Speech and Hearing Sciecne - Chapter 11 Speech Perception

Hearing and Theories of Speech Perception

speech is rapid, continuous and ___ across speakers and context

VARIES

when giving out instructions as an SLP. what should you be mindful of ?

the clients preferred speech perception! And will that match the level of your speech production?

acoustic features are/are not invariant?

are not

different values of VOT could yield…

perception of voicing in plosives

different values of F2 steady states may yield perception of a particular vowel

minimal meaningful unit of speech that we process

phoneme

minimal meaningful unit by itself

morpheme

but are we processing a morpheme as a whole? not really

unit of analysis

features, phonemes, syllables, contextual variants of these units

there is a lack of clear____ between phonemes

segmentation

define normalization

process of simplification by smoothing out the variability or “noise” and the superfluous variability to get the essence of the signal.

is speech perception uniquely human?

think of your dog? it understands commands, so speech perception isn’t uniquely human.

categorical shift

aka quantum change - but not unique to speech

• like shade of colors ?

duplex perception

two components of one syllable

one phoneme is the base, the other phoneme is the chirp.

/da/ vs /ga/

the F3 formant to achieve /ga/ from /da/

• example of specialixzed percention

mcGurk effect

perceptual illusion

hear one thing and see a different thing. literally an illusion

contextual effect

experiment with sine wave speech. this is a pure tone freq. central frequencies of vowels are the only listened during speech.

how to understand the full text?

its called gating (separate experiment) - is when you hear word as successive fragments. requires 300ms of word identification. more fragments = better guess

recap ear anatomy (structures)

pinna

outer ear

TM

ear canal

malleus,incus,stapes

vestibuli

cochlea

hair cells

mechanical to electrochemical energy

main function of external ear

acoustic gain (frequency dependent)

main function of middle ear

impedance matching (overall gain)

main function of inner ear

tonotopic organization, intensity driven, temporal processing

main function of auditory neural pathway

continued speech processing, integration (binaural, audio visual)

conductive hearing loss

perceive the sounds diminished

reduced audibility

mechanical issue

sensorineural hearing loss

may perceive sounds diminished and distorted

frequency resolution challenges, altered loudness

theory of speech perception

bottom up theories- based on input. data driven. presented new info? probably bottom up.

top down theories - higher order information reliant

active theory (i obvi know what an apple is) vs passive theory (i’m using context clues to guess what you’re inferring) based on cognition and interpreting the acoustic signal

autonomous theory - doesnt rely on contextual factors

interactive theory - DOES rely pn contextual facotrs

MOTOR THEORY ( for speech perception)

based on invariant aritculatory gestures. not actual articulation, but the motor program /command for production.

speech perception is specialized. lack of invariance doesnt matter for this theory!

THIS IS TOP-DOWN THEORY

Analysis by synthesis - matching features to a basic unit such as a syllable

• there is something called “synthesis by analysis” - it is the opposite (bottom up)

motor theory states that

we perceive speech because our motor programs are active

mirror neurons: - in the premotor cortex theres a network of neurons representing a motor action activated when we see an action

• ie: we see someone jumping, motor plans in our brains register the jumping.

what is a problem in motor theory

there will always be a difference between seeing and speaking

specifics is not established

acoustic landmarks and distinctive features theory

acoustic driven

relies on both input characteristics and stored knowledge

imput processing yields landmarks dections

• landmarks are constriants

3 types of landmarks

1. vocalic

2. glide

3. consonantal

articulator free

the motor theory of speech production is an exclusively bottom-up theory of speech perception. (t/f)

f

speech perception in babies

can change based off of environment, stage of development.

2 types of research for babies

• reaction of stimuli

• new reaction to different stimuli

motory theory problems with speech perception in babies

no stored information in babies! what then?!

we assume motor programs are innately present.

native language magnet theory

incoming stimuli help strengthen their neural maps. sensory drives motor learning.

exposure creates better maps

what is extralinguistics

indexical information

information derived from other aspects of language- lexical semantics, pragmatics, morpho-syntaxindex

indexical info might not be

accurate

listening to speech sample and trying to assume the person”s gender dialect, social status are examples of this!

which features would be relevant for indexical information that may be derived using properties of a speech signal?

• accentedness

• gender

• race

all of these