What Is Language - Cognitive Neuroscience What is language?...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Cognitive Neuroscience What is language? The fundamentals of word knowledge Language and the Brain th Since the 19 C great progress in our understanding of (a) brain and (b) language But little progress regarding the relationship between brain and language brain cognitive neuroscience language Why not? No animal model The more "interesting" aspects are distant from stimulus and response Why ask "what"? Treatment: A.D. 98135: Celsus believed that the tongue, not the brain, was the source of speech disorders > treatment: tongue massages and gargles 1657: William Harvey was treated for his speech loss with a cut in the frenulum of the tongue (to loosen it) cupping, leeching, bleeding were accepted treatments for aphasia th into the 19 C CNS research: The localization of function can only be as good as the theory of the function There is ALWAYS a theory of function guiding the work (explicitly or implicitly) Instincts Language as an Instinct "Language is not a cultural artifact that we learn the way we learn to tell time or how the federal government works. Instead, it is a distinct piece of the biological makeup of our brains" (Pinker, 1994). Chomsky argued that children are innately equipped with a plan common to the grammars of all languages--a Universal Grammar. "No one would take seriously the proposal that the human organism learns through experience to have arms rather than wings....human cognitive systems...prove to be no less marvelous and intricate...Why, then should we not study...language...as we study some complex bodily organ?" (Chomsky, 1975). Language as an instinct: Arguments Develops spontaneously, without instruction, without awareness of the underlying "rules" Same developmental milestones across languages * Critical periods Critical Periods In vision (but not chess) exposure during a critical period is crucial for normal development similarly for language: (1) children not exposed to language before adolescence fail to acquire it later in life (2) adult/child differences in language acquisition abilities Suggests a biological process with its own "clock" Critical Periods Adult immigrants (without instruction) > pidgins Pidgins: no consistent word order, no prefixes/suffixes, no tense marking, simple clauses only But: Children of immigrants on Hawiian sugar plantations exposed only to pidgins (isolated from parents and reared by a worker who spoke to them in a pidgin) > creoles Creoles: bona fide languages, standardized word order, grammatical markers How can we explain this? Innate language acquisition blueprint + critical periods Sign Language Critical Periods: Deaf adults (i.e. neurologically normal) exposed to ASL only as adults > ungrammatical ASL Deaf children exposed to ungrammatical ASL > grammatical ASL Nicaragua--until recently no sign languages in 1979 deaf children brought together in residential schools to teach them lip reading and speech those attempts largely failed but the children developed their own bona fide sign language from the gestures used at home with their families Sources of our language knowledge Genetic blueprint: Neural/cognitive machinery to represent language stimuli in specific ways The same across languages (Universal Grammar) Learning: The characteristics of the specific language exposed to Both universal (biological) and languagespecific (learned) language knowledge: phonology morphology syntax orthography semantics Phonology: Languagespecific knowledge Inventory: Our knowledge of the legal sounds of a language Phoneme: smallest unit of a language sound that serves to distinguish one word from another: pot/pod rot/lot h *spot/p ot Rules: Our knowledge of the legal combination of sounds English: blin /*bnin Arabic: *blin/ bnin Lexicon: the specific combinations of sounds that comprise the meaningful units of a language English: k t Spanish: g a t ou Morphology: Languagespecific knowledge Inventory: Our knowledge of the meaningful units of the language Rules: How they can be legally combined in words morpheme: the smallest meaningful unit of language generalizations general+ize+tion+s *general+s+tion+ize Orthography Inventory: Our knowledge of the letters of the language z, j, y but not , , Rules: How they can be legally combined in words Word initially: PS (psyche) not BS How letters relate to phonemes SH "sh" CH "sh" (chef), "k" (choir), "ch" (chew) Syntax Our knowledge of which words are necessary to understand the relationships among words the boy hit the ball the boy was hit by the ball Our knowledge of how words can be combined to express meaning (order) the student praised the teacher the teacher praised the student *praised the student the teacher Language knowledge: phonology morphology syntax orthography semantics: word meanings Language Knowledge Our language knowledge is: Detailed Systematic Abstract Unconscious Pluralization (morphology) What's the plural of: cab mop road rock How do you do this? look up rules Pluralization Look up? necessary for irregulars (childchild footfeet, mousemice) Why not look up everything? What's the plural of: jat mun Pluralization How might the rule be stated? {singular} + /s/ > {plural} /k t/ + /s/ > /k t s/ How well does it work? lock bat cap laugh log fad cab cave Pluralization How about? banjo day cry sea due Or? jat/jad jaf/jav voe Pluralization Revised rule: for singular ending in /t/, /p/, /f/, /k/: "s" lock bat cap laugh "z" banjo day cry hen car hotel {singular} + /s/ > plural for singular ending in /d/, /b/, /v/, /g/, /n/,/m/,/r/,/l/, vowel: {singular} + /z/ > plural log fad cab cave Pluralization Problems? Doesn't explain why there are two different plural sounds Doesn't explain the grouping of ending sounds with plural forms. Note: only required for plurals days/mace sighs/mice dens/dense purrs/purse Pluralization If we consider each phoneme as a set of features, the grouping becomes nonarbitrary Feature dimensions: place of articulation (placement of tongue, lips, etc.) manner of articulation (manner in which air is released) voicing (+ or movement of vocal folds) Pluralization + voice /b/ /g/ /d/ /v/ vowels, /n/, /m/, /l/,/r/ New rule: If final sound is + voice add /z/ (+voice) If final sound is voice add /s/ (voice) voice /p/ /k/ /d/ /f/ Question Formation (syntax) How do we generate questions from statements? the boy is crazy is the boy crazy? the girl can sing can the girl sing? Rule? Prepose the first auxiliary verb Question Formation The boy who is smoking is crazy *Is the boy who smoking is crazy? The boy who is smoking is crazy Is the boy who is smoking crazy? New rule: Prepose the auxiliary following the subject noun phrase. Question Formation Sentence (subject) Noun Phrase Noun Verb Phrase Verb Phrase is crazy The boy who is smoking Sentence comprehension The spy saw the cop with the binoculars. Who had the binoculars? a) the cop has binoculars b) the spy has binoculars Sentence Comprehension Where's the difference? not in the stimulus rather, in the mental representation of the sentence's structure: Language Knowledge Characteristics: Innate Complex Abstract Systematic Unconscious Components: phonology morphology syntax orthography semantics Language knowledge expresses itself over units of different sizes and complexities phonology morphology syntax orthography semantics phonemes morphemes phrases sentences words Word Knowledge Luxurious seagoing vessel semantics Noun, plural +s Grammatical features YACHT /y a t/ orthography phonology Word Knowledge What do we know when we know a word? Meaning: semantics Grammatical properties (gender, grammatical category, etc.): syntax/morphology Sound: phonology Spelling: orthography semantics grammar phonology Word Knowledge We can categorize our word knowledge in this way, but does the brain do so? That is, although these kinds of information are certainly stored in the brain, are the distinctions respected in terms of the neural instantiation? How can we know????? different neural geographies revealed by selective impairment and/or selective activation Lesion evidence Dissociations: Semantics > syntax Semantics > phonology Syntax > phonology Etc. Syntax > Semantics "Colorless green ideas are sleeping furiously" Chomsky B.H. (Badecker, Rapp & Caramazza, 1996) 45year old, righthanded male Master's degree in management Excellent premorbid writing Traumatic brain injury (airplane accident) 6 years prior to investigation Damage to right frontalparietal and left frontal lobe white matter and right internal capsule Spoken output minimal Severe anterograde amnesia Leftsided neglect in reading and linebisection B.H. 54% of his responses were semantically anomalous 83% were syntactically appropriate Just a minute ago She drank four The man is being we turked everything of the yallards dresswracked Lesion evidence Dissociations: Semantics < syntax Double dissociations: Syntax < semantics Why are double dissociations useful? All dissociations and double dissociations to support these distinctions have been documented Luxurious seagoing vessel semantics Noun, plural +s Grammatical features YACHT /y a t/ orthography phonology Dissociable aspects of word knowledge Knowledge types are represented in neural substrate in a manner such that they can be dissociated Localization? Where is language? Summary: Language knowledge Characteristics: innate complex abstract systematic unconscious Components: phonology morphology syntax orthography semantics Units: phonemes morphemes words, phrases, sentences letters ???? PB Components: phonology morphology syntax orthography semantics Units: phonemes morphemes words phrases sentences PB video Boy will fell, accident It seems that crooked in the chair Boyit seems like.... get k,k,..cooks to give a /g ou l/ Water s s sink, f f f Water is fall and water down to floors And also, I guess, like, the floors is wet there Woman cleaning of...like plate....washing I guess Semantics > Phonology R.G.B. Caramazza & Hillis (1990) 62yearold, right handed Retired personnel manager, highschool education CVA 4 years prior to investigation Left frontoparietal infarct Dense hemiplegia R.G.B. percent correct 100 100 100 67 62 64 Aud word/pix match Vis word/pix match Aud/Vis word match Oral reading Oral namingpix Oral namingtactile R.G.B. stimulus RECORDS GREY SUBWAY reading radio blue bus definition you play'em on a phonograph....can also mean notes you take and keep color of hair when you get old you ride on them from one area to another...they have'em in NY and now we have one in Baltimore. Goes on tracks underground they're long an dhave a point...animals, porcupines have them a bill... a hundred cents Indians used to wear them no, kind of fuit you get down south...like an orange QUILL DOLLAR MOCCASINS CITRUS feather money shoes apple Syntax > Phonology Dante Badecker, Miozzo & Zanuttini (1993) Male, 24yrsold, 8 years of education Suspected meningoencephalitis Hypodensity in frontotemporoparietal regions Fluent speech w/ word finding difficulties, good comprehension Anomia or tipof thetongue state A raised platform on which a speaker may sit or stand Dante Task: name 100 pix & 100 sentence completions when in an anomic state, asked to make a forced choice judgments of: grammatical gender (masc/fem) first letter (T/D) word length XXXX/XXXXXX last letter (S/M) rhyming word Dante: Results Correct naming: 56% 88 anomic responses Accuracy on forced choice questions for the 88 anomic trials: Gender Word length First letter Last letter Rhyming word 98% 50% 53% 47% 48% Orthography > Phonology RGB (Caramazza & Hillis, 1990) Oral reading Oral namingpix *semantic errors 67 62 Written naming* Writing to dictation* *no semantic errors 94% 94% Double Dissociation RGB (Caramazza & Hillis, 1990) RCM (Hillis, Rapp & Caramazza, 1999) Oral reading Oral namingpix Written naming Writing to dictation 67 62 94 94 97 100 53 47 Dissociations indicate independence of representation. What is an alternative interpretation of a dissociation? How do double dissociations rule this out? ...
View Full Document

This note was uploaded on 07/29/2008 for the course NEUROSCIEN 70 taught by Professor Whitney during the Spring '08 term at Johns Hopkins.

Ask a homework question - tutors are online