language - speech perception Flashcards
components of the mental lexicon
syntax
phonological
semantics
orthographic
challenges for lexical access (6)
- speech is a continuous stream
- Homonyms - Bank (£) versus Bank (river)
- homophones - Aisle vs Isle
- Co-articulation
- Different Accents
- Invariance problem - Problems of definition of acoustic properties - phonemes, syllables, words
ambiguity in speech stream - word boundaries comedy example
Four candles or Fork handles
disambiguating the speech stream - how word boundaries are distinguished (4)
Categorical perception
- Ability to distinguish between sounds on a continuum based on voice onset times
Voice Onset Time
* Vocal cord vibration – VVVVa vs FFa
Perceptual Learning
- Adjust categorical perception based on sounds we hear
- Seems to be hard-wired - babies and primates can do this
Top-Down Processing
- e.g. “The state governors met with their respective legislatures convening in the capital city.”
- cough disguising one sound in “legislatures” - top down processing allows us to recognise the word, and not identify which sound was blocked by the cough
spreading activation
predictions of what may be coming up next via activation of items that are related to the acoustic input
e.g. apple –> appeal, apron, apollo, apply
lexical characteristics - speed of lexical access (3)
word length –> long words = slower to process
neighbourhood density –> lots of neighbours = slower to process
frequency –> more frequently accessed words in lexicon = quicker access
5 things lexical access is based on
- Bottom Up - Acoustic input
- Top down processing - disambiguating the speech stream
- Lexical characteristics
- Context
- Spreading activation that facilitates predictions
3 options for mechanics of lexical access
- gradually activate the word that matches the acoustic input
- activate all words that start with the same sound as the acoustic input and gradually de-activate words that no longer match the sounds
- gradually activate the word that matches the acoustic input more than other words
mechanism of lexical access - 1. gradual activation of the word that matches the sound
different sounds can build up to a word
like phonics - breaks down a word
as the different sounds in the word are produced we gradually find the correct word
e.g. a –> ape –> april –> apricot
mechanism of lexical access - 2. activate all words that sound like the start of the word, then gradually deactivate non-matches
as word is said, sounds are processed as the word is built up
e.g.
a –> a, ape, april, apricot
ape –> ape, april, apricot
april –> april, apricot
apricot –> apricot
mechanism of lexical access - 3. gradually activate word that matches acoustic input more than other words
words with the sound in it - regardless of where it is in the word, not just at the start of a word
e.g.
a –> ape, pay, say, april, apricot
ape –> ape, april, apricot
april –> april, apricot
apricot –> apricot
2 models of speech perception
Marslen-Wilson. (1987) –>The Cohort Model
access words in the lexicon via activation of all words sharing initial features and gradually de-activate words that stop matching the features (option 2)
Elman & McClelland. (1999) –> The TRACE model
features activate phonemes that activate words with a gradual increase in activation of words that match all features so that the word with the most activation wins (option 3)
cohort model - lexical activation
activation of cohort that match the input
e.g. “ap-“ –> apricot, apex, apple, apart, april
then gradual deactivation of items that fail to match input
e.g. “apri-“ –> april, apricot
then find a uniqueness point - only one word activated
e.g. “apric-“ –> apricot
items that do not match the word onset are not activated (e.g. cot, prickly - match other word sounds within the word apricot)
neighbourhood effects in cohort model
words that match the acoustic input compete for activation
e.g. apricot and aprikol
learning “aprikol” slows down recognition of the word “apricot” because of this
frequency effects in cohort model
high frequency = high resting states = less activation required to recognise high frequency words
apricot would be recognised more quickly than aprikol (lower frequency word)