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LANGUAGE AND THE HUMAN BRAIN.
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Evolvement of human speech.... More...
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Paper Abstract:
Evolvement of human speech. Examines several theories regarding co-evolution of the brain and language. Argument of linguists that language cannot evolve out of an animal communication system. Noam Chomsky's Innateness theory; natural selection and adaptations. Language as an innate part of being human. Climate theories. Darwin. Neurophysiologist research.
Paper Introduction:
CO-EVOLUTION OF THE HUMAN BRAIN AND LANGUAGE: A DISCUSSION OF HOW NATURAL SELECTION MAY HAVE EFFECTED BOTH THE PHYSIOLOGICAL AND NEUROLOGICAL CHANGES THAT BROUGHT ABOUT LANGUAGE AND SPEECH
Introduction
During the Middle Ages, scholars accounted for human thought and speech by assigning a central part of the brain as the area where the “straw of raw sensory input got turned into the gold of thought” (Gutin 86). This is where the picture of the steeple and sound of the bell combined to mean “church” in the human brain. These scholars assumed that this area, which they called the common sensorium (where we get the term “common sense”)(86), was the sole property of humans -- an idea that has persisted for centuries.
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As noted before, the hypoglossal nerve runs from the brain stem,out the base of the skull, to the tip of the tongue (Cartmill 58). 992.Pennisi, Elizabeth. Additionalresearch has discovered a comprehensive fossil record that details agradual increase in brain size and complexity, as well as in the physicalcapacity for speech and the growth of complex social groups requiringknowledge of cooking, throwing weapons, and making tools. Current TheoriesThe Linguistic Theory of Innateness No discussion on the theory of language evolution is complete withoutat least a brief discussion of Chomsky's theory of how language is aninnate part of being human. Vol. The hyoid bone "floats" in thethroat, suspended by ligaments and muscles attached at the base of theskull and the tip of the jaw. Apes, however,have some capacity for social communication, but not the vocalmodifications. Potts notes thatmany animals that had previously flourished by the lake, became extinct atthis time, yet stone tools and debris left by early hominids reveal thatthey survived throughout the habitat shifts. Usingfossils of the interior of crania, Falk asserted that in the process ofremaining on the savanna, A. New York: Harcourt Brace & Co. Vol. This may also help explain why, although apes, such as bonobos, orrhesus monkeys, may have a symbolic language of sorts, and even a syntax,when communicating with one another, that their communication has notbecome more complex than it presently is (Hart 437).Physical Changes Outside the Brain With this increase in complexity of the brain, there needs to be anadjustment in the physical body to help promote communication in more thanjust general sign language. Animals and young humans are both known to compensatefor this short coming by making noises through a closed or pursed mouth,thereby lengthening the tube and so lowering the tone of the sound made.This makes the sound more "threatening" (for the animal) or more "adult"(for the child) (Lieberman 1998 135). Background Ever since Darwin publish The Origin of Species in 1859, there hasbeen conflict over the evolution of language. 2, p. Most recently,research will be presented by Lieberman at the Evolution of Language:Fourth International Conference (2 2) on how human linguistic andcognitive ability evolved from neural systems initially adapted for motorcontrol. June 1998. By studying skull fossils, scientists have tried to pin down when,exactly, the human larynx descended. Yet, Chomsky (2 ) admitted that there was no"innateness hypothesis", and advanced the opinion that there were only"specific hypotheses about the innate resources of the mind, in particularits language faculty" (66). Typical mammals, early hominids, and as pointed out previously, babyhumans, have a slightly different structure, however, as the larynx istypically high in the back of the throat. Science. According to Philip Lieberman, Professor of CognitiveSciences and Anthropology at Brown University, who admits that formerly hewas a firm believer in the Chomsky assertion that language is innate (1998134), notes that sounds coming out of the shorter tube also tend to behigher in register. 11, p. February 26, 1993. There have been many theories put forth since then as to why and howhuman speech has evolved and why animals do not seem to have the samecapacity for language that humans do. Brain Evolution and neurolinguistic preconditions. This agrees with previousresearch indicating that Stone Age groups responded to recurring crisissituations by pooling information and making effective collective decisions(359). Vol. 2 .Cartmill, Matt. This paper will examineseveral different areas of theory regarding the co-evolution of the humanbrain and language, specifically, Chomsky's "Innateness Theory", howvariations in climate may have changed the body through natural selection,how adaptations to complex communications may have spurred naturalselection, and physical changes that needed to occur outside of the brainfor speech to take place. October 13, 199 . Science. Darwin, however, was "fully convinced,as I am, that man is descended from some lower animal, is almost forced tobelieve a priori that articulate language has developed from inarticulatecries" (196). 48, iss. Falk contended that, once hominidsbegan walking upright, had the blood run straight back down the jugularvein, the jugular veins would have burst (232). New York: W.W. 2 .Chomsky, Noam. The base of the skull is actually theroof of the vocal tract (167). If language is a system which is superimposed upon another older sensory-motor-regulatory neural system, then we might hope to see the actor-action-object paradigm in the more primitive system (1983 156).Further research has been done in this area and this does seem to be apossibility. Brain Evolution: Climate Shifts Into Gear. Vol. This has been the primary motivationfor attempting to teach non-human primates, who share 98% of the same genesthat humans do, how to communicate (Hart 437). 437(2).Lieberman, Philip. Although he meant to attack the theories of behaviorists, such asB.F. In his opinion, the concept of "human" as apsychic whole will never be part of the study of the natural sciences orevolution (139). afarensis,as well as other "gracile" hominids, such as A. Contraction of the hyoid-tongue, orhypoglossal, muscle retracts the tongue with respect to the larynx (239).According to Deacon, it is this precise organization of muscles thatpermits them to be articulate enough for human speech (239). 83, iss. Current Science. 2 .Lundmark, Cathy. The larynx, in fact, is low in the neck,close to the esophagus, which why it is so easy for humans to choke on foodand for food "to go down the wrong pipe" (Cartmill 1998 57). Then thereare the tongue muscles, which are not only connected to the hyoid bone, butalso are where the hypoglossal nerve run from the middle of the brain stemto the tip of the tongue (Deacon 1997 239). Although it had expanded significantly over a million yearsago, over the next 5 , years, through a series of earthquakes andclimate changes, the lake changed sizes, shifted to different areas, andeven disappeared altogether at one point (Bower 359). In response, Muller and his followers were successful inbanning all presentation on language evolution from the Linguistic Societyof Paris (196). One put forth by Dean Falk is that about 2.5million years ago, global cooling caused the expansion of open, grassysavannas in southern and eastern Africa. March, 2 , 2 2.Coyne, Jerry A., Ph.D., Professor of Ecology and Evolution, University of Chicago. February 1998. New Horizons in the Study of Language and Mind. 17, Iss. Vol. Vol. Eve Spoke: Human Language and Human Evolution. 15, p. 1, p. Yet, symbolic representation had to grow with language, andthe body be physically adapted in order to express these symbols to others. africanus, chose to stay onthe savanna, whereas other hominids, such as the robust australopithecines,moved to the wooded areas near lakes and rivers (Bower 199 233). Calvin and Bickerton (2 ) also suggest that increase in complexity, aswell as brain enlargement, was the result of evolutionary pressures such asintelligence and motor coordination for making tools and throwing weapons(8 ). November 1998. As stated before, Deacon (1993) asserts thatas hominids had to adapt to a more complex social structure, theircommunication had to become more symbolic (1251). For example, it has beendemonstrated that the fetal brain growth phase of modern humans is about 3weeks longer than that of monkeys (McKinney 113). Later on, Chomsky (2 ) backed down slightly from his stance,however, he continued to assert that linguists do not understand whyevolutionists seek the separation, or pure state of being, of language fromthe language faculty (77-8). Inmodern humans, the bony canal that this nerve passes through is relativelylarge, about twice as big as that of similar sized chimpanzee. 1997.Gibbons, Ann. Becoming Human: Evolution and Human Uniqueness. Mullerfurther declared language to be the boundary that "no brute will dare tocross" (Calvin and Bickerton 196). When Chomsky first announced his theory, ahundred years after Darwin's Origin had been published, the consensus wasthat the human brain was a clean slate at birth, and children learnedlanguage by imitation (Calvin and Bickerton 197). Further, he declared, this faculty may bebroken down into two components: 1) The cognitive system that stores theinformation; and 2) The performance system that makes use of theinformation (117). In response to these unusual cognitive demands, the brain not onlyenlarged in the prefrontal cortex area, but it also usurped other areasthat had previously been used for vision, smell, and specializedvocalizations for the purpose of speech, language, and empathy (125 ).This dovetails with research by William H. One of the first problems that early hominids had to overcome was thesize of the brain. Vol. Lingua ex Machina: Reconciling Darwin and Chomsky with the human brain. As Homo habilis adapted to make stone tools to huntgame and prepare meat, the "unusual demands" criteria of evolution was metas these hominids had to find new ways to communicate symbolically (Gibbons1251). CO-EVOLUTION OF THE HUMAN BRAIN AND LANGUAGE: A DISCUSSION OF HOW NATURAL SELECTION MAY HAVE EFFECTED BOTH THE PHYSIOLOGICAL AND NEUROLOGICAL CHANGES THAT BROUGHT ABOUT LANGUAGE AND SPEECH Introduction During the Middle Ages, scholars accounted for human thought andspeech by assigning a central part of the brain as the area where the"straw of raw sensory input got turned into the gold of thought" (Gutin86). McKinney (1998) takes this argument further by pointing out thatthough brain and body size have both increased between Homo habilis, forexample, and modern humans, the brain has increased relatively faster toproduce a high brain-to-body ratio. Along with brain growth is growth incomplexity, a main component in cognition. Since the rib cage portion of the cord controls musclesused for the lungs, it was concluded that this youth may not have had theneural control over breathing movements that is needed for speech (Cartmill58). November 25, 1995. 18, iss. 51, iss. Currently, in further defense of the language faculty, Chomsky(2 1), maintains that "lots of people reject the proposal. 5 99, p. Presumably, the hypoglossal nerve grewto accommodate the movements needed for speech, and the canal grew toaccommodate the muscle and nerve (58). Excavations in southern Kenya have uncoveredevidence of dramatic environmental changes as demonstrated by the past lifeof the lake. 1979.Deacon, Terrence W. 1998. BioScience. Tool use,language, and social behavior all benefit from this increase in complexity. Max Muller, a leadinglinguist of his day, was of the opinion that humans and animals wereirrevocably distinct, thus siding with Judeo-Christian ideology. Vol. and Jennie Wakefield. Norton and Company. Additionally, since thelarynx is high, this reduces the length of the pharynx, or tube, that thesound vibrates through. 125 (2).Gutin, Jo Ann C. 1995.Westrup, Hugh. BioScience. This also helped tospur brain growth. Humans only make a few sounds where air isexhaled through the nose, and these tend to be nasal, such as consonantslike "m" or "n", or words such as the French "bon" or "vin". Nature. 259, iss. This shortness limits the ability of themusculature around the throat to be manipulated into different sounds(Tattersall 168). Discover. New Delhi, India: Oxford University Press. On Language. Other Sources Consulted and/or ConsideredClark, Tom. Human Language and Our Reptilian Brain. More recent research by archaeologist Richard Potts, points to aprocess of accommodating to habitat variability that may have spurred braingrowth, certainly increasing density and plasticity of the neuralconnections (Bower 1995 359). 6, p. Sounds aregenerated in the air that rises out of the lungs through the action of thelarynx. 283, iss. 1998.Lieberman, Philip. The Architecture of Language: Based on New Delhi Lectures. April 24, 1998. First, however, there will be a brief sectioncovering the background of the subject. Additionally, wherepostnatal development and myelination continues in monkeys for up to 3.5years, in humans it continues up to twelve years of age (114). In other words, sentences are discrete strings ofwords, such as 6 or 7 words, but not 6 1/2 words. Apes May Hold Clues to Language's Origins. This is what is known about themodern human. Norton and Company. The hyoid, which floats freely, helps in the ability of the muscles toarticulate separately during speech. It should be pointed out, however, that there were manyskeptics to these assertions, who used the giraffe as an example of anupright mammal with a large jugular who lives on a hot savanna (234). .but nobodyever answers them" (5 ). Although there have beenmany discussions, there still have been no decisions as to what thisdiscovery reveals about speech in the Neanderthal (17 ). Apes and baby humans have typicallyflat skull bones and adult humans have a more rounded skull with a strongdownward flexion. A Brain That Talks: Interview with Marty Sereno. Studying skulls has not produced a neat picture ofgradual descent, however, as a fairly recent Neanderthal was shown to haveonly a"modestly flexed cranial base" (Tattersall 169). Determining when the descent happened does not give information as towhy the descent happened, however. Calvin, theoreticalneurphysiologist, who asserts that, we must seek a neurological basis of the linguistic actor-action- object equivalence relations in the anatomy and physiology of the brain. and Derek Bickerton. There needs to be some kind of "unusualdemand" made in the natural selection process to start such a physiologicalchange, especially one that puts the animal in question in danger ofchoking. These scholars assumed thatthis area, which they called the common sensorium (where we get the term"common sense")(86), was the sole property of humans -- an idea that haspersisted for centuries. Yet, studies with non-human primates havediscovered some symbolic ability as well as syntax development. Works CitedBower, Bruce. This is further proof, in his opinion, that language isunique to Homo Sapiens and is an expression of genetic make-up (51).Climate Theories Although Chomsky was able to break words and meanings down to deepstructure and to theorize on linguistic concepts, he was unable to explainhow the human animal was able to get from a hominid such as Neanderthal orHomo Erectus to the current mammal today. As a result,non-human animals make mostly nasal sounds (57). 2 1.Chomsky, Noam. Further, heasserted that this faculty is the sole property of the species Homo Sapien(86). Science News. 11, p. 22, p. Vol. At that time, Hadar A. June 1996. Because thisskeleton was nearly complete, they were able to determine that the spinalcord was proportionately thinner in the region of the rib cage than it isin modern humans. Montvale, NJ: Williams & Wilkins. 2 2.Stedman's Medical Dictionary. BioScience. If Neanderthals didspeak, it was probably very nasal sounding (59). This not only prevents choking,but also makes most of the air exhaled, exit through the nose, rather thanthe mouth (Cartmill 57). 56(6).Chomsky, Noam. The Symbolic Species: The co-evolution of language and the brain. Although the ligature and musculature that normallysurround the hyoid had long decomposed, the hyoid is similar in structure.Yet, there is no way to tell if it functioned that same in the Neanderthalthroat as it does in the modern human throat. Deacon, a neurobiologist, put forward a theorythat seems similar, but is based on the need to adapt to complexcommunication needs. He contends that the language organ is analogousto the visual system (Chomsky 3) in its function and that one of the mostelementary properties of this system is the "discrete infinity" of speechand syntax (51-2). (1993 Annual Meeting of the American Association for the Advancement of Science). November 2 1. Harvard University. Montvale, NJ: Medical Economics Company, Inc. In a later work byDeacon (1997), he asserts that without the symbolic representation thatlanguage gives the human species, there is no internal life or virtualthought (22). According to Chomsky(2 1), this ability is virtually unknown in the biological world, with theexception of arithmetical capacity, which may be an offshoot of thelanguage faculty. Discover. 1983.Calvin, William H. africanus and their ancestors developed a moreefficient system of body cooling by growing a radiator of veins thatdiverted blood to the vertebral plexus, an extensive network of veinsrunning down the torso (Bower 232). This was the first time a line had been drawn betweenlinguists and evolutionists, and it determined their interaction fordecades to come (196). Althoughscience knows what the heart does and how it does it, asking how the heartgot where it is, is not considered a functional question (86). Did Cooked Tubers Spur the Evolution of Big Brains? 19, iss. Further, Falk assertedthat the network of veins helped create a network of blood exchange thatkept the brain cool under a hot savanna sun (233). Chomsky compared this faculty to the heart. 138, iss. Then, inKebara Israel, a Neanderthal skull was discovered with an intact hyoid bone(Tattersall 17 ). Skinner, it was also an attack on evolutionists, and so continued theconflict between linguists and evolutionists (Calvin and Bickerton 197). If the larynx descended as result of the need for intricatemating practices, then this would be an exaptation waiting for the brain'sability to string together symbols to catch up (Gutin 88). Vol. In the 198 s, a skeleton of young Homo male was discovered insome 1.5 million-year-old deposits in northern Kenya. Yet, there are in fact, manyevolutionists who theorize on how the human animal has evolved into aspecies who not only have the mental capabilities to converse, but thephysical capabilities as well, something early hominids did not show signsof having. Accessed March 19, 2 2.Lieberman, Philip. Behavioral and Brain Sciences. Skull Thwarts Species-Splinters. http://www.ling.ed.ac.uk/evolang2 2/abstracts/lieberman.txtMcKinney, Michael L. Conclusion Linguists continue to insist that language cannot evolve out of ananimal communication system. New York: W.W. The Throwing Madonna: Essays on the Brain. Vol. Does Kanzi Ape Language? The Juvenilized Ape Myth - Our 'Overdeveloped' Brain. Chomsky (1979), however,asserted that there was a faculty within the human brain, not to be brokendown any further or explained, but which was where language originated from(Chomsky 86). Yet, other scientists are studying to find out if the "unusualdemands" for speech came about as a mating requirement, their logic beingthat birds have the intricate vocal modifications needed for variouswarbles, but do not have the brain for symbols or syntax. There are several theories that discuss how braingrowth could have occurred. The Great Brain Drain: A Controversial Theory Takes Ancestral Brain Growth in Vein. March 27-3 , 2 2. Cambridge, England: Cambridge University Press. The Gift of Gab. Another way that scientists have tried to discover when hominids werefirst capable of speech is by studying the hypoglossal canal in skullfossils. "Hominids had to adapt to environmental extremesthat altered the conditions of natural selection under more stableconditions" (Potts quoted in Bower 359).Complex Communication Adaptation Theory In 1993, Terrence W. 2 4(1).Physician's Desk Reference. New York: McGraw Hill Company. March 26, 1999. 359.Calvin, William H. Evolution of Mammalian Brains. 6.Wilkins, Wendy K. "Darwin, Charles Robert." World Book Online Americas Edition, Available online at: http://www.aolsvc.worldbook.aol.com/wbol/wbPage/na/ar/co/14866 . Science News. Baby humans are born with a high larynx that only begins to descendonce the baby begins to learn speech (Tattersall 167). Yet, later skulls, around 4 , yearsold, have bigger bony canals (59). As Tattersall (1998) asserts, although increasing complexity in thebrain as it enlarged over time may have lead to a language capacity, thesounds necessary for speech are processed outside of the brain by the vocaltract (167). Boston, MA: MIT Press. In the modern human, involved in this process is the larynx,which is the structure in the neck that contains the vocal folds or cords,and the pharynx, which is the tube that rises above the larynx and opensinto the oral and nasal cavities. 148, iss. 541 , p. . Empathy and brain evolution. 161-226. Norton and Company. 82.Hart, Stephen. This is where the picture of the steeple and sound of the bellcombined to mean "church" in the human brain. 6, p. Up until recently, it was not determined what, if any, partthat the hyoid had to play in the throat of the early hominid. 232(3).Bower, Bruce. Some scientists have gone further in this implication by saying thatdescent of the larynx was first due to a need to strengthen respiratorycontrol, and was an exaptation for speech (Tattersall 168-171). Cambridge, Massachusetts: Harvard University Press. Similarly,australopithecines have smaller canals like those of apes, suggesting thatthey were incapable of speech. It is probablyno accident that the earliest hominids with modern size brains,approximately 5 , years ago, also seem to be the first ones with largerhypoglossal canals and more intricate tools (Cartmill 61). 48, Iss. 1 9(8).Tattersall, Ian. Sentences may alsostring together phrases and embed other phrases within each other, so theremay be an infinite number of words in a sentence. As a result of this adaptation, the ratio of brain size to body sizein early hominids, which had been similar to other primates up to thispoint, began to bulge. January 1995. 15, p. New York: W.W. Yet, an earlierNeanderthal skull from Italy revealed a greater degree of flexion, implyinga better ability to speak (169). Abstract from future talk to be given at the Evolution of Language: Fourth International Conference, 2 2. Yet, with all the current evidence, much is still hotly debated inthe evolutionist and linguistic circles. For this to happen, several things about the hominid body needed tochange, specifically, the larynx, the pharynx, the hypoglossal nerve, andthe hyoid bone.
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