PSY2002 SEMESTER 1 - WEEK 2 Flashcards
define bottom up processing
based on sensory input and built up to semantic understanding
define top down processing
semantic understanding paired to sensory inputs
is speech comprehension concious or not
not conscious, automatic
define prosodic cues
hints to sentence structure and intended meaning by pitch, intonation, stress, timing
outline processes in mental lexicon
- hear word “text”, access it in mental lexicon to gain understanding
- phonology breaks it down (tekst)
- activate relevant syntax (noun/verb)
- activate relevant semantic meanings
- represent an orthographic representation (how it looks)
name challenges to lexical access
- continuous speech stream (no gaps inbetween words)
- homonyms (money bank vs river banks) and homophones (aisle vs isle)
- co-articulation (need tongue dexterity, influenced by prior sentance phoneme0
- accent
- invariance problem
explain segmentation in relation to lexicon access
having to separate out phonemes and words from pattern of speech sounds
give example of a homonym
money bank vs river bank
give a example of homophone
aisle vs isle
why is coarticulation difficult
require tongue dexterity, also dependent on speakers pronunciation of prior phonemes, and next one
increases variability of speech signal but is a useful cue for predicting next phonemes
what is invariance problem
problems of definition of acoustic properties that can occur at phoneme, syllable or word level
name ways of solving challenges of lexical access “disambiguating speech streams”
- categorical perception
- segmentation
- perceptual learning
- top-down processing
explain categorial perception as method of solving challenges of lexical access “disambiguating speech streams”
ability to distinguish between sounds on continuum based on Voice Onset TIme
explain segmentation processes as method of solving challenges of lexical access “disambiguating speech streams”
breaking speech signals into consituent words, using cues and where speaker places stress, with 3 categories of cue:
lexical - syntax + word knowledge
segmental - coarticulation
metrical prosody - word stress
explain perceptual learning as method of solving challenges of lexical access “disambiguating speech streams”
adjust categorical perception based on sounds we hear. become accustomed to different VOT’s of our own language, pick up on sounds which are important to us
explain top-down processing as method of solving challenges of lexical access “disambiguating speech streams”
phonemic restoration effect to process missing phoneme as if it were present
what 3 lexical characteristics affect speed of lexical access
- word length: long words slow to process
- frequency: more frequently word are accessed in lexicon, quicker it can be accessed
- neighbourhood density: lots of neighbours, processed more slowly
outline the McGurk effect
mismatch between spoken and visual info leads listeners to perceive sound/word involving blending of auditory and visual info
when is McGurk effect strongest
when auditory input lags 100ms behind visual input, as lip movement used to predictively anticipate next sound
why is top down processing important for McGurk effect
effects stronger when crucial word formed by blending auditory and visual input presented in semantically congruent sentence
in summary what are lexical access based on
- bottom up= acoustic input
- top down= disambuguate speech streams
- lexical characteristics
- context
- spreading activation that facilitates predictions
outline Elman & McClelland TRACE model
predicts that features activate phonemes that activate words with gradual increase in activation of words that match all features so that word with most activations win
explain evidence for TRACE model
gradually activate matching word more than others eg; ei____ activate say and pay, then hear ei____pr and activate more like april, apricot
gradual activations of items which match input, also works with rhyming competitor = lexical competitive inhibition
explain why TRACE is a implemented computational model
based on connectionist principles
- processing units/nodes at 3 levels correspond to mental representations of features, phonemes, words
- still rely on bottom-up from acoustic input
- nodes influence each other according to their activation levels and strengths of connections
- activation develops as pattern of excitation from faciliations/inhibition
- candidate words activated based on activation patterns
- bottom up/top-down process
all activated word involved in competitive process to inhibit each other words
explain how TRACE involves nodes
nodes influences each other depending on activation level and connections strength
feature nodes are connected to phoneme nodes which are connected to word nodes