Brain and Language

Islamic Azad University-NajafabadIsfahan

Saeedeh Shafiee2016

Outline

Brain’s anatomy

Aphasia

Brain lateralization

Split Brains

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LEFT HEMISPHERE OF HUMAN BRAIN (Heny 639)

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LEFT HEMISPHERE(Fromkin Rodman Hyams)

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Figure 16-1

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CORPUS CALLOSUM

With the corpus callosum intact, the two halves of the body have

no secrets from one another. With it sectioned (as in severe

epilepsy), the two halves become two different conscious

mental spheres, each with its own experience base and control

system for behavioral operations…. Unbelievably as this may

seem, this is the flavor of a long series of experimental studies

first carried out in the cat and monkey.”

(Fromkin Rodman Hyams)

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Cerebral Lateralization of Function

Major differences between the function of the left and right cerebral hemispheres

The two Cerebral hemispheres communicate through the corpus callosum

Split-brain patients – what happens when the connections are severed?

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Cerebral Lateralization of Function

Aphasia

deficit in language comprehension or production due to brain damage –usually on the left

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Aphasia

Broca’s area – production– Damage > expressive aphasia, agrammatic

– Normal comprehension, speech is meaningful – but awkward

Wernicke’s area – comprehension– Damage > receptive aphasia

– Poor comprehension, speech sounds normal – but has no meaning – ‘word salad’

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BROCA’S APHASIA

“Cookie jar…fall

over…chair…water…empty…ov…ov…[Exami

ner: “overflow?”] Yeah.”

(Heny 637)

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People with Broca’s aphasia sometimes substitute synonyms of

the words they mean: freedom for liberty, parrot for canary,

overseas for abroad, long for large, small for short, long for tall.

Or they may substitute the word in its wrong grammatical

category: decision for decide, concealment for conceal, portrait

for portray, bath for bathe, dliscussion for discuss, and memory

for remember.

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BROCA’S APHASIA IS LIKE

TELEGRAPHIC SPEECH

Compare the Following:

Broca’s Aphasia

Children’s Language

Tarzan’s Language

The Lone Ranger’s friend Tonto’s Language

Genie’s Language

The Language of a Telegram

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WERNICKE’S APHASIA

Well, this is…mother is away here workingout

o’here to get her better, but when she’s

working, the two boys looking in the other

part. One their small tile into her time here.

She’s working another time because she’s

getting, too.”

(Heny 638)

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People with Wernicke’s aphasia might use sentences like these collected by Harry Whitaker:

There is under a horse a new sidesaddle.

In girls we see many happy days.

I’ll challenge a new bike.

I surprise no new glamour.

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Dyslexia

Dyslexia – reading difficulties

Developmental dyslexia – apparent when

learning to read

Acquired dyslexia – due to brain damage

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Copyright © 2006 by Allyn

and Bacon

SLIPS OF THE TONGUE, EAR, PEN,

AND HAND

In 1973, Victoria Fromkin edited an important book entitled Speech Errors as Linguistic Evidence.

In 1980, she edited another important book entitled Errors in Linguistic Performance: Slips of the Tongue, Ear, Pen, and Hand.

Fromkin shows how slips of the tongue, ear, pen and hand (in signing) give important insights into the way the human mind works.

TOT: “Tip of the Tongue” Phenomenon: Sometimes when we are searching for a word in our brain, we come up with a near miss. The wrong word sounds like, scans like, or has a similar meaning to the right word:

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SIGMUND FREUD

Sigmund Freud said that slips of the tongue often are evidence

of people’s subconscious desires, as when the President of

the Lower House of Parliament opened a meeting by saying:

“Gentlemen, I take notice that a full quorum of members is

present and herewith declare the meeting closed.”

(Nilsen & Nilsen 8)

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Brain Lateralization and Plasticity

Evidence for plasticity and lateralization

• Hemispherectomy

• Split-Brains

• Dichotic listening

• Event-related bran potentials

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The Split Brain

Corpus callosum– Transfers learned information from one hemisphere

to the other

– When cut, each hemisphere functions independently

Studying split-brain and monkeys– transect corpus callosum and optic chiasm so that visual information can’t cross

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RIGHT-BRAIN SPECIALTIES:

Synthetic and Creative Activities

Holistic Processing, Gestalts, and Overall Patterns

Spatial Relations

Nonspeech Sounds

Music Appreciation

Emotion

(Heny 643)

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LEFT-BRAIN SPECIALTIES:

Analytical Processing

Temporal Relations

Speech Sounds

Mathematics

Intellectual Activities

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Dichotic listening

Verbal and nonverbal stimuli

Event-related bran potentials

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THE CRITICAL AGE FOR

LANGUAGE LEARNING

For human babies, the brain is very flexible, and the left hemisphere is not dominant. By the Critical Age, the left hemisphere is dominant and Broca’s area and Wernicke’s area become less adaptable to new language stimuli.

(Heny 649)

“The critical-age hypothesis assumes that language is biologically based and states that the ability to learn a native language develops within a fixed period, from birth to middle childhood.”

(Fromkin Rodman Hyams [2007] 53)

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Autonomy of language

Specific language impairment

Savants

Genetic disorders

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Theories about the Origin of Language

Otto Jespersen (1921):

Human language originated while

human beings were enjoying

themselves

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The Divine Source Theory

In most religions: divine source provides

humans with language

Genesis (2:19): God created Adam and

‘whatsoever Adam called every living

creature that was the name thereof‘

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The Divine Source Theory

Hindu:

Language comes from goddess

Sarasvati, wife of Brahma, creator of

the universe

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Experiments

Egyptian pharaoh Psammetichus (600 B.C)

two new-born infants

two years in the company of a mute shepard

Phrygian word: bekos (meaning bread)

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Experiments

James IV of Scotland:

similar experiment

children were reported to have started

speaking Hebrew

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The Natural Sounds Source Theory

Hypothesis: primitive words are

imitations of the natural sounds which

early man and women heard around

them

E.g.: object flew by cuckoo

soundname cuckoo

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The Natural Sounds Source Theory

Explanation for onomatopoe(t)ic words:

splash, bang, boom, rattle, buzz, hiss

Also called bow-wow (Wauwau) theory of language

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The Natural Sounds Source Theory

Natural cries of emotion: pain, anger, joy:

e.g. ouch

Yo-heave-ho theory: sounds of a person involved

in physical effort e.g. when lifting trees or

mammoths

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The Oral Gesture Source Theory

hypothesis: link between physical gesture and

orally produced sounds

developed by Sir Richard Paget (1930)

movement of the tongue when saying goodbye

resembles movement of waving of the hand

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Physiological Adaptation Theory

physical features of human beings:

good clues for their capacity for speech

human teeth: upright, even in height

human lips: flexibility, needed for sounds like p,b

and w

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Physiological Adaptation Theory

human larynx (Kehlkopf): position lower than with

monkeys

longer cavity called pharynx (Rachenhöhle)

acts as resonator

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Physiological Adaptation Theory

human brain: lateralized

has special functions in each of the two hemispheres

left hemisphere: analytic, tool using, language

right hemisphere: holistic, music, visuo-spatial skills

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