason to believe that languages are not acquired this way. If human languages can be acquired only through the unfolding of biologically determined characteristics, a shift from one set of principles to another becomes highly implausible, even more so than a simple jump from protolanguage to language. Such a process would imply that one type of processing mechanism in the brain grew and flourished for a time but was then replaced by another. Although such possibilities cannot be completely discounted, there would seem little point in adopting them if a more convincing alternative exists. (Bickerton 179).
Deacon discusses such an alternative, but skips around the requirement for the brain flourishing in an area, then replacing it with something else: the brain reorganized itself in such a way that allowed a fairly stable protolanguage (highly based on indexical reference) to exist while language evolved around it. Specifically, Deacon believes that the brain was reconfigured over time to have a very large prefrontal lobe, while relatively maintaining the left temporal lobe, allowing both language subsystems to co-exist.
Magnetic resonance imaging (MRI) techniques have been used to inspect blood flow of the brain during mental activities to help neuroscientists see which parts of the brain are being used. Tests have shown that activities involving heavy usage symbolic reference (e.g. thinking of which word best describes an object in an image) highlight usage of the prefrontal cortex (roughly located behind the forehead). Tests with activities involving indexical reference with concrete terms (e.g. given the word “bicycle”, a test participant is asked to point to the image of a bicycle), the left temporal lobe (located close to the left temple) lights up. Accidents or strokes causing damage to one of these areas has compounded evidence of these brain locations being highly related to these language centers; damage to the prefrontal cortex leads to the inability to speak in complex sentences (profuse swearing is often observed, as swearing is akin to an animal call indicating frustration); damage to the left temporal lobe is correlated with William’s disease, where the afflicted often has enhanced powers of glibness, story-telling, and conversation, but has great difficulty memorizing facts and concrete concepts. While linguistic evidence of an intermediate language does not exist, evidence provided by paleoneurologists have found that the skull transformations that took place since the earliest known hominid skull formation concur with Deacon’s theory that the prefrontal cortex enlarged considerably with respect to other parts of the brain.
In analyzing our own cognitive evolution, we often end up trying to pigeonhole a version of a human/animal chimera into the “just beneath” human position. This usually ends up distorting everything (humans, ancestry, ape relatives) and does not work towards an end of knowing why other species think differently than humans, or why only humans are suspected of having language. While Bickerton manages to avoid this path, his largely linguistic approach to the problem is likely not to succeed in furthering scientific research into the subject of the origins of language. In contrast, Deacon, a biological anthropologist with a background in linguistics, has hypothesized that brain-language co-evolution restructured cognition from the top-down and that prefrontal enlargements rewired brains considerably, leading to higher-order learning processes, and has a significant amount of evidence behind his claims.
Bickerton, Derek. Language & Species. Chicago and London: University of Chicago Press, 1990.
Deacon, Terrence. The Symbolic Species: The coevolution of language and the brain.
Deacon, Terrence. “PBS interview” Accessed April 2006.