21 - Models and Theories of Speech Perception

Question 1

What are the 3 main categories of speech perception theories?

Answer 1

Active vs Passive
Bottom-up vs Top-Down
Autonomous vs Interactive

Question 2

How do active and passive speech perception theories differ?

Answer 2

Active - link between speech production and speech perception
Passive - passive sensory processes

Question 3

How do bottom-up and top-down theories differ?

Answer 3

Bottom-up: info in the acoustic signal leads to sound and word recognition
Top-down: linguistic and cognitive processes play an important role in sound and word recognition

Question 4

How do autonomous and interactive speech perception theories differ?

Answer 4

Autonomous - sound is processed in a serial manner with limited interaction between levels or stages
Interactive - lots of parallel interactions among levels

Question 5

What is the proposed basic unit of perception in the Motor Theory?

Answer 5

The intended articulatory gesture
-this theory proposes that speech is perceived by processes that are also involved in its production, and perception involves a matching between incoming acoustic-phonetic info and stored representations for articulatory gestures

Question 6

What are the strengths of the motor theory?

Answer 6

It proposes solutions to the unit of speech, context-sensitivity, and segmentation problems
- suggests that, despite well known acoustic variability of speech, the underlying motor commands and articulatory gestures are relatively invariant

Question 7

Name 2 of the 5 criticisms of the motor theory

Answer 7

• difficult to obtain empirical support for the role of articulatory gestures in speech perception
• may be more efficient to propose that we go directly from acoustics to phoneme identification instead of intermediate step of gesture matching
• articulatory data has shown that speech gestures are highly variable and demonstrate context-sensitivity
• children born with severe speech production and planning disorders often demonstrate normal speech perception
• adults with acquired disorders can show normal speech perception

Question 8

How does the motor system participate in speech perception (i.e what evidence supports this)?

Answer 8

• motor units in muscles related to speech production show enhanced excitability when individuals listen to speech
• speech motor regions of the cortex (primary motor cortex and Broca’s area) activated when individuals hear words
• mirror neurons in the cortical motor areas are activated both during execution and observation of actions
• transcranial magnetic stimulation of speech production regions of the cortex can lead to faster recognition of phonemes

Question 9

Why should we be cautious of using mirror neurons as support for the motor theory?

Answer 9

Mirror neurons in motor areas appear to respond to a wide range of sound/environmental noises and may not be specific to speech sounds

Question 10

The motor theory of speech perception is a long standing and controversial theory. Why does it continue to be relevant today?

Answer 10

Recent research appears to support the idea that speech production processes may play a role in speech perception