Psychological Foundations of Language

王敏

摘要：語言在我們的進化史中只是新近才出現的一種現象，而導致這驚人發展的力量是什么尚不清楚。我們知道部分原因是特化于語言功能的腦結構的演變。語言行為，和所有的行為一樣，要通過腦結構的作用，但因為語言極其微妙并涉及多個方面，所以要在大腦中有一個特別復雜的表征。我們會看到，我們語言能力的各個方面，不是純粹的抽象物，而是在鬧中有獨立的，能具體說明的表征。另外，語言的心理學基礎研究會擴展我們對語言理解，語言產生和語言習得的討論。

這篇文章首先對語言的心理學基礎做了一個簡單的介紹使我們對為什么要做這個研究有一個清晰的觀點。然后討論了大腦機制和語言。不同的語言技能涉及腦的不同部位，遭受腦受傷的個體常常只是在語言的某些方面表現缺陷。接著描述了語言進程的側化，對腦裂病人和正常人的研究表明，對大部分人來說，腦的左半球控制語言，特別是句法過程和語言產生，而右半球則是語用方面和語言理解。最后，對關于大腦的智力，性別和遺傳因素和語言的關系做了簡要的描述。

關鍵詞：心理學基礎；大腦機制；語言過程的側化

Abstract：The emergence of language occurred only recently in our evolutionary history, and the set of forces that led to this extraordinary development is not yet clear. We do know that part of the story concerns the evolution of brain mechanisms specialized for language functions. Language behavior, like all behavior, is mediated by brain structures, but because language is extremely subtle and multifaceted, it has a particularly complex representation in the brain. We will learn that various aspects of our language capacity are not mere abstractions but rather have separate and specifiable representations in the brain. Moreover, the study of the psychological foundations of language extends our discussion of language comprehension, production and acquisition.

This paper first have a brief introduction of the psychological foundations of language so that we have a clear of idea of the reason why we should do research on this topic. Then it comes to discuss the brain mechanisms and language. It points out that different language skills are represented in different parts of the brain and individuals who have sustained brain damage often show deficits only in selected aspects of language. Furthermore, it describes the lateralization of language process. Studies of split-brain and normal individual reveal that the left hemisphere of the brain controls language, especially syntactic processes and language production, for most people. The right hemisphere is essentially mute but plays a role in comprehension and in the pragmatic aspects of language. Finally it lists some factors such as the intelligence, sex and heredity in the brain, which have something to do with language.

Key words:psychological foundations; brain mechanism; lateralization of language process

中圖分類號：G633.4 文獻標識碼：B 文章編號：1672-1578（2016）06-0135-03

1. Introduction

Language development is a process starting early in human life, when a person begins to acquire language by learning it as it is spoken and by mimicry. Children's language development moves from simple to complex. Infants start without language. Yet by four months of age, babies can read lips and discriminate speech sounds. The language that infants speak is called 'gibberish'. Usually, language starts off as recall of simple words without associated meaning, but as children grow, words acquire meaning, with connections between words formed. In time, sentences start as words are joined together to create logical meaning. As a person gets older, new meanings and new associations are created and vocabulary increases as more words are learned. Infants use their bodies, vocal cries and other preverbal vocalizations to communicate their wants, needs and dispositions. Even though most children begin to vocalize and eventually verbalize at various ages and at different rates, they learn their first language without conscious instruction from parents or caretakers. It is a seemingly effortless task that grows increasingly difficult with age. Of course, before any learning can begin, the child must be psychologically and socially mature enough.

Linguists do not all agree on the psychological factors contributing to language development, however most do agree that our ability to acquire such a complicated system is specific to the human species. Furthermore, our ability to learn language may have been developed through the evolutionary process and that the foundation for language may be passed down genetically. The ability to speak and understand language requires a certain vocal apparatus as well as a nervous system with certain capabilities.

From a psychological perspective, language has been regarded as special in the sense that it is a dividing line between humans and other species. The emergence of language occurred only recently in our evolutionary history, and the set of forces that led to this extraordinary development is not yet clear. We do know that part of the story concerns the evolution of brain mechanisms specialized for language functions. Language behavior, like all behavior, is mediated by brain structures, but because language is extremely subtle and multifaceted, it has a particularly complex representation in the brain. Although speculation about the brain has been going on for centuries, scientific knowledge about the brain and language has only accumulated in the last century in the last century or so.

It is important to know about the biology of language for two reasons. First, the study of brain regions related to language clarifies our discussion of language comprehension and production. We will learn that various aspects of our language capacity are not mere abstractions but rather have separate and specifiable representations in the brain. Second, the study of the psychological foundations of language extends our discussion of language acquisition. If specialized brain mechanisms enable children to acquire language, then how much language is possible in species such as nonhuman primates that lack these mechanisms?

Human knowledge is organized by linguistic competence through language performance, and our exploration of reality is always mediated by language (Danchin 29). Most of the higher vertebrates possess or intuitive knowledge? Which occurs as the result of slow evolution of species? However, the ability to create knowledge through language is unique to humans. According to Benjamin Whorf, language is not merely a reproducing instrument from voicing ideas but rather is itself the shaper of ideas. We dissect nature along lines laid down by language (Joseph 249). In addition, the development and acquisition of language seems to be related to complex sequential processing and the ability to form concepts and to classify a single stimulus in a multiple manner (Joseph: 178). Antione Danchin suggests that the knowledge we create through language allows us distinguish ourselves from the rest of the world to produce models of reality, which become more and more adequate due to the "self-referent loop" which enables us to understand ourselves as objects under study. This "path from subject to object," which is common to all humans, Danchin claims, suggests the existence of a universal feature of language.

Psychological foundation of language may contribute significantly to such universality. The issue here is not whether language is innate, for, clearly, language must be learned. Nor is the issue whether the aptitude for learning a language is inborn: it takes a human being with a functional brain to learn a tongue. The question to explore is whether there is psychological foundation at the root of organization and internal structure of language.

2.Brain Mechanisms and Language

One common way of studying language function is by analyzing various language disorders and deficits. Lesions to certain parts of the cortex lead to loss or deficit of certain functions. Studying of the language performance in association with lesions in the brain has been recognized well over 100 years. In general, these studies suggest localization of language functions in the brain: a lesion to certain part of the brain may only the production of language without disturbing the ability to comprehend spoken speech. The aphasias are most commonly divided into three main types: Wernicke's aphasia which is characterized by a major deficit in comprehension; Broca's aphasia which is characterized by deficit in production; and conduction aphasia which is characterized by a combination of syndromes of both Broca's aphasia and Wernicke's aphasia.

Broca's aphasia results from damage to a region in the left hemisphere near the motor cortex and leads to deficits in language production and syntactic analysis. Wernicke's aphasia is due to injury to an area adjacent to the auditory cortex in the left hemisphere and is associated with deficits in comprehension and semantic organization. Conduction aphasia results from dissociation of an intact Broca's area from an intact Wernicke's area and leads to a deficit in repetition. Thus, the distinction between comprehension and production and between syntax and semantics are not mere conceptual distinction but relate in specifiable ways to the organization of the brain.

Patients with speech problems gave early researchers the first clues about how the brain is involved with language. The loss of the ability to speak is called "aphasia." The ancient Greeks noticed that brain damage could cause aphasia. Centuries later, in 1836, Marc Dax described a group of patients who could not speak properly. Dax reported that all of these patients had damage to the left side of their brain. A quarter century later in 1861, Paul Broca described a patient who could say only one word..."tan." For this reason, Broca called this patient "Tan." When Tan died, Broca examined his brain and found that there was damage to part of the left frontal cortex. This part of the brain has come to be known as "Broca's Area."

In 1876, Karl Wernicke found that damage to a different part of the brain also caused language problems. This area of the brain ("Wernicke's Area"), was further back and lower in the brain compared to Broca's area. In fact, Wernicke's area is in the posterior part of the temporal lobe. Broca's area and Wernicke's area are connected by a bundle of nerve fibers called the arcuate fasciculus. Damage to the arcuate fasciculus causes a disorder called conduction aphasia. People with conduction aphasia can understand language, but their speech does not make sense and they cannot repeat words. In most people (97%), both Broca's area and Wernicke's area are found in only the left hemisphere of the brain.

In the early 1950s, the famous neurosurgeon Wilder Penfield and his colleague Herbert Jasper, described how electrical stimulation of certain areas of the brain blocked language. These neurosurgeons were able to perform these studies asking their patients questions during the surgical procedure. More recently (late 1980s), Dr. George Ojemann at the University of Washington has used electrical stimulation experiments to show that there can be a large difference in the brain area that is important for language from person to person. Nevertheless, the results of these studies agree with the earlier findings of Broca and Wernicke.

In 1960, another technique was discovered that allowed researchers to study the brain mechanisms of language. This method, called the Wada Test, uses a fast acting anesthetic called sodium amytal to put one hemisphere of the brain asleep. The sodium amytal is injected into the right or left carotid artery. The right artery supplies the right cerebral hemisphere and the left artery supplies the left cerebral hemisphere. Therefore, either the right or left hemisphere can be "put to sleep" temporarily. If the left hemisphere is put to sleep in people who have language ability in the left hemisphere, then when asked to speak, they cannot. However, if the right hemisphere is put to sleep, then these people will be able to speak and answer questions.

Studies performed in people who have received electroconvulsive shock treatment have also confirmed that language is found most often on the left side. Language can also be studied using brain imaging techniques. Positron emission tomography studies show that many of the expected areas of the brain have increased blood flow during language tasks, but there are also areas on both hemispheres that are activated. Therefore, it appears that even the hemisphere that is not dominant for language (usually the right side) has some involvement in language. Actually, people have problems communicating the emotions involved with language when they have damage to the right side of the brain in the area where on the left side it is used for language. This disorder is called an "aprosodia."

Studies of aphasia can offer an incredible insight to organization of the brain for language. The occurrence of specific language disorders caused by lesions to certain parts of the brain further illustrates localization of functions in the brain. Given certain language disorder, we can correlate it to a physical problem in a specific region of the brain. Such evidence suggests that there is certain preexisting universal psychological order in the brain. If they did not preexist, how would the many brains build synaptic connections that were similar to one another, even the brains of people that speak different languages? Localization of linguistic functions in the brain suggests that there are innate physical structures of the brain which govern our learning of language.

3.Lateralization of Language Processes

Without a doubt, language has psychological basis. A multitude of neuronal structures and fiber pathways are involved in the formulation, expression, and comprehension of speech and verbal thought (Joseph: 253). Close studying of the organization of language in the brain may give us important clue as to how much language acquisition is governed by psychological structures.

Dr. R. Joseph asserts that the right and left half of the brain utilize different means of communication and sometimes rely on different language systems. There is strong evidence that information processing is carried on differently in each hemispheres of the brain. In majority of humans, the left hemisphere, is efficient at processing spoken language but has great difficulty processing social or emotional sounds. The right hemisphere on the other hand is very efficient in social and emotional sounds, but is deficient in language skills (Joseph: 12).

The fact that human brain is unsymmetrical is well known. Specialization of the left hemisphere for language in right handed people, with relatively a few exceptions, has been generally accepted for more than a century (Bogen: 13). Although more recent studies suggest that there is a complementary hemispheric specialization of language functions in the brain (as opposed to the left hemisphere being the language facilitator), the evidence still holds that left and right hemispheres differ in their language functions.

The left hemisphere specializes in analytical thought. The left hemisphere deals with hard facts: abstractions, structure, discipline and rules, time sequences, mathematics, categorizing, logic and rationality and deductive reasoning, knowledge, details, definitions, planning and goals, words (written and spoken and heard), productivity and efficiency, science and technology, stability, extraversion, physical activity, and the right side of the body. The left hemisphere is emphasized in our educational system and in our society in general, for better or for worse; as Marshall McLuhan speculated, "The day when bureaucracy becomes right hemisphere will be utopia." The right hemisphere specializes in the "softer" aspects of life. This includes intuition, feelings and sensitivity, emotions, daydreaming and visualizing, creativity (including art and music), color, spatial awareness, first impressions, rhythm, spontaneity and impulsiveness, the physical senses, risk-taking, flexibility and variety, learning by experience, relationships, mysticism, play and sports, introversion, humor, motor skills, the left side of the body, and a holistic way of perception that recognizes patterns and similarities and then synthesizes those elements into new forms.

We tend to use one half more than the other. During childhood, we develop "brain dominance" —— the inclination to act and think in the mode of either the left or right hemisphere. The decision is affected by our genetics, childhood experiences, and family environment. The dominance is not total; whether we are "right-brained" or "left-brained," we permit the other hemisphere to lead occasionally. We tend to distrust or even dislike the non-dominant half. If we generally use our left hemisphere, we might be annoyed by our right hemisphere as though it were an undisciplined child; contrarily, a right-hemisphere person might consider his or her left hemisphere to be a spoil-sport. These same attitudes might be projected onto other people. For example, if we favor the right hemisphere, but our co-workers are oriented toward their left hemisphere, we are likely to judge them as boring and rigid; if we favor the left hemisphere, we probably view our right-hemisphere co-workers as unreliable and disorganized. But both types of people can be effective if permitted to work in their own way, as some employers have discovered. We need to develop both hemispheres. This is necessary because, as stated previously, some tasks require the left hemisphere primarily, and others predominantly call on the right hemisphere. Our brain dominance stays the same —— a right-hemisphere person does not change into a left-hemisphere person —— but we can develop the skills of the other half, so that that half will be more effective when we need to use it.

4.Intelligence, Sex, Heredity and Language

Intelligence is the term used to refer to a hypothesized "general factor" which underlies our abilities to master and use a whole range of academic skills. As McDonough (1981:126) emphasizes, it refers to capacity rather than contents of the mind. That is, it is the underlying ability to learn, rather than the actual knowledge that is supposedly measured by intelligence tests. The relationship between intelligence and language is much more controversial. One of the more progressive points is that certain aspects of intelligence, such as judgments of space and time, are largely independent of language (Aitchison: 64).

Human language itself has no sex discrimination. However, the differences between male and female speech, to some extent, reflect individual or social value and trend. It is believed that males and females in most countries have different linguistic birthrights. The paper mainly focuses on "sex and language variation" .Language and illustrates the differences between both sexes in language use and linguistic choice, to further exhibit that speech variety reflects on sex differences. It is usually supposed that women on average have greater verbal fluency and stronger than men on the language competence.

Heredity in the brain is also important for language. All humans talk but no house pets or house plants do, no matter how pampered, so heredity must be involved in language. But a child growing up in Japan speaks Japanese whereas the same child brought up in California would speak English, so the environment is also crucial. Thus there is no question about whether heredity or environment is involved in language, or even whether one or the other is "more important." Instead, language acquisition might be our best hope of finding out how heredity and environment interact. We know that adult language is intricately complex, and we know that children become adults. Therefore something in the child's mind must be capable of attaining that complexity. Any theory that posits too little innate structure, so that its hypothetical child ends up speaking something less than a real language, must be false. The same is true for any theory that posits too much innate structure, so that the hypothetical child can acquire English but not, e.g. Bantu or Vietnamese. Therefore it is generalized that some language deficits have something to do with heredity.

5. Conclusion

From the above discussions about the psychological foundations, we get to know that different language skills are represented in different parts of the brain. Individuals who have sustained brain damage often show deficits only in selected aspects of language. Studies of split-brain and normal individual reveal that the left hemisphere of the brain controls language, especially syntactic processes and language production, for most people. The right hemisphere is essentially mute but plays a role in comprehension and in the pragmatic aspects of language. In addition, some factors such as intelligence, sex and heredity in the brain also have some close relationship with language, which is also worthy our further exploration.

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