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Cognitive Neuroscience

Cognitive Neuroscience. What is language? The fundamentals of word knowledge. Language and the Brain. Since the 19 th C great progress in our understanding of (a) brain and (b) language But little progress regarding the relationship between brain and language

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Cognitive Neuroscience

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  1. Cognitive Neuroscience What is language? The fundamentals of word knowledge

  2. Language and the Brain • Since the 19th 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

  3. Why ask “what”? • A.D. 98-135: 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 into the 19th C • The localization of function can only be as good as the theory of the function

  4. Instincts

  5. 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).

  6. Language as an instinct: Arguments • Develops spontaneously, without instruction, without awareness of the underlying “rules” • Same developmental milestones across languages • Cannot be reduced to a general capacity to use symbols, need, intelligence, general characteristics of human information processing * Critical periods

  7. 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 • adult/child differences in language acquisition Suggests a biological process with its own “clock”

  8. Critical Periods: Creoles and Pidgins • Adult immigrants (without instruction) -> pidgins Pidgins: no consistent word order, no prefixes/suffixes, no tense marking, simple clauses only But: • Children of immigrants exposed only to pidgins -> creoles Creoles: bona fide languages, standardized word order, grammatical markers How can we explain this? -Innate language acquisition blueprint

  9. Genetic Blueprint + Learning • Genetic blueprint: • Neural/cognitive machinery to organize/represent language stimuli in specific ways • The same across languages (Universal Grammar) • Learning: • The characteristics of the specific language in the environment are learned

  10. Linguistics and Psycholinguistics Language knowledge: • phonology • morphology • syntax • semantics • orthography

  11. Phonology • Our knowledge of the phonemes of the language and their legal combinations phoneme: smallest unit of language sound that serves to distinguish one word from another: pot/pod rot/lot pot/phot Some knowledge is language universal: all languages have CV syllables Some is language-specific: English: blin /*bnin Arabic: *blin/ bnin

  12. Morphology • Our knowledge of the meaningful units of the language and how they can be legally combined in words morpheme: the smallest meaningful unit of language generalizations general+ize+tion+s *general+s+tion+ize

  13. Syntax • Our knowledge of how words can be combined to express meaning the student praised the teacher the teacher praised the student *praised the student the teacher

  14. Linguistics and Psycholinguistics Language knowledge: • phonology • morphology • syntax • semantics: knowledge of word meanings • orthography: knowledge of word spellings

  15. Language Knowledge Examples to illustrate that our language knowledge is: • Detailed • Systematic • Abstract • Unconscious

  16. Pluralization What’s the plural of: cab mop road rock How do you do this? • look up • rules

  17. Pluralization Look up? • necessary for irregulars (child-child; foot-feet, mouse-mice) Why not look up everything? What’s the plural of: jat mun

  18. Pluralization How might the rule be stated? {singular} + /s/ -> {plural} /k æ t/ + /s/ -> /k æ t s/ How well does it work? lock bat cap laugh log fad cab cave

  19. Pluralization How about? banjo day cry sea due Or? jat/jad jaf/jav voe

  20. Pluralization Revised rule: for singular ending in /t/, /p/, /f/, /k/: {singular} + /s/ -> plural for singular ending in /d/, /b/, /v/, /g/ or vowel: {singular} + /z/ -> plural

  21. 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 (e.g., days/mace; sighs/mace; dens/dense)

  22. Pluralization If we consider each phoneme as a set of features, the grouping becomes non-arbitrary 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)

  23. Pluralization + voice-voice /b/ /p/ /g/ /k/ /d/ /d/ /v/ /f/ vowels, /n/, /m/, /l/ New rule: If final sound is + voice add /z/ (+voice) If final sound is – voice add /s/ (-voice)

  24. Question Formation 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

  25. 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.

  26. Question Formation Sentence Verb Phrase (subject) Noun Phrase is crazy Noun Verb Phrase who is smoking The boy

  27. Sentence comprehension The spy saw the cop with the binoculars. Who had the binoculars? • the cop has binoculars • the spy has binoculars

  28. Sentence Comprehension Where’s the difference? -not in the stimulus -rather, in the mental representation of the sentence’s structure:

  29. Language Knowledge What is the nature of our language knowledge? • Detailed • Complex • Abstract • Systematic • Unconscious

  30. PB video • Boy will fell • Crooked in the chair • Boy get k,k,..cooks to give a /g ou l/ • Water sink • Water is fall and water down to floors • Floors is wet there • Woman cleaning of…like plate….like washing

  31. 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)

  32. 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

  33. Word Knowledge Noun, plural +s Luxurious sea-going vessel Y-A-C-H-T /y a t/

  34. Semantics/Phonology • R.G.B. • Caramazza & Hillis (1990) • 62-year-old, right handed • Retired personnel manager, high-school education • CVA 4 years prior to investigation • Left fronto-parietal infarct • Dense hemiplegia

  35. R.G.B. percent correct Aud word/pix match 100 Vis word/pix match 100 Aud/Vis word match 100 Oral reading 67 Oral naming-pix 62 Oral naming-tactile 64

  36. R.G.B. stimulus reading definition RECORDS radio you play’em on a phonograph….can also mean notes you take and keep GREY blue color of hair when you get old SUBWAY bus 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 QUILL feather they’re long an dhave a point…animals, porcupines have them DOLLAR money a bill… a hundred cents MOCCASINS shoes Indians used to wear them CITRUS apple no, kind of fuit you get down south…like an orange

  37. Syntax/Phonology Dante Badecker, Miozzo & Zanuttini (1993) • Male, 24-yrs-old, 8 years of education • Suspected meningoencephalitis • Hypodensity in fronto-temporo-parietal regions • Fluent speech w/ word finding difficulties, good comprehension

  38. Anomia or tip-of the-tongue state • A raised platform on which a speaker may sit or stand

  39. 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

  40. Dante: Results Correct naming 56% with 88 anomic responses Accuracy for forced choice queries on anomic trials: Gender 98% Word length 50% First letter 53% Last letter 47% Rhyming word 48%

  41. Phonology/ Orthography RGB (Caramazza & Hillis, 1990) Aud word/pix match 100 Vis word/pix match 100 Aud/Vis word match 100 Oral reading 67 Oral naming-pix 62 Oral naming-tactile 64 Written naming* 94% Writing to dictation* 94% *no semantic errors

  42. Phonology/ Orthography • Good phonology, poor orthography (and vice versa) RCM (Hillis, Rapp & Caramazza, 1999) Aud word/pix verification 100% Vis word/pix verification 100% Oral reading 97% Oral naming-pix 100% Written naming* 53% Writing to dictation* 47% *primarily semantic errors

  43. Word Knowledge Noun, plural +s Luxurious sea-going vessel Y-A-C-H-T /y a t/

  44. Dissociable aspects of word knowledge • Knowledge types are represented in neural substrate in a manner such that they can be dissociated • Localization?

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