Psycholinguistics LECTURE20 Psycholinguistics CHIMP STUDIES A number of

Psycholinguistics LECTURE#20

Psycholinguistics • CHIMP STUDIES • A number of projects have investigated whether other primates (especially chimpanzees) can acquire language if properly taught. • Positive evidence would have important implications for nativist theories of language acquisition by humans. • If chimps can be shown to recognize semantic categories like FOOD and to apply syntactic patterns (e. g. word order), then it might suggest that they too have access to the basic principles underlying language.

Psycholinguistics • This would lend itself to one of three interpretations: • Chimps share the human language mechanism in some form, but lack a genetically transmitted trigger which sets it off as part of maturation. • There is no innate mechanism peculiar to human beings: acquiring a language depends upon the input a child receives. • Language maps on to established cognitive operations which human beings share with other primates.

Psycholinguistics • Chimps do not have an appropriate vocal apparatus to produce the sounds of human speech. • Early attempts were therefore made to teach them a modified form of the sign language used by the deaf. • One (Washoe) mastered 130 signs in three years – a rate of acquisition much slower than that of a human infant. • Washoe managed to produce sequences of two or three signs, including some original combinations; but never developed a consistent word order. • Another chimp (Nim Chimpsky) managed strings of up to four signs; and produced an impressive variety of sequences. • However, Nim’s productions involved much repetition of the same items and, like those of Washoe, showed great inconsistency of Subject-Verb-Object word order.

Psycholinguistics • More recently, researchers have trained chimps to communicate by indicating lexigrams, simple abstract shapes in various colours. • Each shape is associated with a word such as JUICE or BANANA, but they bear no resemblance to the objects they refer to. • The lexigrams appear on large keys mounted on a computer screen in the chimpanzee’s cage. • One chimp, Lana, learned over 100 of these symbols. • Two others, Austin and Sherman, were taught only a few and were then rewarded for semantically correct combinations (EAT þ BANANA rather than DRINK þ BANANA). • After thousands of trials, they came to recognize these combinations and (importantly) proved quick to categorize new items of food and drink when they learnt them.

Psycholinguistics • One of the most successful results has been achieved with a bonobo (or pygmy chimpanzee) called Kanzi. • He was originally present at the training sessions of his foster mother, Matata. • When the researchers felt that he was old enough to begin learning, he showed that he already knew much of what they wanted to teach him. • He mastered combinations of lexigrams without the thousands of trials that Austin and Sherman had needed. In all, he learnt about 400 symbols. • More importantly, he could group them in lexical sets and showed signs of using a consistent word order. • He could understand some simple spoken English, and could respond appropriately to commands such as ‘Put the soap on the apple’.

Psycholinguistics • Kanzi’s relative success has suggested that chimp training should begin earlier. • Deacon (1997) links the Kanzi findings to the ‘less is more’ view of language acquisition, which suggests that at a certain point children are particularly sensitive to the symbolic nature of a system such as language precisely because they have not yet fully developed cognitively. • However, it is not clear whether Kanzi can be said to have acquired a form of ‘language’ which resembles the human one in structure or complexity. • It may be that the whole concept of chimp training is misleading because it aims to teach a form of communication that is a quintessential product of the human mind.

Psycholinguistics • CHOMSKYAN THEORY • Noam Chomsky (b. 1928) formulated what is currently the leading model of language, generative grammar. • His goal was to create a set of rules to account for the creativity of language: the way in which a potentially infinite number of sentences can be generated from a finite set of words. • A Chomskyan grammar offers a symbolic representation of the system which native speaker-hearers internalize in acquiring the language, a system which enables them to formulate or to understand sentences that they may never have said or heard before.

Psycholinguistics • The grammar is generative in that its rules serve to specify all possible sentences which are grammatically correct and to exclude from consideration all those which are not. • These ‘rules’ are not the prescriptive rules of traditional grammar. • They are more like the laws of physics, which account for disparate natural phenomena in terms of general underlying principles.

Psycholinguistics • Chomksyan theory highlights the fact that language is structure dependent, and provides models of standard phrase types. • These are taken to represent the underlying form of an utterance, its deep structure. • In the first version of theory, a set of transformational rules showed how the user might reorganize the constituents of a deep structure string to produce a surface structure one. • For example, they showed, in stages, how a speaker derived a passive sentence from an underlying active form.

Psycholinguistics • Current theory has replaced the cumbersome transformational rules with movement rules. • These show diagrammatically how the deep structure (now dstructure) constituents are moved to new slots to provide a derived s-structure pattern. • See how a wh- question is derived from the d-structure string Sara is reading what. • An important feature of this revised theory, sometimes referred to as government and binding, is that when a constituent is moved it leaves behind a trace (t). • This enables the listener to retrieve the original deep structure from the sentence that is heard. Studies in psycholinguistics have attempted to verify the existence and effect of such traces.

Psycholinguistics • Chomskyan theory has recently taken a new direction, known as minimalism, which emphasises the importance of simplicity in formulating syntactic rules. • One development is that much of what is traditionally represented as syntax can be explained by reference to the constraints which are imposed by lexis. • Thus, if one decides to construct a sentence around the verb GIVE, the choice of verb determines the possible structure VP þ NP (Elizabeth gave Philip a book). • This information is stored as part of the lexical entry for GIVE in the user’s lexicon.

Psycholinguistics • Chomskyan theory provided a boost for cognitive psychology. • It moved the discussion on from the simplified accounts provided by behaviourism; and redirected attention to the mental processes involved in the production and understanding of language, processes which behaviourism regarded as inaccessible or non-existent. • Chomsky made an important distinction between competence, the set of principles which enable a native speaker to generate an infinite set of grammatically acceptable sentences and performance, the spoken/ written language to which the system gives rise. This differs somewhat from de Saussure’s distinction between langue and parole. • Where de Saussure defines ‘langue’ in relation to the speech community which shares the language in question, Chomsky relates competence to the individual user of the language. •

Psycholinguistics • Chomsky argues that linguistic theory needs to be based upon competence, not performance. • The goal of the linguist should be to specify the means by which the native speaker-hearer constructs grammatically correct sentences rather than to analyze what he/she actually says. • Generative grammar thus assumes an ideal speaker-hearer, one from whose speech idiolectal, dialectal and hesitational features have been removed. • It is here that linguistic approaches and psychological ones diverge, since the data upon which a psychologist traditionally works is provided by examples of human behaviour in performance.

Psycholinguistics • In psycholinguistics, those who work within the Chomskyan tradition follow a theory-driven approach which seeks evidence of the psychological reality of Chomsky’s constructs. • However, they face a problem in attempting to tap into competence rather than relying on performance data. • A solution adopted by many researchers is to ask subjects to make grammaticality judgements. • They might, for example, be asked to decide if a sentence such as Who did you introduce the man you got the present from to? is grammatically acceptable.

Psycholinguistics • A second complication is that Chomsky’s grammar is specifically a model of language. • Chomsky has much to say on the human mind; but he does not claim that phrase structure and movement rules represent the actual process taking place within the mind of the user as he/she constructs a sentence. • Hence there is discussion as to whether these generative rules are psychologically real. • Early research in syntactic parsing attempted to demonstrate that the complexity of a transformational rule did, indeed, influence the listener’s ability to process a sentence. • The hypothesis was not supported.

Psycholinguistics • Chomskyan thought has had a strong impact on psycholinguistics in the area of language acquisition. • Chomsky argues strongly for a nativist view. • His main point relates to the ‘poverty of stimulus’ afforded by child directed speech. • The language to which the infant is exposed in its early years could not possibly, he suggests, cover the whole range of possible sentences. • Furthermore, it is ‘degenerate’ in that it constitutes performance data (complete with ungrammatical forms, hesitations, false starts etc. ). • How then can the infant succeed in deriving competence from it in a comparatively short time?

Psycholinguistics • Chomsky concludes that we can only account for first language acquisition by assuming that a child is born with an innate knowledge of the principles of language and a predisposition to employ them in analyzing the speech which it encounters. • Current theory attempts to bridge the gap between the universal principles with which we are born and the specific form of the language which we finally acquire. • We are said to be endowed with a Universal Grammar (UG) in the form of an innate awareness of the nature of language and the various forms that language adopts. • UG is represented in terms of a set of principles common to all languages and a set of parameters which are adjusted to reflect the characteristics of the specific language to which the infant is exposed.

Psycholinguistics • CLUTTERING • A disorder affecting fluency, in which the sufferer attempts to speak too quickly, resulting in distorted articulation and disrupted rhythm. • Syllables may be truncated, words repeated, sounds omitted or misarticulated. • It is possible that planning at the phonetic level is implicated: speech is uttered in staccato bursts, which sometimes interfere with syntax. • As the utterance proceeds, the speaker may well speed up (festination) rather than slowing down. • Cluttering sometimes occurs in conjunction with stuttering. • One possible cause is brain damage.

Psycholinguistics • COGNITION • The use or handling of knowledge; hence, (a) the faculty which permits us to think and reason and (b) the process involved in thought and reasoning. • It is sometimes contrasted with metacognition, which can be defined as ‘thinking about thinking’ and involves pre-planning a cognitive process, exercising control over the process or taking steps to ensure that its results are stored long term.

Psycholinguistics • Metacognition involves some degree of awareness, whereas cognitive processes may not be available to report. • An important issue is whether language is part of general cognition or is a separate faculty. • One argument supporting the latter (modular) view is the fact that all normally developing infants achieve a first language whatever their cognitive capacities in other areas.

Psycholinguistics • COGNITIVE PSYCHOLOGY • The study of human mental processes and their contribution to thinking, sensation and behaviour. • The discipline is often traced back to Wundt, who founded a psychology laboratory in Leipzig in 1879. • Wundt’s method was to ask subjects to perform a mental process, then report on the experience. • This introspective approach produced inconsistent results. • There was a strong reaction against it by psychologists who took an anti-mentalist stand, arguing that the mind was unknowable. • They insisted that the only scientific source of data for psychology was human behaviour, which was observable in a way that mental processes were not. • From this grew the movement known as behaviourism.

Psycholinguistics • Another influential movement in the early twentieth century was led by the Gestalt group of psychologists, who investigated how the mind shapes our perceptions of the world. • In particular, they examined how we perceive separate elements (e. g. dots on a page) as falling into groups and patterns. • Reaction against behaviourism came from an information processing approach developed in the 1950 s which aims to chart the flow of information through the mind as a particular cognitive task is performed.

Psycholinguistics • It underpins much current thinking in cognitive psychology. • From it has developed a view of much human rational behaviour as based upon problemsolving; this has especially informed research into the nature of expertise. • A recent movement in cognitive psychology has been connectionism, an attempt to model in computer programs the neural networks which form the basis of the operations of the brain.

Psycholinguistics • COGNITIVISM • Approaches to language acquisition which view the process as closely linked to general cognition and to cognitive development. • Some accounts leave open the extent to which certain aspects of language are innate; but all take the view that acquisition is primarily driven by the way in which the infant’s cognitive abilities are brought to bear upon the input to which it is exposed. • These cognitive abilities may reflect developing awareness of objects, spatial relations, defining characteristics etc. , or they may take the form of perceptual biases which incline the child to recognize patterns in linguistic material.

Psycholinguistics • Among views on acquisition which can be characterized as ‘cognitive’ are: • An infant cannot express concepts in language unless it has previously developed them. • Example: A child cannot use language to refer to objects that are not visible unless it has grasped the idea of object permanence. • For Piaget, language was the product of cognitive and perceptual processes. • His research with children led him to conclude that there were four stages of cognitive development. • They represent a gradual progression and not a sudden shift in behaviour; and the age at which a particular child goes through each varies considerably. • However, they are closely linked to linguistic development.

Psycholinguistics • Both language and cognition are part of a staged maturation program, in which they operate in parallel, supporting each other. • For Vygotsky, thought exists pre-verbally. • There is initially a separation between thought and language: the infant’s first words are devoid of thought. • During three phases, the separate roles of thought and language become established. • Innate cognitive tendencies may predispose us: • a. To find patterns in language data (as in data in general). • A theory of syntactic bootstrapping postulates that infants reach conclusions about words on the basis of their inflections and other grammatical properties: • thus the child learns that the difference between It’s sib and It’s a sib serves to distinguish real-world entities that are mass from those that are count.

Psycholinguistics • b. To adopt certain strategies in response to language data. • Slobin (1973) concludes that infants apply a set of universal strategies or operating principles in order to deconstruct the input to which they are exposed. • (Pay attention to the ends of words. Pay attention to the order of words and morphemes. ) • More cognitively complex features are acquired later. • c. To apply individual learning styles to language data. Some infants appear to break the input into words, while others acquire chunks of language in a holistic manner.

Psycholinguistics • The infant’s limited cognitive capacity renders it more sensitive to the features of language than it might be before or later. • The ‘less is more’ argument holds that it may be the very limitations of the infant’s early cognitive state which enable it to identify structure in language and to recognize that language constitutes a set of inter-related symbols.

Psycholinguistics • • COHORT THEORY A model (Marlsen-Wilson, 1987) of the way in which words are retrieved from the lexicon in listening. A listener processes an utterance at a delay of around a fifth of a second behind the speaker; this is often not enough to provide full evidence for a particular word. Cohort Theory adopts the hypothesis that the listener retrieves a set of words (a cohort) which match the evidence of the signal so far. Thus, on hearing the phonetic string [k{p] they would retrieve CAP, CAPITAL, CAPRICORN, CAPTURE, CAPTAIN, CAPTIVE, etc. as word candidates. If the next sounds proved to be [t] and [I], the cohort would narrow to CAPTAIN, CAPTIVE and CAPTIVATE. Finally, the sound [n] would mark a uniqueness point, where only one word match, CAPTAIN, was possible. The uniqueness point of a word is not necessarily its last phoneme: for example, the word PSYCHOLOGY becomes unique at the /l/.

Psycholinguistics • A major objection to the early version of Cohort Theory was that it was heavily dependent upon correct identification of word-initial phonemes. • If a slip of the tongue led a speaker to produce ‘shigarette’ rather than cigarette, the appropriate cohort would not be selected. • In addition, account needs to be taken of phonetic accommodation, which leads many words to diverge from their citation forms when they occur in connected speech. • The model was therefore revised to include a principle of closeness of fit rather than exact match. • An activation dimension was added: the cohort is now represented as a set of lexical items whose strength is boosted or weakened by incoming perceptual evidence until one of them achieves a match. • Contextual evidence can play a role in narrowing down the cohort; • but it is not taken into account until after about 150– 200 milliseconds of the word; this is referred to as bottom-up priority.

Psycholinguistics • A weakness of the model remains the fact that it assumes that a word is a discrete and easily identified unit. • Many sequences that appear to constitute monosyllabic words may prove instead to be the initial syllables of polysyllabic ones, and vice versa. • Using the ‘captain’ example, how is one to know if a match has been achieved after the word CAP or if one has to continue reducing the cohort? • There may also be ambiguities of lexical segmentation where word candidates cross boundaries (for example, the word SISTER occurs within the sequence insist upon).

Psycholinguistics • The ‘uniqueness’ concept has also been challenged. • A study of the lexicon has suggested that over a third of words in normal speech are not unique by their offsets, while there is evidence that many monosyllabic words are not identified until well after their offsets. • Nevertheless, the notion of the cohort is implicitly or explicitly adopted in many accounts of auditory processing.