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Lateralization of phonology DAY 22 – Oct 18, 2013. Brain & Language LING 4110-4890-5110-7960 NSCI 4110-4891-6110 Harry Howard Tulane University. Course organization. The syllabus, these slides and my recordings are available at http://www.tulane.edu/~howard/LING4110/ .
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Lateralization of phonologyDAY 22 – Oct 18, 2013 Brain & Language LING 4110-4890-5110-7960 NSCI 4110-4891-6110 Harry Howard Tulane University
Brain & Language - Harry Howard - Tulane University Course organization • The syllabus, these slides and my recordings are available at http://www.tulane.edu/~howard/LING4110/. • If you want to learn more about EEG and neurolinguistics, you are welcome to participate in my lab. This is also a good way to get started on an honor's thesis. • The grades are posted to Blackboard.
Brain & Language - Harry Howard - Tulane University Hickok & Poeppel’smodel on the brain Dorsal Ventral
Brain & Language - Harry Howard - Tulane University Mirror neurons Example of a F5 mirror neuron selectively discharging … during observation of a grasping movement done by the experimenter and during monkey grasping movements. Arrows denote the onset of the movement. Six trials are shown for each condition.
Brain & Language - Harry Howard - Tulane University Lateralization of phonology
Review of prosody • Prosody is the quality of spoken language that provides its melodic contour and rhythm, features which help the hearer to decode syntactic and lexical meaning as well as emotional content. • Prosody differentiates, say, the neutral statement of fact “It’s my fault” from the sarcastic question-like rejoinder “It’s MY fault?”. • Such distinctions are produced by variation in three parameters, which are borne in turn by three qualities of sound waves, respectively: As a first approximation, we can say that the RH is sensitive to pitch/fundamental frequency, while the LH is sensitive to higher frequencies, e.g. formants. Brain & Language - Harry Howard - Tulane University
Brain & Language - Harry Howard - Tulane University Prosody and the RH • It has been known since the 1970s that the right hemisphere dominates in the perception of prosody. Initial evidence thereof were the descriptions of lesions in the right hemisphere resulting in a pattern of aprosodias (deficits either in the expression or understanding of prosody) analogous to the well-documented pattern of left hemisphere lesions resulting in the various aphasias. • With respect to production, the speech of patients with right hemisphere lesions has been characterized as monotonous and unmodulated. For instance, Ross & Mesulam (1979) report a patient who had difficulty disciplining her children because they could not detect when she was upset or angry. She eventually learned to emphasize her speech by adding "I mean it!" to the end of her sentences. • With respect to perception, studies such as that of Tucker, Watson & Heilman (1977) asked people to identify semantically-neutral sentences that were intoned to convey happiness, sadness, anger, or indifference. Patients with RHD were impaired on both identification and discrimination of such affective meanings, in comparison to both healthy controls (NBD) and LHD.
Brain & Language - Harry Howard - Tulane University Names for RH prosodic impairments • Auditory affective agnosia (Heilman, Scholes & Watson 1975) • Aprosodia (Monrad-Krohn 1947, Ross 1981, 1993) • Dysprosody (Monrad-Krohn 1947, etc. p. 77) • ‘Prosodic impairments’
Brain & Language - Harry Howard - Tulane University Research on RH prosodic impairments • Assumptions that have guided research • RH prosodic deficits occur with intact sensorimotor & linguistic processes. • Emotional prosody is more affected than linguistic prosody. • RHD patients have problems in interpreting emotional material in other domains, such as facial expression and stories and scenes. • Prosodic comprehension deficits were thought to be unique to RHD. • Drawbacks • Subjects selected on basis of unilateral hemispheric damage and not prosodic deficits > subjects may or may not have prosodic deficits
Brain & Language - Harry Howard - Tulane University Emotional prosodic deficits with RHD • Perception • Impaired in discriminating emotions conveyed by a single hummed vowel. • Impaired in discriminating emotions after filtering to remove semantic content. • Comprehension • Reduced ability to discriminate and identify mood in neutral sentences presented without supporting context on the basis of prosodic contour. • Reduced ability to identify mood in sentences in which the meaning is incongruent with prosodic contour. • Production • “… a flattened, monotone pattern that is characterized by attenuated variation in stress, duration, and fundamental frequency.” (Duffy 1995) • Problems in matching prosodic contour to emotional content. • Reduced reliance on pitch variation to convey emotions. • Increased reliance on semantic information to convey emotions.
Brain & Language - Harry Howard - Tulane University Hypotheses about emotional prosodic deficits • Similarity to depression • result of alterations in subjective emotional experience; • but coming out of depression does not cure prosodic deficit. • General disturbance in encoding emotional behavior • co-occurs with reduced expressiveness of gestures and facial expressions.
Brain & Language - Harry Howard - Tulane University Kinds of linguistic prosody • Lexical and phrasal prosody, see next 2 slides. • Sentence type and prosodic contour. • Contrastive (or emphatic or focal) stress. • Determining whether two sentences are identical based on any of these stress patterns.
Brain & Language - Harry Howard - Tulane University Lexical prosody (CAPS mark stressed syllable) • Noun vs. verb in English (±15) • CONvert vs. conVERT • Thai, a tone language • naa with a rising pitch tone means “thick” • naa with a falling pitch tone means “face” • LHD (but not RHD) affects both of these rules
Brain & Language - Harry Howard - Tulane University Phrasal prosody • Compound noun rule • noun phrase:hot DOG (a dog that is hot) • adjective+noun: HOTdog (a frankfurter) • noun+noun: SHEEPdog (a breed of dogs) • Stress retraction • After eating fourTEEN,CAKES did not tempt him. • After eating FOURteenCAKES, he threw up. • LHD (but not RHD) affects both of these rules
Brain & Language - Harry Howard - Tulane University Contrastive (or emphatic or focal) stress [clausal prosody] • Examples • The horses were racing from the BARN. • The HORSES were racing from the barn. • LHD (but not RHD) affects this
Brain & Language - Harry Howard - Tulane University Sentence type and prosodic contour • Types • declarative: fall in pitch at end • I eat chocolate. • interrogative: rise for yes-no question (a); fall for interrogative pronoun (b) • Do you eat chocolate? • What do you eat? • imperative: even pitch throughout; rise in intensity at end • Eat chocolate! • RHD (but not LHD) reduces accuracy and variation in pitch
Brain & Language - Harry Howard - Tulane University Summary LH (preserved in RHD) RH (preserved in LHD) emotional prosody sentence type declarative, interrogative, imperative • lexical stress • CONvert ~ conVERT • tone languages • phrasal stress • noun compounding • stress retraction • clausal stress • contrastive stress
Brain & Language - Harry Howard - Tulane University NEXT TIME Q6 Theories of lateralization