lecture 4 - speech perception

Question 1

comprehension skills =

Answer 1

reading (visual word recognition)

Question 2

speech perception harder than reading because…

Answer 2

greater memory demands
ambiguous signal
harder to segment
transitory (not permanent)

Question 3

categorical perception

Answer 3

an abrupt boundary between categorisation of 2 phonemes and stimuli that intermediate between the 2

Question 4

decoding =

Answer 4

extracting discrete elements (phonemes or sounds)

Question 5

5 stages of speech perception

Answer 5

1) decoding
2) phoneme/syllable identification
3) word identification
4) interpretation
5) meaning of current sentence is integrated with preceding speech to construct overall message

Question 6

Mattys et al: 2 types of adverse conditions =

Answer 6

1) energetic masking = distracting sounds cause intelligibility to be degraded (other voices/noise)
2) informational masking = cog load makes speech perception harder (affects top-down processing)

Question 7

co-articulation

Answer 7

pronunciation of phoneme depends on preceding and following phonemes e.g. ‘bill, ‘rub’ - increases variability in signal BUT allows you to predict next phoneme
more co-articulation within words than between them

Question 8

assimilation

Answer 8

phonemes take on acoustic properties of neighbouring phonemes

Question 9

stress

Answer 9

in English, initial syllable of most words is stressed - strings of words without initial stress are misperceived

Question 10

Mattys et al’s Hierarchical approach to segmentation: 3 categories of cues

Answer 10

1) lexical (syntax, word knowledge or semantics) - optimal interpretative conditions
2) segmental (e.g. co-articulation) - poor lexical info
3) metrical prosody (e.g. word stress) - poor segmental info
(LSM - i love matty so much)

Question 11

McGurk effect

Answer 11

when watching someone say /ga/ with sound /ba/ we hear /da/
multimodal perception - relying on speech - triggered by automatic bottom-up proces triggered by discrepant visual and auditory signals
effect is stronger when crucial word is presented in semantically congruent way

Question 12

2 extreme positions of context effects

Answer 12

‘interactionist account’ = context affects processing at early stage & influences word perception
‘autonomous account’ = context affects later processing - can only contribute to evaluation and integration of lexical processing not its generation

Question 13

phonemic restoration effect (context effect)

Answer 13

evidence that sentence context can influence phoneme perception e.g. phoneme replaced with a cough - perception of that word was influenced by the sentence it was in

Question 14

Ganong effect (AKA lexical identification shift) (context effect)

Answer 14

tendency to perceive ambiguous sound as a phoneme that would complete a real word rather than completing nonsense words

Question 15

TRACE model (McClelland & Elman)

Answer 15

bottom-up and top-down pricessing interact flexibly in word recognition - all sources of info are used at same time

Question 16

TRACE model assumptions:

1) there are prcessing units/nodes at 3 different levels:

Answer 16

1) features (voicing/manner of production); 2) phonemes; 3) words
feature words are connected to phoneme nodes which are connected to word nodes - connection between nodes operate in both directions and are always facilitatory
connections between nodes at same level = inhibitory & bidirectional (once a unit is activated it inhibits its competitors)
nodes influence each other in the strength of their interconnections

Question 17

TRACE model: process

Answer 17

as excitation and inhibition spread across nodes, a pattern of activation develops
the word identiied = determined by activation level of possible candidate words

Question 18

TRACE model: bottom-up and top-down activation

Answer 18

bottom-up activation = proceeds upwards from feature level to phoneme to word level
top-down = from words to features

Question 19

activation from word level to phoneme level would facilitate phoneme detection =

Answer 19

word superiority effect (evidence for top-down processing)

Question 20

TRACE model can explain Ganong effect

Answer 20

top-down activation from word level is responsible

Question 21

TRACE model can explain categorical perception

Answer 21

discrimination boundary becomes sharper because of mutual inhibition between phoneme units at phoneme level - one phoneme becomes increasingly activated whilst others become inhibited (evidence for top-down processing)

Question 22

TRACE model criticisms

Answer 22

1) attaches excessive importance to top-down processes (mispronunications have strong negative effect)
2) may be too flexible to be tested
3) model was tested only on small set of short words and is yet to be tested on more complex vocabularies

Question 23

TRACE model support

Answer 23

1) copes well with noisy input (emphasis on top-down)
2) accounts for:
Categorical speech perception
Lexical identification shift
Word superiority effect in phoneme naming
Word frequency effect

Question 24

Cohort model (Marslen-Wilson & Taylor) - 3 stages

Answer 24

focus more on bottom-up processes
3 stages:
1) access stage (all words conforming to sound sequence so far become active = the cohort)
2) selection stage (words are eliminated if cease to match further info from presented word or inconsistent with context)
3) integration stage (semnatic and syntactic properties of chosen word are used to integrate it into sentence

Question 25

uniqueness point (cohort model)

Answer 25

point when only one word is consistent with accoustic signal

Question 26

parallel interactive processing (cohort model) =

Answer 26

various sources of info are processed in parallel, allowing for their interaction

Question 27

isolation point (cohort model) =

Answer 27

point in a word where proportion of listeners identify word correctly but may not be confident about it (typically earlier than uniqueness point - biased by context)

Question 28

lexical access (cohort model) =

Answer 28

point at which all info about a word becomes available following recognition

Question 29

integration (cohort model) =

Answer 29

at start of comprehension process, proper, semantic and syntactic proerties are integtrated into higher level sentence representation

Question 30

revised cohort model:

Answer 30

words vary in their activation
original = context influences selction stage; revised = context only influences later integration stage (greater emphasis on bottom-up)
Word-initial cohort may include words with similar (rather than exact) matches to the initial phoneme

Question 31

shadowing task (cohort model) =

Answer 31

pps listen to speech containing distortions & repeat it back
50% of the time participants repeat back as it should be, without the distortion
Most frequent when distortion was slight, on final syllable and word predictable from context

Question 32

Listening for mispronunciations task (cohort model) =

Answer 32

pps listen to speech where a sound is distorted & detect changes
Participants are more sensitive to changes to the beginning of the words (e.g., poot – boot)

Question 33

common ground and egocentric heuristic

Answer 33

we make more use of common ground when talking to people we are familiar with than listening to strangers