EXAM 3: Biological Foundations of Language Flashcards
Language for humans
Is universal
Humans can’t help but do language (typically)
Language creation shows that language is intrinsic. Humans create their own if there is no model to learn from
Nicaraguan Sign Language
A complete and complex language system developed by deaf Nicaraguan children at a school for the deaf
The children each had their own home signs, but no shared language within the school
Home signs
Signs deaf children used at home for their specific familial communication purposes
NSL Study
Question:
How did this complex language system develop?
Study:
Examined verb-agreement inflections (i.e. -ed, -s) and year of entry to school and age
1st factor: Generation
Before 1983 (1st cohort)
After 1983 (2nd cohort)
2nd factor: Age
Young, old, middle
Results:
Younger learners produced more inflections in both cohorts
Later cohort used more inflections in general compared to early cohort
New inflections and changes/advancements to language comes from young language learners
Children are the engines that drive language creation as NSL has become richer over the generations as newer gen acquires it
Universal phenomena: Gen Z/Alpha lingo
Hudson Kam and Newport (2005)
Question:
Can children acquire consistent, accurate and systematic language from inconsistent/corrupt input?
Study:
Taught an artificial language to both adults and 5-7 year old children
Language is consistent, but has some inconsistent patterns with determiners
Determines change depending on whether it is a countable noun or mass noun
Participants for both adults and children split into 2:
1st group: Exposed to determiners correctly only 60% of the time, the rest 40% were either omitted or incorrect (60% group) (inconsistent and variable/omitted)
2nd group: Exposed to determines correctly 100% of the time (100% group) (consistent and invariable)
Results:
Adults: those in the 60% group did not produce determiners reliably, could only produce it correctly if they were exposed to it correctly 100% of the time
Children: Those in 60% group although slight different, was able to use the language reliably
Even if input is correct, many still produced the correct system reliably
Conclusion: Children and adults learn from input in different ways, most notably that children can learn the correct language system from incorrect input
Cerebral cortex
Outer layer specializing in higher mental functions and localization
Front, temporal, parietal, occipital
Front: Executive function, motor and planning
Temporal: Hearing and understanding
Parietal: Sensing
Occipital: Vision
Lateralization
Left/Right hemisphere?
Different hemispheres of brain in charge of different functions
Localization
Where in the brain specifically is the function?
I.e. frontal, parietal, temporal, occipital
Functional Asymmetry (Lateralization)
Asymmetry of functions between 2 hemispheres
One hemisphere is more important/involved for particular function
Left hemisphere: Language
Right hemisphere: Visual-spatial
Milner (1977)
Normal speakers:
Right handed: left-hemisphere
Left handed: Left hemisphere dominant but bilateral ~10% right
Left hemisphere damage:
Right handed: left dominant but bilateral with right ~10%
Left handed: left 20%, bilateral 10%, right 50%
Results:
Shows the potential to recover from left hemisphere damage by letting right side take over
Especially for children with high neural plasticity
Weniger D. (2001)
Question: What is the lateralization functions?
Study:
3 different tasks:
1. Semantic (is dog an animal?)
2. Lexical (is “buv” a word?)
3. Complex visual tasks (Does “A” have an enclosed space?)
Slight error: Cannot be solely visual, understanding the question is already lexical/semantic!
Results:
Left hemisphere more active during lexical processes
Right hemisphere and left hemisphere involved in semantic processes
Suggests right hemisphere involvement in language, especially semantics (probably because semantics is more challenging/complex)
Lambertz (2010)
Question:
What does lateralization look like for infants?
What do infants prefer? nonspeech? speech?
Study:
Used fMRI to study organization of brain activity in 2 month olds when listening to 3 different stimuli:
1. Music
2. Mother speech
3. Stranger speech
Results:
Lateralization of brain:
Left for speech, right was not speech/very little speech
Infants brain as young as 2 month old was lateralized to the left for speech
Preferred speech over nonspeech; more brain activity for speech sounds
Preferred mother speech over stranger speech
Contralateral Function
Each part of the brain responds to the opposite side of body (contralateral)
i.e.
Left eye stimuli processed in right hemisphere
Right eye stimuli processed in left hemisphere
Split brain patients
No corpus callosum that bridges the 2 hemispheres
Each hemisphere acts individually with the info that they receive contralaterally
No sharing of information from hemispheres
Meaning, if info was received from right eye, it will ONLY go to left hemisphere and VV
Split brain patient task 1
See a word on the RIGHT vision field with RIGHT eye
Processed by LEFT hemisphere
left hemisphere in charge of language
patient can say the word
Split brain patient task 2
Sees a word in the LEFT vision field by the LEFT eye
Processed by RIGHT hemisphere
Right hemisphere not in charge of language
Although they knew the word, they cannot say it
Left hemi (lang) has no idea what’s going on because stimuli is not shared
BUT they can draw the word since that is a right hemisphere function
Split brain patient another task
A word is separated from left and right vision field (HE/ART)
“ART” only perceived by right eye, processed in left hemisphere, left can say language, says “ART” only
“HE” only perceived by left eye, processed in right hemisphere, cannot say language, says “ART” only
Split Brain conclusion
Inability to verbally indicate whenever stimuli is perceived on left side and processed in right hemisphere
Right cannot speak
Left can speak only if it knows the stimuli
Provides evidence for left hemisphere dominance in language
Aphasia
Impairment of language, usually caused by left hemisphere damage to either the broca’s or wernicke’s area
Broca’s area
Left frontal
Speech production (motor/planning) in frontal lobe
Wernicke’s area
Left temporal
Speech understanding and comprehension in temporal lobe
Broca’s aphasia
Difficulty with producing motor speech
lacking:
grammatical structure, morphemes, syntax, and difficulty producing speech
Damage to frontal left hemisphere
SEAT OF GRAMMAR
Broca’s aphasia: Cookie theft picture
Asked a patient with broca’s aphasia to describe a picture of children stealing jar of cookies
Characteristics of response:
Lots of pauses “…”
produces individual words, no syntax or grammar
But seems to know the meaning/semantics of words
Difficulty producing
Wernicke’s aphasia
No difficulty producing speech, but speech makes no sense
Very fluent speech with no pauses and any syntactic/grammatical errors
but nonsense
Inability to “understand” what they are saying/hearing disregarding what they think they understand
Doesn’t realize that there is a problem since they don’t understand what they’re saying makes no sense – it makes sense to them
Grammatically fluent but lexically incomprehensible
Damage of left temporal
SEAT OF MEANING
Development of left hemisphere specialization
Question:
When does left hemisphere specialization develop? Was it always the left or does it develop with maturity?
Equipotential hypothesis
Left is NOT specialized for language at birth
Left and right have EQUAL potential to specialize, but left specializes with development
IF this is true, children should have different lateralization that adults and lateralization should change with development
Invariance hypothesis
Left specialization for language since at birth
Lateralization does not change with development
If this is correct, children should have the same lateralization as adults
Evidence for Invariance hypothesis
Lambertz (2010) study
Children at 2 months old use left hemisphere more for speech, but 2 months old is NOT at birth
Evidence for equipotential hypothesis
Szaflarski (2006)
Question:
How does lateralization develop?
Study:
Asked 170 individuals ranging from 5-67 years old to do verb generation task and used fMRI to see lateralization
Results:
Language lateralization proportion consistent from young to old
But differing degrees of involvement of hemispheres
Language lateralization of left increases from 5-20 years, plateaus, then decreases with age
Supports the equipotential hypothesis as it shows LH lateralization with development
Plasticity
Ability of different parts to take over function, the malleability of the brain
Children have high neural plasticity, which is why they can recover language even after left hemi damage (right takes over) faster
Critical period hypothesis
Biologically determined period where language acquisition must occur if it will ever
Nim Chimpsky
Was taught ASL
Could do 100 signs and sign combinations
Problems:
MLU constant 1-1.6 signs
No increase of MLU with development
Long utterances were repetitions, not more complex/content
Followed the instructor’s sign more often than not
Not conversational, limited signs, lack of syntax/reference
Almost no grammar
Conclusion: Chimps cannot acquire human language
