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Introduction to psycholinguistics Babarczy Anna [email protected] www.cogsci.bme.hu/~ktkuser/KURZUSOK/BMETE47MC36/2014_2015_1/ What is psycholingusitics? • Study of the processes behind the – Production – Comprehension – Acquisition of language What is language? • Language is a communication system that is – – – – – Rule-driven Symbolic Hierarchically structured Creative Species-specific • Speech ≠ Language (sign languages) Language • A system of symbols and rules that makes communication possible? • Is communication the most important function? • Is there a separate system of rules? • Language in apes? Bee dance? • Focussing on specific areas makes answering questions simpler: – Semantics, syntax, morphology, phonology, pragmatics Another view of language • http://www.youtube.com/watch?v=ZFD01r6ersw&fe ature=related • A Bit of Fry and Laurie...Tricky Linguistics (1989) Requirements for language (comprehension and production) 1. Biological apparatus 2. Abilities for acquisition 3. Knowledge of words and rules 4. Knowledge of social context and rules 5. Knowledge about others’ knowledge and beliefs Topics in psycholinguistics • • • • • • • The organisation of language in the brain/mind Speech and language processing Speech and language production Language Acquisition: Language evolution: How did human language emerge? Human language vs. Animal communication Human language and other human cognitive skills Psycholinguistics • Comprehension and production of language involves several sub-tasks: 1. The ability to produce and recognize sounds of the message 2. Recognition and production of words in the message (segmentation), and the pairing of word forms with their meanings. 3. Processing and production of the grammatical structure of the message. 4. Evaluation of the message in the given context, or fitting the message to a given context. 1. The ability to produce and recognize sounds of the message • Relies on phonetic and phonological knowledge • Knowledge of the phoneme inventory of the language, the identification and differentiation of different phonemes. – (ˈsɪŋ ər) vs. (ˈsɪn ər) vs. (ˈlɪŋɡə) – Hungarian: enged • Successful use of a language also depends on knowledge of its phonotactics, or the ability to combine sounds into words • Which one is a better candidate for an English word? • blicket or lbnuxst Sounds -> signs • Speech processing through auditory channel • Sign processing through visual channel – Similar processes: segmentation, recognition, production 2. Word recognition and associating word forms with meanings • The lexicon: the mental inventory of words • Also requires knowledge of morphology, or the knowledge of word formation Words Units of language Crystal: the smallest unit of language that can form a complete utterance in itself, and that is separated by space from the rest of the text in writing. Smaller units: syllable, sound, morphemes. tables table – morpheme corresponding to the concept ‘table’, -s: plural morpheme Irregular forms (go-went or sing-sang versus walk-walked): do they still contain two morphemes? The mental lexicon • Words are stored in the mental lexicon • In many ways, similar to a real lexicon: pronunciation, meaning, written word form, category, syntactic roles, etc. • But different principles of organization: e.g. frequency and meaning. Alphabetical order is not central. • Cca 70,000 words in the adult lexicon (estimates vary between 15,000-150,000). The mental lexicon One of the central topics in psycholinguistics • The organization of the lexicon • What is stored and how • Lexical retrieval for production and comprehension • How do we know whether it contains a word or not • Are there differences between spoken and written word forms? 3. Processing and production of the grammatical structure of the message • The ability to combine words into phrases and phrases into well-formed sentences relies on syntax. • Knowledge of syntactic rules (grammar) generates well-formed (grammatical) sentences, and does not generate sentences that are not well-formed. (?) – Rule-based approach – Statistical (template-based approach) 4. Evaluating the message in context • Successful expression and comprehension of a message also relies on pragmatic knowledge – formulating or decoding the message according to the given social context (genre, purpose, audience) – conveying/recovering messages not explicitly encoded in the text A brief history of psycholinguistics History psycholinguistics • Started in the 1950s • First use of word: conference on Cornell, USA, 1951 • Osgood and Sebeok, 1954: Psycholinguistics: A survey of theory and research problems • Before that: – Sir Francis Galton examined word associations in 1867 – In 1895 Meringer and Mayer analysed speech errors with surprisingly modern methods in Germany Early psycholinguistics • The language processor is a simple device that generates or accepts sentences by moving from one state to another. • Two important influences: information theory and behaviorism. • Information theory – The role of redundancy and probability in language: at a given point, what is the most probable continuation of a sentence? • Behaviourism – stimulus, response, reinforcement to establish the relationship between them. – Only relevant topic is behavior; language is one kind of behavior. – Language acquisition also proceeds following the principles of reinforcement and conditioning Modern psycholinguistics • 1959 Chomsky’s critical review of Skinner’s Verbal Behavior • Beginning of 60s: psycholinguistics tries to relate language processing to transformational grammar • It has left linguistics since, and became an autonomous field of study • Roots both in psychology and in linguistics The influence of generative grammar • Chomsky sweeping criticism: rapid change of views • New kind of language theory: transformational grammar, which accounts for speakers’ knowledge of language besides the underlying structure of sentences. • Part of psycholinguistics’ success is due to the fact that it tried to test Standard Theory and its consequences Generative Grammar • Noam Chomksy, 1950s: Theory of Transformational Generative Grammar (Standard Theory) The generative tradition • The aim of the study of syntax is to describe the set of rules that makes language production and comprehension possible. • Distinction between idealized language competence and actual language performance • Linguistics: competence--implicit knowledge of rules The generative tradition • Grammar contains rewrite rules of phrase structure, which operate on terminal and nonterminal items • SNP + VP • NPDet +N • VPV+NP • Ncat, dog, John, plate, etc. • Vdropped, ate, hates, run etc.. • Deta, the • John dropped the plate. The generative tradition • Standard Theory distinguishes between deep structure and surface structure. • The deep structure of the sentence is the idea (together with its logical structure); the surface structure is the linguistic form which expresses the underlying thought. – Mary had waffles for breakfast. – What did Mary have __ for breakfast? • The surface structure is derived from the deep structure through transformations (special rewrite rules). • The same surface structure may have different underlying deep structures showing the ambiguity of the sentence: – Visiting relatives can be boring. Psycholinguistic models: focus on performance • Realistic models of human sentence comprehension must account for: – – – – – – Language has structure Robustness to arbitrary input Accurate disambiguation of words and sentences Inference on basis of incomplete input Processing difficulty is differential and localized Errors in processing and production Processing factors • Besides abstract linguistic representations, other characteristics of words and sentences are also important – How often a word is used influences how easily we can retrieve that word. – How often a particular sentence type occurs in actual discourse influences how easily we can process it. – Practice does make perfect. • Cognitive capacities relevant for language: memory resources, attentional resources, etc. These also affect linguistic performance in any task. • Factors to consider: – word frequency, word length, concreteness, age of acquisition, part of speech, quality of picture, transitional probability of bigram, typicality or probability of X in Y context, morphological complexity, speech rate, duration of stimulus, number of words in a sentence, position on screen, repetition, ambiguity. Well-formedness I think when she finally came to the realization that, you know, no, I can not, I can not take care of myself. ... I mean, for somebody who is, you know, for most of their life has, has, uh, not just merely had a farm but had ten children had a farm, ran everything because her husband was away in the coal mines. And, you know, facing that situation, it’s, it’s quite a dilemma. (The woman is facing being put in a resting home.) . . . but usually we come to understand it pretty well anyway. The 70’s • Psycholinguistics becomes part of mainstream cognitive psychology • Information processing or computational models • Flowcharts (before translations into computer programs) with processing levels. How one level of linguistic representation is translated into another • The mind uses rules that transform the input (speech or sight) into symbols. Cognition is symbol manipulation. • The cumputational metaphor and experimental techniques made psycholinguistics a separate branch of science • Just like in other fields of cognitive psychology, reaction time measurements became central. Cognitive science • A multidisciplinary approach: philosophy, linguistics, anthropology, neuropsychology and AI. • AI: get the computer do something that requires intelligence • Traditional AI research: analysis of human behaviour, goals and plans • Explicit • A pro and con at the same time: loss of flexibility, many assumptions have to be built in • Early optimism Eliza (Wizenbaum, 1966) -- Men are all alike. IN WHAT WAY? --They’re always bugging us about something or other. CAN YOU THINK OF A SPECIFIC EXAMPLE? --Well, my boyfriend made me come here. YOUR BOYFRIEND MADE YOU COME HERE. --He says I’m depressed much of the time. I AM SORRY TO HEAR THAT YOU ARE DEPRESSED. Eliza (Wizenbaum, 1966) --It’ true that I’m unhappy. DO YOU THINK COMING HERE WILL HELP YOU NOT TO BE UNHAPPY? --I need some help, that much seems certain. WHAT WOULD IT MEAN IF YOU GOT SOME HELP? --Perhaps I could learn to get along with my mother. TELL ME MORE ABOUT YOUR FAMILY. http://nlp-addiction.com/eliza/ Winograd: SHRDLU • 1968-70 MIT • “put the green cone on the red block” • IBM Watson: http://www.youtube.com/watch?v=yJptrlCVDHI