Ling/Psyc 370B, Biological Bases Lecture #5 & #6

Biological Bases of Language

• Course Title: LING/PSYC 370B
• Dates: January 20th & 23rd
• Instructor: Gabrielle Manning

Roadmap

• Characteristics of human language
• Language creation & input
• Animal communication
• Genetics & neural bases

Characteristics of Human Language

• Species-specific: Only humans have language.
• Species-general: All communities and individuals within a community have language.

Hockett's Design Features

• Vocal-auditory channel: Language produced through the vocal tract is perceived through the auditory channel.
• Broadcast transmission and directional reception: Listeners can identify/receive signals.
• Rapid fading: Speech sounds fade quickly.
• Interchangeability: People can send and receive the same message.
• Total feedback: Internalization of a message, control, and adjustment of the message.
• Specialization: Language sounds are purely for communicative purposes.
• Semanticity: Associations between language units and places/people/things.
• Arbitrariness: Associations between language and the world are arbitrary.
• Discreteness: Language units are distinct; every language has a limited number of sounds (between 10-100).
• Displacement: Language can be used to communicate about things/places/people that are not present.
• Productivity: Novel messages can be created from discrete units.
• Cultural transmission: Language is learned through communicative interaction with others.
• Duality of patterning: Combination of different sounds (with no intrinsic meaning) to create words that convey meaning.
• Reflexiveness: Language can be used to describe or refer to language.
• Learnability: Language users can learn a second, third, or fourth language.
• Prevarication: Language can be used to make false statements, intentionally or unintentionally.

Animal Communication

• Animals communicate with one another in various ways.
• Despite sharing some features, animals do not have language.
• Examples of animal communication include the honeybee waggle dance and vervet monkey alarm calls, and ape communication using tools, which, in some cases, shows some degree of displacement.

Ape Communication

• Washoe (first non-human to learn sign language): Knowledge of ~350 signs; use of productivity.
• Koko: Sign language training at age 1; knowledge of >1000 signs; use of productivity.
• Kanzi: Uses keyboard with lexigraphs; understands complex syntactic sentences (e.g., "put the soap in the water," "click here to see"). Shows use of displacement and other complex communication.

Language Input & Creation

• Humans use cultural transmission to help with language learning

• Children deprived of language input can create properties of language.

• Examples include Pidgins and creoles

• Homesign: A gestural communication system created by a deaf person to communicate with others who do not know sign language.

• Nicaraguan Sign Language: A shared homesign system created from traditional transmission, undergoing generational progression. Younger students altered the system for more fluent expression and compact gestures.

Pidgins & Creoles

• Pidgins: A form of communication using lexical items from each language, creating a new grammar. Structurally simple (e.g., Russenorsk).
• Creoles: A pidgin that becomes a native language; a more grammatically complex version that provides information on the biological bases of human language.

Homesign

• A gestural communication system created by a deaf person to communicate with others who don't know sign language.

Nicaraguan Sign Language

• Younger students learned the system from older students, altering the system to be more fluent, creating more compact gestures. Benefited the most from structured input in terms of language learning.

Critical Period Hypothesis

• Critical period: When children appear to have an easier time learning language.

• "Wild" children: Socially isolated children (e.g., Victor of Aveyron, Genie), often have difficulty learning language.

• Late acquisition: Children who are born to hearing parents and learn ASL later in development can have limitations in their language ability compared to those who learn sign as infants.

• Sensitive/Optimal period for language learning? Is it a definite clear start and end point?

• Length? 5, 7, 13 years? Is all language learning equal? How about adult second language acquisition? Evidence and more questions about this ongoing research.

Genetics & Neural Bases

• Fun facts about the brain: The brain weighs approximately 3 pounds, a grain-of-sand sized piece of brain tissue could contain around 100,000 neurons, there are about 100 billion interconnected neural cells, and the brain is always active.

• Neurolinguistics: the study of how the physical brain relates to language behaviour.

• Specific language impairment (SLI): atypical language development without neurological damage, cognitive impairment or hearing issues, often leading to late speaking and ungrammatical sentences. Genetic component is strongly suspected.

• Hereditary component: example of FOXP2, a gene known to have a strong hereditary component impacting language learning, production, and grammar.

• Broca's area: A region of the frontal lobe, implicated in speech production and grammatical structure. Damage here leads to fragmented speech and difficulties. Case-study of "Tan".

• Wernicke's area: A region of the temporal lobe, implicated in language comprehension. Damage here leads to difficulties with comprehension while speech may be fluent but nonsensical.

• Aphasia: Language disruption (comprehension & production) caused by brain damage

• Broca's aphasia: Difficulty with word choice, halting speech, but intact comprehension.

• Wernicke's aphasia: Nonsensical but well-articulated fluent speech, difficulty with language comprehension.

• Possible causes of aphasia: stroke, trauma, head injury, tumor, overactive immune system.

• What about signed languages? • ASL patients show characteristics of Brocas and Wernickes' aphasia, but language is still expressed via hand movements, signifying a similar brain structure and function is present; further study needed.

Lateralization

• Brain lateralization: brains tend to specialize into hemispheres for different functions; impairment in language with damage to left-hemisphere indicates language exists in one side of the brain, providing evidence of lateralization.
• Supported by split-brain patients and healthy brain dichotic listening.

Separate Knowledge Systems

• Double dissociation: Evidence for two independent mental processes.
• Tasks (e.g., speech perception and word recognition) recruit different networks.