英语语言学课件Chapter 15 Language and the Brain

The Critical Period
• lateralization: the apparent specialization of the left hemisphere for language • The lateralization process begins in early childhood • During childhood, there is a period when human brain is most ready to receive and learn a particular language
Dichotic listening test
• An experimental technique: the language functions must be located in the left hemisphere • Basic assumption: a signal coming in the right ear will go to the left hemisphere and a signal coming in the left ear will go to the right hemisphere • right ear advantage • The right hemisphere handles non-verbal sounds and the left hemisphere handles language sounds
Aphasia
• Conduction aphasia: damage to the arcuate fasciculus • No articulation problems • Fluent, but may have disrupted rhythm because of pauses and hesitation • What is heard and understood cannot be transferred to the speech production area
Tongue tips and slips
• Tip-of –the tongue: you know the word, but it just won’t come to the surface • Slip-of-the tongue: results in tangled expressions • Slip-of-the ear: errors in hearing
Parts of the Brain
• Wernicke's Area: responsible for speech comprehension (close to auditory areas) • The motor cortex: controls the movement of the muscles for articulation • The arcuate fasciculus: a bundle of nerve fibers connecting Broca’s area and Wernicke's Area
Genie’s case
• In 1970 • 13 year old girl, spent most of her life tied to a chair in small closed room • Physical, sensory, social emotional deprivation • After brought into care, she developed an ability to speak and understand a fairly large number of English words • Provides some evidence against the notion that language cannot be acquired after the critical period • The remarkable fact: Genie was using the right hemisphere of her brain for language functions
Parts of the Brain
• Two nearly symmetrical halves, the right and left hemispheres • Corpus callosum: a bundle of nerve fibers, connecting the two hemispheres • cortex: supports "higher" brain functions, including language ; thin, folded sheet on surface of brain • Broca’s area: responsible for speech production (close to motor arimpairment of language function due to localized cerebral damage which leads to difficulty in understanding and/ or producing linguistic forms • Broca's Aphasia • Identified 1861 by Paul Broca, a Parisian neurologist • Also called ‘motor aphasia’ • Characterized by a substantially reduced amount of speech, distorted articulation and slow, often effortful speech
Aphasia
- Wernicke’s aphasia -Identified 1873 by Carl Wernicke, eminent German neurologist -Results in difficulties in auditory comprehension -also called ‘sensory aphasia’
The localization view
• Specific aspects of language ability can be accorded specific locations in the brain • Other views • - ‘pathway’ metaphor • -Freud’s ‘steam engine’ metaphor • -Aristotle ‘cold sponge’ metaphor
Chapter 15
Language and the Brain
Neurolinguistics
• The study of the relationship between language and the brain • The case of Phineas Gage: a huge metal rod had gone through the front part of Mr. Gage’s brain, his language abilities were unaffected