Week 8 - Speech & Language Flashcards
Hearing
Stimulus- sound waves
Amplitude & loudness:
High- big sound waves & loud sounds (SHOUTING)
Low- small sound waves & low sounds (WHISPERING)
Frequency & pitch:
High - many sound waves close together & high pitch
Low- few sound waves far apart & low pitch
Complexity & timbre:
A mixture of frequencies reflects a sound’s quality or character. A sound’s complexity reflects its timbre
Direction of sound:
Brain automatically determines this by calculating the slight difference in the time that it takes the sound waves to reach the two ears.
Sound localisation
Echolocalisation
Complexity
Identifying the source of the sound waves
Identifying the location of the sound waves
Detect and interpret complexity of the sound waves to enable speech & music perception
Language
Definition
A form of communication that involves learning complex rules to make & combine symbols into meaningful sentences
Language - knowledge
Schema theories
Schemas are organised packets of information stored our memory about the world, events, or people
Schemas allow us to form expectations & they influence comprehension
Language - knowledge
Schema theories - Bartlett’s theory
Schemas play an important role in determining what we remember from stories
Conflict between presented story and relevant prior schematic knowledge
Rationalisation: tendency to produce errors in the recall of stories that conform to the cultural expectations of the rememberer
(Up) Errors (up) retention interval
Language - knowledge
Kintsch’s construction-integration model
Propositions (that convey meaning of text) are constructed from each sentence
Each proposition leads to retrieval of associated propositions form long term memory
The two combine to form an elaborated propositional net
Spreading activation process selects propositions for text representation. Clusters of highly interconnected propositions attract the most activation & are more likely to be included in the text representation (episodic text memory). Irrelevant ones are discarded. This is the integration process.
Three levels of representations:
- surface representations (the text itself)
- propositional representations
- situation representation (deep, conceptual, pragmatic, inferences)
ELAN: syntactic violations
ELAN (early left anterior negativity):
Indexes violations of syntax and grammar
N400: semantic violations
N400:
Indexes violations of word meaning & world knowledge
Speech production
McGurk Effect
A video shows a person repeating the sound gah
An audio plays the sound bah
Neela says to the waiter, “I take coffee with cream and smog.”
Which ERP would be evoked for the type of language error in that statement?
A.MMN
B.N1
C.ELAN
D.N400
D. N400
Speech perception
Ganong effect
Shows that word recognition processes use lexical information to guide perception when the speech signal is underspecified.
•Ganong (1980) constructed speech segments were to be ambiguous.
e.g., a sound designed to be acoustically
intermediate between /g/ and /d/
- A pair of test items that began with this ambiguous stop consonant, with one member of the pair having “ulf” appended, and with the other member of the pair ending in “usk.” Listeners reported hearing “gulf” rather than “gusk” and “dusk” rather than “dulf”
- Perception of the ambiguous segment is biased toward a sound that produces a word rather than a nonword.
The phonemic restoration effect, the Ganong effect, and the McGurk effect all show that speech perception cannot be understood solely in terms of the mapping between an acoustic (or gestural) event and a phonetic percept; speech perception is also guided by additional information sources available to the perceiver.
Speech perception
Dual route model
Dorsal stream:
Translating acoustic-based representations of speech signals into articulatory representations essential for speech production.
Ventral stream:
Processing speech signals for comprehension and meaning.
Speech production
Classic model: wernicke-lichtheim-geschwind (WLG)
Shared neural circuitry
Broca’s area - Speech production
Wernicke’s area - Speech comprehension
Shared neural circuitry
Unification
Indicates the real-time assembly of the pieces retrieved from memory into larger structures with contributions from context.
●Unification operations take place at the syntactic, semantic and phonological levels. Conceptual and lexical elements are combined and integrated into larger structures.
Which sentence is more difficult to understand?
“The reporter who the senator attacked admitted the error”
“The reporter who attacked the senator admitted the error”
The increased difficulty to understand (semantic) is due to differences in the structure of object and subject relative clauses (syntax).
Unification refers to the ongoing combinatorial operations in language, which include both context-driven predictions and integration of the lexical information into a representation that spans the whole utterance.
●Predictions work forward in time, whereas integration works backward in time; in the latter case, information is integrated into a context that preceded the currently processed lexical item.
Aphasia
Aphasia is an impairment of language, affecting the production or comprehension of speech and the ability to read or write.
●Aphasia is always due to injury to the brain-most commonly from a stroke, particularly in older individuals.
●Brain injuries resulting in aphasia may also arise from head trauma, from brain tumors, or from infections.
MIDDLE CEREBRAL ARTERY
Stroke (Arterial Blockage/Bleeding)
Symptoms - Disorders of Production
Poor articulation, anomia/ problems with word finding, paraphasia / unintended words / phrases, loss of syntax / grammar, inability to repeat aural information, low verbal fluency.
Symptoms - disorders of comprehension
Poor auditory comprehension, poor visual comprehension
