Deric Bownds

Chapter 11

Linguistic Mind

We can trace a quite obvious continuity between the primate and human versions of the perceiving, acting, and emoting minds discussed in previous chapters. Mechanisms revealed in animal experiments are frequently found in our own brains, and vice versa. However, there is nothing in the language-like behavior of chimps or other animals that remotely approaches the language abilities of 3-year-old humans. Thus we have only ourselves to observe in trying to understanding the development of our language competence and the underlying cortical mechanisms. Recall that we have touched on issues surrounding language several times. In Chapter 5 we looked at some speculations on how language might have arisen during hominid evolution from a precursor mimetic intelligence, and we also noted that the appearance of language made possible a mythic intelligence that accelerated the pace of evolution by transmitting culture and ideas between generations. And in Chapter 7 we briefly noted some stages in language development in human children.

Clearly, we have some genes and developmental routines lacking in chimps that ultimately facilitate the formation of a set of "language organs" universal in all modern humans. These organs effect a universal grammar or tree-like set of rules that can generate many possible languages. All these languages use the technique of metaphor to make varied descriptions of our world. What is not clear is how direct the linkage is between our genes and the operations of grammar and syntax. Is the wiring that underlies the distinction among subject, object, and verb categories instructed by the same sort of genetically programmed molecular markers that direct cells in the lateral geniculate body to send axons to the visual cortex? Or does each developing human brain itself invent the wiring of subject, object, and verb operations as a best solution to problems posed by the environment of other humans? We address this issue below, after offering evidence that humans do have an innate language capacity. The sections that follow then deal with brain mechanisms of language that are revealed by lesion and imaging studies and with the use of metaphors in constructing language.

The Language Instinct

One line of evidence for a universal and innate human language capacity comes from the observation that every known human culture has a language with complex grammar. None of these grammars is simple, and the complexity of a culture's language seems quite independent of the complexity of its social organization or technology. Different groups of humans, isolating themselves from each other, grow different languages. 1 The inhabitants of the highlands of Papua New Guinea have been isolated from other humans for 40,000 years and speak about 700--800 different native languages within an area similar in size to Sweden. No single one of those languages is spoken by more than 3 percent of the population. One can move 20 miles across rain forest and cross the territories of three different xenophobic tribes who, fearing each other, have very little contact. Their languages have fundamentally different structures, rules of syntax, and grammar. The differences among these languages are much greater than the differences among modern European languages. A similar situation exists in West Africa, where more than 700 distinct languages are encountered. The languages are most numerous in areas of greatest rainfall, where each group can produce its own food and doesn't need to communicate with outsiders to trade. 2

New languages can evolve within a generation or two from the rapid mixing of existing tongues. The new languages that arise because different groups need to communicate are called pidgins and are very crude. But whenever a group that contributes to a pidgin begins to adopt the pidgin itself as its native language, a creole develops, which has all the complex features of a normal language. The creole is invented by the children of the people who speak the pidgin. The fact that they aren't exposed to a complete language and yet make up one is a strong argument for a genetic blueprint for language-making ability. This blueprint gets carried out, however, only in the appropriate milieu of other humans. Language is absent in feral human children raised by wild animals, and in some severely abused children deprived of normal human contact.



When two adult populations who speak different languages mix together and must communicate, a crude form of a new language takes shape. Within a generation, children of these adult groups are able to invent a new, hybrid language, sometimes with unique features not shared by the parent languages.


Creoles, whether invented in South America, Africa, or the Pacific islands, are remarkably convergent. They place subject, verb, and object in that order; use singular and plural pronouns for the first, second, and third person; and employ relative clauses, anterior tense, and conditional mood. One of the best-documented examples of the evolution of a creole is a study of language in Hawaii after its annexation by the United States in 1898. 3 Sugar planters had imported workers from China, the Philippines, Japan, Korea, Portugal, and Puerto Rico. The children of the original immigrants, who had maintained their normal language and a learned pidgin, had the problem of trying to speak with other children using this pidgin, which was an impoverished and inconsistent version of a human language. They spontaneously expanded the pidgin into a consistent and complex creole within a generation, by 1920. Researchers talking with adults of various ages obtained snapshots of the stages in the pidgin-to-creole transition, depending on the adults' birth year. Many features of Hawaiian creole grammar, whose vocabulary is largely English, differ from both English and the workers' native languages.

Universal Language

Not only is having a language universal; so also is the fundamental design. Noam Chomsky is credited with uncovering universal properties of natural human languages, and some accord him a position in the history of ideas comparable to that of Darwin or Descartes. 4 We have an inherited neural capacity for generating a system of rules into which words are plugged---a universal grammar underlying all languages. Every sentence, according to Chomsky, has a deep structure, a pattern in the mind, that is mapped onto surface structure, the actual spoken utterance, according to rules or "transformations." The details of the transformations vary from language to language, but all share certain abstract properties that constitute the universal grammar.

All languages use nouns and verbs, subjects and objects, cases and agreement, and vocabularies in the thousands or tens of thousands of words. Almost all languages have the same basic word order of subject and object. The 4000--6000 languages known today are sufficiently alike that an extraterrestrial observer might consider them all one language. A sentence in any spoken language can be diagrammed as an inverted modular tree containing noun phrases, verb phrases, and prepositional phrases that can be fitted inside each other. The technical jargon (N-bar, V-bar, X-bar) used to describe sentence structure is fully as intricate as the vocabulary used to describe visual pathways in the brain.

The Case for Language as an Evolutionary Adaptation

Both Chomsky and the evolutionary biologist Stephen Jay Gould deny that language is an evolutionary adaptation but suggest, rather, that it is an accidental consequence of having a complex cortex, or perhaps a by-product of some other faculty on which selection acted, as in Calvin's throwing model (see Chapter 9). The psychologist Steven Pinker and many other linguists argue, to the contrary, for the more plausible view that we have a language instinct that has appeared as a consequence of natural selection, just like our liver and our ears. 5 In addition to the universality of language and its design, the stereotypic development of language in children of all cultures supports this view. In the uterus, human embryos react to the melody, stress, and timing of the mother's native speech, and immediately after birth they suck much harder when hearing their native language than when hearing a foreign one. Children begin to babble during their first year, and words appear after about 12 months. Inborn linguistic mechanisms (such as simple word combinations like "more candy") take off at about 18 months, are fully operating at about 3 years, and decline by puberty. Over a relatively narrow window of 6 months to around the age of 2, the entire grammar of a language appears.

The language instinct does not require conventional spoken language for its expression. The fact that congenitally deaf babies can babble in sign language and the fact that those who can neither hear nor speak communicate in a distinctly human way make a convincing case for the ability of humans to use abstract symbols independently of conventional language as a means of communicating with each other. Manual babbling occurs in deaf children who are exposed to signed languages from birth. The similarities between manual and vocal babbling suggest that babbling is a product of an amodal, brain-based language capacity. 6 The speech modality is not critical. Rather, babbling is tied to the abstract linguistic structure of language and to an expressive capacity capable of processing different types of signals (signed or spoken). One interesting report is of a deaf boy, the son of deaf parents who signed incorrectly (using American Sign Language learned after they were adults). The boy nevertheless appears to have learned correct grammar on his own, a remarkable result consistent with an innate ability to construct grammar. 7 Even more dramatic is the invention of a complex sign language by a group of more than 500 deaf children in a Nicaraguan school. 8 This is similar to the invention of creoles by children of parents who speak a more rudimentary, pidgin language.



The appearance of language in infants follows a stereotyped time course that is similar across cultures. The ability to manipulate symbols, which underlies language competence, is amodal: It can be expressed by vocal or manual signs.


The Learning of Language

Saying that language is an innate ability of humans, invented and expressed as human children grow up together, is not the same thing as saying that there is genetic control over formation of the detailed cortical modules, domains, or representations that make up linguistic competence. The alternative model is that our developing brains contain robust learning devices that permit each of us invent, independently, very similar arrays of "language organs." This distinction brings us back to the nature-nurture debate discussed in Chapter 7, a debate that comes into sharpest focus as we try to understand the relationship between genes and language.

Genetic Determinants of Language Ability

If it could be shown that a mutant gene influenced a detailed aspect of grammar, this might provide evidence that the gene in question was necessary for some fairly detailed brain wiring. It would not necessarily be a gene for grammar, but it presumably would be required for the relevant neuronal circuits to form. Showing that a gene mutation has an effect that is specific to language, sparing other abilities, would constitute powerful evidence for a segregated and genetically specified language faculty.

It appeared for a while that just such a mutation had been found, expressed in 16 of 30 individuals in a British family over three generations. 9 Though they were able to memorize words and their meanings and to perform some grammar operations, these individuals frequently failed to perform past tense operations (such as generate -> generated) and pluralization operations (cat -> cats). A number of studies have now reported other families in which a form of developmental dysphasia (reflected by inability to distinguish singular from plural, and tenses of regular, but not irregular, verbs) is distributed in a way consistent with inheritance as a single autosomal-dominant mutation. 10 However, subsequent studies of the British family members, as well as of other cases, have revealed that the deficits are not restricted to specific aspects of language. Rather, they cause low performance on a wide variety of language tests and are correlated with lower verbal and nonverbal IQ and poor control of oral-facial muscles.

Another candidate for genetic specification of grammar has been suggested by studies of abnormal development: the syndrome known as specific language impairment, or SLI. The syndrome, which has a clear genetic basis, delays language development and causes abnormal grammatical morphology, but nonlinguistic intelligence can be normal. It appears now that affected individuals are deficient in the processing of rapid temporal sequences of auditory, visual, and motor systems. 11 These deficits are general, even though their most obvious effect is on language. Thus far, no inherited language deficits have been shown to be independent of more general brain developmental or processing mechanisms. 12

Rather than searching for genetic links to specific language deficits, another approach would be to seek out genetic defects that spare language as a "module of mind" but compromise other aspects of cognition. This would suggest the presence of genes that permit the development of a separate language competence even when other intelligences are compromised. One such case is found in Williams's syndrome, 13 a genetic defect that occurs in about one of every 20,000 births. It involves deletion of a region of chromosome 7 14 that contains a gene for the protein elastin and a gene for an enzyme-modifying protein (a protein kinase) whose mutation has been shown to correlate with impaired visuospatial constructive cognition. Subjects have an elfin appearance, a narrowed aortic valve, and an IQ of around 50. They are unable to perform simple chores for themselves, have impoverished spatial abilities, and maintain the animism (belief that all moving objects are alive) that is left behind in normal development. Their language, however, is rich and fluent, and they are very sociable.

Those with Williams's syndrome are similar in general cognitive abilities to those with Down's syndrome, which is caused by another chromosomal abnormality (trisomy of chromosome 21). Autopsies and brain imaging show that the cerebral cortex has shrunk on both sides but that the frontal lobes, medial temporal lobes, and neocerebellum are closer to normal size. The neocerebellum is a thin layer of cells atop the older cerebellum brain region. It evolved more recently, along with the prefrontal cortex. Humans are the only animals with large versions of these two brain regions and the only animals with language. Moreover, brain imaging studies show that the neocerebellum is activated only when semantic reasoning is required. Perhaps this recently evolved circuit underlying language and sociability is spared in Williams's syndrome, and the gene deletion that marks the syndrome impairs an older set of instructions for brain development, while leaving the newer language circuit intact. It is interesting that in many autistic children who are antisocial and poor at language, but good at spatial tasks, these areas are small compared to their size in nondisabled children and those with syndrome.



Observations on some language idiot savants provide further support for a language faculty that can remain intact in a brain that has developed abnormally. There is the case of the 29-year-old subject with a nonverbal IQ of 65 who could not draw simple figures, add 2 and 2, or tie his shoes. He could speak 16 languages. His language abilities were independent of his cognitive ability; he never mulled over the meaning of passages and was not able to think about what he translated. 15


In spite of striking cases such as language idiot savants and children with Williams's syndrome, there is still no evidence that the language faculty is a wholly independent function. The current view is that it is more likely to consist of refinements of systems that coordinate nonlinguistic elements with each other. This suggestion is reinforced by the brain localization work described below.

Language Development and Brain Structure

We have already mentioned several times, in Chapters 3 and 5, the two areas in the left frontal and temporal lobes (Broca's and Wernicke's areas) that are associated, respectively, with the production and comprehension of language. These are illustrated again in Figure 11-1. If these locations had the same constancy from individual to individual as do the primary sensory and motor cortices, this would provide an argument for their strong genetic specification. Quite to the contrary, however, children who have left focal lesions or who have undergone removal of the left hemisphere can develop language functions "within the normal range" using the right hemisphere, although deficits in syntactic and phonological tasks are frequently found. Deficits that the lesions cause in the development of spatial cognition do not show the same plasticity. Part of the explanation for this may lie in the fact that spatial cognition is an ancient system, having evolved throughout the vertebrate line, whereas the language system is much more recent. Although this system is usually located in the left hemisphere, the underlying genetic equipment permits other placements.

Figure 11-1

Some of the cortical areas implicated in language functions. The external view of the left hemisphere shows Broca's and Wernicke's areas, which are involved in the generation and comprehension of speech, respectively. The right hemisphere has been displaced in the drawing to show its inside surface with the anterior cingulate cortex, which is involved in arousal and attentional control in speech, and the supplementary motor cortex, which plays a role in speech initiation. Also shown is the location of the corpus callosum, which connects corresponding areas of the two hemispheres. Anatomical studies on other primate brains have shown rich reciprocal interconnections between these areas (arrows), but the corresponding anatomy in humans is not so well known.

Different languages can be put in different places. A stroke in one part of the brain can knock out a native language and leave intact languages learned later, or vice versa. Imaging of normal bilingual brains shows that two languages, such as French and English, can activate slightly different areas of cortex. 16 The first language learned by a child is normally tightly organized in terms of nerve circuits in the left hemisphere, but later languages are more loosely organized. This is why it often takes longer to find words in them.

The normal placement of language in the left hemisphere usually involves both spoken and written language, but there is the fascinating case of a woman whose right hemisphere controlled writing. This was revealed because she underwent an operation for epilepsy that cut the bundle of fibers (corpus callosum) connecting the left and right hemispheres. Words that were presented to her right visual field (and thus to the left hemisphere) could be spoken out loud but could not be written. Words presented to her left visual field (right hemisphere) could not be spoken but could be written down with her left hand. 17 Perhaps reading and writing, because they were invented much more recently than the evolved capacity for spoken language, can more easily be wired up in the brain wherever there are "spare areas."

A closer look at language development in children reveals that the developing language system is not the same as an immature version of the adult system. Massive reorganization occurs with experience. Brain imaging and electrical recordings demonstrate that word recognition tasks that at 13 months recruit both right and left cortexes condense by 20 months to activate mainly parietal and temporal regions of the left cortex. Left hemisphere injury that causes delays and deficits in the perception and production of fine-grained perceptual detail correlates with difficulties in expressive language, perceptions, and storage of the many sounds and meanings that are crucial for articulate speech. Right hemisphere injury that causes difficulties with integrating details into a coherent whole has a greater impact on word and sentence comprehension. 18

One theory is that children do not begin with innate representation for language but rather have innate left-right differences in the speed and style of processing, including a predisposition for extraction of perceptual detail on the left and for integration across inputs on the right. Under normal circumstances, the left temporal area recruits left frontal cortex into an integrated system for the comprehension and generation of speech. Early focal brain injury can delay or redirect this process.

Language Development as Invention

One argument for innate specification of language mechanisms in the brain has been that the linguistic environment faced by a human baby is such a disordered cacophony that rules for extracting what is relevant must be preformed, not discovered. Against this argument, it has recently been found that 8-month-old human infants who are exposed for only 2 minutes to unbroken strings of nonsense syllables are able to detect the difference between three-syllable sequences that appeared as a unit and sequences that also appeared in their learning set but did so in random order. This means that infants are using simple statistical procedures to discover word boundaries in connected speech, at just the age when systematic evidence of word recognition starts to appear. 19 The ability to recognize words after only a few exposures and to retain this knowledge for a long time might be taken as evidence for a dedicated language-learning mechanism, but it turns out that this capacity is also seen in other domains than language learning, such as matching novel objects and sounds. 20

There appears to be an increasing consensus that genetic determination, or innateness, applies to the basic principles of brain organization, such as maturational schedules, input (sensory) and output (motor) pathways, processing, and representation. These are the basis of learning devices that generate higher cognitive functions, including language. Phonetic or grammatical structures may have evolved to exploit particular natural biases of the brain's perceptual and motor systems. This could make it appear that our brains were especially adapted to acquire natural language, but in fact it would be natural language that has had to change to fit the mechanisms of our brains. 21

Children are not just passively soaking up bits of language; they are actively constructing and inventing language as the brain develops. The modern cortex, including the areas on the left side that normally develop language functions, is multipotential in its early stages of development. Functional specificity derives from the specificity of sensory input and motor output, and linguistic knowledge and processing result from the rich connectivity that develops in between. 22 The plausibility of these constructive models is enhanced by recent work on artificial neural networks simulated in computers, showing that they can detect patterns in input, extract phonetic and phonological structures from raw speech, and extract grammatical regularities. 23 Models that grow by small and gradual changes show sudden vocabulary spurts of the sort that are observed in young children. Lesions in artificial networks can cause dissociations between, or differently influence, abilities to form regular and irregular verbs. Such dissociations are indeed observed in patients with brain lesions. 24

Brain Mechanisms of Language

Normally, the language faculty that each human child develops localizes the bulk of its operations in the left cortex. Sign language, like spoken language, also normally emanates from the left cerebral hemisphere, even though sign language relies on visuospatial signals that are usually processed in the right hemisphere. 25 The lateralization of linguistic gesture (spoken or signed language) and nonlinguistic gesture (pantomime) has been compared in deaf and hearing individuals and in deaf signers with left hemisphere aphasia. The observations demonstrate a linguistic specialization of the left hemisphere that is distinct from motor or symbolic communication. A deaf signer with left hemisphere aphasia could spontaneously substitute pantomime for signs. This differential disruption of the linguistic gesture of signing and the symbolic gesture of pantomime emphasizes their functional separability and reinforces the idea that the mimetic intelligence discussed in Chapter 5 can be distinguished as an entity separable from language.



You can demonstrate one consequence of the lateralization of language functions to one hemisphere with the following simple exercise. Ask a friend to start speaking, and then repeat what is said while he or she is saying it---that is, "shadow" your friend's speech. Now, at the same time, tap the third finger of your right hand in a regular rhythm. Then try the same thing tapping your left finger instead. Is tapping with the right finger a bit harder? For most people it is, because the right finger competes with language for the resources of the left hemisphere. The same thing happens for most deaf people when then shadow one-handed signs in American Sign Language while tapping their fingers.


Multiple Language Areas in the Cortex

The brain location of specific language functions is being studied in increasingly fine detail by the analysis of discrete brain lesions that compromise some functions, and by the imaging of normal living human brains while they are performing those same functions. The results often are complementary. The number of "language areas" identified is multiplying on an almost daily basis as the temporal and spatial resolution of imaging techniques improve, just as is the case with other areas of perception and cognition. 26 You might look back at the imaging experiment shown in Figure 3-8, which illustrates that speaking words activates motor areas of the left frontal lobe whose damage (as in Broca's aphasia) can interfere with speaking but not understanding. Recognition of spoken words engages the temporal-parietal areas whose damage (as in Wernicke's aphasia) can compromise understanding but not speaking. Visual presentation of words recruits the visual areas mentioned earlier.

Frontal and temporal areas become active when meaning must be attached to words, as in generating verbs to go with nouns or in grouping together related words or concepts, and the effect of practice can be monitored. An instruction to associate a verb with each noun projected on a screen initially activates frontal lobes. But after 15 minutes of practice, the activation has contracted mainly to those areas used in simply reading a word out loud. Not surprisingly, brain activation increases with the complexity of a task being faced; complex sentences cause more activation of Broca's and Wernicke's areas than simple sentences. 27

Different regions of the left temporal lobe, outside the classical language areas, are involved in retrieving words from our mental dictionary. Studies of patients with brain lesions and imaging studies on unimpaired patients suggest that knowledge of unique persons is associated with the anterior portion of the temporal lobe, knowledge of animals with activity in the middle part of the inferior temporal cortex, and knowledge of tools with the posterior part of the inferior temporal cortex (see Figure 11-2). 28 Thus there appears to be a partial segregation of the systems required to bring these different classes of words or concepts into their spoken form.

Figure 11-2

Regions of the temporal lobe that become active when information about persons, animals, or tools is being processed and verbally expressed. 29

Each of these systems, at its deepest level (the mental dictionary, or concept level), associates an object (such as a dog) with its semantic features (furry, domestic, pet). The next level assigns proper syntax (grammatical features such as gender), and a final level matches the syntactic elements to the sounds required to make an utterance. It is at this final stage that the "tip-of-the-tongue" phenomenon can occur, when you can describe an object (furry, has four legs) but can't quite say the word.



Language relies on our current perceptions and actions as well as on our memories of objects and actions, and so it is not surprising that imaging experiments show that large areas of cortex that process sensory information and control motor output are involved not only in memory and learning but also in language. 30 For example, speaking color words can selectively activate a region in the ventral temporal lobe just anterior to the area involved in the perception of color, and speaking action words activates an area just anterior to visual areas involved in motion perception, as well as parts of motor areas of the frontal cortex.


Language as Accessory to Other Fundamental Brain Mechanisms

It seems reasonable to imagine that subject-verb-object ensembles (as in "I throw rock") were categories and actions that were chunked, localized, or given domains in the prelanguage brain. Language would then have been a useful adaptation that could "piggyback" on these fundamental operations by applying labels to what was already going on. Recall the evidence already cited that language is some sort of accessory module. Uniquely human capacities are found in the complete absence of language; in abnormal cases such as brain lesions and congenital lack of hearing and speech; and also in mime, tool making, and social intelligence (including the ability to comprehend complex events and remember roles, customs, and appropriate behavior). The conventional language system might be viewed as one kind of input and output domain, parallel to a mainstream of thought and awareness, possibly derivative of the basic perceiving, acting, and emotional intelligence we have discussed in the last several chapters.

The implication is that knowledge of objects that is accessible to language is stored in a distributed way, with attributes of objects stored close to the regions of cortex that perceive those attributes. 31 At the level of word meaning, language systems have to be coordinated with nonlinguistic brains areas that represent object and perceptual meanings. Brain lesion studies show that extensive systems in the left and right hemispheres process nonlanguage interactions between the body and its environment, categorizing representation (such as shape, color, sequence, and emotional state) and also more complicated, symbolic representations of objects, events, and relationships. There seems to be substantial overlap in the processing of the meanings of words and visual images. 32 A word, with all the different kinds of information related to it, might be represented by a very far-flung net of neurons that code the thing it stands for, its sound, its syntax, its visual image, and its logic. Areas of the brain devoted to different aspects of language, grammatical rules, or storage of word meanings might be spread out in patterns, like the stripes or blobs of the visual cortex, but with finer resolution than can be revealed by brain lesions or current brain imaging techniques.

Studies on the classical aphasias we mentioned before (sensory, motor, and conduction aphasia) have been expanded to show just how discrete lesions can be, behaviorally and anatomically. The use of different aspects of language, such as proper nouns, common nouns, and irregular or regular verbs, can be specifically disrupted, which suggests that they are processed in different areas of the brain. 33 These areas vary from person to person. The reading and/or writing of language can be disrupted by brain damage (alexia and agraphia) without damage to the hearing or speaking of language. The damage is usually in the parietal-temporal-occipital association cortex concerned with integration of visual, auditory, and tactile information.



An interesting point comes from studies of reading and writing disturbances among the Japanese. There are two distinct systems of writing Japanese. Kata kana is phonetic, with 71 graphemes in the system. Kanji is ideographic, based on the Chinese character system, with over 40,000 ideograms. Lesion of the angular gyrus of the parietal-temporal-occipital association cortex can disrupt reading of kana but leave comprehension of kanji intact.


The different functions and brain areas listed here do not send their signals to a common destination for integration, as though language appeared on a movie screen in the brain. There is no evidence for a central place where it all comes together to form the "I" that we subjectively experience when we listen and speak. Rather, language and other aspects of our cognition, such as vision, are governed by some yet-to-be-defined mechanisms that bind different brain areas together in time. How are our perception and generation of language unified? Some interesting clues on how we normally generate sentences come from normal slips of the tongue. In one rare form of aphasia, jargon aphasia, patients seem entirely normal and have normal intelligence, yet they utter sentences that are complete gibberish, like a "word salad." They do not perceive any problem as they emit complete but unrelated phrases and sentence fragments. It seems as though the underlying process that normally orders the fragments into longer, more meaningful sequences has gone awry. Speech errors such as Freudian slips (the unintended expression of a repressed sentiment) and spoonerisms (the transposition of parts of two or more words) point to how grammatical and lexical rules are working. They suggest that the act of speaking involves the generation of many possible options that vie with each other to be in a final utterance. Most of the options never reach awareness but can be revealed, for example, if we happen to say something like "barn door" when we mean "darn bore." 34 The idea is that there is a competition among many sequences, or candidates, held in short-term unconscious memory, an interpretation not unlike the Darwin Machine model for choosing movement sequences that we described in the last section of Chapter 9. Most of these sequences are discarded after the winner---the actual utterance---has emerged.

Metaphor and the Construction of Language

We have said little thus far about the school of generative semanticists---heirs to Chomsky who place major emphasis on how context directs the shape and form of language. 35 They claim that much of language is constructed by metaphoric operations (projections of a pattern from one domain of experience in order to structure another domain of a different kind) based on fundamental bodily functions. The idea is that the logic of muscle action in the world (up, down, sideways, in, out, containing, rotation) might be a foundation upon which logic operations of language are built. Recurring dynamic patterns of our perceptual interactions and motor programs give coherence and structure to our experience. A verticality scheme, for instance, emerges from our tendency to employ an up-down orientation in picking out meaningful structures of our experience (trees, stairs, flagpoles, other humans). Our brains during development form themselves in an interaction with vertical stimuli; some nerve cells are wired to specialize in them. Consider the simple and pervasive metaphorical understanding that "more is up." 36 This derives from the verticality schema---we are understanding quantity in terms of the verticality schema---as in "prices keep going up," and "his earnings fell." The metaphorical projection from up to more is natural, because it is related to common everyday experiences. When we add more liquid to a container, the level goes up. When we add more objects to a pile, the level goes up. There is, then, a physical basis for our abstract understanding of quantity. In this and many other cases, embodied human understanding is indispensable for meaning and rationality.

The in-out scheme gives rise to container metaphors based on the human body, our own in-out orientation. Examples include our speaking of moving into or out of a forest and our asking, "Are you in the race on Sunday?" (where the race is spoken of as a container.) We use metaphors as a central tool in talking about our own mental states and the minds of others, usually without being aware of how this biases our inquiries at the outset. Most of us view our minds as containers and conceive of thoughts as being like physical objects inside them; we also take thoughts to be natural language utterances inside our heads. If you say "part of me doesn't believe he is telling the truth," you are using the convention of talking about mind parts as persons. 37

The hypothesis is that many of these operations are so fundamental to living in a human body that they lead to a class of perceptions, behaviors, and language conventions that are universal. They are part of the basis of the "universal mind" that we discussed in Chapter 5. The metaphorical operations used to build language, however, can be tied to specific cultural surroundings. For most of us, time not only has its basic meaning but also is treated as though it were money. ("You're wasting my time." "This gadget will save you hours." "He's living on borrowed time." "I've invested a lot of time in her."). Some cultures don't use this metaphor, just as they don't equate active with up and passive with down. In many cultures there is a metaphoric mapping of masculine and feminine onto many other dimensions, such as light-dark, public-private, science-arts, rational-intuitive, active-passive, and hard-soft. 38 One counter-reaction to our immersion in metaphor is to argue that there is no "correct" way to perceive the world---that all the truths of our culture, including scientific dogma, are relative. Arguments against this position were outlined at the end of Chapter 7. Metaphors function as mind-tools, or as a scaffolding on which to arrange our complex physical and social reality, but they should not be taken as our only means of approaching and understanding it.


The take-home message of this chapter is that the genetic endowment of all modern humans equips them to generate brain modules for processing language if they grow up in the company of other humans. The complex social organization that language makes possible is a quantum leap beyond that of our primate precursors. Studies of both human development and comparative anthropology show that isolated groups of humans can invent new languages with complex grammars and communicate them either by speaking or by making manual signs. Although we will never know exactly how and when the ability to deal with symbols in verbal or manual form first appeared, it is clear that the many specializations of our vocal apparatus that support spoken language are adaptations that have enhanced its usefulness. The same is probably true of the brain mechanisms that permit processing and analysis of rapid sound sequences. There are no obvious "language genes" whose appearance might have correlated with the evolution of language competence. It seems likely that this evolution entailed the refinement and expansion of many of the cognitive faculties already involved in sensing, acting, memory, and communication. Observations on brain lesions and imaging data both suggest that many areas of the cortex are recruited during language operations. The fact that the usual brain locations of language operations can be changed by genetic or developmental perturbations, as well as by injury, suggests that there is great plasticity in the mechanisms that put language components in place. These components appear to generate our language utterances by yet another "Darwin Machine" mechanism, in which an array of candidates for expression vie for predominance. The streams of information we emit then apply a variety of techniques, such as the use of extended metaphors, to stack meanings upon meanings to categorize our experience of the external world. It is this process that permits us to engage the topics of Part IV of this book---to share our thinking about how our self consciousness and modern minds are integrated into a unitary whole.

Questions for Thought

1. A robust current debate centers on whether language is an evolutionary adaptation, or whether it is an accidental byproduct of humans having developed a very complex cerebral cortex. Can you offer some arguments relevant to one or the other side of this issue?

2. Several lines of evidence suggest that interacting children spontaneously invent the elements of language. Language development is not observed in the several known examples of feral children raised by animals in the wild. Can you develop the position that these observations are not relevant (or, alternatively, that they are relevant) to the question of whether stages in language development require the expression of "language enabling genes" unique to humans?

3. Brain lesions can cause specific language deficits, such as inabilities to understand, speak, write, or deal with specific categories of knowledge. Genetic mutations which influence human language ability do cause such specific deficits. What does this suggest about how the more specific faculties are constructed?

4. Roughly normal language development can be observed in children who have had one hemisphere removed at an early age. Can you offer a suggestion for why, then, during normal language development, a number of language functions distribute between the two hemispheres?

Suggestions for further general reading

Pinker, S. 1994. The Language Instinct. New York: William Morrow. If you are going to read only one popular book on language, this should probably be that book. It describes the construction of languages, argues that all humans have a similar evolved capacity to learn language, and discusses some of the brain mechanisms involved.

Diamond, J. 1992. The Third Chimpanzee. New York: Harper Collins. Chapter 8 of this book describes anthropological studies that elucidate how different groups of humans grow different languages.

Crystal, D. 1987. The Cambridge Encyclopedia of Language. Cambridge, England: Cambridge University Press. A presentation of the structures and varieties of languages.

Lakoff, G., & Johnson, M. 1980. Metaphors We Live By. Chicago: University of Chicago Press. This book argues that many linguistic operations derive from basic physical operations of the human body and are further developed by the use of culturally specific metaphors.

Reading on more advanced or specialized topics

Gazzaniga, M.S., Ivry, R.B., & Mangun, G.R. 1998. Cognitive Neuroscience. New York: Norton. Chapter 8 of this book is devoted to language and the brain and is an up-to-date summary of what we have learned from lesion and imaging studies.

Elman, J.L., Bates, E.A., Johnson, M.H., Karmiloff-Smith, A., Parisi, D., & Plunkett, K. 1996. Rethinking Innateness: A Connectionist Perspective on Development. Cambridge, MA: M.I.T. Press. This book takes a position opposing the argument of Pinker and others that many detailed aspects of language are genetically determined.

Nobre, A.C., & Plunkett, K. 1997. The neural system of language: structure and development. Current Opinions in Neurobiology 7(2):262--268. This is a summary of neuroimaging and brain lesion studies that suggest that the neural system for language is widely distributed and shares organizational principles with other cognitive systems in the brain.

1. Diamond, 1992, Ch. 8

2. Glausiusz, 1977.

3. see Diamond, 1992, pp 161-162

4. Harris, 1993

5. Pinker, 1994. See also Pinker's chapter in Brockman, 1995.

6. Petitto and Marentette, 1991

7. Kolata, 1992a

8. Horgan, 1995c.

9. These studies are reviewed by Elman et al., 1996, pg. 372 ff.

10. Gurd and Marshall, 1992a. See also Pinker, 1994, Ch. 10.

11. Bishop, 1997; Stein and Walsh, 19777.

12. Recent studies (See Bloom, 1999), however, are beginning to suggest that certain aspect of grammar have an autonomous psychological and neural basis, even though much of language arises from more general cognitive capacities.

13. Bishop, 1997; Stein and Walsh, 19777.

14. A protein kinas gene adjacent to the elastin gene has been correlated with impaired visuospatial constructive cognition. See Frangiskakis et al, 1996. See Bellugi, 1999, for recent review of Williams syndrome.

15. Blakeslee, 1991

16. Kim et al., 1997.

17. Blakeslee, 1996.

18. Material in these paragraphs is taken from Elman et al. 1996, Ch. 5, and Nobre and Plunkett, 1997.

19. Bates and Elman, 1996; Saffran et al, 1996. Marcus et al., 1999, show that 7-month-old infants can extract simple rules from language-like sounds.

20. Markson and Bloom, 1997.

21. Clark, 1997, Ch. 10.

22. Muller, 1996.

23. Elman et al., 1996.

24. Nobre and Plunkett, 1997.

25. Corina et al.,1992; Hickok et al., 1996.

26. Raichle, 1994; Maratsos and Matheny, 1994

27. Just et al., 1996.

28. Damasio et al, 1996.

29. Upper regions of the brain's temporal lobe are important both for hearing and for comprehending spoken language. Nishimura et al., 1999, have found that these regions can be activated by sign language in congenitally deaf subjects, even though the temporal lobe normally funcitons as an auditory area. This provides another example of the sort of brain plasticity discussed in Chapter 6.

30. Ungerleider,1995.

31. Martin et al., 1995. A useful review of the neural system of language is given by Nobre and Plunkett, 1997.

32. Vandenberghe et al, l996.

33. Pinker, 1997.

34. This examples is from Dennett, 1991, Ch. 8.

35. Harris, 1993; Johnson, 1987.

36. Many of the examples in these paragraphs are taken from Johnson, 1987. See Lakoff and Johnson, 1999, for further development of the idea that metaphors based on the body permeate our lives.

37. Barnden, 1992

38. Haste, 1994.

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