神经语言学和心理语言学.ppt

1、Chapter 12,Language and the Brain,Two Branches of Linguistics,Neurolinguistics 神经语言学 Psycholinguistics 心理语言学 Traditionally, linguists pay more attention to language system itself. Now, the technological advances enables more investigation of the human brain and language processing.,Neurolinguistics,

2、Neurolinguistics is the study of two related areas: language disorders and the relationship between brain and language. It includes research into How the brain is structured What function each part of the brain performs How and in which parts of the brain language is stored How damage to the brain a

3、ffects the ability to use language,The focus of this Section,A brief survey of the brain structure and its function The methods used in the study of the brain in terms of evideces for lateralization (referring to cognitive functions controlled either by the left or the right side of the brain)（边侧性）

4、The different types of language disturbance that result from the brain damage,The biological foundations of language,By far, human beings are the only species that possess language ability. Our linguistic ability is a biological gift of the speciess gene program.,Speech organs,These organs consist o

5、f lips, teeth, tongue, oral cavity, nasal cavity, palate(硬腭), velum(软腭), pharynx(咽), epiglottis(会厌), vocal cord(声带), pulmonic cavity(肺腔) and so on.,The structure and function of the human brain,cartoon,weight: 1,400 grams Component: ten billion nerve cells called neuron and billions of fibers that c

6、onnect these neurons. Neuron: the basic information processing units of the nervous system,Two sections of the brain,The lower section： the brain stem the higher section: cerebrum,the brain stem,Connecting to the spinal cord（脊椎） and shared by all animals, keeps the body alive by maintaining the esse

7、ntial functions such as respiration, heart rate, and muscle co-ordination,Cerebrum,The cerebrum that differs in different species is not essential for life.,Gyrus 脑回 Sulcus 回间沟 Fissure 裂缝,Cerebral Cortex,The cerebral cortex is the decision-making organ of the body and storehouse of “memory”. It rece

8、ives messages from all the sensory organs and initiates all voluntary actions. It is the cerebral cortex that accounts for the human distinctness in the animal world and it is within the human cortext that the secrets of language representation and processing are to be found. Animals, reptiles and a

9、mphibians have no cortex at all.,Cerebral hemispheres,The left and the right brain The main connection between them is a bundle of nerve fibres known as the corpus callosum胼胝体, a pathway leading one to another, allowing the two hemispheres to communicate with each other.,Each hemisphere of the human

10、 brain is responsible for different functions. Each hemisphere controls the opposite half of the body in terms of muscle movement and sensation.,The left hemisphere seems to do better in language, rhythmic perception, temporal-order judgments and mathematical thinking The right hemispheres show dist

11、inct abilities and responsibilities, complex mental activities such as language do not always fall neatly into one hemisphere or the other but involve the coordinated functioning of both hemispheres.,4 lobes of cerebral cortex,Responsible for planning, prediction, speech and discrete movement of the

12、 body,Reading ability and sensations,Audition, memory processing and sensory integration,Visual processing,Revision The structure of the human brain,Three parts in human brain (1) brain stem (脑干): keeps the body alive by maintaining the essential functions such as respiration, heart rate, and muscle

13、 co-ordination. (2) cerebellum (小脑): responsible for controlling body equilibrium and regulating the function of voluntary movements. (3) cerebrum (大脑): important for language psychology The surface of the cerebrum: cerebral cortex (大脑皮层) is the information processing and decision-making organ and t

14、he biological basis of human psychology.,The structure of the human brain,The importance of cerebral cortex,It is the cerebral cortex that accounts for the human distinctness in the animal world and it is within the human cortex that the secrets of language representation and processing are to be fo

15、und.,Major mental functions under the control of each cerebral hemisphere,Such localization of cognitive and perceptual functions in a particular hemisphere of the brain is called brain lateralization.,Complex mental activities involve the coordinated functioning of both hemispheres.,Methods for the

16、 study of the brain and evidences for lateralization,Autopsy studies 验尸 Methods to the study of the brain SAT 阿米妥纳试验 CT scanning 计算机化轴向层面射线摄影法 PET 阳电子发射X线体层摄影法 MRI 磁共振成像 fMRI 功能磁共振成像 Methods to examine the behaviour associated with the braining Dichotic listening 双耳分听试验 Split brain studies 裂脑试验,Auto

17、psy studies (验尸),It has been and continues to be an important tool in the understanding of the brain. Method: to examine the brain after the patients death in order to find the relationship between the area of brain damage and the type of disorder the patient displayed while alive. A woman with epil

18、epsy 癫痫,羊角风,French neurologist,Methods to the study of the brain,CT Scanning,MRI,fMRI,Dichotic listening,split brain studies,Methods to examine the behaviour associated with the brain,Right ear advantage: Most people report the stimuli heard in the right ear more accurately than that in the left one

19、. How to explain such a phenomenon? e.g. the dichotic listening research (双耳分听试验) The majority of normal human beings have speech located primarily in the left hemisphere.,The cerebral hemispheres are connected by the corpus callosum (胼胝体). What may happen when the brain is split surgically? Informa

20、tion from the left side of the body is received only by the right side of the brain and vice versa. Right hemisphere can understand and comprehend information, but it is mute. Split brain studies (裂脑试验): the experiments that investigate the effects of surgically severing the corpus callosum on cogni

21、tion.,Methods to examine the behaviour associated with the brain,Verbal information processing is realized mainly through a number of language centers situated in the left hemisphere. 1) Brocas area (布罗卡区) anterior language area It lies in the frontal part of the left brain. 2) Wernickes area (韦尼克区)

22、 posterior language area It leans behind Brocas area. 3) Angular gyrus (角形脑回) It lies further behind the Wernickes area. It is by this part that human beings match a spoken form with a perceived object, name the objects and comprehend the written language.,Language center and aphasia,Aphasia (失语症),A

23、phasia refers to a number of acquired language disorders due to the cerebral lesions (大脑损伤) caused by vascular problems (血管问题), a tumour, an accident and so on. The study of aphasia is by far the most important tool in the investigation of language in the brain.,Brocas aphasia (布罗卡失语症),Paul Broca, F

24、rench doctor, 1861 Any lesion of the anterior part of the left hemisphere will lead to speech production difficulties. (expressive aphasia, non-fluent aphasia) e.g. Yes ahMondayDad and Peterhospital and ah Wednesday, nine oclockand ah doctors twoerteethyah. Symptoms: poor articulation express a sing

25、le word at a time omit articles, conjunctions, and other functional words omit grammatical inflections (- telegraphic speech),Wernickes aphasia (韦尼克失语症),Carl Wernicke, German physician, 1874 Any lesion in left cortex behind the central sulcus (脑沟) will lead to speech comprehension deficits. (recepti

26、ve aphasia, fluent aphasia) e.g. Colorless green ideas are sleeping furiously. Symptoms: fast and fluent speech good intonation, pronunciation inappropriate content even nonsense difficulty in comprehension,Acquired dyslexia (习得性失读症),Acquired dyslexia: damage in and around the angular gyrus of the p

27、arietal lobe (顶叶) often causes the impairment of reading and writing ability. Two types of acquired dyslexia: 1. phonological dyslexia (拼音性失读症): patients can only read words that they have seen before. They seem to have lost the ability to use spelling-to-sound rule. 2. Surface dyslexia (浅层诵读困难): pa

28、tients seem unable to recognize words as wholes but must process all words through a set of spelling-to-sound rules.,Acquired dyslexia (习得性失读症),Psycholinguistics,Psycholinguistic research methods Field work Experimental methods Linguistics and language processing Phonetics and phonology Morphologica

29、l processing Syntax Psycholinguistic modeling,Psycholinguistics,In the1940s, the term psycholinguistics came into being. The publication of Psycholinguistics: A Survey of Theory and Research Problems (1954) (by Charles Osgood and Thomas Sebeok) A milestone, marking the birth of the new science Psych

30、olinguistics is the study of psychological states and mental activity associated with the use of language. It concerns the representation of language in the mind, the planning, production, perception and comprehension of speech, and language acquisition.,The focus of this sectionWhat do psycholingui

31、sts do?,Explore: how language is represented and processed in the mind How the concepts and principles are used in different levels of language processing How speech is produced,Psycholinguistic research methods,Field work spoonerisms 首音互换 Experimental methods Lexical Decision The priming experiment

32、 Timed-reading experiments Eye movement experiments Event-related potential experiment,11.2.1 Psycholinguistic research methods,Language production is a process of conversion from thoughts to speech. Easy or difficult to study? Why? Difficult to study. It is almost impossible to observe the internal

33、 ideas or the involved processes. Now, language production can only be studied through indirect evidence: 1) the analysis of pauses in spontaneous speech 2) the analysis of instances of speech errors (slips of the tongue),Field work: Pauses or silence,Around 40%-50% of an average spontaneous utteran

34、ce consists of pauses. Types of pauses: breathing they pause inside them. Conclusion: There is overlapping in the planning and production of clauses. That is, we begin to plan the next clause while still uttering the present one.,Spoonerisms 斯本内现象 首音互换,William A. Spooner,Phonological segments or fea

35、tures: 1, 2, 3 Whole words or even phrases: 4, 5,Speech Errorsslips of tongue,Phonological errors primarily in content words, not in grammatical morphemes, such as s, or ed Words and lexical morphemes (used for the construction of new words, such as black in the compound blackbird and ship in friend

36、ship) may be interchanged, but grammatical morphemes may not be; The intonation contour remains unchanged as in the intended utterances, even when the words are disordered Errors tend to occur at only one linguistic level per utterance. That is when a person clearly says the wrong word, the sentence

37、 is syntactically, prosodically, and phonologically intact. All these slips of the tongue provide evidence that the morpheme, rather than the word, is the fundamental building block of English sentence production.,Field work: Speech errors,e.g. You have hissed my mystery lectures. I saw you fight a

38、liar in the back quad. In fact, you have tasted the whole worm. (Dr. William Spooner),Eight types of speech errors (Psychology of Language, D. W. Carroll, 1986),石头把玻璃没打碎。 黄飞鸿 （hui) 这个电影真可怖。 他在柏林一天工作三星期。,Finding: Errors tend to occur at only one linguistic level per utterance. Conclusion: 1. A senten

39、ce must be planned before it is produced. 2. The morpheme, rather than the word, is the fundamental building block of English sentence production.,Experimental methods,Lexical Decision The priming experiment Timed-reading experiments Eye movement experiments Event-related potential experiment,Words

40、organized, accessed and represented in the mind,Sentences processed,Lexical decision (词汇判断) a participant sees a string of letters and is required to decide whether the string is a word or not. The time is recorded. It can be used to measure the speed and accuracy with which words in the mental lexi

41、con are accessed.,The priming experiment (启动试验): a participant sees a string of letters and is required to decide whether the string is a word or not. But before the appearance of the target word, another stimulus (called prime) is presented. The time is recorded.,Aim: to know to what extent the pri

42、me influences the subjects lexical decision performance on the target stimulus. Finding: Times are shorter when the prime is a semantically related word than when it is an unrelated word.,priming effect,Finding: Longer bar-pressing times for processing most nouns and verbs and relatively less time f

43、or function words.,Timed-reading experiment 限时阅读试验,Finding: Fixation times are typically longer for less frequent words. Fixation are typically centred on content words than on function words.,Eye movement experiment (眼动试验):,Difficult sentence structures create longer fixation time and more regressi

44、ve saccades.,Event-related potential experiment (ERP),Finding: ERP experiments have shown that sentence processing is immediate and online. When reading a sentence we do not wait until the entire string is complete, but rather constantly building interpretations of the sentence as it unfolds.,Whenev

45、er what is presented to us contradicts our expectations based on our going interpretative processes, a negative voltage is observed.,Language comprehension,Speech thoughts e.g. He said he would resign if nothing changed. 1) perceptual level: perceive individual speech sounds coming in a continuous s

46、tring. 2) lexical level: activate our internal lexicon and retrieve the lexical representations of the words that have been stored in our long term memory, and then integrate them into the ongoing linguistic context. 3) sentential level: use our syntactic and semantic knowledge to build in our short

47、-term memory. 4) discourse level: rely on preceding context to identify the person that he refers to.,Linguistics and language processing,Bottom-up processing Top-down processing It must be noted that the four levels operate at roughly the same time upon language input and may influence the operatio

48、n of other levels. They are mutually dependent.,The levels of language processing,Phonetics and Phonology cohort model “交股模型” (心理学的发展与未来展望） Morphological processing selectional restrictions hierarchical structure Syntax garden path sentences sentence ambiguity,Phonetics and phonology,cohort model “交

49、股模型” (心理学的发展与未来展望） Candle candy, can, cattle can The phoneme rather than the syllable seems to be the fundamental unit of auditory word recognition. However, the syllable plays an important role in speech perception.,Morphological processing,Selectional restrictions suffix -en: sharpen, shorten, Hierarchical structure uneatable: -able eat eatable un- uneatable refi